Photochemical conversion of tachysterols to previtamins is conducted in the presence of a polymeric photosensitizer which has the appropriate chromophore groups, e.g. anthracene groups, attached to a medium or high molecular weight, substantially uncrosslinked polymer backbone. The polymeric photosensitizer is soluble in solvents normally used for conducting the photochemical reaction (diethyl ether, dioxane, THF, t.butyl methyl ether) but insoluble in lower alcohols and hydrocarbons, so that it may be readily and simply recovered from the product mixture by use of such non-solvents.
聚合光敏剂具有适当的发色团(如
蒽基),并附着在中等或高分子量、基本上未交联的聚合物主干上。 聚合光敏剂可溶于通常用于进行光
化学反应的溶剂(二
乙醚、
二噁烷、
四氢呋喃、
叔丁基甲基醚),但不溶于低级醇和烃,因此可通过使用此类非溶剂从产品混合物中轻松简单地回收。