Process for manufacturing dialkyl carbonate from urea and alcohol
Patent 5565603 Issued on October 15, 1996. Estimated Expiration Date: 
December 20, 2013. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
December 20, 2013. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 2834799 Process for the preparation of carbonic acid esters Process for the preparation of carbonic acid esters Preparation of carbonates Urea cosolvents for organic carbonate process Process for preparing alkylene carbonates Patent #: 5003084 InventorsApplicationNo. 170468 filed on 12/20/1993US Classes:558/275, Benzene ring attached indirectly to the -O-C(=O)O- group by nonionic bonding549/454, The chalcogen, X, is in a -C(=X)- group549/473, Acyclic -C(=X)-, wherein X is chalcogen, attached directly or indirectly to the hetero ring by nonionic bonding558/260, Carbonate esters (i.e, compounds having the -O-C(=O)O- group bonded directly to at least one carbon, which carbon may be single bonded to any atom but may be multiple bonded only to carbon)558/277Two identical or diverse alkyl groups bonded directly to the -O-C(=O)O- group (e.g., dimethyl carbonate, methyl ethyl carbonate, etc.)ExaminersPrimary: Shah, Mukund J.Assistant: Wong, King Lit Attorney, Agent or FirmForeign Patent References
International ClassC07C 069/96AbstractA process for making a dialkyl carbonate which comprises reacting urea with a first alcohol in a carbamate reactor at a temperature and pressure sufficient to convert said urea to an alkyl carbamate; and reacting the alkyl carbamate with a second alcohol in the presence of a dialkyl isocyanato alkoxy tin catalyst or derivatives in a carbonate reactor at a temperature and pressure sufficient to convert the alkyl carbamate to a dialkyl carbonate, wherein the molar ratio of alkyl carbamate to second alcohol is in the range between about 2:1 to about 10:1 and wherein dialkyl carbonate is present within the carbonate reactor in an amount between about 1 to about 3 weight %, based on total alkyl carbamate and second alcohol content, and wherein the second alcohol is either the same as or different from the first alcohol or a mixture of alcohols.Other References
Field of SearchTwo identical or diverse alkyl groups bonded directly to the -O-C(=O)O- group (e.g., dimethyl carbonate, methyl ethyl carbonate, etc.)Benzene ring attached indirectly to the -O-C(=O)O- group by nonionic bonding Carbonate esters (i.e, compounds having the -O-C(=O)O- group bonded directly to at least one carbon, which carbon may be single bonded to any atom but may be multiple bonded only to carbon) |
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