Jacobus Henricus van ‘t Hoff
gigatos | November 16, 2021
Summary
Jacob Hendrick (August 30, 1852 (1852-08-30), Rotterdam – March 1, 1911, Berlin) was a Dutch chemist, one of the founders of stereochemistry and chemical kinetics, the first winner of the Nobel Prize in Chemistry (1901) with the wording “in recognition of the great importance of the discovery of the laws of chemical dynamics and osmotic pressure in solutions.”
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Early Years
Jacob Hendrik Vant-Goff was born in Rotterdam on August 30, 1852. His family belonged to an old Dutch family. Jacob”s father, Jacob Hendrik Vant-Goff the elder, was a physician, and his mother, Alida Jacob Colf, was a housewife. He was the third child in the family and had four brothers and two sisters.
At the age of eight, Jacob went to a private school near Rotterdam. It was a school with a broad curriculum. Natural sciences, humanities, foreign languages, drawing and singing were taught there. Already here the outstanding abilities of the future scholar began to appear. He achieved the greatest success in mathematics and physics.
In 1867, at the age of fifteen, Vant-Goff successfully passed his entrance examinations and entered the fourth grade of a five-class city high school. At this school, the focus was on science and mathematics. It was here that the future scientist became interested in chemistry and began to conduct his first experiments.
In 1869, after leaving school, Jacob went to Delft, where he enrolled at the Polytechnic School, wishing to obtain a degree in chemical engineering. Vant-Goff spent most of his time in chemistry and mathematics. He studied hard, which allowed him to graduate in two years instead of three.
During his first student vacation, Vant-Goff goes on an internship. It took place in a sugar factory in North Brabant. During the internship the novice scientist was engaged in determining the concentration of sugar using a polarimeter. He found this work to be thoughtless and monotonous, but it was the monotony and routine of technological operations that awakened in him a desire for a deeper understanding of chemical processes.
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The Student Years
In October 1871, Vant-Goff becomes a student at Leiden University. He studies diligently, as he always does, and is fascinated by poetry and philosophy. He even has the idea of devoting himself entirely to poetry. But his first experiments in this direction are unsuccessful, and he returns to the path of a research chemist.
Soon Vant-Goff realized that for a serious study of modern chemistry he should move to another university. He moves to Bonn and begins work at the University of Bonn, where Friedrich August Kekule was then professor of chemistry.
After enrolling, Vant-Goff immediately began experimental research. Kekule immediately noticed Vant-Goff”s outstanding diligence, but a conflict soon arose between the professor and the trainee, caused by Kekule”s desire to use Vant-Goff”s knowledge and abilities to perform his own research. In one of his letters to his parents, Vant-Goff wrote:
“A little argument with Professor Kekule: he has some new ideas about camphor and turpentine, and he wants to use a few laboratory assistants to handle them, that is, he wants to turn the few paid laboratory assistants into unpaid private assistants. I did not accept this offer and was forced to look for my own subject to develop, and now that I am engaged in this subject, Professor Kekule does not treat me as he did before, and continues to recruit new assistants.”
As a result, Vant-Goff decided to leave Kekule”s laboratory. But in order to continue his work successfully, he needed to get a certificate from the professor about the success of his experimental work. However, the case ended safely. After much research, Wang Goff presented his results to the professor. To the young scientist”s surprise, the professor, after a short dialogue, said: “You will get a certificate and a very good one.” Indeed, on June 17, 1873, Vant-Goff received his certificate from Kekule. In addition, the professor advised the young scientist to continue his research at some other university. Before following his advice, Vant-Goff went to Utrecht, where, on December 22, 1873, he successfully passed the doctoral examination entitling him to seek his doctorate.
In January 1874, Vant-Goff went to Paris to continue his research in organic chemistry in the laboratory of Charles Adolphe Wurz. In this laboratory, Vant-Goff became acquainted with A. R. Genninger and J. A. Le Bel, who later became his close friends. However, at the end of October 1874 Vant-Goff, having received a certificate from Wurz, returned to Utrecht. Here within a few months he completes his student education and on December 22, 1874 defends his doctoral thesis on the synthesis of cyanoacetic and malonic acids.
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Beginning of scientific activity
Shortly before the defense of his doctoral thesis, in September 1874, he published a small pamphlet in Dutch under the long title “Proposal to represent the currently used structural formulas in space and the related remark on the relation between optical rotativity and chemical constitution of organic compounds”. Later, at the end of 1875, this pamphlet appeared in German, translated by F. Hermann, an assistant of I. Wisselius.
While preparing a reprint of the article in French, Vant-Goff was preoccupied with finding work. In this respect he had no luck for a long time, and was forced to give private lessons. It was not until March 1876 that he succeeded in obtaining a position as assistant professor of chemistry at the Veterinary School in Utrecht.
