Patent ID: 6437173
Filing Date: 2002-08-20
Classification: C07C

Abstract:
A process for the continuous manufacture of a dialkylaminoalkyl (meth)acrylate of formula (I): in which: R1 is a hydrogen atom or a methyl radical; A is a linear or branched C1-C5 alkylene radical; and R2 and R3, which may be identical to or different from each other, each represent a C1-C4 alkyl radical, by reaction in a stirred reactor R between a compound of formula (II): in which A, R2 and R3 have the same meanings as above, and a compound of the formula (III): in which: R1 is as defined above; and R4 is a linear alkyl group containing 1 or 2 carbon atoms, in the presence of a tetraalkyl titanate as a transesterification catalyst and in the presence of at least one polymerization inhibitor, the compound (III)/R4OH azeotropic mixture being removed continuously during the reaction, wherein the transesterification catalyst is a tetrabutyl, tetraethyl or tetra(2-ethylhexyl) titanate, the reaction being carried out in the stirred reactor at a temperature of 90-120Â° C., and subsequently; distilling a crude reaction mixture comprising desired heavy ester (I) with, as light products, compound (II) and unreacted light ester (III), and, as heavy products, catalyst, polymerization inhibitor(s) and heavy reaction products, in a first distillation column (C1) under reduced pressure, to obtain: at the top, a flow composed essentially of the heavy ester (I) and the light products, containing a small fraction of heavy products, but free of catalyst; and at the bottom, a flow of heavy products with a small fraction of heavy ester (I) and the catalyst; distilling the flow from the top of the first distillation column (C1) in a second distillation column (C2) under reduced pressure, to obtain; at the top, a flow of the light products with a small fraction of heavy ester (I); and at the bottom, the heavy ester (I) containing traces of light products, heavy reaction products and polymerization inhibitor(s); and distilling the flow from the bottom of the second distillation column (C2) in a third distillation column (C3) under reduced pressure, in which a rectification is carried out to obtain: at the top, desired heavy ester (I); and at the bottom, essentially polymerization inhibitor(s).