Infra-Red Spectrum and Molecular Structure of Phthiocerane

Abstract

THE properties of phthiocerane, the hydrocarbon derived from the wax alcohol phthiocerol^1,2 of the tubercle bacillus, for a pure specimen of which we are indebted to Prof. R. J. Anderson, Yale University, indicate a branched-chain structure³, probably a long chain with a methyl side-chain near one end⁴. For comparison with phthiocerane, a series of hydrocarbons having a total of 34, 35 and 36 carbon atoms*, with a methyl side-chain in position 2-, 3-, 4-, or 5- from one end, have been synthesized at Uppsala, partly by the use of new synthetic methods⁵. The melting points of the synthetic hydrocarbons are plotted in Fig. 1 (the data for the n-hydrocarbons (1-methyl) are from Piper et al.⁶). The 2-methyl compounds melt at much higher temperatures than phthiocerane, and also differ in thermal behaviour and crystal structure (crystallize when pure only in tilted forms). The 3-, 4-, and 5-methyl substituted hydrocarbons, on the other hand, crystallize from acetone like phthiocerane with vertical chains, and also behave similarly on melting and solidification.