I have found that propylene glycol can be formed by heating glycerol to 302 F in the presence of a catalyst, which may be either an ion exchange resin or a small amount of sulfuric acid. In the process of heating Metol in glycerol, the sulfuric acid attached to the Metol was detached and served as a catalyst, and what I may have is Metol base in propylene glycol. As to what becomes of the sulfuric acid, perhaps it winds up as a sulfate of either the glycerol or the propylene glycol. Comments please.
Only the very skilled in the art could figure out where was found what is claimed in the first sentence.Could you give a reference?