| 摘要 |
Polyglycerol carboxylic acid esters are made by reaction of a, typically C2 to C30, particularly C6 to C22. carboxylic acid with glycerol carbonate, particularly with base catalyst, and desirably at temperatures from 170° C. to 250° C. Other carbonates e.g. cyclic diol carbonates such as ethylene or propylene carbonates, may be used in combination with the glycerol carbonate to make novel mixed polymeric esters. The molar ratio of carboxylic acid group to glycerol carbonate is typically from 2 to 30, but can be up to 100. The base catalyst is desirably alkali metal hydroxide, carbonate or alkoxide. The reaction is desirably carried out in an inert atmosphere, and reducing agent such as phosphorous acid, hypophosphorous acid or borohydride and/or activated carbon, may be included to improve product colour.
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