Patent ID: 6462224
Filing Date: 2002-10-08
Classification: C07C

Abstract:
A process for the preparation of 1,1-cyclopropanedicarboxylic diesters, comprising:a) reacting in a solvent-free environment malonic diester, 1,2- dihaloethane and alkali metal carbonate in the presence of available or in-situ-produced phase transfer catalyst and polyalkylene glycol or at least one derivative of polyalkylene glycol which is capped at one or both ends; wherein a molar ratio of malonic diester: 1,2-dihaloethane: alkali metal carbonate is 1:(1 to 7):(1 to 1,4); wherein a reaction temperature is &gE;70Â° C.; b) azeotropically distilling off water produced during the reaction with 1,2-dihaloethane; c) separating off the reaction salt by a mechanical separation operation; d) distilling off an excess of 1,2-dihaloethane; and e) fractionally distiling off said 1,1-cyclopropanedicarboxylic diester; wherein said reacting proceeds according to the schematic reaction equation wherein R and R1 independently are an unbranched or branched alkyl group having from 1 to 6 carbon atoms; Z is nitrogen or phosphorus; and R2,R3,R4 and R5 independently are an unbranched or branched alkyl group having from 1 to 16 carbon atoms, an aryl, alkylaryl or arylalkyl radical having from 6 to 12 carbon atoms or a 1,2dihaloethyl group; n is an integer or a fraction from 1 to 30; R6 is an ethylene radical, a propylene radical, or a mixed compound with ethylene and propylene radicals, and R7 and R8 independently are a hydrogen radical, an unbranched or branched alkyl group having from 1 to 6 carbon atoms or an acyl group having from 2 to 7 carbon atoms; Y and Yâ€² independently are chlorine, bromine or iodine; Yâ€³ is chloride, bromide, iodide or hydrogen sulfate; and X is Na or K.