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OTTO WALLACH: The First Organizer of the Terpenes WILLIAM S. PARTRIDGE and ERNEST R. SCHIERZ University of Wyoming, Laramie, Wyoming
March 27, 1947, marks the 100th anniversary of the birth of Otto Wallach. In cornmemoration of this event the authors haw compiled this brief biography of the 1910 Nobel prise winner.
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was crude and homemade, and his experiments, not always resulting in too fragrant products, found little sympathy from such a great family of lawyers. At the age of 20 Wallach decided to study chemistry in Goettingen, where he attended the lectures of Woehler and worked in the laboratory under Fittig and Huehner. However, Woehler, who was 67 years old a t the time, did not appeal to Wallach and neither did his lectures. The town of Goettingen also seemed unfriendly t,owardhim because he was a Prussian. He took his second semester in Berlin where he attended lectures by A. W. Hofmann, who had just come from London as a successor to Mitscherlich. The chnditions there, however, were extremely unpleasant under Sonnenschein and so he returned to Goettingen and little sympathy and his Otto W d a o h . About 4s Year. family had little to do with Woehler. There followed a time of restlessactivity. In o- l-d Woehler's laboratory indolence was not tolerated. his career in chemistry. His father was transferred from Koenigsherg to Stet- Anyone who did not occupy his working place regularly tin and then to Potsdam when Otto was eight years old. received from the Hojrat a letter summoning him to vacate it. The hours in the laboratory were from 7:00 Here he received his elementary education. Wallach was always sickly and rather weak. He suf- A.M. until 5:00 P.M., a t which time the gas was turned fered from occasional fainting spells and frequently had off. Some of the students would continue working by t o miss school. Nevertheless, his father insisted he the light of candles brought to school in their pockets. make up the work he missed, which was virtually im- As Wallach was an extraordinary student, he was perpossible for the boy. As a result his father considered mitted to obtain his Doctor's degree in the summer of him a poor student and wanted to take him out of 1869, after only five semesters of study. school, but a t this time young Wallach showed that he The next winter Wallach went to Berlin as assistant had a good mind and passed his final examinations even to Wichelhaus, where he attended meetings of the Geragainst his father's wishes. Just why he wanted to re- man Chemical Society and became acquainted with main in school is hard to say, but he later said that it many of hi$ contemporaries. In the spring of 1870 he was largely because of his friends. Another incentive accepted an assistantship in Bonn offered to him by was a club a t Potsdam to which he belonged that en- Kekul6, another chemist who was an artist a t heart. couraged the study of literature and the history of art. The two men got along well together, hut their temperaHere Wallach's artistic temperament first came to ments were very different. Wallach was continually light, and he felt an urge toward art and its history. working in his laboratory, while Kekul6 did more of his Throughout his later life he continued his interest in work a t his desk than he did in the laboratory. art, and one of the advantages of his home a t Bonn was The two men worked together a t Bonn for 19 years that i t was close to the Belgian and Dutch schools of except for one brief interruption when Wallach went to art. He spent many vacations a t these schoolsstudying Berlin to work as a chemist in a newly formed enterart and made a large collection of water-color paintings. prise, the Aktien-Gesellschajt fur Anilin-Fabrikdion Like many other young chemists of that day, much (Agfa). However, the noxious gases in the factory were of his early chemical education came from Stoeck- so harmful to his health that he soon resigned his posihardt's "Schule der Chemie." The apparatus he used tion and returned to Kekul6 a t Bonn. 100 years ago, Otto Wallach-the man whom Flueckiger called "the Messiah of the Terpenesn- was born in Koenigsberg, Prussia. His father was a Prussian state official. Young Otto was rather short in stature, with clear blue eyes and a fine, discriminating countenance. Reared in a - familv of "
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Kekul6 gradually withdrew from active participation in the laboratory work. In 1879, with the death of Mohr, the instmctiou of pharmacy a t Bonn passed on to Wallach. Although this was a comparatively foreign field to him, it did have its compensations because it was through hi lectures in pharmacy that he became interested in the chemistry of the volatile oils. In October, 1889, Wallach was called to Goettingen as the successor to Victor Meyer. He stayed there until his death, serving as director of the Institute until he retired in 1915. At a meeting in 1909 celebrating the appearance in Liebig's Annulen der Chemie of Wallach's 100th paper concerning ethereal oils, he took the opportunity to describe how in 1884 he actually got started on the research while eventually earned for him the Nobel Prize. As recorded by Ruzicka(1) ; In a cupboard in KekulB's private laboratory there had stood for 15 years several unopened flasks conteining ethereal oils, which Kekul6 had procured for research purposes but had not used. Kekul6 granted Wallsch's request for permission to carry out a research on the mysterious contents of the flasks, with the wonds, "Yes, if you can make anytliing out of them!" accompanied by the ironical laugh that he gave only when he believed someone to be on the wrongtrack.
Thus Wallach started on the work which earned h i the name of "Messiah of the Terpenes." His first paper on terpenes appeared in Liebig's Annalen der Chemie in 1884 (2). The terpene field at that time was in a state of utter confusion. For instance, the hydrocarbon now known as pinene had been referred to in chemical literature by no less than 20 names, derived for the most part from the plant sources from which it had been isolated. In 1891 Wallach gave a lecture before the German Chemical Society in which he said (3): . . If one casts a glance over the oldliterature of the terpenes,
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i t does not appear a particularly enticing subject for investige tion. There were isolated observations in almost inoommehensible abundance. The textbooks listed a large number-of terpenes which were designated by special names according to their origin and were held to be ~ e a l l ydifferent from one another in virtue of their physical properties. h is to be seen from the liters, ture, it may be that some of the investigators who had carried out extensive researches in this field of work had formed correct and definite ideas about the relations between the terpenes.. Red clarity had heen reached on no point. To introduce clearness into this widely branched and tangled subject, it was necessary to strive for the followine: (1) All tcrpcues thn;'arc really diUerent from one soother must be sharply and drfmitcly chsrseterized by their properties so that recognition ortd digtinction of the chemical mdiriduals mrght be possible without difficulty. (2) The behavior and the mutual relations of the individual hydrocarbons must be exulicable on the basis of such an exact characterization. (3) Only after the fulfillment of both of these preliminary conditions would it be possible to investigate successfully the individual compounds with regard to their constitution.
