Without catalysts, our world would look very different: Many chemicals, pharmaceuticals, and everyday products would not exist without these reaction accelerators. But the optimal catalyst has not been found everywhere. Catalyst research is therefore one of the “hot” topics in chemistry today.
Without catalysts, not only would car exhaust gases be dirtier, but many things around us, perhaps even most of them, would not exist at all: no plastics, fewer medicines, and no artificial fertilizers. Catalysts also help to reduce emissions that are harmful to the climate. So we owe a lot to reaction accelerators.
It is estimated that catalysts are used in 80 to 90 percent of all chemical processes. The products created with them contribute up to one-third of the world’s gross domestic product. They are one of the most important technologies in human history.
What are catalysts good for?
The history of catalysis is practically as old as that of the chemical industry. Even without a theoretical background and without knowing the mechanisms involved, practitioners learned early on that many important reactions take place more quickly under certain conditions.
One of the earliest examples of industrial catalysis is the lead chamber process developed in 1746 for sulfuric acid production. In this process, nitrogen dioxide catalyzes the oxidation of sulfur dioxide to sulfur trioxide. In the contact process developed in the 19th century, first platinum and later vanadium pentoxide acted as catalysts.
The facilitators
Wilhelm Ostwald, 1909.
Whether it’s chlorine, nitric acid, plastics, methanol, the blue dye indigo, or ammonia, which is important for fertilizer production, catalysts make it possible to achieve significant conversion rates in the synthesis of countless important chemicals. One of the earliest definitions of catalysis came from Wilhelm Ostwald, who, at the end of the 19th century, had intensively studied the influence of catalysts on chemical reactions. In this, he already took the effect on the reaction rate into account.
Later, he derived from this the description that is still valid today, according to which a catalyst is a substance that increases the speed of a chemical reaction or makes it possible for a reaction to take place without itself being consumed. Ostwald compared this effect to the effect of lubricating oil on the wheels of a clockwork. In both cases, existing resistances would be reduced: in the clockwork, due to mechanical friction; in the chemical reactor, due to the energy barrier.
Ostwald was awarded the Nobel Prize in Chemistry in 1909 for his fundamental work.
What can a catalyst do—and what cannot it do?
Important in this context: A catalyst can only accelerate or enable reactions that are also thermodynamically favored, i.e., in which the energy level of the products is lower than that of the reactants. Equally important, the thermodynamic equilibrium of a reaction is not influenced by catalysts. A characteristic feature of a catalyst is that it reduces the activation energy that must be expended to break existing bonds so that a new state with new bonds can be created.
Typically, catalysts lower this energy expenditure by enabling particular transition states that can be achieved with less energy input. They do this, for example, by temporarily forming covalent or hydrogen bonds with one of the reactants and thus influencing its reactivity.
Incidentally, “not being consumed” is not always true in practice. Particularly in heterogeneous catalysis, in which the catalysts are usually applied to a solid phase, changes do occur in the course of the process, such as coking or sintering. Operators of such processes must therefore renew their catalyst material from time to time.
What is asymmetric organocatalysis?
Many molecules occur in two mirror-image variants, the enantiomers. (Credit: NASA)
A look at Stockholm proves how significant catalysis is for chemistry. Since 1909, a total of ten Nobel Prizes in Chemistry have been awarded for catalysis research in the narrower sense. Among the laureates were such well-known chemists as Fritz Haber and Carl Bosch. Six of the ten Nobel Prizes for catalysis have only been awarded since 2000, demonstrating how “hot” this field of research still is.
The last in the illustrious line of Nobel Prize winners in 2021 were Benjamin List of the Max Planck Institute for Coal Research in Mülheim and David MacMillan of the University of California at Berkeley. They received the prestigious prize “for the development of asymmetric organocatalysis.” Around the turn of the millennium, both researchers, independently of each other, opened the door to this new specialty field of catalysis.
Chemists speak of “organocatalysis” when the catalysts are organic molecules. It has long been known that these can accelerate chemical reactions. Justus von Liebig already made use of this almost 200 years ago when, among other things, he used cyanide as a catalyst for the formation of aromatic α-hydroxy ketones or later discovered the catalytic effect of acetaldehyde on another synthesis.
What was new about List and MacMillan’s work, however, was asymmetric synthesis with organic catalysts. By “asymmetric,” it means reactions that selectively lead to only one of two possible enantiomers. These mirror-image isomer pairs exist, for example, when a molecule contains a stereocenter. Syntheses that selectively lead primarily to one enantiomer are often required for substances that are to be used in biological systems, such as drugs, pest control agents, or fragrances and flavorings.
The reason for this is that often only one of the two enantiomers has the desired effect, for example, a pharmaceutical effect or a certain smell and taste. According to a 2017 estimate, about every second substance used in medicine has a stereocenter. However, by no means do all manufacturers succeed in enantioselective synthesis.
Spatial control is what counts
The requirements for an asymmetric catalyst are high. It is not enough if it merely lowers the activation energy. In order to have an enantioselective effect on the course of the reaction, it must create a very specific spatial environment for the molecules involved in the reaction. This is the only way to ensure, for example, that the attachment of one reaction partner to the other can only take place from one side because the other is shielded.
In the case of enzymes, the complex structure of the protein molecule provides this “steric control.” In the case of catalysts based on transition metals, the effect is achieved by surrounding the metal atoms beforehand with suitable molecular frameworks, also known as ligands. In both cases, for spatial (steric) reasons, the decisive reaction leads preferentially to only one enantiomer, while the formation of the mirror image molecule is significantly more difficult.
It also works with small organic molecules
Not so long ago, it was assumed that only transition metal complexes and enzymes were suitable for asymmetric catalysts. It was not until the 2021 Nobel Prize winners in Chemistry discovered and proved that small organic molecules such as proline are also suitable for this purpose. Max Planck chemist Benjamin List initially researched protein catalysts based on antibodies. Crystal structure analyses revealed that both an amino and an acid group of the antibody were involved in the catalysis.
List wondered, might a simple organic molecule have the same effect if it has an amino group and an acid group? For example, an amino acid? In his first experiment, he tested whether the natural amino acid L-proline could enantioselectively catalyze the aldol reaction of acetone with aldehydes. It succeeded: the enamine state formed in the process by ketone and proline did indeed undergo spatially controlled reactions with aldehydes.
Only a little more than 20 years have passed since organocatalysis was first developed. During that time, the field of organocatalysis developed rapidly.
Cheaper, more environmentally friendly, and simpler
Many research groups around the world are now working on organocatalysis. Unlike most metal compounds, organocatalysts are generally simpler, can in principle be produced from sustainable raw materials, and are usually cheaper in price and non-toxic.
Transition metals, on the other hand, often have to be extracted under ecologically difficult conditions from ore deposits that are in any case limited and sometimes difficult to access.
And in the best case, the reaction conditions are also moderate. The aldol reaction with proline, for example, takes just a few hours at room temperature. Reasons enough, then, to accelerate as many chemical reactions as possible with the aid of organic catalysts.
Why “mirror image” separation is important
The active ingredient thalidomide was sold in the drug thalidomide as a mixture of both entantiomers. However, only one variant acts as a sleeping pill; the other caused malformations of their unborn children when taken by pregnant women.
The fact that these are also suitable in principle for asymmetric catalysts has particularly spurred research. After all, these reactions often cause headaches for industry.
If the mirror-image products of a reaction cannot be controlled, this has two disadvantages. First, it reduces the yield of the desired enantiomer if some of the starting materials react to form the undesired isomer. Second, it takes effort, energy, and expense to separate the desired enantiomer from its mirror image. Manufacturers strive to make the synthesis as selective as possible.
However, there are still cases where enantioselective synthesis has not been successful at all, and manufacturers have to accept lower yields and enantiomer separation. For the sake of simplicity, many drugs contain the racemate, i.e., the mixture of both enantiomers. Of course, this is only possible if the undesired variant of the molecule is harmless.
Successful examples
Against this background, organic catalysts can certainly set new trends. One example is the synthesis of sitagliptin, an active ingredient in drugs for the treatment of type 2 diabetes. For the final synthesis step, enantioselective hydrogenation, a solution using an organic catalyst known as a dithiomalonate has also been available for some years, avoiding the technical challenges of using the metal catalysts commonly used in the past.
Another example is the reaction of hydrocyanic acid with 2-butanone, which leads to an important precursor of some active pharmaceutical ingredients. For a long time, there was no appreciable enantioselective route. In 2022, Benjamin List and his team published for the first time an organic catalysis with high enantioselectivity. The catalyst molecule is significantly larger and more complex than proline. According to List, this is now common and is partly because it gives us greater spatial control over reactions.
