Method for the manufacture of methyl acrylate and methyl methacrylate monomers

摘要

Methyl acrylate monomer or methyl methacrylate monomer, free from polymers is obtained by treating directly in a single stage the aseotropic mixture of vapours coming from an esterification column, with that quantity of water or an aqueous solution of an alkali metal or alkaline earth metal salt which will condense the vapours and give an organic phase substantially free from dimethyl ether. In a typical example, the vapours of a methyl methacrylate esterification column were condensed with water containing 0.025% of hydroquinone. The temperature of the uncondensed vapours was 70-72 DEG C. and there were introduced into the distillation apparatus at the rate of 14.9 Kgs of methyl methacrylate, 9.6 Kgs of methanol, 3.8 Kgs of water and 1 Kg of dimethyl ether per hour. After cooling to 20-25 DEG C. 13.1 Kgs were collected per hour of an organic phase having 95.3% by weight of methyl methacrylate free from polymer, and 63 Kgs of an aqueous phase containing 14.6% methanol, 3.9% methyl methacrylate and 0.8% of dimethyl ether. The aqueous solution may contain 270 to 465 grams of calcium chloride per litre.