Wilhelm Ostwald
Wilhelm Friedrich Ostwald was a Baltic German chemist and philosopher. Ostwald is credited with being one of the founders of the field of physical chemistry, with Jacobus Henricus van 't Hoff, Walther Nernst and Svante Arrhenius.
He received the Nobel Prize in Chemistry in 1909 for his scientific contributions to the fields of catalysis, chemical equilibria and reaction velocities.
Following his 1906 retirement from academic life, Ostwald became much involved in philosophy, art, and politics. He made significant contributions to each of these fields. He has been described as a polymath.
Early life and education
Ostwald was born ethnically Baltic German in Riga, Russian Empire to master-cooper Gottfried Wilhelm Ostwald and Elisabeth Leuckel. He was the middle child of three, born after Eugen and before Gottfried. Ostwald developed an interest in science as a child and conducted experiments at his home, particularly related to fireworks and photography.Ostwald entered the Imperial University of Dorpat in 1872. He completed his Kandidatenschrift examinations there in 1875. During his time at Dorpat, Ostwald had significant exposure to the humanities, the arts, and philosophy, which became a focus of his endeavors after his 1906 retirement from academia.
Academic career
Ostwald began his career as an independent unpaid investigator at the University of Dorpat in 1875. He worked in the laboratory of Carl Schmidt, along with his contemporary Johann Lemberg. Lemberg taught Ostwald many of the basics of the analysis of inorganic compounds and measurements of equilibria and chemical reaction rates. Lemberg also taught Ostwald the chemical basis of many geologic phenomena. These endeavors formed part of the subjects of Ostwald's later research efforts. In addition to his work in Carl Schmidt's laboratory, Ostwald also studied in the university's physics institute with Arthur von Oettingen.Around 1877, still continuing his work as an unpaid investigator in the Chemistry Laboratory at the University of Dorpat, Ostwald became a paid assistant in the Physics Institute, after Oettingen's assistant moved to Riga.
He also supported himself for a time by teaching mathematics and science at a Dorpat high school.
Ostwald was deeply interested in questions of chemical affinity and the reactions that formed chemical compounds. This was the central theoretical question facing chemists at the time. As part of his early work, Ostwald developed a three-dimensional affinity table that took into account the effects of temperature as well as the affinity constants of acids and bases. Ostwald also investigated mass action, electrochemistry, and chemical dynamics.
Ostwald completed his Magisterial degree at the University of Dorpat in 1877, enabling him to give lectures and charge for teaching.
Ostwald published his doctoral dissertation at the University of Dorpat in 1878, with Carl Schmidt as his thesis advisor. His doctoral thesis was entitled Volumchemische und Optisch-Chemische Studien. In 1879, he became a paid assistant to Carl Schmidt.
In 1881, Ostwald became a Professor of Chemistry at the Riga Polytechnicum. In 1887, he moved to Leipzig University where he became Professor of Physical Chemistry. Ostwald remained on the faculty at Leipzig University until his retirement in 1906.
He also served as the first "exchange professor" at Harvard University in 1904 and 1905.
During Ostwald's academic career, he had many research students who became accomplished scientists in their own right. These included future Nobel Laureates Svante Arrhenius, Jacobus Henricus van 't Hoff, and Walther Nernst.
Other students included Arthur Noyes, Willis Rodney Whitney and Kikunae Ikeda. All of these students became notable for their contributions to physical chemistry.
In 1901, Albert Einstein applied for a research position in Ostwald's laboratory. This was four years before Einstein's publication on special relativity. Ostwald rejected Einstein's application, although later the two developed strong mutual respect. Subsequently, Ostwald nominated Einstein for the Nobel Prize in 1910 and again in 1913.
Following his 1906 retirement, Ostwald became active in philosophy, politics, and other humanities.
During the course of his academic career, Ostwald published more than 500 original research papers for the scientific literature and approximately 45 books.
