| 摘要 |
510,168. Polyvinyl acetals. GROVES, W. W. (I.G. Farbenindustrie Akt.-Ges.). Jan. 27, 1938, No. 2633. [Class 2 (iii)] Polyvinyl alcohols or derivatives thereof still containing free alcoholic hydroxyl groups are reacted with a.carboxylic acid that contains a reactive carboxyl group. Derivatives of polyvinyl alcohol include partially saponified esters' of polyvinyl alcohol with organic acids such as polyvinyl acetate, formate, propionate or butyrate, or polyvinyl alcohols wherein part of the hydroxyl groups have been reacted with an aldehyde or ketone such as formaldehyde, acetaldehyde, butyraldehyde, isobutyraldehyde, cyclohexanone or methylcyclohexanone. Suitable azo-carboxylic acids, which may also include other groups such as halogen, nitrohydroxy or amino-groups, include aldehydecresotinic acid, glyoxylic acid, levulinic acid, acetone dicarboxylic acid, o-, m-, or p-benzaldehyde carboxylic acid, salicyladehyde carboxylic acids, terephthalaldehyde-carboxylic acid, 3:4- dimethoxybenzaldehyde carboxylic acid, 4- chlorobenzophenone-21-carboxylic acid, 3-nitrobenzophenone-2'-carboxylic acid, 3-aminobenzophenone-21-carboxylic acid and cyclohenanone-1-carboxylic acid-3. The starting materials may also be compounds which are saponifiable during the reaction to the desired starting materials, such as the acetal of glyoxylic acid. In examples. (1) glyoxylic acid is reacted with an aqueous solution of polyvinyl alcohol; (2) m-benzaldehyde carboxylic acid is reacted with a suspension of polyvinyl alcohol in methanol; (3) polyvinyl acetate is reacted with glyoxylic acid in the presence of sulphuric acid ; (4) the ester-acetal of glycollic acid is reacted with polyvinyl alcohol in the presence of sulphuric acid. |
