Conant

Remarkably accurate experimental results have been obtained, also by Kistia-kowsky (Conant and Kistiakowsky, 1937), which permit indirect calculation of the enthalpy change of this isomerization AThe enthalpy diagram for isomcn/atioii of 2-butciic is given in Fig. 5-.5. We shall use TINKER and PCMODEL U) (ind the length of each arrow in Fig. 5-5. We shall also use the PCMODEL GUI. a powerful tool for tile construetion. 

If has long been known that the enthalpy of hydrogenalion of benzene (49.8 kcal moU Conant and Kistiakowsky, 1937) is not the same as three times the enthalpy of hydrogenation of cyclohexene (3 x 28.6 kcal moU ). Evidently, the double bonds that w e write in the Kekule structure of benzene... 

James Bryant Conant, Harvard University, EditOT in-Chief. vu+ioo pages, 6by9J 3 figures. Cloth, 1.50 mt. 

EDITORIAL BOARD Henry Gilman, Editor-in-Chief Roger Adams J. B. Conant... 

Jakes Bbyant Conant, Editor-in-Chief. 100 pages. 

Louis F. Fieser (1899-1977) was born in Columbus, Ohio, and received his Ph.D. at Harvard University in 1924 with James B. Conant. He was professor of chemistry at Bryn Mawr College and then at Harvard University from 1930 to 1968. While at Bryn Mawr. he met his future wife, Mary, then a student. In collaboration, the two Fiesers wrote numerous chemistry texts and monographs. Among his scientific contributions, Fieser was known for his work in steroid chemistry and in carrying out the first synthesis of vitamin K. He was also the inventor of jellied gasoline, or napalm, which was developed at Harvard during World War II. 

Submitted by Kurt H. Meyer. Checked by J. B. Conant and W. C. Boyd. 

Submitted by Arthur Larworth and Wilson Baker. Checked by J. D. Conant and Mildred Evans. 

Mechanistic understanding of azo coupling reactions was initiated by Conant and Peterson (1930) and Wistar and Bartlett (1941) in two pioneering studies done at Harvard University (see Sec. 12.7). 

The best source of information on preparative aspects of coupling reactions is still the book of Fierz and Blangey (1952). Four examples of coupling reactions can be found in Organic Syntheses (Conant et al., 1941, and Fieser, 1943 Azo coupling with 1- and 2-naphthol Hartwell and Fieser, 1943 8-Hydroxy-l-naphthylamine-2,4-di-sulfonic acid Clarke and Kirner, 1941 A/,7V-Dimethylaniline). 

It is well known that the rates of all azo coupling reactions in aqueous or partly aqueous solutions are highly dependent on acidity. Conant and Peterson (1930) made the first quantitative investigation of this problem. They demonstrated that the rate of coupling of a series of naphtholsulfonic acids is proportional to [OH-] in the range pH 4.50-9.15. They concluded that the substitution proper is preceded by an acid-base equilibrium in one of the two reactants, which was assumed to be the equilibrium between the diazohydroxide and the diazonium ion, in other words, that the reacting equilibrium forms are the undissociated naphthol and the diazohydroxide. 

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