The New Complexion of Organic Chemistry

A final brief case study from this period further illustrates the new atmosphere in the discipline and is one more curious instance of hot pursuit by simultaneous workers on a set of fruitful new structural in-

vestigations. A variety of actors were involved: Hugo Müller, a student of Wöhler and Liebig, assistant to Warren De la Rue and a close friend of Kekulé from his London years; Hans Hübner, a student of Wöhler and of Kekulé before becoming Privatdozent at Göttingen; Wurtz' protégés Lieben, Friedrich Beilstein, and Maxwell Simpson (the latter also a former Kolbe student); and Simpson's British countrymen Crum Brown, W. H. Perkin, and Duppa. The relevant reactions all involved the Kolbe-Frankland technique of replacing halogen with cyanide, then hydrolyzing the cyanide to carboxyl. The net effect of this sequence is to replace a halide with a carboxyl group, thus adding a carbon atom. By such means, the chlorine in Kekulé's monochloroacetic acid could be used to form a second carboxyl group and so transform acetic to malonic acid; an analogous route, apparently, could transform propionic to succinic acid—in short, monoacids into diacids. A closely related route is to start with ethylene bromide, which would give rise to succinic acid by double hydrolysis. Working with Kekulé in Ghent in 1862, Hübner published on cyanoacetyl compounds, but did not report hydrolysis to malonic acid. About the same time, Simpson published on the ethylene bromide to succinic acid route.^[74]

From the summer of 1863 to January 1864, Kolbe described in letters to Frankland his work on this kind of malonic acid synthesis; he mentioned that on 17 January 1864 he had learned that his former student Crum Brown was working on the same problem. (Crum Brown's project in Kolbe's lab in 1862 had concerned diacids). On 12 February Kolbe sent Frankland and Erlenmeyer identical copies of a preliminary notice, with the request that the former translate and communicate it to the very next meeting of the Chemical Society, and the latter print it "as soon as possible ."^[75] Erlenmeyer dutifully inserted the note into the next issue of his Zeitschrift für Chemie , and Frankland had the paper read in English at the Chemical Society on 18 February.^[76]

Two days later a few unnamed Marburgers visited Göttingen and informed Hübner of Kolbe's work. Hübner, who thought he had reserved the topic to himself by his earlier publication, was indignant and crestfallen over all the effort he had now spent in vain in trying to isolate pure malonic acid product. Beilstein, then a fellow Göttingen Privatdozent, was nearly as angry. He described the affair in a letter to Kekulé, with whom he had studied in Heidelberg before going to Wurtz, saying that Kolbe had "stolen" malonic acid from Hübner in the "unkindest possible manner." The situation was even worse than it may seem, Beilstein continued. In the fall of 1863 he had visited Marburg; Kolbe had asked him about Hübner's work and how far along it was, and Beilstein had reported to Kolbe fully and freely. A few short months later, Kolbe was now claiming the reaction as entirely new.^[77]

Kekulé immediately reported the scandal to friend Müller in Lon-

don, for he knew Müller was interested in the diacids. Müller responded by confessing to Kekulé that he had "committed the same sin as Kolbe, by preparing not only malonic acid, but also succinic acid." He had been working for some time on this reaction, he said. He remembered Hübner's work on similar approaches, but it had not given clean results and had not been continued; in any case, he knew of no publication by Hübner on cyanoacetic acid, which was the important point. He also happened to know that Perkin and Duppa were working on the same reaction, but so far without success. He happened to have been present at the meeting of the Chemical Society on 18 February when Kolbe's note was read on this very subject. He was disconcerted, but had the presence of mind to report extemporaneously on his own results; the Society then resolved to published Kolbe's and Müller's notes together.

