| 摘要 |
Polymers containing hydroxyl groups are esterified by a process which comprises mixing to bring about esterification an acid halide dissolved in an organic solvent phase, and hydroxide or alkaline reacting salt of an alkali metal or alkaline earth metal dissolved in an aqueous phase and the polymer dissolved or dispersed in the aqueous or organic phase, the concentration of the polymer being at least 0.01 mole/litre as hydroxyl group concentration and that of the alkali being greater than 0.05 mole/litre and the acid halide being present in and amount of at least 10% more than the theoretical amount, allowing the phases to separate into two layers and recovering the polymer from the organic solvent layer. The organic solvent phase preferably comprises a mixture of hydrophilic and hydrophobic solvents. Specified polymers are polymers and copolymers of vinyl alcohol, cellulose and starch. The halides may be fluorides, chlorides, bromides and iodides of carboxylic acids and sulphonic acids. In Examples (1) an aqueous solution of polyvinyl alcohol and sodium hydroxide is mixed with a methyl ethyl ketone/toluene solution of cinnamoyl chloride; and the process repeated using (2) and (5) vinyl alcohol/vinyl acetate copolymers, (3) an ethylene/vinyl alcohol copolymer and (4) starch in place of the polyvinyl alcohol, (6) potassium hydroxide in place of the sodium hydroxide, (7) tetrahydrofuran/xylene in place of methyl ethyl ketone/toluene and (8) acrylyl chloride in place of cinnamoyl chloride. |