Today’s catalyst molecules are specifically designed to work much more effectively, so you need fewer of them. Whereas proline still had to be added to the reaction partners in concentrations of more than 20 percent for the aldol reaction, less than one percent, and in some cases significantly less, is sufficient for many modern organocatalysts.
Magic wand of chemistry
For Benjamin List, the fact that, in extreme cases, a single catalyst molecule is sufficient to manufacture products on a ton scale is precisely what fascinates him about his field of work. He also likes to talk about “magic molecules” because they can certainly be compared to “the magic wand” of a magician. The magician transforms objects with it, the chemists transform molecules.
Catalysis as a helper in climate protection and energy transition
Together with his team, Benjamin List, is working tirelessly on further catalysis innovations, certainly also with the aim of profoundly changing chemistry. Among other things, List hopes that many important chemicals can be synthesized more easily and in fewer reaction steps in the future, perhaps even directly from the components of crude oil, which for the time being remains an irreplaceable raw material for many chemical products.
The current challenges facing mankind, such as climate change or energy conversion, will only be solved with the help of catalysis.
To capture CO2
With regard to the most important greenhouse gas, carbon dioxide, he personally has a very special vision. In bold moments, he dreams of simply extracting this gas from the atmosphere and using UV light to break it down directly into carbon and oxygen. “You could bury the carbon,” List muses. But a prerequisite for the whole scenario would first be a suitable catalyst that cracks the strong double bonds between carbon and the two oxygen atoms without directly forming new bonds.
Nevertheless, it will not be possible to find an organic catalyst for every reaction. And where it does exist, it does not automatically have to be the better solution. There are cases where metal catalysts are almost impossible to replace. But scientists consider organocatalysis to be an important additional tool in the repertoire. Metals and enzymes nevertheless retain their purpose in catalysis.
As a rule, however, organic molecules often have clear advantages, such as greater sustainability, if they are even close to the same level of efficiency. Ultimately, it is also a matter of becoming “greener” for the entire chemical industry. That means working with processes that require less energy, are based on raw materials that are as sustainable as possible, and generate hardly any waste.
Atoms are the building blocks of all matter, including the oxygen you breathe, the water you drink, the page of the magazine you are holding in your hands, and everything else. Atoms measure a few hundred billionths of a millimeter on a side. These fundamental building blocks are made up of a positively charged core nucleus that is surrounded by one or more electrons that have a negative charge and “gravitate” around the nucleus.
The formal rules of electromagnetism state that two particles with opposing charges attract one another. Because of this, the electrons need to be firmly attached to the nucleus. Despite this, they continue to keep a safe distance. Imagine. If the nucleus of an atom were the size of a tennis ball, then the average distance that separates it from an electron would be… three kilometers. Why are electrons not subject to the attractive force of the nucleus?
At the turn of the 20th century, the physicists Ernest Rutherford and Niels Bohr put out an explanation for this aversion. In the manner of a planet, the electron would revolve about the nucleus at a rate that was sufficient to balance out the pull exerted by the latter and, as a result, maintain its circular orbit.
However, this model does not follow reality. In point of fact, if we use the equations of classical physics, we should expect the electron to lose energy while it is rotating about its own axis. This would cause it to be forced to pursue a trajectory that was not circular, but rather in the shape of a spiral. At the conclusion of this trajectory, it would crash into its nucleus extremely swiftly. Why does this collision not take place? The solution lies in an understanding of the quantum properties of matter.
When seen on the size of atoms, the electron is not a tiny ball that revolves around the atom’s nucleus but rather a wave. This wave does not concentrate at a single spot; rather, it propagates all the way around the nucleus. On the contrary, not in any manner! It conforms to the geometrical shape that allows it to expend the least amount of energy overall.
This state of the atom, which has the lowest energy and is often referred to as the ground state, is the most stable. The total of the potential energy, which is tied to the attractive force of the nucleus, and the kinetic energy, which is linked to the wavelength, is what is meant to be referred to as the “global energy” of the wave. This total is not always the same; rather, it fluctuates depending on the volume that is being occupied by the wave. The shorter the wave’s wavelength becomes, as a result of being contained in a smaller region, the higher the kinetic energy it has.
Yes, its potential energy decreases. But the rate at which the kinetic energy grows is greater than the rate at which the potential energy drops. The end result is that the wave’s total energy rises proportionately to the degree to which it is constrained (that is, the closer it gets to the nucleus). If the electron were to get trapped on the nucleus, this is exactly what would occur. The energy level of the system would rise to a point where the atom could no longer be stable. Because of this, it is very improbable.
In contrast, if there is no confinement, the wave spreads out enough to lower its kinetic energy but stays near enough to the nucleus to lower its potential energy. This is because potential energy is proportional to distance from the nucleus. This middle ground refers to the state of the atom that is the most stable and dictates the geometric form of the wave (sphere, balloon, etc.).
In the case of the hydrogen atom, for instance, the wave fills a volume that is shaped like a sphere with a radius that is 50 billionths of a millimeter. To summarize, the electron and the nucleus do not get entangled with one another since doing so would demand an excessive amount of energy.
In modern times, Alfred Bernhard Nobel (1833-1896) is remembered mostly as the man who established the Nobel Prizes, widely regarded as the most prestigious scientific honor. However, who was Alfred Nobel in the first place? How did the man who discovered dynamite end up giving his money to promote world peace and science?
The invention of dynamite, which has practical and lethal applications, launched Alfred Nobel’s career and made him wealthy. By using it, Nobel was able to convert nitroglycerin, a very dangerous explosive, into a more manageable and portable form for the first time. The invention of dynamite made possible the completion of the Gotthard Tunnel, one of the world’s most complex and challenging engineering projects. However, Alfred Nobel’s discovery was not without flaws. Rapidly becoming a dangerous weapon due to its explosive potential.
Success in selling his “Nobel’s Safety Powder” brought Nobel a wealth, which he used to create the Nobel Prize in order to recognize those who have made significant contributions to humankind. Every time the Nobel Prizes are handed out, the scientific community takes a moment to reflect on the life and legacy of its namesake, the brilliant scientist and businessman Alfred Nobel.
The Apprenticeship Years
When Alfred Nobel was a boy.
On October 21, 1833, into a family of engineers, Alfred Nobel was born in Stockholm. However, the Nobel family only remained in Sweden for a brief time after the birth of their son. They eventually settled in St. Petersburg. They lost everything in the construction business and decided to start again in Russia, where they had more luck.
Father Immanuel quickly established his own engineering works and foundry, eventually hiring over a thousand people at once. He had a prodigious capacity for innovation, which he put to good use by rapidly creating new devices, particularly for use in battle. Immanuel Nobel and his family prospered as a result of the company’s success and the Tsar’s court’s approval.
Traveling From Lab to Lab for Research Purposes
The thriving firm made it possible for Alfred and his brothers to have a solid education. The boys’ private teachers had them proficient in Russian, English, French, and German in addition to Swedish. In fact, Alfred considered taking up writing since he had such a deep and abiding love for reading.
While music was his first love, technology and chemistry were close seconds, and his father’s enthusiasm for the latter was a major influence. He immediately began to provide the young kid with specialized instruction, with an initial concentration on the discipline of chemistry. As early as age 17, he sent young Alfred on a two-year educational excursion around the United States, Germany, and France. The first trip was to the Parisian labs of the famous scientist Théophile-Jules Pelouze.
An Unforgettable Run-in
Invention of nitroglycerin credited to Ascanio Sobrero.
Here, Alfred Nobel met the Italian Ascanio Sobrero, an important person on his journey toward the big discovery that would make him renowned. The scientist had created nitroglycerin, the first liquid explosive, a few years previously. Sobrero’s face was badly injured in the explosion caused by mixing glycerin, sulfuric acid, and nitric acid. It seemed the explosive was too risky to be used in any meaningful way.
Upon hearing about nitroglycerin for the first time, Nobel thought about how it might be better managed, even back in Paris. However, when he got back to St. Petersburg in 1852, this wasn’t a factor at first. Nobel had a lot on his plate at the family company during the following four years. The development of armaments during the Crimean War resulted in huge revenues for the “Fonderies & Ateliers Mécaniques Nobel & Fils.”
But there is a tragic aspect to this success story: the end of the war meant no more orders. As a family, they faced some cash problems. They were on the brink of financial ruin and returned to Sweden in 1859. In light of the current economic crisis, Alfred Nobel’s chemistry tutor highlighted the unrealized potential of this substance.
Nobel made a quick decision to do what Sorbrero had not done, fearing the deadly potential of his invention. He hoped that by making the explosive marketable, he could save his family from their plight.
An Innovation With Potential to Explode
Alfred Nobel.