Ultimately this is a dirty trick, but I squandered the synthesis of succinic acid from ethylene [as Simpson's paper had already appeared]; the synthesis [of succinic] from propionic acid I intend to hang on to as tightly as possible. Kolbe may well be angry that I am contending with him about the further development of his own reaction, namely the introduction of CO₂ by the intermediate unit CN. In any case, I believe I can only do what my duty and obligation is. I am now working on preparing mono- and dibromosuccinic acid, possibly in order to produce the acids C₅ H₆ O₆ and C₆ H₆ O₈ . I hope that ultimately I don't end up by encroaching on you in this direction.^[78]

Frankland reported the events of 18 February to Kolbe. Kolbe responded by sending Frankland a letter to deliver to Müller proposing a collaborative approach. But in his cover letter to Frankland, Kolbe expressed concern that he might be too trusting. Was Müller a "Gentleman"? Perhaps Frankland should just keep the letter. "From what I hear, Müller is a good friend of Kekulé's, whom I do not consider a gentleman. I confess, this friendship between Müller and Kekulé makes me a bit doubtful. I place the matter entirely in your hands."^[79] Frankland did deliver Kolbe's letter, and Müller agreed to Kolbe's proposal. Müller's article appeared together with Kolbe's in the April issue of the Journal of the Chemical Society , and they resolved to stay in touch about their research plans. They subsequently agreed that Kolbe would henceforth work on cyanoacetic and cyanomalonic acids, and Müller on dicyanoacetic and cyanosuccinic acids.^[80]

Three months later Beilstein reported these events to Adolf Baeyer, whom he had befriended while both were working in Kekulé's Heidelberg lab in 1857. Not only had Kolbe acted unethically toward Hübner, Beilstein thought, but Simpson had also stolen a closely related

reaction from Adolf Lieben. (Beilstein claimed to know this because he had been Simpson's neighbor in Wurtz' lab in 1858-1859, where Lieben also then worked.) Finally, Beilstein claimed that Müller had behaved even worse, for Beilstein knew (presumably through Hübner) that Hübner had told Müller directly about his work on this reaction as early as the fall of 1861.^[81] Müller also failed to keep his word to Kolbe, publishing an article in the summer of 1864 on the reaction of trichloroacetic acid with potassium cyanide without letting Kolbe know. Kolbe was understandably wroth, and contact between the two ceased.^[82]

It is diffcult to assess blame in such matters at this distance of time, nor for our purposes is it useful or necessary to do so. What seems clear, at least, is that the practice of organic chemistry had suddenly become far more ruthless than it had ever been, and traditional customs of courtesy and ethics were often slighted or even ignored. Müller provided an appropriate postscript to all of this in a letter to Kekulé: "Doing chemistry these days is an accursed business; you never know when you are going to be overtaken by someone else."^[83] Kolbe and Erlenmeyer were not necessarily being paranoid when they speculated that some scientists used collegial visits to rival laboratories for espionage purposes.^[84]

Beilstein's complaint was slightly different, but rooted in the same phenomenon:

Everywhere we see indicated isomerisms and possibly existent compounds, which are becoming so numerous that even all the masses of material now known appears by comparison as but a drop. I was involuntarily reminded of the old saying, "Organic chemistry is the science of nonexistent bodies." Do these billions of compounds really exist? . . . I could never imagine that the dear Lord would want to make life so hard for chemists.^[85]

Beilstein was fundamentally nontheoretical and was genuinely distressed at the sudden diversity. He criticized Butlerov's textbook privately for making too many predictions of novel structural isomers. "Our students are already frightened by the mass of material; imagine their faces when they have predicted for them the existence of God knows how many additional compounds. . . . I am firmly convinced that experiment will considerably diminish the numerous isomerisms."^[86] Liebig's reaction was not very different; he wrote to Hofmann, "Through isomerisms, organic chemistry is gradually becoming enough to make one mad."^[87] The explorers of Wöhler's primeval jungle were emerging with daunting numbers of new chemical species.

Whether the issue was subtle distinctions between predicted be-

havior of polyfunctional compounds (as in the matter of lactic acid derivatives), or a sudden proliferation of similar isomers, all of which had to be interpreted according to structure-theoretical precepts, and many of which were being worked on simultaneously (such as the new alcohols), or cases of multiple discoveries of new reactions with consequent hurt feelings and priority disputes (as in the diacids), the new pattern was clear. Chemistry, particularly organic chemistry, had seen a sudden acceleration, essentially an explosion, datable to around the year 1860. This acceleration produced noticeable changes in the way work was done and reported, and was felt by all who were active in the field.