The Quiet Revolution "nsd0e8535"

12— Aromatic Chemistry

1. A. W. Hofmann, "Chemische Untersuchung der organischen Basen im Steinkohlen-Theerö1," Annalen , 47 (1843), 37-87. [BACK]

2. Hofmann, "On Insolinic Acid," Proceedings of the Royal Society , 8 (1855), 1-3. [BACK]

3. See Richard Anschütz' discussion, in his August Kekulé , 2 vols. (Berlin: Verlag Chemie, 1929), 1 , 296-305. It is known that Kekulé had read, and disapproved of, the work of both men. [BACK]

4. Kolbe to Frankland, 3 and 17 March 1852, Frankland Archive 01.08.604 and 01.08.610; Kolbe, "Über Synthese der Salicylsäure," Annalen , 113 (1859), 125-127. [BACK]

5. B. W. Gerland, "Über Anthranilsäure, Benzaminsäure, und Carbanilidsäure," Annalen , 86 (1853), 143-156, the work having been done "auf den Rath und unter der Leitung von" Kolbe; note by Kolbe, ibid., pp. 148-149. [BACK]

6. Gerland, "Über Benzaminsäure," Annalen , 91 (1854), 185-198 (on p. 194). We may presume this was Gerland's idea because Schmitt, no doubt reflecting his teacher's view, still expressed faith in the earlier hypothesis in his paper "Vorläufige Notiz über die Einwirkung der salpetrigen Säure auf Sulfanilidsäure," Annalen , 112 (1859), 118-121. [BACK]

7. Schmitt, "Vorläufige Notiz"; Kolbe and Lautemann, "Über die Constitution und Basicität der Salicylsäure," Annalen , 115 (1860), 157-206. Lautemann was at work on the project at least as early as 1859, for Kolbe mentions this in his ''Synthese der Salicylsäure," p. 127. [BACK]

8. Kolbe, "Synthese der Salicylsäure."

9. Ibid.

10. ibid. This is clear from the language in ibid., and also from a statement in Schmitt's paper "Über die Umwandlung der Weinsäure und Apfelsäure in Bernsteinsäure," Annalen , 114 (1860), 106-111 (on p. 111), paper dated 10 March 1860. [BACK]

8. Kolbe, "Synthese der Salicylsäure."

9. Ibid.

8. Kolbe, "Synthese der Salicylsäure."

9. Ibid.

11. Kolbe and Lautemann, "Über die Constitution and Basicität der Salicylsäure," Annalen 115 (1860), 157-206 (on pp. 158 and 161-163). The matter in parentheses is discussed in chap. 9.

12. Ibid., pp. 168-171; Kolbe to Liebig, 16 April 1860, Liebigiana IIB. Modern chemists consider benzyl alcohol to be C 6 H 5 CH 2 OH and cresol to be HOC 6 H 4 CH 3 ; "benzyl" in modem vocabulary is C 6 H 5 CH 2 -, not C 6 H 5 as for Kolbe. [BACK]

11. Kolbe and Lautemann, "Über die Constitution and Basicität der Salicylsäure," Annalen 115 (1860), 157-206 (on pp. 158 and 161-163). The matter in parentheses is discussed in chap. 9.

13. Warren De La Rue and Hugo Müller, "On Some Products of the Action of Dilute Nitric Acid on Some Hydrocarbons of the Benzol Series," JCS , 14 (1861), 54-57; Müller to Kekulé, 15 February 1861, August-Kekulé-Sammlung. [BACK]

14. August Kekulé, "Beiträge zur Kenntniss der Salicylsäure und der Benzoësäure," Annalen , 117 (1861), 145-164 (on pp. 161-164). [BACK]

15. Anschütz, Kekulé , 1 , 77, 82, 124, and 177-182; 2 , 141, 145-146, and 162-186. For a historical discussion and analysis of these events, see A. J. Rocke, "Hypothesis and Experiment in the Early Development of Kekulé's Benzene Theory," Annals of Science , 42 (1985), 355-381, esp. pp. 364-368. [BACK]