Alfred Nobel founded a family business in Stockholm with his father Immanuel and brother Oskar-Emil, experimenting with nitroglycerin. Not surprisingly, dealing with such a potentially dangerous substance was a difficult task. But the Nobels had their first taste of success in 1861 when they successfully mass-produced their “explosive oil”.
But the fundamental problem remained: the metastable material could explode at the slightest vibration or impact. It was therefore extremely dangerous to transport it by standard means, such as freight trains or horse-drawn carriages. Furthermore, detonators could not be used to detonate the liquid as simply as with black powder.
To detonate, nitroglycerin just needed a quick spark. However, how would one safely set off such a massive explosion? As the explosion was about to fizzle out, Nobel had an idea that set it off. He created a tiny container, filled it with black powder and nitroglycerin, and hanged it in a blast hole.
Nobel devised the first ignition, a chemical that could be exploded with a fuse and then causes the nitroglycerin underneath it to explode due to the pressure wave created. His first description of his package was a “patent detonator.” Subsequently, he reformulated the device to utilize fulminated mercury instead of black powder and dubbed it a detonator.
What a Horrible Accident
One of the first dynamite was created by Nobel using diatomaceous earth and nitroglycerin. Source: NobelPrize.org
Yet nitroglycerin was still sensitive to impacts. Nobel learned painfully how dangerous this property could be. A sizable explosion shook residents in the southern part of Stockholm one morning in September 1864. A laboratory facility containing 125 kilograms of explosives derailed at the Nobel estate. The explosion killed five people, including Nobel’s younger brother.
Nobel eventually perfected the Kieselguhr method, a type of diatomaceous earth, to stabilize the dynamite. Even after this terrible disaster, the scientist worked relentlessly to improve his method and eventually spread it to Germany. The mining industry was growing and new railroad lines were being rapidly built, creating ideal conditions for the marketing of Nobel’s explosive oil.
The Long-Awaited Breakthrough
Nobel constructed an industrial facility in Krümmel’s Geesthacht neighborhood despite the lack of a satisfactory answer to the transportation issue. However, in May of 1866, a horrific explosion took place there, as well. Not long ago, a vessel off the coast of Panama carrying the deadly cargo exploded. Public opinion and legislative pressure were rising. The nitroglycerine’s destructive potential must be brought under control.
During the same time period, Alfred Nobel made a groundbreaking discovery. He discovered that by combining nitroglycerin with diatomaceous earth, a powder derived from the shells of microscopic sea animals, the liquid could be shaped into a manageable bulk and carried with relative ease. Some say he made the finding by sheer happenstance. However, Alfred Nobel himself denied these claims.
From Dynamite to Explosive Gelatin
To be sure, in 1867, Nobel sought patents in several countries on his new explosive, which he termed dynamite (from the Greek for “power”). An enormous amount of money was made from the new material. However, Nobel was not content just yet. With the addition of diatomaceous earth, he succeeded in making nitroglycerin less dangerous. However, it was now only about five times as potent as black powder and had lost part of its explosive strength over time.
In 1876, Nobel developed a workable alternative to diatomaceous earth by combining nitroglycerin with collodion wool. As a consequence, they came up with blasting gelatine, a dynamite explosive that was both stable under pressure and highly explosive. This improved variant of the original dynamite remained one of the most potent commercial explosives available today.
Progress and Death Hand in Hand with Nobel’s Dynamite
It didn’t take long for Nobel’s dynamite to become the industry standard worldwide.
Black powder has been the sole kind of explosive known to mankind for almost a thousand years. However, the material is not powerful enough for widespread explosions. Explosives like Nobel’s dynamite ushered in a new age since they were the first chemicals to significantly outperform black powder while being relatively safe to use (though mishaps using dynamite are unfortunately common).
Shortly after its introduction, Nobel’s invention quickly became the most popular explosive in the world. Tunnels, canals, and mines could all be carved out of the earth with its aid. With the advent of dynamite, construction workers could finally realize their wildest dreams.
1 Million Pounds (lbs) Of Dynamite Used in a Tunnel Construction
Major projects, like the 15-kilometer Gotthard Tunnel that snaked its way through the summits of the same-named mountain range in Switzerland, demonstrated the efficacy of the new explosives. Engineers drilled into the mountain to a depth of around a meter before using dynamite for blasting. Construction of the Panama Canal also made use of the explosive.
However, the invention of dynamite resulted in not only a powerful industrial explosive but also a terrifying weapon. The brutal use of dynamite dates back to the Franco-Prussian War, long before Alfred Nobel improved his explosive by combining it with blasting gelatine to make it even more destructive.
In addition, dynamite was crucial to a wave of terrorist assaults that swept over Europe at the close of the 19th century. So many working-class revolutionaries and anarchists used dynamite to strike the ruling class and wreak widespread destruction.
The Russian Tsar Alexander II was their most recognizable victim. While on a carriage trip through St. Petersburg, he was murdered by a dynamite device. After that, many European countries restricted access to dynamite and other explosives due to widespread abuse of the substance.
In 1884, for instance, the German Reich discoureged the “criminal and murderous use of explosives” by passing the so-called Dynamite Law. Despite Nobel’s best intentions, his technology was increasingly being put to lethal use. His creation was a mixed gift and a curse.
The Nobel Prize
Nobel’s will with a surprise.
Alfred Nobel made a fortune and left a legacy by commercializing his innovation on a global scale. The name of the Swedish scientist and businessman was still widely connected with more than just dynamite. His enduring financial legacy was also a perennial newsmaker. After all, it’s the basis for the Nobel Prize, the highest honor in the scientific and social fields.
Acts of Generosity
Nobel, who died childless in 1895, left most of his riches (around 31 million Swedish crowns) to a fund in his testament. The inventor stipulated in his will that the interest accrued be split into five equal parts and “given as rewards to those who have made the greatest contribution to humanity in the last year.”
The prize would be awarded for exceptional work in physics and chemistry, the two scientific disciplines that inspired Alfred Nobel’s idea. The scientist, on the other hand, also saw medicine as a legitimate academic field. Additionally, Alfred Nobel, who wrote numerous short stories and poems himself, included an award for literature in his testament. Also, the fifth portion of the award was meant to recognize “the person who shall have done the most or the best work for fraternity between nations.”
Winners of the Very First Nobel Prizes
The first Nobel Prizes were awarded in December 1901.
After Nobel’s death on December 10, 1896, his will was finalized three and a half years later. The proposal for the Nobel Foundation’s founding laws was approved by the Swedish Government in June 1900. Once the five months passed, the management of the foundation assumed charge of the money. The first Nobel Prize was given out on the fifth anniversary of Alfred Nobel’s death.
Wilhelm Conrad Röntgen, who discovered the radiation we now know as X-rays, was awarded the first Nobel Prize in Physics. Both Dutchman Jacobus van ‘t Hoff, who discovered the rules of chemical dynamics and osmotic pressure in solutions, and German military doctor Emil von Behring, who discovered a treatment for diphtheria, won the first prizes in the Nobel chemistry category. Frédéric Passy, known across the globe as the “Apostle of Peace,” and humanist Henry Dunant will forever be remembered as the first recipients of the Nobel Prizes in Literature and Peace, respectively.
Others followed in their footsteps as Nobel laureates. With the exception of a few years, particularly during times of war, when the award was not presented, the Nobel laureates are announced annually around the beginning of October, and the Nobel Prizes are awarded on December 10. The award money is still paid out of the interest and revenue from the inventor of dynamite’s inheritance. Each winner gets eight million Swedish kronor (now equivalent to roughly 700,000 dollars).
“Merchant of Death” or Advocate for World Peace?
There was widespread surprise when news of Alfred Nobel’s donation of a peace award emerged after his death. After all, people tended to identify the name “Nobel” with explosives and other advances that could be used in conflict, but not with nonviolent causes. In fact, in an erroneous obituary, journalists even referred to the scientist as a “merchant of death.”
Is it possible that the scientist had mixed feelings about the impact of his work in the armaments business, and that he hoped to use the money from the award to atone for the “evil side” of his inventions? It’s impossible to know for sure from where we stand now. It is evident, however, that Alfred Nobel was essentially running in parallel on issues of war and peace throughout his lifetime.
Deadly Inventions
However, he seemed endowed with a lifelong fascination with the science of guns and explosives. His father was also an engineer with a deep interest in this field; he helped create rapid-fire guns and naval mines used in the Crimean War. Dynamite, Nobel’s own great innovation, was also used in war despite its original intention.
And it wasn’t only dynamite; far into his senior years, the brilliant scientist continued to work on a wide range of technologies with the potential to be used as weapons. A patent applicant, he sought protection for a wide range of armaments, including rockets, cannons, and novel formulations of gunpowder.