After the German edition of Vant-Hoff”s pamphlet was published, many scientists were able to read it. However, Vant-Goff”s views were suddenly sharply criticized by authoritative chemists. One of the most powerful opponents of Vant-Goff”s ideas were M. Bertleau and H. Kolbe. The latter even allowed himself to express himself rather bluntly and crudely in the direction of Vant-Goff. However, by the end of the 70”s of the XIX century, a significant part of chemists recognized the stereochemical theory. Many experiments confirmed its applicability in practice. Also later, the connection of the optical rotativity of molecules with the presence of an asymmetric carbon atom in them was accurately established.
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Work at the University of Amsterdam (1877-1895)
Thanks to the recommendations of friends, on June 26, 1877, Vant-Goff receives an invitation to take a position as a lecturer at the University of Amsterdam. A year later, at the age of 26, he became professor of chemistry, mineralogy and geology (and later of physical chemistry). Vant-Goff spent his first few years organizing and setting up a chemical laboratory. Between 1878 and 1884 he published only a few articles, as he was preoccupied with teaching and setting up the laboratory.
The move to Amsterdam was associated with a major event in Vant-Goff”s personal life. In 1878 he proposed to Johanna Franzina Mees (daughter of a Rotterdam merchant), whom he had long been in love with. On December 27 of the same year they were married. They had 2 daughters, Johanna Francina (1880) and Aleida Jacob (1882), and 2 sons, Jacobs Hendrikus(1883) and Govert Jacob (1889). For more than 30 years his wife was his faithful and beloved friend.
In 1881 Vant-Goff”s book “Insights into Organic Chemistry,” which he began working on while still in Utrecht, was published. In this book the scientist tried to establish the relationship between the structure of substances and their physical and chemical properties. However, the attempt was not very successful, and today the book is little known. However, for Vant-Goff himself, this book was an important step in his development. In working on this book he came to the problem of chemical affinity, to the recognition of the importance of chemical thermodynamics, and to the problems of chemical equilibrium and the rate of chemical reactions. From this point on, Vant-Goff can be considered to have become involved in physical chemistry.
In 1884 Vant-Goff”s most famous book, Essays on Chemical Dynamics, was published. The appearance of this book marked the birth of physical chemistry. Vant-Goff first made extensive use of the principles of thermodynamics and mathematical methods to analyze and explain observable chemical processes. In a very small book, Vant-Goff presented in a concentrated form a large and very important material for understanding the nature and mechanism of chemical reactions. Despite this, the appearance of the book initially elicited no reaction in the chemical world. Not only did chemists not notice the appearance of the book, but some of its provisions proved to be incomprehensible to them.
A year later, on October 14, 1885, Vant-Goff submitted for publication a new theoretical work “Chemical equilibria in systems of gases and dilute solutions”, published in 1886. This work is a continuation and detailing of the ideas expressed in general form in “Essays on Chemical Dynamics”, which have gained quite an independent value. Shortly after the publication of “Chemical Equilibrium in Systems of Gases and Dilute Solutions,” the Swedish scientist Svante Arrhenius put forward his famous theory of electrolytic dissociation. The emergence of this theory is most directly related to the work of Vant-Goff.
In 1887 W. Ostwald, together with J. G. Vant-Goff and S. A. Arrhenius founded the international “Journal of Physical Chemistry” (Zeitschrift fur phys. Chemie) in Leipzig, which became widespread and recognized among chemists. This journal became of great importance in the development and promotion of new ideas in physical chemistry. Already in the first volume of this journal appeared the most important articles of Want-Hoff and Arrhenius.
After the publication of his works on chemical dynamics and equilibrium, the name of Vant-Goff became widely known in the scientific world. At the same time he still spent a lot of time teaching at the University of Amsterdam. In addition to lecturing, he supervised the research in the laboratory he created, which in time attracted a large number of trainees and scientists to work under the guidance of the famous scientist.
Between 1888 and 1895 Vant-Goff was mainly engaged in the development of earlier ideas, mainly in the theory of solutions. At the same time he published several papers on stereochemistry and thermodynamics. Of great interest is his work “On solid solutions and the determination of molecular weight in the solid state,” in which Vant-Goff tried to show that the regularities he had obtained for liquid solutions could in some cases be applied to solid mixtures as well. With this article Vant-Goff laid the foundation for the theory of solid solutions, which he further developed.
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Work at the University of Berlin
By the mid-1890s, teaching duties begin to weigh on Want-Goff. Wanting to provide himself with comfortable conditions for research, in 1895 he accepts the very honorable offer of the Berlin Academy of Sciences and the University of Berlin to move to the position of university professor, not required to give lecture courses. On January 30, 1896, Want-Goff was elected a full member of the Prussian Academy of Sciences.