16. Kolbe notebook, December 1860, unpaginated, SSDM 3812; Kolbe to Liebig, 21 February and 7 May 1861, Liebigiana IIB; Kolbe to Vieweg, 30 March 1861, VA 167; Kolbe, "Über die Einführung von Wasserstoff in organische Verbindungen und die Umwandlung der Salicylsäure in Galussäure," Annalen , 118 (1861), 122-124. [BACK]

17. Liebig to Kolbe, 1 March 1861, SSDM 3605. [BACK]

18. Kolbe and Lautemann, "Salicylsäure," pp. 187-190. [BACK]

19. Kolbe, Das chemische Laboratorium der Universität Marburg (Braunschweig: Vieweg, 1865), pp. 174-175n. [BACK]

20. S. Cannizzaro, "Über die Zersetzung der Salylsäure durch Aetzbaryt," Annalen , Suppl.-Bd. 1 (1861), 274; R. Fittig, "Über die Oxydationsproducte des Toluols durch verdünnte Salpetersäure," Annalen , 120 (1861), 214-226 (on pp. 222-223); J. Wilbrand and F. Beilstein, "Über eine neue Reihe isomerer Verbindungen der Benzoëgruppe—Nitrodracylsäure und deren Derivate," Annalen , 128 (1863), 257-273 (on p. 273); E. Reichenbach and Beilstein, ''Untersuchungen über isomerie in der Benzoëreihe," Annalen , 132 (1864), 137-155 (on p. 152); idem, "Dritte Abhandlung. Über die Natur der sogenannten Salylsäure," Annalen , 132 (1864), 309-321 (on p. 311). [BACK]

21. Kolbe, "Bemerkungen zu vorstehenden Abhandlungen," Annalen , 127 (1863), 159-161; Max Herrmann, "Über die Einwirkung des nascirenden Wasserstoffs auf Benzoësäure," Annalen , 132 (1864), 75-82; idem, "Über die Veränderungen, welche die Hippursäure in saurer Lösung durch nascirenden Wasserstoff erleidet," Annalen , 133 (1865), 335-338. [BACK]

22. Kolbe, Laboratorium , pp. 169n. and 174-175n. [BACK]

23. C. Saytseff, "Über Paraoxybenzoësäure" Annalen , 127 (1863), 129-137. Zaitsev had been a student of A. M. Butlerov, who had urged him to study with Kolbe. Although I know of no direct personal relationship between the two men, Butlerov clearly respected Kolbe's work and regarded it as structural in orientation. He may have preferred to send students to Kolbe because he was constantly feuding with Kekulé in these years. [BACK]

24. G. Fischer, "Über Paranitrobenzoësäure" Annalen , 127 (1863), 137-149. Fischer, who was from Frankfurt/Main, was in Kolbe's lab in winter semester 1862/63, when he was already Ph.D., and later worked with Rudolf Schmitt in Dresden: JpC , 127 (1879), 318n. I know nothing else about him. [BACK]

25. Wilbrand and Beilstein, "Nitrodracylsäure," p. 269; H. Hlasiwetz and L. Barth, "Über einen neuen, dem Orcin homologen Körper," Sitzungsberichte der kaiserlichen Akademie der Wissenschaften , Wien, 49 :2 (1864), 203-207; N. Sokolov, "Über die Salze der b -Nitrobenzoësäure," JpC , 93 (1864), 425-492; Beilstein and F. Schlun, "Vierte Abhandlung: Über die isomeren Chlorbenzoësäuren," Annalen , 133 (1865), 239-252. [BACK]

26. Fischer, "Paranitrobenzoësäure," p. 149; Kolbe, Laboratorium , p. 175n. [BACK]

27. For citations and a detailed discussion, see Rocke, "Kekulé's Benzene Theory" (see n. 15). [BACK]

28. Kolbe to Erlenmeyer, 25 February 1865, Dingler Nachlass. That Kolbe did not mean this phrase to be complimentary is indicated by his remark to Frankland the following year, playing again on an equestrian figure: Kekulé's "imagination bolted with his understanding long ago" (Kolbe to Frankland, 23 July 1866, Frankland Archive 01.02.1505). [BACK]