Alfred Nobel: The War Resister
In contrast, Nobel cared deeply about topics related to world peace. Thus, he became quite close with the pacifist Bertha von Suttner via letters. At the tail end of the nineteenth century, the Austrian was one of the primary proponents of the peace movement that was gaining momentum throughout Europe.
Inspired by her, Nobel became a member of the Austrian Peace Society and donated money to its cause. It is likely that von Suttner was also responsible for the rich businessman’s decision to endow a peace award with a portion of his estate.
Alfred Nobel does not seem to find any inconsistency between his work in the arms business and his desire to promote world peace. Instead, he seems to subscribe to the view, widespread in the 19th century, that a scientist is not responsible for the application of his research.
Each new scientific finding, in this perspective, is apolitical at first, but has the potential to be used for either good or evil. Alfred Nobel had a similar nave belief in the possibility of good coming from his arsenal of explosive weapons. In 1963, the “Nobelium” element was named for Alfred Nobel.
In Nobel’s view, only the military might can guarantee lasting peace. He believed that with the appropriate weapon, the idea of deterrence might one day render conflicts inconceivable. Since he passed away so soon, he never got to see the First World War or realize how wrong he was.
The history of the periodic table marks a search for the order of the elements, the fundamental components of all matter, and the building blocks of our existence. Dmitri Mendeleev, who hails from the farthest reaches of Siberia, changed the world with a simple table. What Dmitri Mendeleev proposed in 1869 contained the order of the elements, which is the foundation of the universe. The question of whether there was a fundamental order or regularity underlying the elements was first posed by ancient scholars. They attempted to discern order among the elements after realizing that some substances resembled one another more than others.
But Dmitri Mendeleev and his periodic table of the elements, which others further developed several years later, represented the critical advance. Along with organizing the known elements according to their atomic weights and formative properties, Mendeleev also identified the underlying regularities.
While entire worldviews have crumbled in physics and biology over the past few decades, the Russian chemist’s Periodic Table has stood the test of time. Whether it be nuclear fission, the discovery of new elemental groups, or the understanding of the atomic structure, all advancements in chemistry and atomic physics have only served to confirm and extend Mendeleev’s brilliant design. But what exactly was his discovery’s secret?
What Is An Element?
Aristotle and Alexander the Great. Aristotle envisioned four primordial elements: earth, air, water, and fire.
Finding the Primordial Substance
What is the origin of all things? Why is metal hard and water liquid? Why do coal and sulfur behave differently than copper and silver? These are by no means modern-era issues; ancient people were already troubled by them. They, too, ceased to simply take the natural world for granted and yearned to comprehend its fundamentals.
Early Greek naturalists and philosophers agreed that there must be some kind of order or unifying principle at work in the universe. Maybe there is a primordial material that explains how different substances behave and how they have certain properties. The solution was obvious to the Greek philosopher Thales of Miletus in the year 600 BC: water. He thinks that everything on the Earth’s disk is just a different aspect of this primordial substance. Today we know that when heated sufficiently, even solid, hard metals can change into a liquid state. At most, it was debated whether fire or air—as Heraclitus postulated—was the enigmatic primordial substance.
The Four Elements of Aristotle
Aristotle unified these theories into his four-element doctrine about 300 years later. He gave each “element” characteristics there; for instance, the earth is cold-dry and the water is cold-moist. Because all matter was a combination of its original constituent parts, a substance’s properties and behaviors depend on the ratio of those parts. But above all, in Aristotle’s view, there was still the quintessence, the fifth element, the ether, which gave life to everything else and was the source of all existence.
What Aristotle did not know at the time was that his ideas would influence the Western worldview for almost 2,000 years. The four fundamental elements were referred to by everyone from the Greeks and Romans to the alchemists and doctors of the Middle Ages and the Renaissance.
Robert Boyle: The Irish Rebel
Robert Boyle’s “The Sceptical Chymist” (1661). Credit: Van Pelt Library, Pennsylvania University
A young Irishman named Robert Boyle, the youngest son of the Earl of Cork, announced the sudden end to this age and the start of modern chemistry in the 17th century. Boyle spent some time in the Kingdom when he was twelve years old, as was customary for aristocrats at the time. He visited France, Switzerland, and Italy and studied under the greatest scholars of the day while also making friends with many quacks and alchemists. In 1644, he returned to Ireland and started his own experiments, boiling, evaporating, and distilling while examining the objects under a microscope. He was particularly intrigued by the behavior of gases.
Boyle began to question the four-element theories of Aristotle and Paracelsus more and more as they were based on conjecture rather than actual scientific research. Boyle observed that whether substances combine or just mix does make a difference and that many substances can be broken down to a very great extent, but some cannot. One such substance was phosphorus, which the pharmacist and alchemist Hennig Brand discovered a few years earlier. This substance, which was extracted from urine by evaporation and annealing, appeared to be incredibly stable, resisting being broken down further.
In 1661, Boyle was finally certain that there must be more than four elements. All substances must also be elementary if they cannot undergo further chemical reactions. The Irish scientist and natural philosopher ultimately put an end to the age of alchemy with his new concept, which he published in his book “The Sceptical Chymist”; modern chemistry had arrived.
Karlsruhe Congress Lit the First Spark
The First International Congress of Chemistry
Karlsruhe, September 3, 1860: The second meeting room is humming with activity. 140 men shake hands, talk, and gesticulate while most are dressed in festive dark suits. Then it finally begins. “As provisional chairman, I have the honor of opening a congress that is unprecedented, that has never existed before. For the first time the representatives of a single and indeed the newest natural science have gathered here,” says Karl Weltzien, chemist and meeting organizer at the Polytechnic School in Karlsruhe.
The first-ever International Chemical Congress, which went down in history, was officially opened with these words. Because Karlsruhe Congress served as a catalyst for some of the most important developments in contemporary chemistry, including the Periodic Table. In addition to well-known researchers like Robert Bunsen, Dmitri Mendeleev, August Kekulé, Jean-Baptiste Dumas, Carl Fresenius, and Louis Pasteur, the congress brought together the brightest minds in this young field.
Atomic Weight Disarray
However, there was still a great deal of bickering, debate, and fighting going on. Because the congress was about nothing less than the basis of all things: the atoms. Or more precisely, the atomic weights.
Atoms were already universally acknowledged to be the fundamental units of matter. However, there were six different ways to state an atom’s weight. While some considered hydrogen to be the standard for all things and assigned it the atomic weight 1, others viewed oxygen as the supreme force and based all other atomic weights on it. But not only did this lead to uncertainty, but it also made it challenging to determine whether an analyzed substance was an element or not.
A young Russian chemist named Dmitri Mendeleev was one of the congress attendees. Mendeleev was able to attend the prestigious university in Saint Petersburg despite being from the remotest Russian province, the town of Tobolsk east of the Urals. He had even been sent on a two-year study tour to France and Germany after receiving his Master’s degree. Mendeleev focused primarily on physical chemistry while pursuing his doctorate in the Heidelberg laboratories of Robert Bunsen and later of Gustav Kirchhoff. His research included measuring the molecular weights and the precise volume of liquids.
An Italian Solution
The speech by the Italian chemist Stanislao Cannizzaro was given on the third and final day of the congress. He suggested a solution based on Amadeo Avogadro’s gas law to address the problem of atomic and molecular weights. According to the latter theory, an ideal gas should always have the same number of particles at the same volume, pressure, and temperature. Avogadro used the term “particles” in this context to refer to diatomic molecules. Cannizzaro said in his speech, “The vapor density therefore provides us with a means of unequivocally determining the weight of molecules of different substances, whether atomic or as a compound.”
Dmitri Mendeleev in April 1861.
When Cannizzaro made this proposal, Mendeleev, who was only 26 years old, was also present in the room. In the form of a periodic table, this talk was a starting point for Mendeleev. After all, he had been preoccupied with the issue of how to categorize the roughly 60 known elements for a number of years. Mendeleev later stated in one of his writings that “It is one of the functions of science to discover the existence of a general principle of order in nature and to find the reasons that govern this order. The cathedral of science requires not only material, but a design, a harmony.”
Mendeleev was not alone in holding this opinion; the congress in Karlsruhe, which led to the correction and unification of many atomic weights, set off a veritable race to see who could explain the properties and behavior of the elements first.
Mysterious Similarity Between Various Elements
Even before the 1860 Karlsruhe Congress, many chemists had noted that while all elements were the same, some were more similar than others. This suggested that some elements could be related in some way. For instance, all three of the following elements—chlorine, bromine, and iodine—are gaseous or barely volatile, intensely colored, and highly reactive with metals and hydrogen. However, some substances, like lithium, sodium, and potassium, are solid and have a strong reaction with water.