In March 1896, Want-Goff moved to Berlin, where he immediately began research in a new field – the study of the formation of natural deposits of salt of oceanic origin. He was primarily interested in the causes and mechanisms of the formation of the famous Stassfurt Salt Deposits near Magdeburg. This work represents a bold attempt to use the laws of physical chemistry to explain geochemical processes. The development of this topic allowed one of the most important areas of geology to be illuminated experimentally and theoretically.
Vant-Goff conducted extensive research into the formation of deposits of salts in the Stassfurt deposit in collaboration with his student and friend Wilhelm Meyerhoffer, a Russian-born, talented and quite independent scientist who had previously worked on salt equilibria and was distinguished by his originality in his theoretical views as well.
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Last years of life, death
In 1896 Meyerhoffer, together with Vant-Hoff, founded a small private laboratory in Berlin, where the bulk of the research on the Stassfurt deposits was carried out. The work continued for about 10 years and the results were published in reports of the Prussian Academy of Sciences. A total of 52 reports appeared. The investigations into the conditions of formation of oceanic salt deposits and the results obtained have gained importance in geology and mineralogy, as well as in chemistry. They became the basis for more extensive research carried out in this direction up to the present time.
In 1901. Vant-Goff was the first chemist to receive the Nobel Prize “in recognition of the great importance of the discovery of the laws of chemical dynamics and osmotic pressure in solutions.
The joint work of Vant-Goff and Meyerhoffer, which lasted for ten years, was exceptionally fruitful. But in 1905 it was suddenly interrupted by the serious illness of Meyerhoffer. On April 21, 1906, Meyerhoffer died. Vant-Goff took the death of his friend and collaborator hard. By this time he himself began to feel unwell: there were signs of a severe pulmonary disease – tuberculosis.
Vant-Goff did not want to give up. He was looking for a new field for extensive systematic research. At the end of 1905, he decided to devote himself to the study of the synthetic action of enzymes. Having extensive experience in studies of stereochemistry and osmotic pressure, the scientist now wanted to tackle the issues of biochemistry.
However, a progressive illness thwarted his intentions. Planned research had to be interrupted. The last years of his life were overshadowed by the loss of several people close to him – relatives and colleagues.
On December 15, 1910. Vant-Goff finally collapsed. His attempts to take up his work again a few weeks later proved futile. On March 1, 1911, he died.
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Stereochemistry
Vant-Goff is one of the founders of stereochemistry. His pamphlet “Proposal to represent currently used structural formulas in space and the related remark on the relationship between the optical rotativity and the chemical constitution of organic compounds,” published in 1874 in Dutch and subsequently translated into German and French, was severely criticized by the renowned chemists of the time. Over time, however, the ideas that Vant-Goff presented in this pamphlet became widespread.
Vant-Goff suggested that the quadrivalent carbon atom could be represented as a tetrahedron. Based on this idea, the scientist suggested that the appearance of optical rotativity of molecules could be related to the presence of an asymmetric carbon atom (a carbon atom bonded to four different substituents) in them. This assumption is the most important idea of the stereochemical theory. Subsequently, many experiments were conducted to confirm this idea.
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Physical Chemistry
In 1884, Vant-Goff published his book Essays on Chemical Dynamics. The appearance of this book marks the birth of physical chemistry as such. Vant-Goff was essentially the first to make extensive use of the principles of thermodynamics and mathematical methods in his treatment of chemical processes. When he began his work on the book, Vant-Goff understood that he would have to base his work on the isolated, scattered, and few facts established by his predecessors to provide a basic scheme for the quantitative description of the chemical process.
In this work, Vant-Goff formulates the concept of “molecular transformation” and, based on molecular-kinetic ideas, gives a classification of such transformations according to the number of molecules involved in the reaction. He introduces the notions of the reaction rate constant, mono-, di- and trimolecular reactions, and formulates an important statement: “The course of a chemical transformation is characterized exclusively by the number of molecules that interact to produce the transformation.
Using concrete examples of reactions, Vant-Goff reveals the regularities of mono-, bi- and multimolecular reactions and gives expressions for their rates in the form of the well-known formula:
dcdt=kcn{displaystyle dcdt=kc^{n}}
where c{displaystyle c} is the concentration of the reactants, n{displaystyle n} is the number of molecules involved in the reaction (n{displaystyle n} = 1 – monomolecular, n{displaystyle n} = 2 – bimolecular, etc.), k{displaystyle k} – is the reaction rate constant.
Vant-Goff considers the influence of the shape and size of reaction vessels on the course of reactions, ways of selecting a suitable medium, the effect of vessel walls. In particular, he gives the results of experiments on the effect of coating the inner walls of the apparatus (e.g., with oil). He also gives an overview of ways and methods for determining the number of molecules involved in the chemical transformation.
