| 摘要 |
A process for the alcoholysis of ethylene/vinyl acetate copolymers comprises introducing from above a reaction zone a solution of an ethylene copolymer constituted by (C2H4)x, (CH2CHOCOCH3)y and (CH2CRR1)z, where R is H or methyl, R1 is -COOR, -C6H5, -C1, -CN, -CH3 or CH2=CH-, x:(y + z) is 0.5:1 to 9.0:1 and z:y is 0:1 to 0.1:1, and an alcoholysis catalyst, introducing from below said reaction zone an alcohol vapour so as to contact said solution and vapour countercurrently, and effecting an alcoholysis reaction while discharging alcohol vapour and by-product acetic acid ester from said reaction zone. Specified copolymers are copolymers of ethylene and vinyl acetate, optionally with butadiene, styrene, propylene, methylacrylate, acrylonitrile or vinyl chloride. Specified solvents are alcohols, aliphatic and aromatic hydrocarbons, and ketones. Specified alcohols are C1- 4 alkanols. Specified catalysts are sodium and potassium hydroxides, methylates and ethylates. The reactor may be a plate, perforated plate, packed or welted wall tower, and the reaction may be effected at 40 DEG to 100 DEG C. and 0.01 to 5 atmospheres. Examples describe processes of the invention using methanol vapour and (1) a methanol solution of an ethylene/vinyl acetate copolymer and sodium hydroxide, (2) a t.-butanol solution of an ethylene/vinyl acetate/methyl acrylate copolymer and sodium methylate, (3) a toluene solution of an ethylene/vinyl acetate copolymer and sodium hydroxide, and (4) a methanol solution of an ethylene/vinyl acetate/propylene copolymer and sodium hydroxide. |
