A method for inhibiting the formation of acetaldehyde in a solution of vinyl acetate in an alcohol

摘要

A method for inhibiting the formation of acetaldehyde in a solution of vinyl acetate in an alcohol during polymerization of the vinyl acetate, comprises adding to the solution an aliphatic or aromatic polycarboxylic acid, or a mono- or polycarboxylic acid substituted by a hydroxyl, amino or nitro group, or an alkali metal salt of one of these acids. From 5 to 50 parts of the acid, or from 5 to 10 parts of the salt, are added per million parts of the solution. The polyvinyl acetate obtained may be hydrolysed to polyvinyl alcohol. In examples solutions of vinyl acetate in methanol and ethanol are stabilized with oxalic acid, citric acid, sodium citrate, nitrilo-tri-acetic acid, o-nitrobenzoic acid, phthalic acid, tartaric acid, sodium tartrate and ethylenediamine tetra-acetic acid, the vinyl acetate is polymerized using p a -a 1-azo-bis-isobutyronitrile and acetylperoxide as initiators, and the polyvinyl acetate is hydrolysed to polyvinyl alcohol with sodium hydroxide. Other inhibitors mentioned are malonic acid, succinic acid, maleic acid, glycollic acid, lactic acid, glyceric acid, malic acid, salicylic acid, aminoacetic acid, glutamic acid, imino-di-acetic acid and nitro-acetic acid.ALSO:A method for inhibiting the formation of acetaldehyde in a solution of vinyl acetate in an alcohol comprises adding to the solution an aliphatic or aromatic polycarboxylic acid, or a mono- or polycarboxylic acid substituted by a hydroxyl, amino or nitro group, or an alkali metal salt of one of these acids. From 5 to 50 parts of the acid, or from 5 to 10 parts of the salt, are added per million parts of the solution. In examples solutions of vinyl acetate in methanol and ethanol are stabilized with oxalic acid, citric acid, sodium citrate, nitrilotriacetic acid, o-nitro-benzoic acid, phthalic acid, tartaric acid, sodium tarrate and ethylenediamine tetra-acetic acid. Other inhibitors mentioned are malonic acid, succinic acid, maleic acid, glycollic acid, lactic acid, glyceric acid, malic acid, salicylic acid, aminoacetic acid, glutamic acid, imino-di-acetic acid and nitro-acetic acid.