杂多酸催化环己烯氧化合成己二酸

Catalytic Oxidation of Cyclohexene to Adipic Acid over Heteropolyacids

以 30 %H2 O2 作氧化剂 ,二元羧酸或 8 羟基喹啉等作助剂 ,考察了杂多酸催化环己烯氧化合成己二酸的活性 ,讨论了催化剂和助剂对反应的影响。结果表明 ,钨磷酸在环己烯氧化合成己二酸的过程中显示了较高的催化活性。8 羟基喹啉作助剂时 ,己二酸的收率最高 ,反应 6h ,己二酸的收率可达 75 0 % ;草酸作助剂时 ,反应的最佳条件为 ,n(环己烯 )∶n(H3 PW12 O40 )∶n(H2 C2 O4)∶n(H2 O2 ) =10 0∶1∶1∶5 38,反应温度为 92℃ ,反应时间为 6h ,己二酸的收率可达 70 1%。十六烷基三甲基溴化铵、溴代十六烷基吡啶作相转移催化剂时 ,己二酸的收率也较高 ,反应 6h ,己二酸的收率分别为 73 1%和 71 6 %。对钨磷酸催化环氧环己烷、反 1,2 环己二醇氧化合成己二酸的活性也进行了研究。

The oxidation of cyclohexene to adipic acid catalyzed by heteropolyacids has been investigated, using 30% aqueous hydrogen peroxide as an oxidant, and dicarboxylic acids or 8 hydroxyquinoline as cocatalyst. Adipic acid in yield up to 75 0% was obtained in 6 h, in the presence of 8 hydroxyquinoline. When oxalic acid was used as cocatalyst in condition of 92 ℃, 6 h, n (cyclohexene)∶ n (H 3 PW 12 O 40 )∶ n (H 2 C 2 O 4 )∶ n (H 2 O 2 )=100∶1∶1∶538, the yield of adipic acid was 70.1%. When cetyltrimethyl ammonium bromide or cetylpyridinium bromide was used as phase transfer catalyst, the yield of adipic acid was 73 1% and 71 6% respectively. Catalytic oxidation of cyclohexene oxide or trans 1,2 cyclohexanediol to adipic acid over tungtophosphoric acid were also carried out in order to confirm the reported mechanism of the reaction.