Ian;

I know nothing about benzene sulfonate itself as an antioxidant.

As for the properties of benzene sulfonates or p-tosylates as antioxidants or as helpers in dissolving, it is known from fundamental chemistry that organic aryl amines (metol, pAP, and PPDs) all oxidize rapidly as free bases and dissolve slowly as free bases. If they are predissolved in an equmolar solution of ANY acid, then they dissolve much more rapidly in water and they are much more resistant to aerial oxidation

The key to this is pH though and not antioxidant properties of the benzene sulfonate or p-tosylate. Sulfuric acid was used and before that Hydrochloric Acid was used. Nowdays the develoer is dissolved in the sulfonate solution and this has been saturated with SO2 gas. The SO2 gas is the true antioxidant as is the pH an assist in achieving this effect.

This is true of all Kodak, Fuji and other color developer kits for C-41 and E6 alike.

We were in the process of converting when I was working on the CD-6 problem and I had to convert all of my molarity tables due to the difference in molecular weight of the two salts, the H2SO4 salt and the p-Tosyl salt. I used to get the developers in powder or crystal form and had to dissolve them in water with Sulfite. Remember the "pinch of sulfite" rule in making Metol containing developers?

And, these p-Tosyl salts are major chemical contributioins.

BTW, benzene sulfonic acid is (C6H5)-SO3H and p-Toluene Sulfonic Acid is CH3-(C6H4)-SO3H, differing by CH2 only and it is expressed as a CH3- replacing one H-. They are virtually identical. But, benzene and napthalene sulfonates as sodium salts, especially with ballast groups are better known as detergents.

PE