Jozef Frans Willems

Developing Properties of Alkylhydroquinones and Alkylhydroquinone Sulphonic Acids

AbstractThe developing activity of alkyl-substituted hydroquinones and alkyl-substituted hydroquinone sulphonic acids, alone, as well as in combination with l-phenyl-3-pyrazolidinones, was examined at pH-values of 9·5 and 12. The developing activity of the alkylhydroquinones and the alkylhydroquinone sulphonic acids surprisingly increases quickly with growing length of the alkyl groups. Addition of l-phenyl-3-pyrazolidinones practically eliminates all differences in developing activity in both series.The results obtained indicate that adsorption phenomena play a prominent part in these developing agents. The introduction of alkyl groups with increasing number of carbon atoms considerably reduces the hydrophilic character of the hydroquinones and the hydroquinone sulphonic acids. These compounds manifest a growing tendency to leave the solution and become adsorbed onto a substratum. In some cases, this tendency to become adsorbed would be great enough to overcome the Coulomb’s repulsion so that rapid devel...