Process for the preparation of a bisphenol bischlorocarbonic acid ester
First Claim
1. A process for the continuous production of bisphenol bischlorocarbonic acid esters which comprises feeding a reaction mixture containing an aqueous dialkali metal salt solution of a hydroquinone or of an aromatic dihydroxy compound of the formula ##SPC3##wherein X is alkylene or alkylidene having 1 to 6 carbon atoms, cycloalkylene or cycloalkylidene having 5 to 15 carbon atoms, O, S, SO2 or ##SPC4##and R1 and R2, which may be the same or different, are alkyl having 1 to 4 carbon atoms, chlorine or bromine and containing 2.5-5.0 mol per mol of dihydroxy compound of phosgene dissolved in a water immiscible solvent for the bischlorocarbonic ester product into a pump circulation reactor including a delivery pump on the upstream side of the delivery pump, delaying an interval of at least 1 second after commencing said feeding and then introducing into said reaction mixture, as the sole acid neutralizing agent for acid byproduct, an alkali metal hydroxide solution at a rate to maintain the pH value of the reaction mixture between 9.0 and 12.0, maintaining the reaction mixture in said pump circulation reactor for a dwell time of up to 12 minutes and at a Reynolds number greater than 2,000, separating the organic phase from the resulting reaction mixture and recovering bisphenol bischlorocarbonic acid ester therefrom by distillation, crystallization or a combination thereof.
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Abstract
A continuous process for the production of a bisphenol bischlorocarbonic acid ester wherein an aqueous solution of a dialkali metal salt of a hydroquinone or a bisphenol is reacted in a pump circulating system with 2.5 to 5.0 mol, per mol of dihydroxy compound of phosgene dissolved in a suitable solvent for the bischlorocarbonic acid ester formed in the reaction under the addition of an alkali metal hydroxide solution to keep the pH-value between 9.0 and 12.0, the organic phase obtained is separated wherefrom the bisphenol bischlorocarbonic acid ester is isolated by distillation and/or crystallisation.
12 Citations
6 Claims
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1. A process for the continuous production of bisphenol bischlorocarbonic acid esters which comprises feeding a reaction mixture containing an aqueous dialkali metal salt solution of a hydroquinone or of an aromatic dihydroxy compound of the formula ##SPC3##
wherein X is alkylene or alkylidene having 1 to 6 carbon atoms, cycloalkylene or cycloalkylidene having 5 to 15 carbon atoms, O, S, SO2 or ##SPC4## and R1 and R2, which may be the same or different, are alkyl having 1 to 4 carbon atoms, chlorine or bromine and containing 2.5-5.0 mol per mol of dihydroxy compound of phosgene dissolved in a water immiscible solvent for the bischlorocarbonic ester product into a pump circulation reactor including a delivery pump on the upstream side of the delivery pump, delaying an interval of at least 1 second after commencing said feeding and then introducing into said reaction mixture, as the sole acid neutralizing agent for acid byproduct, an alkali metal hydroxide solution at a rate to maintain the pH value of the reaction mixture between 9.0 and 12.0, maintaining the reaction mixture in said pump circulation reactor for a dwell time of up to 12 minutes and at a Reynolds number greater than 2,000, separating the organic phase from the resulting reaction mixture and recovering bisphenol bischlorocarbonic acid ester therefrom by distillation, crystallization or a combination thereof.
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