David H. Wilcox, Jr. Tennessee Eastman Company Kingsport, Tennessee and Frederick R. Greenbaum 14 south Kniqht - Avenue Margate City, New Jersey
Kekule's Benzene Ring Theory
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A subject for lighthearted banter
The impact of Kekul6's simple elucidat,ion of the structure of benzene1 and its related derivatives was tremendous at, the time; since then it has been of inestimable theoretical and practical value. There have been celebrations in the past to the man and his work, but one in particular st,ands out, as it was unusual and singular. August ICekul6 served as president of the Deutsche Chemisehe Gesellschaft, (Gennan Chemical Society) in 1886, and in the fall of that year there appeared a delightful little spoofing pamphlet entitled "Berichte der Durstigen Chemischen Gesellschaft, Unerhorter Jahrgang, No. 20. (Ausgegeben am 20. September.)" [a "Report of the Thirst,y Chemical Society, unheard of volume, No. 20. (issued on September 20.)"].2 The chemical indust,ry in the unified Gerinany had made great progress, and was beginning to reap the rewards for their successes. The contributions made by Iiekul6, his shdents and associates both in and out of the universities were recognized and appreciated. Since those in the dye industry benefited most3 it is easy to suspect that thrse literary monkey-shines were written by dyest,ained hands. Only the verses and songs bear the ir~it,ialsof either "E. J." or "0. N. W.," which stand for Elnil Jacobsen and Otto N. Witt-two dye chemists. There are many subject,^ emcoinpassed in this "Durst,igenl' issue, and one in particular draws our attention not only because of its author and title, but also for its titilating content as exemplified by the following rendition: F. W.
Findig:
Contribution to the Constitution of Benzene
Received June 81, 1886 The question of the constitution of benzene has occupied the minds of some of the greatest chemists now for quite a long time. Under these circumstances, I cannot resist taking part in a discussion of this problem. I t is clear that the viewpoint 1 His views were published in a series of six articles over a. year's time. The first was read a t Perk on January 27, 1865, and t,he last was published February 8, 1866, in Germany. The final paper, "Untersuchungen iiber aromatische Verbindungen," was published in the Annalen der C h m i e und Pharmacie, 137, 129 (1866). 2 The pamphlet contained 56 pages, and was printed in the s:tme format and type as the usual "Beriehte." A long search ended when a copy was found a t the University of Virginia. Attest,ing to its rarity, Professor John Reid st,ates that the published price was 1 mark, but that s. copy sold for 80 marks in Germany 50 years later. a In the single year of 1886, when the pamphlet appeared, some 36 new colors were produced in the German dye factories which were successful enough to be listed as in production 38 years Inter. From this group Brilliant Yellow, Chrysophenine, Deltapurpurine 5B, Methylme Green and Stilbene Yellow are still vnluahle colors after 78 years.
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from which the constitution of benzene has been considered was rather shortsighted and insufficient. I have looked for s new viewpoint and have made use of the principle that the sciences are mutuelly helpful. I have found that zoology is perhaps the most welcome aid in understanding the behavior of carbon atoms.4 I shall try to clarify this point for the reader, although I doubt very much that he will even then be able to comprehend this relationship. Just as the carbon atom possesses four affinities, so also do the memhers of the monkey family possess four hands with which they can grasp other objects and with which they can hold on tightly. If we now take a group of six members of the monkey family, for instance, the Mameus cynocephalta, and have them form s, ring among themselves by dternatingly reaching with one hand and with two hands then this formation presents a complete analom of Kekul6's benzene hexagon as shown in Figure 1. Besides the four hands, the Maearns C~nocephalusalso pvssesses another grasping tool in the form of a caudal appendix. If one takes this into consideration then the six animals can now form a. ring in a different manner also as is shown in Figure 2.
Journal of Chemical Education
Figurer reproduced from "F. W. Findig's" article.
I t seems to me that this analogy between the Maeaeas curiocephalus and the carbon atom is perfect. In that case every carbon atom possesses a caudal appendix whlch while it cannot be counted as a regular affinity is, however, quite well suited
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There has been some curiosity as to whom "F. W. Findig" might be, and Anschiita thinks that it was Otto PI'. Witt (ANS C H ~ ~ T Z . R I C H ~ D , "August Kekul6," To!. I , \-erlag Chemie, Berlin,'1929, p. 610). ~ e c e n t l ythe following quotation was found in an address of Witt's which supports this opinion: "If we consider how our present chemical industry has been evolved from empirical processes such as our anrestors practiced them . . . we can easily observe a. gradual transformntion similar in many respects to the one that living nature had to go through in evolving the present types of plant and animal life. I t is here that the parallels between biology and chemistry oRer themselves." [ J . Sue. Chrm. Ind. 28,921 (1909)l.
for grssping or linking with other atoms. As soon aa this appendix, to which I have given the name caudal residual affinity, comes into play we can have a second form of Kekulh's hexagon, which is obviously different fmm the first form and must of necessity behave differently. Depending on the situation in which the benzene ring finds itself, it will take on either the one or the other form and, therefore, will have a constantly changing constitution. This is a remarkable case of "Tautomerie"'; a better one could not be imagined. The hypothesis that a molecule may change its constitution to fit most comfortably the needs of the chemist
experimenting with it, is one of the greatest sccamplishrnents of the critically exploring human brain and when applied to the benzene theory is a guiding st= for future research! SCHNURRENBURUMIXPICKEL, PRIVATE LABORATORY, May, 1886.
" This is the correct spelling for this new scientific word introduced by me. The spelling "Traute Marie" [Sweet Marie] belongs to the realm of malicious inventions, as doea its cxplenation, as the nickname I am supposed to have given my favorite hypothesis.
Volume 42, Number 5, M a y 1965
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