29. Rocke, "Kekulé's Benzene Theory," pp. 373-377. [BACK]

30. Ladenburg, "Über das Mesitylen," Berichte , 7 (1874), 1133-1137; idem, Theorie der aromatischen Verbindungen (Braunschweig: Vieweg, 1876), pp. 1 and 28; Kolbe, "Über eine neue Darstellungsmethode und einige bemerkenswerthe Eigenschaften der Salicylsäure," JpC , 118 (1874), 89-112 (on p. 90). See Rocke, "Kekulé's Benzene Theory," and Rocke, "Kekulé's Benzene Theory and the Appraisal of Scientific Theories,'' in A. Donovan, L. Laudan, and R. Laudan, eds., Scrutinizing Science: Empirical Studies of Scientific Change (Boston: Kluwer, 1988), pp. 145-161. [BACK]

31. Kolbe, "Über Ätherschwefelsäuren und ätherschweflige Säuren," Annalen , 143 (1867), 64-72. In this article, Kolbe coined and introduced the word "Alkyl," a contraction of "Alkoholradikal." [BACK]

32. Kolbe, Über die chemische Constitution der organischen Kohlenwasserstoffe (Braunschweig: Vieweg, 1869), p. 5.

33. Ibid., pp. 9-12; Kolbe, Kurzes Lehrbuch der organischen Chemie (Braunschweig: Vieweg, 1883), pp. 365-368. Kolbe had coined the word "methine" to apply to (CH)'" earlier that year; it is still used today by organic chemists with that denotation. [BACK]

32. Kolbe, Über die chemische Constitution der organischen Kohlenwasserstoffe (Braunschweig: Vieweg, 1869), p. 5.

34. Rocke, "Appraisal of Scientific Theories" (see n. 30). In this article I characterized Kolbe's theory, I now believe erroneously, as a noncyclohexamethine theory. [BACK]

35. Adolf Claus, Theoretische Betrachtungen und deren Anwendung zur Systematik der organischen Chemie (Freiburg: Pappen, 1866), p. 208. [BACK]

36. Claus, "Über die chemische Constitution der Diglycolsäure und der Glycolamidsäuren," JpC , 111 (1871), 123-127. [BACK]

37. It could be that Claus recognized the identity of his and Kolbe's benzene formula, but regarded a priority claim as unfruitful for a question so murky. Considering that Claus later argued that his conception of benzene was not in fact a "diagonal" interpretation but rather the same as the much more empirically justified "centric" formula, it may also be that he did not view his and Kolbe's formulas as identical. [BACK]

38. Kolbe, JpC , 111 (1871), pp. 124n. and 134. [BACK]

39. Kolbe, Kurzes Lehrbuch , pp. 373-376. [BACK]

40. Kolbe, Constitution , pp. 11-22; Kurzes Lehrbuch , pp. 367-376. [BACK]

41. Kolbe, Constitution , p. 15. [BACK]

42. Kolbe to Hofmann, 14 December 1868, Chemiker-Briefe; Kolbe to Liebig, 2 February 1869, Liebigiana IIB. [BACK]

43. C. Glaser, "Über die Constitution einiger Zimmtsäurederivate," ZfC , 12 (1869), 111-113; Kolbe, "Bemerkungen zu Glaser's Abhandlung, ZfC , 12 (1869), 160. [BACK]

44. H. E. Armstrong, "The Riddle of Benzene: August Kekulé," Journal of the Society of Chemical Industry , 48 (1929), 914-918 (on p. 914); H. E. Armstrong to Richard Armstrong, 6 February 1870, quoted in J. Vargas Eyre, Henry Edward Armstrong (London: Butterworths, 1958), pp. 51-52 ("my views are diametrically opposite to Kolbe's"). [BACK]

