Jacobus Vant-Hoff Dutch chemist, Nobel Prize winner in chemistry (1901) Date of Birth: 30.08.1852 Country: Netherlands

1. Biography of Jacobus Hendricus van 't Hoff
2. The Discovery of Asymmetric Carbon Atoms
3. Contributions to Chemical Dynamics and Equilibrium
4. Contributions to Osmotic Pressure and Electrolytic Dissociation

Biography of Jacobus Hendricus van 't Hoff

Jacobus Hendricus van 't Hoff, a Dutch chemist and Nobel Laureate in Chemistry (1901), was born in Rotterdam, Netherlands. He was the third child out of seven born to Alida Jacoba (Kolff) van 't Hoff and Jacobus Hendricus van 't Hoff, a doctor and Shakespeare enthusiast. From a young age, van 't Hoff conducted his first chemical experiments at home, dreaming of a career in chemistry. However, his parents convinced him to pursue engineering at the Delft Polytechnic School, as they deemed scientific research to be unpromising. Van 't Hoff completed the three-year program in two years, excelling in his final exams. During his time there, he developed a passion for philosophy, poetry (particularly the works of Lord Byron), and mathematics, interests that he carried throughout his life. After a brief stint at a sugar factory, van 't Hoff became a student at Leiden University's Faculty of Mathematics and Natural Sciences in 1871. However, he transferred to the University of Bonn the following year to study chemistry under Friedrich August Kekulé. Two years later, he continued his studies at the University of Paris, where he completed his dissertation. He then returned to the Netherlands and defended his dissertation at Utrecht University.

The Discovery of Asymmetric Carbon Atoms

In 1848, the French physicist Jean-Baptiste Biot observed that certain crystalline forms of chemical substances could rotate the plane of polarized light passing through them. It was also observed that some molecules (later named optical isomers) rotate the plane of light in the opposite direction compared to other molecules, even though both types of molecules have the same chemical composition and the same number of atoms. In 1848, Louis Pasteur, upon observing this phenomenon, hypothesized that these molecules are mirror images of each other and that their atoms are arranged in three dimensions. In 1874, a few months before defending his dissertation, van 't Hoff published an 11-page article titled "An Attempt to Extend to Space the Present Structural Chemical Formulae. With an Observation on the Relation Between Optical Activity and the Chemical Constituents of Organic Compounds." In this article, he proposed an alternative to the two-dimensional models that were commonly used to depict the structures of chemical compounds at the time. Van 't Hoff suggested that the optical activity of organic compounds is related to their asymmetric molecular structure, with a carbon atom at the center of a tetrahedron and atoms or groups of atoms differing from each other at the four corners. Consequently, the exchange of atoms or groups of atoms at the corners of the tetrahedron can result in molecules that are chemically identical but mirror images of each other in terms of structure. These differences explain their distinct optical properties. Two months later, independently of van 't Hoff, his colleague at the University of Paris, Joseph Achille Le Bel, arrived at similar conclusions. Van 't Hoff extended the concept of tetrahedral asymmetric carbon atoms to compounds containing carbon-carbon double bonds (shared edges) and triple bonds (shared faces) and proposed that these geometric isomers generalize the edges and faces of the tetrahedron. Due to the controversial nature of the van 't Hoff-Le Bel theory, van 't Hoff did not present it as his doctoral dissertation. Instead, he wrote his dissertation on cyanacetic and malonic acids and obtained his doctorate in chemistry in 1874.

Contributions to Chemical Dynamics and Equilibrium

Van 't Hoff's considerations on the asymmetric carbon atoms were initially published in a Dutch journal and did not make a significant impact until his article was translated into French and German two years later. At first, the van 't Hoff-Le Bel theory was ridiculed by well-known chemists, such as A.V. Hermann Kolbe, who referred to it as "fantastic nonsense devoid of any factual basis and completely incomprehensible to a serious researcher." However, over time, it formed the basis of modern stereochemistry, a branch of chemistry that studies the spatial arrangement of molecules. Van 't Hoff's scientific career progressed slowly. Initially, he gave private lessons in chemistry and physics before obtaining a lecturing position in physics at the Royal Veterinary School in Utrecht in 1876. The following year, he became a lecturer (and later a professor) of theoretical and physical chemistry at the University of Amsterdam. For the next 18 years, he delivered five lectures on organic chemistry and one on mineralogy, crystallography, geology, and paleontology each week, in addition to overseeing the chemical laboratory.