Even among these related groups, however, there are clear distinctions: Lithium moves leisurely across the surface of the water, reacting with it and giving off hydrogen until it disappears. A lump of sodium, however, moves across the surface with a furious hoist, but catches no fire. Potassium, on the other hand, catches fire the moment it touches the water, burning with a pale purple flame and spraying globules of itself everywhere.
The Law of Triads
Johann Wolfgang Döbereiner, a German chemist, also noticed these similarities in 1829. When he placed the related elements calcium, strontium, and barium next to one another, the atomic weight of strontium was exactly equal to the average of the other two, indicating that atomic weights appeared to be a factor in these affinities. Lithium, sodium, and potassium created another trio that shared this property. After all, Döbereiner’s “Law of Triads” allowed for the grouping of 30 of the 53 elements that were known to exist at the time. The other elements, such as the gases oxygen, hydrogen, and nitrogen, didn’t want to adhere to his theory. And his contemporaries did as well. They found the entire situation to be “insufficiently conclusive.”
The Law of Octaves
Octaves by Newlands. Each horizontal row indicates a different group of elements.
35 years later, the English chemist John Reina Newlands attempted an elemental sorting as well, bolstered by the “tidied up” atomic weights in Karlsruhe. Newlands started by listing the known elements in ascending order of atomic mass. He quickly noticed that the properties of the elements in this order followed a pattern: the fundamental characteristics of the seven earlier substances repeated after every eighth element. This made John Newlands think of music and the octave principle, which states that the same note can be repeated with a different pitch. He called his discovery the “Law of Octaves” as a result.
Newlands reorganized his series and now arranged the elements in columns with seven rows each to make the parallels even more obvious. There were now a startlingly large number of comparable elements in the table’s rows. In this way, magnesium was next to calcium, strontium, and barium, while fluorine was next to chlorine, bromine, and iodine.
There were also significant outlier elements in between, such as silver in the row between lithium and sodium, or nickel and palladium, which he placed between chlorine and iodine. But this cannot be possible today because of how different their elemental properties are from those of their neighbors. Other series, especially the lowest, were made up entirely of disparate elements with no indication of a system or even of similarities.
Yet why? Newlands believed he was getting close to finally ordering the elements and that his system could not be wholly incorrect. But he was unable to control the “outliers” problem.
But there was also someone else who was also obstinately working toward this problem’s solution thousands of miles to the east: Dmitri Mendeleev.
Mendeleev’s Periodic Law
“It’s all formed in my head”
Early 1869 in Saint Petersburg. Dmitri Mendeleev, who was currently a professor of pure chemistry at the University of Saint Petersburg, had been sequestered in his office for several weeks. Other than his lectures, he didn’t have any free time. Not even for his hairdresser, not for his wife and two kids, not for evening outings to the ballet or the theater. He was searching for something. Like many of his contemporaries, he was searching for the fundamental arrangement of the elements, and he felt as though he was getting close.
Ability of an Element to Bond
How many bonds can an element have? Symbolized right here in Brussels at the Atomium.
Mendeleev had long understood that there must be a link between atomic weights and the characteristics of chemical elements, just like John Newlands. But in contrast to the latter, he also considered valence or value. This characteristic of elements, identified by Edward Frankland in 1852, showed how strong was their ability to form bonds with other atoms, such as hydrogen atoms. Or, to put it another way, the number of “free arms” available for bonding between atoms.
Like Newlands, Mendeleev first arranged the elements in ascending order of atomic mass. He then turned his attention to the valences, noting that these too appeared to occur in cycles. From lithium to fluorine, they rose from one to seven, but sodium then started at one, and the valences rose once more to chlorine. Then, however, the scheme of seven came to an end: the following period was already significantly longer; it appeared that at this point, the elemental behavior had departed from Newland’s rigid octave scheme.
Dmitry Mendeleev in his office. Credit: Serge Lachinov
Elemental Card Game
Which scheme, then, did the elements fit into? When a friend paid Mendeleev a visit in his office at the university in February 1869, this was the exact question that Mendeleev was still struggling with. The friend asked him in horror what he was working on as he turned to face the hollow-cheeked, red-eyed figure with completely wild hair and a beard. Mendeleev explained that although he had found that there was a periodic system of elements, he was unable to create a matching table system or a law. The worn-out chemist laments, “It’s all formed in my head, but I can’t express it.”
Mendeleev, however, was persistent. In a later statement, he said, “When you’re looking for something – be it mushrooms or some kind of law – there’s no other way than to keep looking and trying again.” His primary tool for these experiments was a stack of plain cardboard cards rather than a Bunsen burner or any other chemical apparatus. He noted an element’s atomic mass and its most distinctive properties, such as valences, on each of them. He then shuffled the cards on his table until a system was finally formed.
The Seven Groups
Everything suddenly appeared to be straightforward: the elements were divided into seven groups, each of which combined elements with related properties perpendicular to one another. The atomic masses and valences of the elements rose in the rows of the system’s structure, or its periods, as a result of the placement of these groups next to one another. The group of metals from the alkaline earth came first, then the alkali metals. The “earth metals,” led by boron, were then followed by the carbon, nitrogen, and oxygen groups. The conclusion was formed by the halogens, which included fluorine, chlorine, bromine, and iodine.
Mendeleev now understood that this was the only way the elemental order could function fundamentally. However, at first glance, he too appeared to have some anomalies that disturbed the overall picture.
What Made Mendeleev’s Periodic Table Unique?
German chemist Lothar Meyer also worked on a nearly identical periodic table almost simultaneously with Mendeleev. Although Meyer also understood the fundamental concept of groups and periods, he could only come up with six groups. Meyer also encountered a few factors that significantly disrupted the overall picture, similar to Mendeleev.
How Should Errors and Gaps Be Handled?
For instance, beryllium, which was thought to be the third lightest element, belonged up front. However, it couldn’t fit into the plan because the first group was made up of alkali metals, which beryllium could be a part of. Tellurium, an element with an atomic weight of 127.6 and a valence of 2, also appeared to be positioned incorrectly. According to its atomic weight, the element should be behind iodine, but its valence clearly corresponded to that of the oxygen group, placing it in the element group prior to iodine and the other halogens.
Mendeleev, in contrast to Meyer, had no hesitation whatsoever. Because he was so confident in his theory, he could only conclude that the atomic weights of these anomalies were calculated incorrectly. Despite its lower atomic weight, Mendeleev immediately moved beryllium to the fourth position. Tellurium was categorized with oxygen.
In addition, Mendeleev did something else that his peers found utterly outrageous: he left gaps in the periodic table where, in his view, elements that have yet to be discovered should be included. In his paper, Mendeleev stated that “We must expect the discovery of many yet unknown elements, for example … aluminum and silicon, whose atomic weight would be between 65 and 75.”
The Basic Arrangement of the Elements
Mendeleev published an article in the “Journal of Chemistry” in 1869.
Mendeleev published his periodic table on March 6, 1869, just a few months before Meyer, under the title “On the Relationship of the Properties of the Elements to their Atomic Weights,” in which he also explained atomic weight changes and gaps and stated the laws that underlie his periodic table:
When the elements are arranged according to their atomic weight, their properties exhibit periodicity.
Elements that share similar chemical properties have atomic weights that are either nearly the same (platinum, iridium, osmium) or atomic weights that increase at regular intervals (eg, potassium, rubidium, cesium).
The order of elements and groups in increasing atomic weight corresponds to their valences and, to some extent, to their properties.
The atomic weights of the elements can be used to predict some of their distinctive properties.
For Mendeleev, it was obvious that his periodic system reflected the basic arrangement of the elements, effectively constituting the natural law of chemistry, rather than simply being an arbitrary order.
Mendeleev won the race when his Periodic Table was published. He was the first to be successful in both meaningfully arranging the elements and illuminating the patterns underlying their properties. But his contemporaries didn’t exactly applaud him for it. The exact opposite was the case.
“Unheard of and Unproven”
A direct rival of Mendeleev was Lothar Meyer.
The responses ranged from apathetic coolness to outright rejection. After all, this Russian chemist from the far reaches of the country dared to virtually expose a number of his most illustrious contemporaries and predecessors, accusing them of producing inaccurate results. Such behavior was unacceptable. Meyer chastised his rival in front of the public for his “unjustified speculations.” Others predicted that his system would only last a short time because it would soon become outdated in any case. People were utterly unaware of what Mendeleev’s periodic table was about to bring to applied science.
Concerning the “Eka” Elements
Even so, Mendeleev refused to be deterred. According to Mendeleev, no law of nature, however fundamental it may be, was established all at once. Its laws were always preceded by numerous prejudices. Instead, in 1870, Mendeleev went a step further and made predictions about yet-to-be-discovered elements, saying that under each of silicon, boron, and aluminum, another element was still undiscovered and needed to be found.