45. Lothar Meyer, Die modernen Theorien der Chemie , 4th ed. (Breslau: Maruschke & Berendt, 1880), p. 263; R. Meyer, Erlenmeyers Lehrbuch der organischen Chemie , Abt. II: Die Aromatische Verbindungen (Leipzig: Winter, 1883-1894), pp. 87ff.; Kekulé, "Zur Geschichte der Benzoltheorie," unpubl. MS (1883), first printed in Richard Anschütz, August Kekulé , 2 vols. (Berlin: Verlag Chemie, 1929), 1, 548. Kekulé also pointed out, as I have above, that Kolbe's benzene formula is structurally equivalent to Claus' diagonal formula, "which is now recognized to be untenable" (ibid., p. 544). [BACK]

46. Kolbe, "Vorläufige Mittheilung," JpC , 116 (1873), 41-42; idem, "Synthese der Paraoxybenzoësäure," JpC , 116 (1873), p. 336; idem, "Über eine neue Darstellungsmethode und einige bemerkenswerthe Eigenschaften der Salicylsäure,'' JpC , 118 (1874), 89-112. [BACK]

47. Kolbe, "Über die chemische Natur der Salylsäure," JpC , 120 (1875), 151-157. That the crucial test was devised and performed in June 1873 is indicated in Kolbe's letter to Volhard, 22 June 1873, SSDM 3662 (where the quoted phrase is found). [BACK]

48. Kolbe, "Chemischer Rückblick auf das Jahr 1874," JpC , 118 (1874), 449-456 (on p. 451-453); Ost, "Über das Verhalten der Chlorsalylsäure, Salicylsäure und Paraoxybenzoësäure gegen schmelzende Alkalien," JpC , 119 (1875), 385-401. [BACK]

49. Kolbe to Bertha Ost, no date, DM 6803; Kolbe to B. Ost, 4 July [ 1880], DM 6804. [BACK]

50. Kolbe to Volhard, 28 September 1873, SSDM 3664. How this view of salylic acid can be reconciled with his crucial test of Beilstein's hypothesis performed three months earlier, and which he regarded then as "unambiguous proof" of the compound's nonexistence, is unclear to me. [BACK]

51. Kolbe to Volhard, 5 October 1873, SSDM 3665; Kolbe to Varrentrapp, 8 October 1873, VA 315. [BACK]

52. Kolbe, "Vorläufige Mittheilung" (30 November 1873). [BACK]

53. In a letter to Volhard of 25 December 1881 (SSDM 3685), Kolbe was still very optimistic that he could identify the pure compound. A letter from Kolbe's assistant G. Schmidt dated 13 March 1884 and sent to his vacation resort on the Italian Riviera (SSDM 3807) reports a number of unsuccessful experiments on this subject. Schmidt concluded that either salylic converts readily to benzoic acid at room temperature or Beilstein was right all along and salylic acid is simply impure benzoic acid. [BACK]

54. Kolbe to Varrentrapp, 1 January 1874, 11 March and 17 July 1875, VA 316, 326, and 332; Kolbe to Frankland; 1 January 1874, Frankland Archive 01.03.604; Ernst von Meyer, Lebenserinnerungen (n.p., n.d., ca. 1918), pp. [BACK]

55. Wilhelm Vershofen, Wirtschaftsgeschichte der chemisch-pharmazeutischen Industrie: Eine wirtschaftshistorische Studie , 3 vols. (Aulendorf: Cantor, 1949-1958), 3 , 52. [BACK]

56. Kolbe's expected production cost is mentioned in Kolbe to Frankland, 1 January 1874 (Frankland Archive 01.03.604); retail price is mentioned in JpC , 119 (1875), 219. By 1878 the price had dropped to around 2½ thalers per pound (Schlenk, Fabrik , p. 25). For the sake of comparison, commercial grade salicylic acid today (1990) sells at retail for about $7 per pound. [BACK]

57. A London entrepreneur attempted to evade fees by patenting the novel process in England and licensing production to Merck in Darmstadt, the product then being imported and sold in England. Kolbe and Heyden sought an injunction, which was granted; Armstrong's testimony for the plaintiffs then won the appeal. Merck had been selling salicylic acid in England at 7s. 6d. (equivalent to around two thalers) per pound. See Law Times Reports , 42 (8 May 1880), 300-303. [BACK]

