METHOD FOR PURIFYING MIXTURE OBTAINED THROUGH CATALYTIC VAPOR-PHASE OXIDATION OF PROPENE AND/OR ACROLEIN, BY SEPARATION TREATMENT INDUCING PHASE FORMATION

摘要

PPROBLEM TO BE SOLVED: To provide a method for purifying acrylic acid or methacrylic acid, whereby high purity and a high yield of the acid are achieved. PSOLUTION: (a) A mixture comprising the acrylic acid or methacrylic acid is subjected to a stringently defined separation treatment essentially in the absence of an organic solvent, this phase is then taken off, (b) at least a part of a residual phase from step (a) is subjected to a less stringently defined separation treatment, and (c) one of phases formed in step (b) is fed to the stringently defined separation treatment in step (a). This method offers a possibility that the overall economical efficiency of the treatment is increased through circulation and that the economical efficiency is improved even when static crystallization is omitted. PCOPYRIGHT: (C)2007,JPO&INPIT