Mendeleev named these elements Eka-aluminum, Eka-boron, and Eka-silicon after the Sanskrit word for “one” — “eka” — and had previously described their characteristics, including their atomic masses, specific weights, the types of salts they formed, and even the location of their melting points. Eka-aluminum, for instance, would be a silvery-white metal with an atomic weight of 68 and a density of 6. Again, Mendeleev received more derision for this than praise.
However, Gallium Does Exist
Gallium. Credit: W. Commons.
This would not alter until November 1875, five years later: French chemist Paul-Émile Lecoq de Boisbaudran found two violet spectral lines in a zinc ore’s emission spectrum that did not match any of the known element signatures. Soon after, Boisbaudran was successful in removing an unidentified silvery-white metal from the zinc blende. He gave it the name gallium, probably in tribute to his native France. He and others did not realize that his gallium corresponded precisely to the eka-aluminum predicted by Mendeleev until after he published his discovery.
Later, in 1879, the second element predicted by Mendeleev, eka-boron, was found by the Swedish chemist Lars Fredrik Nilson. German chemist Clemens Winkler made the discovery of the third element, germanium, in a mine close to Freiberg, Saxony, in 1885. Mendeleev had by this point, at the very latest, been not only vindicated but also formally acknowledged as one of the greats in chemistry.
But a few years later, something occurred that could potentially rock his entire periodic system once more.
Discovery of Noble Gases From Mendeleev’s System
Elements to Disrupt the Periodic Table
Lord Rayleigh’s experimental design was based on Henry Cavendish’s earlier research. Credit: Encyclopaedia Britannica, 1911
In a lab at the University of Cambridge in England in 1892, John William Strutt, Lord Rayleigh, a physicist, leaned intently over his workbench. In front of him, oxygen bubbled through ammonia liquid before vanishing into a copper tube that was extremely hot. The other end showed the emergence of much smaller bubbles. The gas that Rayleigh was worried about in this situation was nitrogen. When oxygen and ammonia’s hydrogen reacted, this is what was released.
In an effort to finally determine the atomic weight of nitrogen, Rayleigh had been attempting to measure the density of this gas more precisely than before for some time. Rayleigh repeated the test several times to make sure that there were no methodological flaws. He also employed a different measurement technique in which the nitrogen was taken straight out of the air by passing it over hot copper.
An Enigmatic Deviation
William Ramsay.
The physicist described how “again a series in good agreement with itself resulted” in his 1904 Nobel Prize lecture. According to him, the densities obtained by the two methods, had differed by a thousandth, which, though small, was completely beyond possible experimental errors. The nitrogen gas extracted from the ammonia was smaller in density than that from the air. And the question arose whether the difference could be attributed to recognized impurities.
Rayleigh consulted William Ramsay, a Scottish chemist conducting research at University College London, to address this issue. Both believed that the nitrogen in the atmosphere might contain an unidentified element. A tiny bubble of colorless gas, that was denser than nitrogen and could not be animated to react by anything, always remained, and this was confirmed by no fewer than two experimental approaches. But what was the point? Ramsay created a picture based on the spectral lines, or the chemical fingerprint, in spectroscopy, a relatively new technique.
Elements Without Space
The lines that emerged from the gas analysis were distinct from all known elemental signatures. It must be an entirely new, unexplored element. In honor of the Greek word “argos,” which means inert, Ramsay and Rayleigh gave the gas the name “argon” and made their discovery official on January 31, 1895. A closer look revealed that the atomic weight of argon was just under 40. Therefore, theoretically, it would be positioned in the periodic table between calcium (atomic weight 40) and potassium (atomic weight 39).
But of all places, Mendeleev did not discover a gap between alkali and alkaline earth metals. Was perhaps his periodic table incorrect after all? How could there be an element that did not fit into the scheme if he allegedly understood the law of elements?
Formation of a New Group
The typical purple glow from Argon gas
Nothing less than the overthrow of the recently established periodic order was threatened by an intense discovery. Ramsay, however, found a solution. As the gas didn’t want to interact with anything or anyone, he concluded that argon must have a valence of 0. As a result, it did not fit between potassium and calcium, which had different valences. It would instead be a member of a different, as of yet undiscovered group in the periodic table. Ramsay then positioned argon behind chlorine to form the eighth group of gases, the noble gases. However, there must be other elements in this group because no element in the periodic table could exist alone.
In fact, Mendeleev’s “Law of the Elements” turned out to be eerily prescient once more: Ramsay discovered in 1895 that a previously unidentified gas had been isolated from a uranium mineral in the USA and examined it in the spectroscope shortly after. The lines were made of helium, an element that had been seen in the Sun before but has not yet been classified. Ramsay had now established that helium was a noble gas as well because it was holding the group’s top position with an atomic weight of four. Ramsay found three more noble gases a few years later, naming them neon, krypton, and xenon, filling the eighth group.
The Periodic Table Today
Credit: Google.com
With the discovery of the noble gases, the Mendeleev-identified elemental order triumphed in its first trial by fire. The periodic table was now unshakeable, not even by the later discovery of yttrium and other rare earth elements. The laws that the Russian chemist discovered, however, are still in force today.
New Knowledge Reinforces the Old Order
Later discoveries have since upended entire worldviews in physics or biology, but Mendeleev’s “fundamental order of the elements,” the periodic table, has in fact turned out to be universal. Instead, a number of significant advancements in chemistry, from the structure of the atomic shell to the way that elements bond, have since supported his Periodic Table system.
Niels Bohr demonstrated in 1913 that the distribution of electrons in the atomic shell served as the basis for the bonding behavior of the elements by starting with the concept of valences, for instance. His discovery simultaneously gave physicochemical proof of Mendeleev’s theory that each group of elements in the periodic table has a specific number of electrons in their outer shells. They were largely responsible for the elemental properties, which in turn allowed Mendeleev to accurately predict the particular properties of as-yet-undiscovered elements.
Guiding Star for the Search for Elements
The “prediction” principle developed by Mendeleev is still employed by his successors today. Mendeleev’s periodic law is the guiding star. When the first artificial element was created in the 1940s, the big question was how to identify it and describe its properties. Because the International Union of Pure and Applied Chemistry (IUPAC) ruled that a newly discovered or created element was not officially recognized and named until its properties could also be described. For the extremely unstable and quickly decomposing transuranium elements, for instance, this is hardly feasible.
We now identify 118 elements, which means, there are 118 elements on the periodic table. It has proven to be quite easy to infer the properties of an element from its periodicity. Mendeleev and his contemporaries could not have imagined some of the exotic properties of those elements. And there are still more and more of them, produced in massive particle slingers under the harshest circumstances. Nobody is exactly sure where the upper limit is or how many more elements there could be in the periodic table.
Three scientists will share the 2022 Nobel Prize in Chemistry for developing “click chemistry,” a modular synthesis in which standardized reactions can produce practically any organic compound from basic starting ingredients. It was American scientist Barry Sharpless who initially proposed the concept of click chemistry; Danish chemist Morten Meldal created one of the nuclear reactions for it, and American chemist Carolyn Bertozzi refined the techniques for application in live cells.
Thanks to the efforts of these two men and one woman, “click chemistry” can be used to synthesize organic compounds in a modular fashion.
Different molecules can be obtained by combining the elements of the periodic table through chemical reactions and chemical bonding. However, chemical synthesis, especially of complex compounds and active substances, frequently needs a series of consecutive reaction stages, each of which must be accomplished under certain circumstances. Because of this, many chemicals were produced way too slowly and inefficiently for a long time.
Three organic chemists will share the Nobel Prize in Chemistry in 2022 for their ground-breaking work in the field that has significantly streamlined chemical synthesis.
Barry Sharpless and molecule construction
To connect the starting molecules, a “click reaction” occurs when two molecules containing azine and alkyne react with one other.
A U.S. scientist named Barry Sharpless, who was awarded the Nobel Prize in Chemistry in 2001, is considered to be the catalyst for this whole endeavor. He was on the lookout for ways to streamline the molecular synthesis process at the time. His theory was that via modular synthesis, a large range of products might be obtained from basic starting ingredients. This could be accomplished by using a set of simple, generally applicable reactions as tools.
You might think of this method as being similar to Ikea’s, where you get a set of pre-fabricated, standardized parts along with some basic tools and put them together to make whatever shelves or cabinets you need. Sharpless and his colleagues characterized this concept in a 2001 technical publication as “clicking” modules together. That’s how Sharpless started the whole “Click Chemistry” thing.
