Patent ID: 6469203
Filing Date: 2002-10-22
Classification: C07C

Abstract:
A process for continuously recovering a monomeric ester of a substituted or unsubstituted acrylic acid free from a depolymerization residue from a polymer material having corresponding structural units, which comprises the steps of:(a) continuously supplying a hot heat transfer medium heated to a temperature between 400 and 900Â° C. to an inlet of a fluidizing reactor containing an inner wall and intermeshing rotating shafts which are provided with mixing tools; (b) adding the polymer material having corresponding structural units to an inlet in the fluidizing reactor; (c) depolymerizing in the fluidizing reactor at a temperature of 300 to 650Â° C. the polymer material with the hot heat transfer medium where the polymer material and the hot heat transfer medium are mechanically fluidized by intermeshing rotating shafts which are provided with mixing tools for rubbing the polymer material to prevent an accretion of a residue on the inner wall of the reactor, said residue resulting from the depolymerization of the polymeric material thereby preventing an agglomeration of the depolymerization residue in the reactor to obtain vapors of the monomeric ester of a substituted or unsubstituted acrylic acid free from the depolymerization residue and cooled heat transfer medium containing the depolymerization residue wherein the vapors of the monomeric ester have a dwell time in the fluidizing reactor of less than 6 seconds; (d) continuously separately discharging from outlets in the fluidizing reactor the vapors of the monomeric ester of a substituted or unsubstituted acrylic acid free from the depolymerization residue and the cooled heat transfer medium containing the depolymerization residue; and (e) condensing the vapors of the monomeric ester of a substituted or unsubstituted acrylic acid free from the depolymerization residue to obtain a condensate free from the depolymerization residue and a non-condensable gas.