Vapour Pressures and Heats of Sublimation of Some Azo Disperse Dyes

The vapour pressures, latent heats of sublimation and associated entropy changes of some azo disperse dyes have been determined by the transpiration method. The compounds have been found to have vapour pressures of 0.00132-0.00315 torr over the temperature range 191.5-211.0 °C. The heats of sublimation are discussed in terms of molecular structure. Paper supplements results on vat dyes published previously by K Nishida, Y Ando, S Sunagawa, A Ogihara, I Tanaka and A Koukitsu (JSDC, Vol. 102, January 86, p. 18)