Overview: A study to determine whether ammonium methyl sulfate thermally converts to methylamine hydrogen sulfate, offering a simple route to methylamine. A small test suggested methylamine formation at high temperature. The method was scaled up, producing a crude mixture containing methylamine salts. The methylamine was liberated by reacting the crude product with hot sodium hydroxide to form a gas, which was bubbled through water and then captured by neutralization with hydrochloric acid, yielding ammonium chloride and methylammonium chloride. Purification with hot ethanol produced methylammonium chloride crystals, with ammonium chloride as a minor impurity. The final product, methylamine hydrochloride, amounted to about 30 g from 155 g starting material (roughly 30% dry yield; up to 37% theoretical). The product is highly hygroscopic and was dried in a calcium chloride desiccator. The authors believe the process could be optimized further.
