| abstract |
Provided is a method for manufacturing diisocyanate and an optical lens in which, during the manufacture of diisocyanate from diamine via diamine hydrochloride, use is made of an aqueous hydrochloric acid solution and an organic solvent instead of hydrogen chloride gas and solid-phase triphosgen instead of phosgen gas while reaction conditions are controlled, whereby the diisocyanate of high quality can be manufactured at excellent yield, with the causation of less environmental problems. |