Scientific contributions
Nitric acid process
Ostwald invented a process for the inexpensive manufacture of nitric acid by oxidation of ammonia. He was awarded patents for this process. Ostwald's patent made use of a catalyst and described conditions under which the yield of nitric acid was near the theoretical limit. Aspects of the basic process had also been patented some 64 years earlier by Kuhlmann. Kuhlmann's process did not become industrially significant, likely due to the lack of an inexpensive source of ammonia. Shortly after Ostwald's finding, inexpensive ammonia became available as a result of Haber and Bosch's invention of a process for nitrogen fixing process for ammonia synthesis. The combination of these two breakthroughs soon led to more economical and larger-scale production of fertilizers and explosives, of which Germany was in short supply during World War I. The process is often referred to as the Ostwald Process. The process remains in widespread use in contemporary times for manufacture of nitric acid.Ostwald's dilution law
Ostwald also conducted significant research on dilution theory leading to his conceptualization of the law of dilution which at times is referred to as "Ostwald's Dilution Law". This theory holds that the behavior of a weak electrolyte follows the principles of mass action, being extensively dissociated at infinite dilution. This characteristic of weak electrolytes can be observed experimentally, such as by electrochemical determinations.Catalysis
Through his research on chemical reaction rates and velocities and his studies of acids and bases, Ostwald found that the concentration of acid or the concentration of base in a solution of certain chemical reactants can have a strong influence of the rate of chemical processes. He realized that this is manifestation of the concept of chemical catalysis first articulated by Berzelius. Ostwald articulated the idea that a catalyst is a substance that accelerates the rate of a chemical reaction without being a part of either the reactants or the products. Ostwald's advances in the understanding of chemical catalysis were widely applicable in biological processes such as enzymatic catalysis and also in many industrial processes. A catalyst is used in the nitric acid process that Ostwald invented.Crystallization
Ostwald studied the crystallization behavior of solids, especially those solids that are capable of crystallizing in different forms, in the phenomenon known as polymorphism. He discovered that solids do not necessarily crystallize in their most thermodynamically stable form but instead sometimes crystallize preferentially in other forms dependent on the relative rates of crystallization of each polymorphic form. Ostwald found that the relative rates were dependent on the surface tension between the solid polymorph and the liquid form. Many common materials exhibit this type of behavior, including minerals and various organic compounds. This finding came to be known as Ostwald's rule.Ostwald realized that solid or liquid solutions can continue to evolve over time. While the a non-thermodynamically preferred polymorph may crystallize first, more thermodynamically stable forms can continue to develop as the solution ages. Often this results in large crystals forming, since they are more thermodynamically stable than are large numbers of small crystals. This phenomenon came to be known as Ostwald Ripening and is observed in many situations. An everyday example is the gritty texture that ice cream develops as it ages. On a geologic timescale, many minerals exhibit Ostwald Ripening as their crystal forms evolve as the mineral ages.
Related to solubility and crystallization was Ostwald's finding that dissolution of a solid depends on the size of the crystal. When the crystals are small, typically less than a micron, the solubility of the solid in the solution phase is increased. Ostwald quantified this effect mathematically in a relationship that became known as the Ostwald-Freundlich equation. Ostwald first published his finding in 1900, and his mathematical equation was refined by German chemist Herbert Freundlich in 1909. This mathematical relationship also applies to the partial pressure of substance in the system. The Ostwald-Freundlich equation takes into account the surface tension of the particle in the system, in addition to curvature and temperature. The size dependence of solubility is sometimes utilized in the formulation of pharmaceuticals that have low solubility so as to enhance their uptake by the patient. The size dependence also has a role in Ostwald Ripening.
Collaborating with German chemist Raphael E. Liesegang, Ostwald recognized that substances can crystallize in a periodic fashion wherein the crystallization behavior follows a spatial or temporal pattern. In certain circumstances, the result of this periodic crystallization behavior is easily visually observed, for example, in various geologic formations. Liesegang had previously investigated this phenomenon in specific laboratory experiments, showing his results to Ostwald. Ostwald then developed a mathematical model for the phenomenon that served to explain the observations and realized how widespread is the periodic crystallization behavior. These observations came to be known as Liesegang rings.
Atomic theory
Ostwald introduced the word mole into the lexicon of chemistry around 1900. He defined one mole as the molecular weight of a substance in units of mass grams. The concept was linked to the ideal gas, according to Ostwald. Ironically, Ostwald's development of the mole concept was directly related to his theory of energeticism, in philosophical opposition to atomic theory, against which he was one of the last holdouts. He explained in a conversation with Arnold Sommerfeld that he was convinced by Jean Perrin's experiments on Brownian motion.In 1906 Ostwald was elected a member of the International Committee on Atomic Weights. As a consequence of World War I, this membership ended in 1917 and was not resumed after the war. The 1917 Annual Report of the committee ended with the unusual note: "Because of the European war the Committee has had much difficulty in the way of correspondence. The German member, Professor Ostwald, has not been heard from in connection with this report. Possibly the censorship of letters, either in Germany or en route, has led to a miscarriage".