Patent ID: 6664419
Filing Date: 2003-12-16
Classification: B01D,C07C

Abstract:
A process for the purification of acrylic acid comprising:crystallizing a molten material or a mixture comprising acrylic acid and at least one impurity having a tendency to precipitate; adding solvent or a solvent mixture to the molten material or the mixture in a quantity sufficient to retain at least one impurity having a tendency to precipitate in solution, wherein the solvent has a superior dissolving capacity for at least one of the impurities having a tendency to precipitate, compared to acrylic acid and wherein the mixture comprises two or more impurities having a tendency to precipitate selected from the group consisting of maleic acid, an anhydride of maleic acid, and phenothiazine, a quantitatively more significant impurity having a tendency to precipitate is retained in solution and wherein a solvent or a mixture of solvents is added which is suitable for retaining multiple impurities in solution; and removing the impurity having a tendency to precipitate, which is retained in solution, from the crystal.