58. All of this is related in Kolbe's letter to Frankland of 15 November 1878 and 3 May 1879 (Frankland Archive 01.04.381 and 01.07.357); see also Heyden's appreciative letter to Frankland, 26 November 1878 (Frankland Archive 01.04.0386). The Prussian litigation was with E. Schering's firm in Berlin; both sides publicized their dispute in pamphlets published in 1876 and 1877. See Vershofen, Wirtschaftsgeschichte , 3 , 25-26; Schlenk, Fabrik , p. 25; and Kolbe to Varrentrapp, no date (but ca. 11 April 1875), VA 327. [BACK]

59. R. Schmitt, "Beitrag zur Kenntniss der Kolbe'schen Salicylsäure-Synthese," JpC , 139 (1885), 397-411. [BACK]

60. Kolbe, "Eigenschaften der Salicylsäure"; "Weitere Mittheilungen über Wirkungen der Salicylsäure," JpC , 119 (1875), 9-23; idem, "Ist anhaltender Genuss kleiner Mengen Salicylsäure der Gesundheit nachtheilig?" JpC , 125 (1878), 347-350; Kolbe to Vieweg, 12 and 15 October 1878, VA 421 and 422 (quoted passage from VA 421). A gram of salicylic acid is equivalent to about three modern aspirin tablets. Kolbe's habit may well have lengthened his life, if one makes the likely assumption that salicylic acid shares aspirin's anticoagulant properties. Seven years after beginning this daily habit, Kolbe died of a heart attack caused by severe atherosclerosis. [BACK]

61. Kolbe, "Bemerkenswerthe Eigenschaften," pp. 108-111; "Weitere Mittheilungen," p. 18; Meyer and Kolbe, "Versuche über die gährungshem-mende Wirkungen der Salicylsäure und andere aromatischen Säuren," JpC , 120 (1875), 133-151; idem, "Über die antiseptischen Wirkungen der Salicylsäure und Benzoësäure in Bierwürze und Harn," JpC , 120 (1875), pp. 178-203; Kolbe, ''Chemische Winke für praktische Verwendungen der Salicylsäure," JpC , 121 (1876), 106-120; idem, "Zerstörende Wirkung der Holzsubstanz auf Salicylsäure," JpC , 129 (1880), 443-447 and 130 , 112; idem, "Antiseptische Eigenschaften der Kohlensäure," JpC , 134 (1882), 249-255. Otto

Krätz reproduces extensive excerpts on this subject from Kolbe's laboratory notebooks from the years 1874-1880 in his Historische chemische und physikalische Versuche (Cologne: Aulis Verlag Deubner, 1979), pp. 198-201. [BACK]

62. Ost, HK, p. 130. [BACK]

63. Carl Thiersch, "Klinische Ergebnisse der Lister'schen Wundbehandlung und über den Ersatz der Carbolsäure durch Salicylsäure," Volkmann's Sammlung , nos. 84 and 85, 1875. [BACK]

64. Kolbe, "Bemerkenswerthe Eigenschaften," pp. 111-112; "Weitere Mittheilungen," p. 19; "Weitere Mittheilungen über Wirkungen der Salicylsäure," JpC , 119 (1875), pp. 213-215; Kolbe to Pettenkofer, 26 March, 20 November, and 26 December 1874, Pettenkoferiana II 2, Bayerische Staatsbibliothek; Kolbe to Varrentrapp, 3 August 1874, VA 322. [BACK]

65. Kolbe to Varrentrapp, 10 August and 9 October 1875, VA 333 and 334. [BACK]

66. W. Walter Cheyne, Antiseptic Surgery: Its Principles, Practice, History and Results (London: Smith, Elder, 1882), pp. 136-139 and 404; Just Lucas-Charbonnière, Antiseptic Surgery , 2d ed. (Portland: Loring Short & Harmon, 1881), pp. 227-228. [BACK]

67. Jan R. McTavish, "Aspirin in Germany: The Pharmaceutical Industry and the Pharmaceutical Profession," Pharmacy in History , 29 (1987), 103-115. [BACK]