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AssigneeMitsui Takeda Chemicals, Inc.
InventorsTsutomu Yoshida, Masaaki Sasaki, Satoshi Kuroiwa, Fumiaki Hirata
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A method for producing carbamates that enables carbamates to be produced at low costs, with high selectivity and high yield, and in a simple manner, and a method for producing isocyanates that enables isocyanates industrially used to be produced by using the carbamates obtained by the carbamates producing method. Nonaromatic amine selected from the group consisting of aliphatic amine, alicyclic amine, and aralkyl amine is allowed to react with alkylaryl carbonate to thereby produce carbamates. Also, the carbamates thus obtained are thermally decomposed to thereby produce isocyanates. When carbamates are produced in this method, alkyl carbamates can be obtained with high selectivity and at high yield by using simple equipment. Also, when isocyanates are produced in this method, polyisocyanates used industrially as the raw material of polyurethane can be produced in a simple manner and with efficiency.
A method for producing carbamates, wherein nonaromatic amine selected from the group consisting of aliphatic amine, alicyclic amine, and aralkyl amine is allowed to react with alkylaryl carbonate as is expressed by the following general formula (1):
A method for producing isocyanates which comprises the step of producing carbamates by reacting nonaromatic amine selected from the group consisting of aliphatic amine, alicyclic amine, and aralkyl amine with alkylaryl carbonate expressed by the following general formula (1), and the step of producing isocyanates by thermally decomposing the carbamates obtained:
Dependencies are inferred from the claim text.