Jacobus van't Hoff Pioneer of Physical Chemistry
The World's First Nobel Chemistry Prize Winner
Nov 19, 2008
Born in Rotterdam in 1852, van’t Hoff studied chemistry at several European institutions including Paris, where he studied with Kekulé. Van’t Hoff received his PhD at the University of Utrecht in 1874. For more than four decades van’t Hoff carried out ground breaking research on chemical kinetics, chemical equilibria, osmotic pressure and crystallography.
Optical Activity in Organic Molecules
Van’t Hoff’s first major contribution to chemistry came just before he received his doctorate with the publication of a small pamphlet which sought to account for optical activity in organic molecules. This phenomenon gives rise to different forms (or isomers) of carbon containing molecules, each with distinctive optical properties including the ability to rotate light in different directions.
Van’t Hoff fought off serious criticism by more renowned colleagues to describe the tetrahedral structure of organic molecules and how this explained optical isomerism. Van’t Hoff’s 3D structures accounted perfectly for the natural isomers known at that time and opened up the field of stereochemistry as set out in his book “La chimie dans l'éspace” published in 1875. Independent confirmation of van’t Hoff’s revolutionary theories came from the French chemist Joseph Le Bel and helped to establish his reputation.
Chemical Affinity and Equilibria involving Reversible Reactions
The years 1894 to 1895 proved momentous for van’t Hoff as he published research on chemical kinetics in his “Études de Dynamique chimique”. This work described new graphical methods for studying the speed ( kinetics) of chemical reactions. The modern concept of “chemical affinity” which explains how chemically unlike species can undergo reaction was also described by van’t Hoff at this time.
More important however than his work on either kinetics or chemical affinity was the application, by van’t Hoff, of the laws of thermodynamics to describe chemical equilibria involving reversible reactions. Specifically van’t Hoff showed the link between the enthalpy change of a reaction and the shift in direction of a chemical equilibrium when it undergoes temperature change.
A more general exposition of Van’t Hoff’s findings, including the effect of pressure changes on equilibria, was produced by Le Chatelier in 1895and gave rise to the so called van’t Hoff /Le Chatelier Principle, an important cornerstone of modern chemistry.
Chemical Equilibria in Gases and Dilute Solutions
The same year saw the publication of van’t Hoff’s “Chemical equilibria in gaseous systems or strongly diluted solutions” in which the great chemist proved that thermodynamic laws are valid for very dilute solutions as well as for gases. Van’t Hoff’s proofs were based on his studies of aqueous solutions at a given temperature and concentration. He showed that osmotic pressure can be described by a simple formula very similar to that for gas pressure. Van’t Hoff was also able to provide excellent evidence for his theories by very accurate empirical measurement. The general validity of van't Hoff's pressure laws was demonstrated brilliantly by Arrhenius, who joined van’t Hoff in Amsterdam in 1888 and led, eventually, to the pioneering work of Jean Perrin 20 years later.
The Nobel Prize in Chemistry
The last 15 years of van’t Hoff’s life were devoted to a variety of scientific pursuits, including important work in mineralogy and crystallography as a contribution to Prussia's chemical industry and the co-founding of “The Journal of Physical Chemistry" with another distinguished scientist, Wilhelm Ostwald.
Worldwide recognition of van’t Hoff’s work on solutions came in 1901 when he was the first person to be awarded the Nobel Prize in Chemistry.
Van 't Hoff died from tuberculosis on March 1, 1911, at Steglitz near Berlin.
