PURPOSE: To promote the urethanization reaction by adding a protonic acid to a diisocyanate compound obtained by the reaction of a diamine with dimethyl carbonate produced essentially without using phosgene in the reaction process.
CONSTITUTION: A dialkyl carbonate is produced essentially without using phosgene e.g. by reacting carbon monoxide with an alcohol and oxygen in the presence of a catalyst or reacting an alcohol with an alkylene carbonate produced by the reaction of an alkylene oxide with carbon dioxide. The dialkyl carbonate is made to react with a diamine to obtain a diisocyanate compound. The urethanization reaction of the diisocyanate compound can be promoted by adding 1×10-7 to 1×10-1 equivalent (preferably 1×10-6 to 1×10-2 equivalent, based on 1 equivalent of NCO group of the compound) of a protonic acid to the diisocyanate compound.
MARUYAMA TOSHIHIDE
MURATA KIYOKAZU