In order to make their modular synthesis method as broadly applicable as possible, Sharpless and his team also established criteria for the reactions and starting materials involved. Specifically, they instructed chemical reactions to be occured in the presence of oxygen and water, and without the use of any special solvents. Further, the input and output materials should be conveniently accessible and separate as well. Theoretically, scientists have already suggested the first reactions that can be used in click chemistry.
Morten Meldal: The single most useful response mechanism for “clicking”
Second-place winner of the 2022 Chemistry Nobel Prize, Morten Meldal of Denmark presented one of the reactions mentioned by Sharpless and his colleagues at a conference the same year. Meldal discovered that the addition of copper to the azide-alkyne cycloaddition reaction in organic chemistry greatly improved its efficiency, eliminating the need for high temperatures while allowing the reaction to continue almost autonomously and with high yields.
The azine and alkyne groups in this copper-involved azide-alkyne cycloaddition combine like their click analogs. When attached to any organic molecule, they allow for the “clicking” of ever more complicated molecular structures.
This reaction is now the cornerstone of chemical synthesis, which is employed in the creation of innumerable useful products in technology, medicine, and science, including medicines, plastics, and more.
These glycan sugars on the surfaces of cells were coupled to a green fluorene marker using a modified azide-alkyne reaction. (Bertoni et al. / PNAS 2007)
U.S. scientist Carolyn Bertozzi, who came in third place for the 2022 Chemistry Nobel Prize, expanded the use of this fundamental click chemical reaction to live cells, where it can be utilized to bind fluorescent marker proteins to biological components. However, copper is poisonous to cells, so she had to come up with a version of the azide-alkyne cycloaddition that works without this catalyst but still doesn’t need any more energy to proceed.
The chemist accomplished this by using an alkyne version with a ring structure.
As an additional step, Bertozzi improved upon a well-established synthesis process called the Staudinger reaction to the point that it, too, could be used to “click together” the molecules in a cellular setting. This cellularly relevant click chemistry was dubbed “bioorthogonal reactions” by the chemist. She defines them as the interactions of functional groups that are sufficiently selective of each other that they may bind molecules together even in a highly dynamic and complicated biological context.
“The achievements and discoveries of Carolyn R. Bertozzi, Morten Meldal, and K. Barry Sharpless have had enormous influence on our society,” the Nobel Foundation stated. “Through the development of inspirational new concepts and highly efficient methods, the laureates have enhanced our capabilities and considerably deepened and widened our knowledge and understanding. Their remarkable accomplishments have increased our means to improve our world and better our lives, truly to the benefit of humankind.”
When the weather starts to get colder, it’s time to crack out the fireplaces and stoves. We love the calming warmth of the fire and the crackling sound of burning logs, even more, when it is chilly and dark outside. But why, when it burns, does wood crackle in the first place? What produces the sparking mini-explosions that sometimes radiate from the logs, and how do they do it?
Tension, heat, and contraction
The cracks happen because tensions in the wood eventually cause a fracture to form. The wood, in turn, tries to contract as a result of the heat, and this is what causes the tension.
The fractured beams in an Alpine Hut originate from the same concept. The moisture content of the wood fibers in the beam progressively evaporates, causing them to conform more closely to their surroundings.
As a direct consequence of this, the beam will progressively shrink as it dries; however, the contraction will occur more across the wood than in the longitudinal direction. Because solid wood does not have sufficient elasticity, it rips, and over time, apparent fractures emerge in the wood.
The situation is the same with fire, except that it develops more rapidly. The crackling and popping sounds are always produced when the wood structure tries to shrink but is unable to due to the strength of the wood itself. After then, it gives in to the strains and fractures. The noise is reminiscent of a branch being snapped in two.
The flying sparks are caused by the resin
However, there are moments when the crackles in the wood are very audible. Sparks often fly, much as they would in a smaller version of the explosion.
There is another explanation for the loud crackling sounds in the burning wood. The noise may be traced to the bursting of resin pockets. These are the cavities in the wood that hold the liquid plaster that the wood produces. The oily resin protects the tree from microbial infections because it has chemicals that kill microorganisms and seal wounds.
The heat of the fire causes the oils found in the resin to evaporate, which then causes the oils to expand. The surrounding hardwood structure is unable to absorb the oil vapors, which causes the material to crackle. This in turn causes the resin galls to rupture explosively. Because the oils that fly out are combustible, they often catch fire when they come into contact with flames, which results in sparks and small explosions or pops.
Cracking is less common in hardwoods and fir
But why do different types of wood crackle at different rates? One cause has to do with the varying amounts of the resin contained in the wood. Pine, for example, has a high resin content and, as a result, produces a lot of crackling noise as it burns. On the other hand, hardwoods rarely experience these kinds of explosions or pops since the hardwoods themselves do not contain any resin.
The sound produced by fir and spruce combustion is noticeably different from one another. The reason for this is that fir wood does not contain any resin, but spruce wood has a significant amount of oil-rich compounds.
The structure and form of the wood
However, the structure and form of the wood can still play a role in causing crackles and pops. For example, light woods like spruce are more likely to crackle than heavier woods. Their wood is not as sturdy, and it is more prone to shatter when subjected to tension. Heavy hardwoods like oak or beech, on the other hand, are less likely to be damaged due to the much denser and more robust structure of these hardwoods.
Crackling may also be affected by the form of the log and the method used to cut it from the trunk. The wood is less likely to crack if it is cut into smaller pieces. This is because the wood warps less in smaller pieces, and the tensions that arise from this are lower, making it less likely that the wood would crackle as a result of these forces.
On earth, several elements can only be found as minerals and not in their elemental states. For instance, silicon is almost always found in silicates, and many other metals may form compounds with oxygen, sulfur, or other non-metallic elements. Because of the unique structure of their crystals, some minerals can store a variety of atoms, which may subsequently be combined to generate a variety of different complex compounds. But what is the maximum number of these elements that exist in a mineral?
A record high
Mineralogists from the Canadian Museum of Natural History and the University of Copenhagen found at least one value in the very uncommon mineral eudialyte that sets a new record. This mineral, which may be pink to brownish in color, is a member of the ring silicates and is a significant source of raw materials for a variety of different products, including the precious metal zirconium.
After the first discovery of anomalies in X-ray crystallography, the scientists decided to dig more into the mysterious mineral in order to get to the bottom of it.
During this procedure, scientists made the compelling discovery that the highly complicated structure of the eudialyte material provides a multitude of potential “docking points” and niches for the intercalation of uncommon elements.
46 different elements
It was discovered that the eudialyte stores more than 46 distinct different elements in its structure. This discovery makes a notable contribution, both financially and otherwise, to the extraction of zirconium and other rare elements. During the period, many more forms of the eudialyte minerals have been unearthed.
Chemistry dominated Linus Carl Pauling’s (or Linus Pauling) entire spiritual and social life, beginning from his youth when he first witnessed a chemical reaction at a friend’s house in Oregon until his final months on his farm in Big Sur Beach, California. When he proposed to his future spouse, he was honest enough to say that marriage would come after his job. Linus Carl Pauling’s passion for science paid off; he made discoveries about the nature of chemical bonds and the basic structure of important biological molecules such as proteins.
Who Was Linus Carl Pauling?
In 1954, Linus Carl Pauling was awarded the Nobel Prize in Chemistry for these discoveries. His scientific expertise also supported his humanitarian efforts. The evidence he provided that fallout from above-ground nuclear tests caused a large number of birth defects and cancers was the main factor in his 1962 Nobel Peace Prize. The award was given on October 10, 1963, on the day the Partial Nuclear Test Ban Treaty entered into force. Linus Pauling became the first person in history to receive two Nobel Prizes on his own.
Linus Carl Pauling was the eldest and only son of three children of pharmacist Herman W. Pauling and Lucy Isabelle Pauling, also the daughter of a pharmacist. Linus spent the first years of his life in Condon, in the monotonous western town of Oregon’s hinterland, where his father’s pharmacy was located. His childhood memories included cowboys, of whom one taught him how to sharpen a pencil with a knife, and Native Americans who showed him how to find and dig edible roots. These seemingly negligible lessons taught him in two ways: there was the right technique to do a job, and experienced people were valuable sources of information.
In the primitive elementary school in Condon, his favorite subjects were arithmetic and spelling because they were only interested in right or wrong answers. Economic difficulties and the fire in the shop caused Herman to move his family to Portland in 1909. Not long after starting a new pharmacy, Pauling’s father died suddenly at the age of 33 of a perforated stomach ulcer.
His mother, who lacked any profitable skills, borrowed heavily to buy a large house in hopes that it would enable boarders and room renters to support her and her children, but she was often in short supply of money and had health problems. Linus had to work at jobs where he delivered milk and newspapers. When he became interested in chemistry, he set up a laboratory in the basement and started doing simple experiments.
