PROCESS FOR THE PRODUCTION OF ALKYL-ISOTHIOCYANIC ESTERS

摘要

Alkyl-isothiocyanic esters having the formula R-N=C=S can be produced by reacting N-alkyl dithiocarbaminates with hydrogen peroxide in aqueous phase at 95 to 130.degree.C. According to the present invention the aqueous N-alkyl dithiocarbaminate solution is reacted with a 20 to 40% by weight aqueous hydrogen peroxide solution in a volume ratio of 1:0.8 to 1 while maintaining a pH value of 1.5 to 4.5. The solutions are preferably sprayed into a reactor while alkylisothiocyanate formed is distilled off in the form of a vapour and the aqueous phase containing the by-products accumulates in the reactor. By means of the process according to the present invention the space-time yield could be increased significantly while, as compared with the conventional process that is carried out at pH 5 to 9, the amount of sulphur formed is substantially reduced and the shut off times for cleaning the reactor can be minimized.