The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 04, 1993
Filed:
Jan. 15, 1991
Gunter Giesselmann, Heusenstamm, DE;
Kurt Gunther, Erlensee, DE;
Degussa Aktiengesellschaft, Frankfurt, DE;
Abstract
Alkylisothiocyanic acid esters having the formula R--N.dbd.C.dbd.S can be prepared by reacting N-alkyldithiocarbamates with hydrogen peroxide in aqueous phase at 95.degree. to 130.degree. C. The aqueous solution of N-alkyldithiocarbamate is reacted with a 20 to 40% by weight aqueous solution of hydrogen peroxide in a volumetric ratio of 1 to 0.8 to 1 while maintaining a pH of 1.5 to 4.5. The solutions are preferably sprayed into a reactor, at which time the alkylisothiocyanate formed distills off in vapor form and an aqueous phase containing the byproducts collects in the reactor. The method is capable of significantly increasing the space-time yield because much less sulfur is formed in comparison to the previously known method, which takes place at pH 5 to 9, thereby minimizing the shutdown times previously required for cleaning the reactor.