Linus Carl Pauling and His Extraordinary Educational Background
Over the past 58 years of marriage, Ava Helen supported his scientific work, fully undertaking housework and household responsibilities, and became the chief collaborator in “peace studies”.
He also took all the science and mathematics courses he could at Washington High School but left without a diploma because he had not taken the mandatory American history courses (instead of those courses, he took mathematics). He later had a well-paid job in a workshop that produced cargo elevators. Her mother wanted her to give up her university plans and continue to support the family. Luckily, Linus’s friend’s father stepped in and made it possible for Belle Pauling to let her son go to OAC, which was now Oregon State University.
Linus Pauling continued his studies in chemical engineering (the only major available for prospective chemists at the OAC) with extraordinary success, while at the same time working in a variety of jobs to support himself, his mother, and his sister. He even had to drop out of school for a year due to his mother’s financial problems. He worked as a road construction supervisor at that time, then became a quantitative analysis assistant at OAC. Around this time, he began reading articles by Gilbert Newton Lewis and Irving Langmuir on chemical bonds. While teaching chemistry to female home economics students in his senior year of school, he met his future wife, Ava Helen Miller.
After graduating from the OAC in 1922, Pauling began his graduate education at the California Institute of Technology (commonly known as Caltech or Pauling’s preferred acronym, CIT). Along with the weighty courses he took, Linus Pauling began research under the supervision of X-ray crystallographer Roscoe Gilkey Dickinson, who directed him to the structural studies of the mineral molybdenite. They wrote an article about it because sulfur atoms in the mineral molybdenite were found to be arranged in a triangular prismatic shape around molybdenum atoms.
Linus Pauling married Ava Helen after her first year at CIT; his husband became the main supporter of scientific research and peace efforts in the ensuing years and held this role throughout their fifty years of marriage. Pauling successfully defended his dissertation, which was based on articles about crystal structure, and got his Ph.D. in 1925.
Determining the Nature of Chemical Bonds
42 structural drawings describing the nature of the chemical bonds of aromatic hydrocarbon naphthalene used in the production of the moth remedy and paints prepared by Linus Pauling for his 1939 book The Nature of the Chemical Bond.
In 1926, he received the Guggenheim Fellowship and went to Europe with his wife. There he explored the possible effects of newly discovered quantum mechanics on his work on the nature of chemical bonds—the gravitational forces that hold atoms together in a unified form. Although he also spent time at Niels Bohr’s Institute in Copenhagen and with Schrödinger at the University of Zurich, he was most influenced by the Arnold Sommerfeld Center for Theoretical Physics in Munich. He started making predictions about the properties of ionic crystals using wave mechanics, Sommerfeld’s favorite type of quantum mechanics.
Linus Pauling returned to CIT in 1927 and began his long and successful career in X-ray studies of crystal structures such as silicate minerals. His work on crystal structures helped make this branch one of the best understood in science. Using what he knew about bond angles and distances, he came up with rules called “coordination theory” that would make it easier for crystallographers to put the right atoms in the right places in different crystals.
During a meeting with Herman Mark in Germany in 1930, electron diffraction caught his attention. Using this technique, he and his colleagues solved the structures of many molecules in gas and liquid.
FerroceneDiamondAcetic Acid
In the 1930s, he used the energy of the displacement (or oscillation) of two electrons in the hybridization analysis (involving the mixing of atomic orbitals—the location of a particular electron in an atom). It was a revolutionary idea featured in his best-known articles on the nature of chemical bonds. Linus Pauling’s knowledge of quantum mechanics was a big part of how he came up with the valence bond theory. In this theory, he said that some molecules, like benzene, could be thought of as intermediates made up of hybrids of two or more structures in which atomic orbits overlap.
The Nature of Chemical Bonds and the Structure of Molecules and Crystals, a book he wrote in 1939 based on the George Fisher Baker Lectures at Cornell University, is a summary of his own experimental and theoretical work as well as that of other structural chemists.
In the mid-1930s, Linus Pauling’s interest began to shift to biological molecules; he and his colleagues conducted magnetic studies on hemoglobin to prove that the magnet attracts hemoglobin in veins but repels it in arteries. Hemoglobin was the protein molecule. That work inevitably led him to be more generally interested in proteins, such as the roles of proteins in the antibody-antigen response. He worked on the denaturation of proteins and the human immune system’s antibodies, which fight against antigens that attack in the form of bacteria or viruses.
The Discovery of the First Molecular Disease
This drawing (left) shows the faulty side chain (right) causing anemia by not stabilizing this part of the hemoglobin molecule.
During World War II, Linus Pauling started to focus on more practical problems, such as providing plasma supplies for wounded soldiers by producing an artificial mixture that could be used in place of blood plasma. He invented the oxygen detector based on the magnetic properties of oxygen particles. This invention was widely used in submarines and aircraft. He had also worked on explosives, rocket fuel, and ink for confidential correspondence. He refused J. Robert Oppenheimer’s offer to lead the chemistry-related arm of the atomic bomb project as he was battling a serious disease called glomerulonephritis. Towards the end of the war, Linus Pauling learned about the inherited disease sickle-cell anemia, where the red blood cells in venous blood take the shape of a sickle. He thought that this sickle shape was caused by a genetic mutation in the globin part of the cell’s hemoglobin. After three years of study, Pauling and colleagues were able to prove that such a molecular defect in hemoglobin was indeed the cause of the disease. Thus, Linus Pauling discovered the first molecular disease.
In the post-war years, Linus Pauling continued to work on proteins. In the early 1950s, he published a cylindrical helix amino acid arrangement of amino acid groups (later called alpha helices) linked by hydrogen bonds. These and other protein structures he published were extremely effective. In addition to that work, Linus Pauling also participated in educating the public about the possible consequences of nuclear weapons. He devoted more and more time to campaigns to stop nuclear weapons testing in the atmosphere. In January 1958, Linus Pauling and his wife submitted to the United Nations an application signed by more than 9,000 scientists to stop the trials.
Although United States officials wanted to undermine his efforts by confiscating his passport, they had to return it when he won the Nobel Prize in Chemistry in 1954. Throughout the rest of the 1950s and 1960s, Pauling and his wife tried to spread the word about this case around the world. For his efforts, Pauling won the Nobel Peace Prize in 1963 (his wife did not share the prize as the Nobel bureaucracy was mostly male and had not nominated her).
Second Nobel and Vitamin C
Linus published No More War in 1958, in which he passionately explained the potentially terrifying consequences of nuclear war for humanity. He gave a copy of the book to everyone in the US Senate, The Senate ratified the Partial Nuclear Test Ban Treaty.
Linus Carl Pauling left the Institute in 1963 as a result of the CIT representatives’ negative response to his peace studies and the Nobel Peace Prize. The laboratory space Pauling used for molecular medicine studies was taken away to punish him. In the mid-1960s, he was working at the Center for the Study of Democratic Institutions. His humanitarian work was supported here; he developed a theory of atomic nuclei (the theory was eventually rejected by many nuclear physicists). He needed a laboratory for his experimental research, and in 1967 he became a professor of chemistry at the University of California, San Diego. Here he dealt with the neglected potential of vitamin C to cure diseases such as the common cold. He accepted the professorship at Stanford in 1969. In 1970, he published a book called Vitamin C and the Common Cold, which had the largest readership and initiated a debate over megavitamin therapy that lasted until the end of his life.
His view on the effects of using large amounts of vitamin C in the treatment of infections, cancer, and other diseases had been largely rejected by medical institutions. Pauling co-founded the Institute for Orthomolecular Medicine in 1973. It was later renamed the Linus Pauling Institute of Science and Medicine, and its main goal was to find evidence in the lab and in real life to backup Pauling’s ideas.
Linus Carl Pauling’s Death and View on Life
Linus Pauling’s institute grappled with personal and legal issues, and he faced further challenges after his wife’s death in 1981 and when he was diagnosed with prostate cancer in 1991. Despite these problems, Linus Pauling keeps working. He developed arguments, in particular, against crystallographers who violated the traditional rules he defended by considering quintet symmetric semi-crystals intrinsic.
What he did in the last 20 years was no different than the years when he hung up tables of chemical substances and their properties on the laboratory desk in the basement of his mother’s boarding house: that is, to investigate the connections between the structures and functions of molecules not only with chemistry but with physics, biology, and medicine.
As an atheist and reductionist, he believed in the power of science to answer any questions people might ask. For him, the universe consisted of only matter and energy. The structure of molecules had the potential to explain all physical, chemical, biological, and even psychological phenomena. He talked about the death of his wife and how it made him feel. At the same time, his cancer spread from his prostate to his intestines and then to his liver, killing him in 1994.
He left behind a unique body of chemical knowledge that he said would lead to wealth, variety, and new discoveries.
