4-溴苯酚的酶催化聚合及其抗自由基性能

Enzymatic polymerization of 4-bromophenol and evaluation of free radical scavenging activities of the synthesized polymer

在有机溶剂和缓冲溶液的混合体系中对4-溴苯酚的酶催化聚合反应进行了研究;利用红外光谱分析了产物的分子结构.结果表明,有机溶剂与缓冲溶液配比对反应产率和产物分子量影响较大.以乙醇为有机溶剂,当其与磷酸盐缓冲溶液(pH=7)体积比为1∶3时,反应产率较高,而聚合产物的分子量随反应体系中乙醇含量的增加呈上升趋势.与此同时,4-溴苯酚聚合物分子链含有苯-苯连接和苯-氧连接两种结构;4-溴苯酚聚合物的热分解温度在250℃左右,具有较好的热稳定性;且其对1,1-二苯基-2-三硝基苯肼(DPPH)自由基和2,2′-联氮双(3-乙基苯并噻唑啉-6-磺酸)二铵盐(ABTS)阳离子自由基均表现出明显的抑制作用.

The enzymatic polymerization of 4-bromophenol in the mixed medium of organic solvent and phosphate buffer was investigated, and the molecular structure of as-synthesized poly mer product was analyzed by infrared spectrometry. It was found that the ratio of organic sol vent to buffer has significant effect on the yield and molecular weight of the polymer product. Particularly, the target polymer is obtained with a high yield while ethanol is adopted as the solvent and its volume ratio to phosphate buffer is selected as 1 ： 3; and the molecular weight of 4-bromophenol polymer increases with increasing proportion of ethanol in the reaction medium. In the meantime, the molecular chain of as-synthesized 4-bromophenol polymer contains phenylene unit and oxyphenylene unit, and the target polymer exhibits good thermal stability （it undergoes thermal decomposition around 250 ℃）. Besides, as-synthesized 4-bromophenol polymer exhibits good free radical scavenging activity towards 1,1-diphenyl-2-trinitrophenyl hydrazyl and 2, 2＇-azino-bis （3 ethylbenzthiazoline-6-sulfonic acid） cation free radicals.