Abstract

The interaction of a specially purified hide powder and each of three pure components of syntans has been investigated by determining the distribution of the aromatic acids at equilibrium at ten or more points on the titration curve. The following mean affinities (kcalfmole) were thus obtained at 25c and 452c, respectively: Schaeffer acid, —76 ± 03, —77 ± 04; Methylene Schaeffer acid, —169 ± 04; and Tanigan Supra LL, —173 ± 06, —178 ± 06. Heats of tanning were calculated from these results and they and the affinities are compared with those derived by other procedures and those obtained by Reich and SieberL. it is concluded that, within the present accuracy of determination, thermodynamic parameters do not provide clear pointers to tanning behaviour.