Vant-Goff also considers the effect of temperature on the chemical transformation. In particular, using the example of the reversible reaction N2O4↽–⇀2NO2{displaystyle {ce {N2O4 <=> 2 NO2}}} he derives the well-known equation connecting temperature with the rate constants of direct k′{displaystyle k”} and reverse k″{displaystyle k””} reactions:
dlnk′dT-dlnk″dT=q2T2{displaystyle dln k”dT-dln k””dT=q2T^{2}}
where q{{displaystyle q} is the number of calories released when a unit of the second substance transforms into the first substance at a constant volume.
On the basis of the data obtained, Vant-Goff carefully analyzes various cases of chemical equilibrium. Vant-Goff notes the close connection between the rates of transformation and equilibrium. He sees equilibrium as the result of two opposite reactions proceeding at certain rates and arrives at another important formula:
dlnk′dT-dlnk″dT=dlnKdT=q2T2{displaystyle dln k”dT-dln k””dT=dln KdT=q2T^{2}}
where K=k′k″{displaystyle K=k”k”}. In this way he relates the equilibrium constant to the rate constants of the forward and reverse reaction.
In 1886, a work by Vant-Goff was published entitled “Chemical Equilibrium in Systems of Gases and Dilute Solutions. The main purpose of this work was an attempt to establish angiologies in the laws describing the behavior of gaseous systems and solutions.
Vant-Goff considers the relationship between osmotic pressure and other physical and chemical parameters. Describing Pfeffer”s device and his proposed method of making semipermeable partitions, Vant-Goff expressed the important idea of reversibility of changes in osmotic pressure. Using notions of semi-permeable partitions, it was possible to carry out reversible circular processes for solutions and thereby establish an analogy between gases and solutions. Thus, it became quite obvious that the laws of gas state are applicable also to the description of osmotic pressure in dilute solutions.
Vant-Goff theoretically and experimentally proved the applicability of Boyle”s and Gay-Lussac”s laws and Clapeyron”s formula to dilute solutions. From this Vant-Goff concluded that Avogadro”s principle is also quite applicable to dilute solutions, and isotonic solutions must be equimolecular.
For dilute solutions, Vant-Goff calculated the value of the gas constant R{displaystyle R} in the Clapeyron equation. The R{displaystyle R} value he obtained from osmotic pressure measurements was close to the value obtained for ideal gases. However, in some cases (solutions of mineral acids and salts) the value of the gas constant differed. In this regard, Vant-Goff rewrote the Clapeyron equation in the form:
PV=iRT{displaystyle PV=iRT}
where P{displaystyle P} is pressure; V{displaystyle V} is volume; T{displaystyle T} is temperature; R{displaystyle R} is the gas constant, which has the same value as for gases; i{displaystyle i} is a correction factor close to unity and depending on the nature of substance to which the equation applies (VanT-Goff called this factor “activity factor”).
In the same way, Vant-Goff showed that
i=5.6mΔ{displaystyle i=5.6mDelta }
where m{displaystyle m} is the molecular mass of the substance; Δ{displaystyle Delta } is the amount by which the presence of the substance (1 : 100) reduces the water vapor pressure. Vant-Goff suggested other ways of determining the coefficient i{displaystyle i}, for example through cryoscopic or ebulloscopic constants. Thus, Vant-Goff proposed a method for determining the molecular weight of a substance based on the physical properties of its solution.
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Salt equilibria
Together with his friend Wilhelm Meyerhoffer, Vant-Goff conducted extensive research into the formation of the Stassfurth salt deposits. These sediments are of marine origin. Chemical analysis of the Stassfurth deposits showed that their chemical composition is quite complex. They mainly consist of chlorides, sulfates and borates of sodium, potassium, magnesium and calcium.
Vant-Goff, together with Meyerhoffer, established that the main factor in the formation of salt deposits is temperature. In some cases, time also plays a major role. Some transformations that were carried out by researchers required several months. The influence of pressure on the crystallization of salts from multicomponent solutions proved to be insignificant.
As a result of studies it was shown that some minerals could not be formed at 25 ° C. Thus, mixtures of kieserite (MgSO4⋅H2O{displaystyle {ce {MgSO4*H2O}}) and sylvin (KCl{displaystyle {ce {KCl}}}) with an admixture of sodium chloride formed from carnallite (KCl⋅MgCl2⋅6H2O{displaystyle {ce {KCl*MgCl2*6H2O}}) and kieserite, could be released only at much higher temperatures. Despite doubts about the possibility of deposition of salts at temperatures above 70 ° C, by comparing the composition of minerals in the sediments it was found that their formation occurred in two temperature intervals – at 25 ° C and 83 ° C.
Determinations of the transformation temperatures in such complex mixtures have yielded several synthetic minerals, both those contained in the Stassfurthian deposits and those not.
In 1970, a crater on the moon was named after Jakob Hendrik Vant-Goff.
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