Purification of methylacetate by distillation

摘要

A mixture comprising methyl acetate, methanol and acetaldehyde, such as may result from the interaction of polyvinyl acetate with methanol, is passed through an inlet 2 to an extractive distillation column 1 to which water is supplied through an inlet 3. Aqueous methanol is withdrawn at the base of the column, and a mixture containing methyl acetate and acetaldehyde vapours passes from the top of the column to a partial condenser 4 and thence to a separator 41. Condensate from the separator 41 is returned by pipe 11 to the top of column 1, and the vapours from separator 41 are passed by pipe 5 to a second partial condenser 6, the liquid and vapours from which are both passed to the lower part of a fractionation column 7. Methyl acetate of reduced acetaldehyde content is withdrawn from the base of column 7 through pipe 10, and the vapours from the top of the column pass to a condenser 8, from which condensate is returned to the top of the column by pipe 12. Acetaldehyde vapour is withdrawn through pipe 9. Dimensions and operational details of a suitable apparatus are given.