Wurtz
(Charles) Adolphe Wurtz was born on 26 November 1817, the eldest son of Jean Jacques Wurtz and the former Sophie Kreiss. The elder Wurtz, the only child of a "simple bourgeois family" of Strasbourg, became a Lutheran pastor in Wolfisheim, a small village three miles west of the city; Sophie's father, also named Jean Jacques (Johann Jakob), was also a Lutheran pastor, at the church of St. Pierre-le-jeune in Strasbourg. It is said that Adolphe's boyhood in Wolfisheim provided him with both a robust constitution and a love of the countryside. He spoke Alsatian with his family, but learned French and Hochdeutsch in his youth (he is said to have spoken both languages without a trace of regional accent).[33]
The parallels here to Hermann Kolbe's family background and up-
bringing are remarkable. Born less than a year apart, both died in 1884 at the age of sixty-six. Despite their different nationalities, both were raised in German-speaking households of the same social class; both were eldest sons of Lutheran country pastors who led congregations in small towns near important university cities. Both remained sincere Protestants and became outspoken nationalists in their later years.
In 1826 Wurtz' father was called to Strasbourg as third pastor at his father-in-law's church, and Adolphe entered the Strasbourg Protestant Gymnasium. His father wanted him to enter the ministry, but Adolphe had conceived a passion for science. As a sort of compromise, Adolphe was allowed to study medicine, entering the Strasbourg Faculty of Medicine in 1835. Between 1839, when he was named the faculty's Chef des travaux de chimie, and his departure for Paris in 1844, he worked mostly in the laboratory of Amedée Cailliot (1805-1884). He also spent five months (summer semester 1842) at Liebig's laboratory in Giessen, and he always considered Liebig as one of his mentors. In the spring of 1844, he went to Paris seeking a chemical career. He started with Balard at the Faculté des Sciences, then after a year was appointed Dumas' préparateur at the Faculté de Médecine. Simultaneously he accepted the post of Chef des travaux chimiques at the École Centrale des Arts et Manufactures, founded by Dumas sixteen years earlier. He soon became Dumas' favorite and ultimately was to inherit the mantle of the master.
Of course, fellow Strasbourger Charles Gerhardt was also a presence in Wurtz' early years. Most biographers note, correctly, that Gerhardt and Wurtz were schoolfellows at the Strasbourg Gymnasium and that Wurtz translated Gerhardt's first book, the Précis (1844-1845), into German. The conclusion has often been drawn that Wurtz came to Paris already in the Gerhardt-Laurent orbit, against the established ideas of such figures as Liebig and Dumas.[34]
The situation was quite the opposite. Although Gerhardt was only fifteen months older than Wurtz, he was two Gymnasium classes in advance and left a year earlier than was normal, when Wurtz was but thirteen years old; they appear not to have become acquainted then.[35] Moreover, Wurtz did not offer to translate Gerhardt's book from a position as disciple. Rather, on a trip home in 1842, Gerhardt inquired of Cailliot regarding an appropriate bilingual Alsatian chemist; Cailliot recommended Wurtz, who was happy to do the work both for the chemical interest and for the money involved.[36] Gerhardt was in Montpellier for the first four years after Wurtz arrived in Paris, and even after Gerhardt returned to Paris in 1848, Wurtz saw little of him. Wurtz scarcely knew Laurent personally.[37] During Gerhardt's lifetime, Wurtz never adopted the new chemical "equivalents" championed in the Pré-
cis . Finally, at the time Gerhardt began work on the Précis and hired Wurtz as translator (1842-1843), he was still on good terms with Liebig. He was rightly seen as a disciple of both Liebig and Dumas and had not yet joined forces with Laurent.
By agreeing to translate Gerhardt's Précis , Wurtz was not declaring his allegiance to Gerhardtian ideas, and those ideas had not yet been labeled as heretical. Rather, he was accepting an assignment that might well lead to professional advancement, as well as providing much needed income. By the time Wurtz finished his translation in 1846, open warfare had broken out between the Gerhardt-Laurent alliance and the uneasy Dumas-Liebig axis, but Wurtz could not have foreseen this situation four years earlier. In short, all the evidence suggests that in the 1840s and early 1850s, Wurtz was a loyal adherent of the established chemical theories of Liebig and especially of his patron Dumas.
