Verfahren zur Herstellung aliphatischer Acrylsaeureester

摘要

1,207,089. Acrylic acid esters. KNAPSACK A.G. 13 Feb., 1969 [17 Feb., 1968], No. 7885/69. Heading C2C. In a process for the preparation of aliphatic acrylic acid esters by the reaction of propylene and/or acrolein with oxygen in the presence of steam and inert gas at between 300 and 600‹ C. and in the presence of a catalyst the resulting reaction gas containing hot acrylic acid is scrubbed with a by-product high boiling organic solvent mixture, distilled and reacted in the presence of an acid ion-exchange resin with an aliphatic alcohol (1-8C). The product ester is distilled off and the high-boiling organic solvent mixture recycled to the acrylic acid scrubbing stage. Examples describe the oxidation of propylene using a silver, iron, bismuth, molybdenum, phosphorus and oxygen catalyst to a mixed product gas which is cooled and scrubbed counter-currently by a high boiler mixture of dimethyl maleate, polyacrylic acid and polyacrylates. The acrylic acid free residual gas from this stage is freed from formaldehyde and returned to the reactor, and the hot acrylic acid containing solution is supplied to a low-boiler distilling column to which stabilizer e.g. phenothiazine, is added. Acetic acid is withdrawn from the column head and the acrylic acid solution at the base is mixed with a 4% methanolic methyl acrylate solution and passed through a cation exchange column, and distilled at atmospheric pressure. The ion-exchange passage and distillation are repeated and the products combined and the base product of the final distillation is refluxed, to the gas wash tower. The preparation of butyl acrylate is also described as is the use of a cobalt molybdate catalyst in a similar process.