| 摘要 |
An improved process for producing ethylenically unsaturated zwitterionic phosphate ester compounds involves a two-step reaction, in the first of which an ethylenically unsaturated compound including a hydroxyl group is reacted with a halophospholane compound to form an intermediate which is subsequently ring opened in a second step using a trialkylamine to produce a zwitterionic product. The solvents used for the first and second steps are different to one another and the first solvent is removed from the product mixture of the first stage using a thin film evaporator with the intermediate being dissolved directly into the second solvent, thereby minimising side reactions. The product has improved purity compared to that made by known processes, which makes it particularly suitable for use in polymers, especially cross-linked hydrogel copolymers, used in ophthalmic applications. |
