| 摘要 |
Polymers of vinyl esters of organic acids are hydrolysed with alcohols in the presence of guanidine carbonate. The term "polymers" includes homopolymers of vinyl esters of carboxylic acids, e.g. polyvinyl acetate, and copolymers of these with other compounds, specifically vinyl halides, vinylidene halides, acrylic and methacrylic acids and their esters and nitriles. The preferred alcohols are methanol and ethanol, the higher alcohols, e.g. propanol and butanol, resulting in slower reaction rates. In one method of carrying out the invention, the guanidine carbonate is dissolved in methanol and the polyvinyl ester added and stirred to produce a viscous solution which is kneaded while heating to reflux the alcohol. The catalyst is destroyed by acetic acid and the methanol and methyl acetate distilled off. Alternatively, the catalyst is initially inactivated by saturating the solution in methanol with carbon dioxide. On heating and kneading the mixture containing the ester, the carbon dioxide is driven off and hydrolysis then commences. |
