14868-03-2Relevant articles and documents
METHOD FOR PRODUCING BISPHENOL, AND METHOD FOR PRODUCING POLYCARBONATE RESIN
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Paragraph 0123-0139, (2020/10/21)
PROBLEM TO BE SOLVED: To provide a method for producing bisphenol using hydrogen chloride gas or a hydrochloric acid as an acid catalyst, which produces bisphenol having good methanol dissolution color, melting color difference, thermal color tone stability and thermal decomposition stability, and produces a polycarbonate resin having a good color tone using the bisphenol. SOLUTION: A method for producing bisphenol includes a first step of condensing ketone or aldehyde and aromatic alcohol in the presence of hydrogen chloride to obtain a reaction liquid containing bisphenol, and a second step of mixing the reaction liquid and water, then phase-separating the mixture into a first organic phase containing bisphenol and a first aqueous phase, and removing the first aqueous phase to obtain the first organic phase. An acid concentration of the first aqueous phase in the second step is controlled to be 2.0 mmol-NaOH/g or more and 10.0 mmol-NaOH/g or less. SELECTED DRAWING: None COPYRIGHT: (C)2020,JPOandINPIT
Method for preparing aromatic bischloroformate compositions
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, (2008/06/13)
Bischloroformate oligomer compositions are prepared by passing phosgene into a heterogeneous aqueous-organic mixture containing at least one dihydroxyaromatic compound, with simultaneous introduction of a base at a rate to maintain a specific pH range and to produce a specific volume ratio of aqueous to organic phase. By this method, it is possible to employ a minimum amount of phosgene. The reaction may be conducted batchwise or continuously. The bischloroformate composition may be employed for the preparation of cyclic polycarbonate oligomers or linear polycarbonate, and linear polycarbonate formation may be integrated with bischloroformate composition formation in a batch or continuous process.
Cyclic monocarbonate bishaloformates
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, (2008/06/13)
Cyclic monocarbonate bischloroformates are prepared by the reaction of a carbonyl halide such as phosgene with a bridged substituted resorcinol or hydroquinone such as bis(2,4-dihydroxy-3-methylphenyl)methane or bis(2,5-dihydroxy-3,4,6-trimethylphenyl)methane in the presence of aqueous alkali metal hydroxide. The cyclic monocarbonate bischloroformates may be used for the preparation of linear or cyclic polycarbonates containing cyclic carbonate structural units, which may in turn be converted to crosslinked polycarbonates.