When Wallach undertook this seemingly impossible work the confusion to be found in the field had discouraged many others who had tried to bring order out of chaos' Through ingenuity he new methods to attack the problems which presented themselves,
and before too long he had sufficiently simplified the complex names and classified the properties of the different terpenes so that many other men soon tookup the work. I n spite of the many problems that he had to overcome, Wallach was able to say, only a year after his first publication, that a great many terpenes, formerly designated differently and alleged to be of various constitutions, were undoubtedly identical. His first attack on the problem was to test natural terpene mixtures with several simple reagents, including hydrogen chloride, bromide, and iodide, nitrosochloride, nitrogen trioxide, bromine, and nitrogen peroxide, to see whether crystalline reaction products were formed. In this way he was able to show that many terpenes, then believed to be different, formed the same compounds when treated in like ways. He also developed new methods of preparation of terpenes. At the end of three years' work he listed eight different terpenes which obviously differed from each other, each of which could be prepared and identified by anyone following Wallach's directions. These eight compounds were pinene, camphene, liionene, dipentene, sylvestrene, terpinolene, terpinene, and phellandrene, of which terpinolene was discovered by Wallach and terpinene had not previously been isolated. In 1891 he published a chart showing the relationship between twelve different terpenes (&). Later, in 1895, the formula of a-terpineol was published simultaneously in different articles by Wallach (6) and Tieman and Semmler (6), and as a consequence, by referring to Wallach's chart showing the reciprocal arrangements of the terpenes, the structure of an entire series was discovered. Thus the foundation was laid-Wallach had pointed the wav for those who followed--and many others took up thework. In 1909, not satisfied merely to republish his works, Wallach published a comprehensive review of all of his life's work to t h i t t i e ("Teraene und Camvher." . ' Leiosig, 1909 and 1914). ~e'dedi'catedit to his former s t k dents. He not only corrected and revised his own works but referred to the work of others where they touched on the same field covered by himself and others.
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"In recognition of the services rendered by him to organic chemistry and chemical industry, through his pioneer work in the field of azoxy compounds" (7), Wallach was awarded the Nobel prize in 1910. At the age of 86 died one of the greatest organizers and research chemists that organicchemistry has known. He never married, but he lived the existence of a man whose life was marked by singleness of purpose and on whom popular acclaim had no influence. Although his activities had boundaries, his educational background was not slighted and therefore his interests were broad and his personality correspondingly attractive. He looked for professional accomplishment and personal attachments and found both. The field of organic chemistry would have a large gap in i t if Wallach's work were missing. His perseverence and careful experimentation did much to bring analysis in organic chemistry to so high a degree of perfection that i t has become possible to follow an analytical procedure therein with nearly the same degree of certainty as the search for the elements in an inorganic substance. I t has been true throughout the history of chemistry that the men who advance the theories-the dreamersdepend on contributions of the careful methodical experimenters. Wallach fell into the latter category. He was of a firm conviction that exact and trustworthy facts always retain their worth, whereas the importance of theories and hypotheses is often overemphasized. He was not a.man to jump at conclusions, but was always extremely exact and thorough in his scientific experiments, so that today all the 129 papers that he pubr o , , , i t - y 1 11 Vr,lion lished stand largely undisputed. His highest ideal was O t t o W d l s r h . Abovt 1913 not theory, not the formula, but carefully and reliably performed experimentation. Chemistry needs more men like him. His work received a great deal of recognition outside of Germany as well as in his homeland. i n 1908 he was LITERATURE CITED elected honorary fellow of the British Chemical SoRnzrcn*, L., J. Chem. Soe., 1585 (1932). ciety, and in 1909 he received an honorary degree of (1) (2) Ann, 225, 314-8 (1844), Doctor of Science from the University of ManChester (3) WALLACE& O., Bw., 24,1525 (1891); L. Rnsrcna, J . Chem. and an honorary degree of Doctor of Medicine from the Soe., 1587 (1932). , 1591 (1932); 0. WALLACH, "Terpene und University of Leipzig. I n the same year he received an (4) R ~ ~ I C KL.,A ibid., camp he^," Leipeig, 1909 and 1914. honorary Doctor of Engineering degree from the WALLACH,0,,Ber,,28, 1773-7(1895), Braunschweig Technical Institute. I n 1912 he was (6) T ~ F., ibid., ~ 28,~ 1079-93 ~ (1895); ~ F., T~~~~~ IWD honored by many societies: the Verein Deutscher F. SEMMLER, ibid., 29,3027-34 (1896). Chemiker tendered him an honorarv membershiv: (7) J. CHEM.EDUC.,7,1225 (1930). the Deutsche Chemische Gesellschaft elected him to its GENERAL BIBLIOGRAPHY presidency; he was elected an honorary member in the ELLMER, A,, Z. angem. Chem., 44,929 (1931). Soci6tg de Bezgiquel and in November of the (1) (2) WINDAUS,A,, Nachr. Ges. Wiss. Goettingen Gerrehmft. Milt.. same year he was awarded the Day Medal by the Royal 58 (1930-31). Society. (3) Bw. Sekimmel& Co., Akt. Ges (1931).
