15.6 C 1.333 Chemical Properties Dimethyl sulfate hydrolyzes slowly in cold water but rapidly in warm water and acidic solutions. The hydrolysis occurs stepwise, initially forming methyl sulfuric acid, then sulfuric acid and methanol. Complete conversion to sulfuric acid occurs at a much slower rate. Salts of methyl sulfuric acid are formed when DMS is hydrolyzed in aqueous alkali. Hydrolysis is almost instantaneous in aqueous ammonia.
Caution is necessary.
Do not use concentrated aqueous ammonia. This can react with DMS with explosive violence. Dimethyl sulfate is a strong methylating agent that reacts with active hydrogen and alkali metal salts to form substituted oxygen, nitrogen and sulfur compounds. As a rule, DMS releases only one methyl group to the reactant. Higher temperatures and concentrations are required for the second methyl group to react.