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A study has been made of the equilibrium with, and rate of diffusion into, wool keratin fibres of (i) hydrochloric acid and (ii) the free acid of Orange I1 @-naphthol-azo-p-benzene sulphonic acid). The effect of temperatures and concentration has been examined and the results analyzed from a thermodynamic viewpoint. The entropy term TAS was found to provide the major contribution both to the equilibrium free energy AG" of desorption and to the activation free energy AG* of diffusion at the temperatures (60"-100" C ) which are usual for the acid dyeing of wool, These phenomena can be attributed to the effect of the solvent (water) whose negative affinity for the dye accounts for the fibre having a large positive affinity, and whose hydration of the polar groups adds to the barrier to diffusion.

The chemical reactivity of 3-chloro-3-cephems was found to be similar to that of the correspondingly substituted 7-aminocephalosporanic acids and 12-13 times greater than that of the correspondingly substituted 7-aminode-acetoxycephalosporanic acids. Cefaclor, 7-(D-2-amino-2-phenylacetamido)-3-chloro-3-cephem-4-carboxylic acid, was found to undergo intramolecular nucleophilic attack at the beta-lactam. Loss of chlorine from 3-chloro-3-cephem may be a general reaction subsequent to beta-lactam opening.

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