25686-28-6Relevant articles and documents
METHOD FOR PRODUCING CARBAMATE AND METHOD FOR PRODUCING ISOCYANATE
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Paragraph 0367; 0369-0379; 0399; 0402-0403, (2021/06/22)
The present invention provides a method for producing a carbamate that includes a step (1) and a step (2) described below: (1) a step of producing a compound (A) having a urea linkage, using an organic primary amine having at least one primary amino group per molecule and at least one compound selected from among carbon dioxide and carbonic acid derivatives, at a temperature lower than the thermal dissociation temperature of the urea linkage; and(2) a step of reacting the compound (A) with a carbonate ester to produce a carbamate.
ISOCYANATE PRODUCTION METHOD
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Paragraph 0419-0430; 0447-0451; 0454-0458; 0462, (2020/05/02)
An isocyanate production method according to the present invention is a method in which an isocyanate is produced by subjecting a carbamate to thermal decomposition, and includes: a step of preparing a mixture liquid containing the carbamate, an inactive solvent and a polyisocyanate compound; a step of conducting a thermal decomposition reaction of the carbamate by continuously introducing the mixture liquid into a thermal decomposition reactor; a step of collecting a low-boiling decomposition product by continuously extracting the low-boiling decomposition product in a gaseous state from the reactor, the low-boiling decomposition product having a boiling point lower than the polyisocyanate compound; and a step of collecting a high-boiling component by continuously extracting, from the reactor, a liquid phase component which is not collected in a gaseous state at the step of collecting the low-boiling decomposition product.
Preparation method for diphenylmethane diisocyanate
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Paragraph 0036-0079; 0086-0087, (2019/11/19)
The invention provides a preparation method for diphenylmethane diisocyanate. The preparation method comprises a step of subjecting diphenylmethane dicarbamate to a pyrolysis reaction in an inert solvent having a boiling point lower than the boiling point of diphenylmethane diisocyanate in the presence of a catalyst so as to produce diphenylmethane diisocyanate. The preparation method provided bythe invention has the advantages of high reaction conversion rate, high yield, simple equipment and process and mild reaction conditions, and can meet the demands of industrial production.