Wurtz' early work illustrates many of these ideas. In Liebig's lab he investigated hypophosphorous acid, presenting the results in terms of Liebig's hydracid theory (and also citing Liebig's predecessors Davy and Dulong).[38] Wurtz' first papers after his association with Dumas exhibit a distaste for dualist ideas and a concern for merging organic and inorganic chemistry under unitary assumptions. They also contain references to Dumas' "edifice" analogy for molecular structure (despite conventional empiricist protestations). Wurtz even proposed PCl3 as the "type" of most phosphorus compounds—choosing a word that had been used in 1839 and 1840 by Liebig as well as Dumas.[39]
As we have seen, from about 1840 both Liebig and Dumas simultaneously and apparently independently retreated from the new directions they had been heading. Both began to pursue more practical and purportedly less theoretical subjects such as agricultural and physiological chemistry. Liebig turned away from his unitary hydracid formulations toward more dualistic oxide formulas. In 1844, Liebig shifted from four-volume Berzelian atomic weights, which he had been using for fourteen years, to Gmelin's four-volume conventional equivalents. In approximate modern terms, this was equivalent to moving from doubled molecular formulas to formulas with doubled numbers of even-valence atoms but correct numbers of odd-valence atoms. This shift was connected to the other changes since the new formulations were regarded as perfectly empirical, in contrast to Berzelius' theoretically derived atomic weights.
For several years, Wurtz mirrored the ambivalence of Liebig and Dumas. On the one hand, he continued to advocate substitutable radicals and the unification of organic and inorganic formulas. On the other hand, he followed Liebig's "empiricist" atomic weight shift of
1844 and continued to use many of the formula conventions attacked by Gerhardt and Laurent. For instance, his novel substance "ammoniacal cyanic ether" (modern ethyl isocyanate, C2 H5 NCO) was written C2AzO,C4 H5 O ,AzH3 , a formulation that reflects an implicit dualism as well as incompatibility with Gerhardt's new atomic weights and with his constitutional ideas.[40] This example is not an arbitrary one: alkaline hydrolysis of this substance led to Wurtz' first major discovery, ethyl-amine, in 1849. It was the first primary amine, indeed the first amine of any kind to be recognized, and the progenitor of an immense number of synthetic organic bases.[41]
Hofmann provided an interesting gloss on this event. Hofmann and Wurtz had become good friends during Wurtz' stay in Giessen in 1842, where Hofmann was assistant to Liebig. From 1847 they had the opportunity to see each other regularly, for Wurtz had frequent occasion to visit his sister and her husband in England, and Hofmann, who was professor at the Royal College of Chemistry in London from 1845, found himself often in Paris.[42] Moreover, they had a major chemical interest in common, namely, organic' bases. Hofmann related that Wurtz had missed the discovery of ethylamine for quite some time since he was assuming that hydrolysis of the ethyl isocyanate ought to proceed analogously to the recently published Frankland-Kolbe hydrolysis of ethyl cyanide, that is, to yield propionic acid and ammonia. Thus, reasoning on the basis of the copula theory, Wurtz assumed that the ammoniacal gas released in the reaction was simply ammonia, and he was long mystified at being unable to isolate any sort of oxidized hydrocarbon in solution. It was only when this gas happened to ignite from a fortuitous flame that light shone in Wurtz' mind, as at his laboratory bench: the gas was in fact the chief product of the reaction, an ethyl-substituted ammonia. Wurtz quickly published the result, commenting that ammonia now could be regarded as the "type" for perhaps all organic bases. Wurtz was only repeating the very words of Liebig, who nine years earlier had predicted the existence and even the properties of ethylamine.[43]
Hofmann, who had been working on substituted anilines, felt he had been forestalled; in a letter to his mentor, he remarked on Liebig's clairvoyant prediction. In his reply Liebig also expressed some chagrin, for he had read Wurtz' paper without even remembering his own earlier remarks, and it was only Hofmann's letter that had brought them to mind (a revealing indication of his disinclination toward chemical theory after 1840). "I was so enchanted by Wurtz' work," he added, "that I wrote him and congratulated him on such lovely discoveries. . . ." He went on to say that Hofmann's studies on aniline had been "very interesting . . . every new compound is the first member of
a new series of homologous compounds, and the thought from which the compounds arose is like a seed corn, which bears its fruits in the minds of others doing similar work."[44] Late that year (1849), Hofmann wrote Liebig about his latest syntheses, the details of which were soon to appear in a major paper published in the Philosophical Transactions: secondary and tertiary amines. "These are incredibly remarkable things you have discovered"; Liebig responded, "we are all ecstatic over them. . . . These are very valuable experiments and fully conducive to lead to a definitive view [of the constitution of the organic bases]. . . . This is not a small jump out in front of the French, although I do not mean thereby to include our friend Herr Wurtz."[45] But it was indeed Wurtz' turn to feel forestalled.