Unlike most chemists of his time, van 't Hoff had a strong mathematical background, which proved useful when he tackled the complex task of studying reaction rates and the conditions that influence chemical equilibrium. As a result of his work, van 't Hoff classified chemical reactions as monomolecular, bimolecular, or multimolecular, depending on the number of molecules involved in the reaction. He also determined the order of chemical reactions for many compounds. Van 't Hoff applied thermodynamic principles to formulate the principle of mobile equilibrium, which arises from temperature changes, in 1884. It was during this time that he also introduced the now widely accepted convention of using double-headed arrows to denote the reversibility of reactions. Van 't Hoff summarized the results of his research in "Studies in Chemical Dynamics," published in 1884.

Contributions to Osmotic Pressure and Electrolytic Dissociation

In 1811, the Italian physicist Amedeo Avogadro established that equal volumes of any gases, at the same temperature and pressure, contain the same number of molecules. Van 't Hoff concluded that this law also applied to dilute solutions. This discovery was crucial, as all chemical reactions and exchange reactions within living organisms occur in solutions. Van 't Hoff experimentally determined that osmotic pressure, which measures the tendency of two different solutions on either side of a membrane to equalize their concentration, depends on concentration and temperature in dilute solutions, thus obeying the laws of thermodynamics for gases. His investigations on dilute solutions provided support for Svante Arrhenius' theory of electrolytic dissociation. Consequently, Arrhenius moved to Amsterdam and collaborated with van 't Hoff. In 1887, van 't Hoff and Wilhelm Ostwald played active roles in establishing the "Zeitschrift fur Physikalische Chemie" (Journal of Physical Chemistry). Shortly before, Ostwald had filled a vacant position as a professor of chemistry at Leipzig University. Van 't Hoff was also offered the position, but he declined the opportunity as the University of Amsterdam promised to build him a new chemical laboratory. However, when van 't Hoff realized that his teaching duties and administrative responsibilities in Amsterdam hindered his research, he accepted an offer from the University of Berlin to become a professor of experimental physics. It was agreed that he would only give lectures once a week and have access to a fully equipped laboratory. This transition occurred in 1896.

Working in Berlin, van 't Hoff applied physical chemistry to solve geological problems, particularly in the analysis of oceanic salt deposits in Stassfurt. The production of ceramics, detergents, glass, soap, and fertilizers heavily relied on these deposits before World War I. Van 't Hoff also delved into the field of biochemistry, particularly in the study of enzymes that serve as catalysts for the necessary chemical transformations in living organisms.

In 1901, van 't Hoff became the first recipient of the Nobel Prize in Chemistry, awarded to him "in recognition of the great importance of his discovery of the laws of chemical dynamics and osmotic pressure in solutions." Representing the Royal Swedish Academy of Sciences, S.T. Ossian Dahl named van 't Hoff the founder of stereochemistry and one of the creators of the field of chemical dynamics, emphasizing that van 't Hoff's research made significant contributions to the remarkable achievements of physical chemistry.

In 1878, van 't Hoff married Johanna Francina Mees, the daughter of a Rotterdam merchant. They had two daughters and two sons.

Throughout his life, van 't Hoff maintained a keen interest in philosophy, nature, and poetry. He died from pulmonary tuberculosis on March 1, 1911, in Steglitz, Germany (now part of Berlin).

In addition to the Nobel Prize, van 't Hoff received the Davy Medal from the Royal Society of London (1893) and the Helmholtz Medal from the Prussian Academy of Sciences (1911). He was a member of the Royal Netherlands Academy of Sciences, the Prussian Academy of Sciences, the British Chemical Society, the American Chemical Society, the National Academy of Sciences, and the French Academy of Sciences. Van 't Hoff was awarded honorary degrees from the University of Chicago, Harvard University, and Yale University.