The competition between Hofmann and Wurtz in no way affected their friendship. Indeed, in March or early April 1850, Hofmann visited Wurtz in Paris; he not only had a delightful time seeing the sights with his comrade, but described the trip in amazing detail in his biography of Wurtz many years later. During this trip, Baron Thenard hosted a dinner party in Hofmann's honor; his son Paul introduced the company to Hofmann with the words, "Voilà tousles jeunes chimistes de Paris, moins les deux. " Hofmann related this incident in a letter to Liebig, commenting that "this is characteristic of the general mood that has gradually formed in France," that is, against Gerhardt and Laurent.[46]
The relationship between Gerhardt and Wurtz was never more than coolly correct. Gerhardt felt a degree of resentment, bordering on animosity, that the younger Wurtz was so favored by the powerful Dumas: Wurtz was made agrégé (loosely, assistant professor) at the Faculté de Médecine in 1847 and then took over Dumas' lectures on organic chemistry two years later, simultaneously continuing his duties at the École Centrale, all while Gerhardt was without any official position. Particularly galling was Dumas' almost fulsome praise in an official report on Wurtz' papers on amines, when in fact Gerhardt felt that Wurtz had used some of his own work without acknowledgment.[47] "Quelle chance il a, çe garçon," he later exclaimed to a correspondent.[48]
In a major summary of the chemistry of the new aliphatic amines that appeared at the end of 1850, Wurtz tried to apportion proper credit to his predecessors and competitors, especially Hofmann and Gerhardt—which he had certainly not previously attempted. In a theoretical conclusion he argued, as Hofmann had earlier that year, that his and his colleagues' results could most easily be explained by expanding Liebig's amidogen theory to include secondary and tertiary amines, in which alkyl radicals such as methyl, ethyl, propyl, and butyl
substitute for hydrogen atoms in ammonia. He also argued that these results were fully compatible with, indeed provide further support for, Kolbe's idea that the homologous organic acids were alkyl radicals substituted for the nonbasic hydrogen of l he simplest acid (although that series progenitor he took, following Gerhardt, to be formic rather than oxalic acid). He also strongly affirmed, with Kolbe, that the elements that form organic molecules are not thrown "pell-mell, without order, without arrangement, without predisposition" (as Gerhardt had sometimes implied), but rather are arrayed in a definite and ordinarily stable structure. He felt that determining those molecular constitutions was one of the most important goals of chemical theory.[49]
The early 1850s were a busy time for Wurtz. He relinquished his position at the École Centrale to open a private chemical laboratory school and to take a position at the short-lived Institut Agronomique in Versailles. The lab school folded in 1851, and the Institut was closed the next year. In the meantime, Wurtz courted and wed Constance Opperman, the daughter of a wealthy Paris banker. At about this time (the beginning of 1852), Dumas decided to take advantage of Wurtz' linguistic skills and his German and English connections by inviting him to prepare abstracts of selected foreign articles for every monthly issue of the Annales de chimie . Finally, in 1853 Dumas retired from teaching in the Faculté de Médecine; Orfila's death at almost precisely the same time (12 March) gave Wurtz two chairs in the Faculté, along with the financial and career security he had been seeking.