磷钨酸催化过氧化氢氧化环己酮/环己醇合成己二酸

Oxidation of Cyclohexanone/Cyclohoxanol to Adipic Acid with H_2O_2 Using Phosphotungstic Acid as Catalyst

在无溶剂、无相转移催化剂条件下,用钨酸钠或磷钨酸为催化剂,30%过氧化氢作氧源,在一定温度下可以将环己酮或环己醇/环己酮混合物高产率地氧化成己二酸。讨论了30%过氧化氢的量、反应时间、反应温度、催化剂用量、醇酮比和草酸对己二酸产量的影响。结果表明:反应温度为90°C,30%H2O2为0.4 mol,草酸作酸性配体,钨酸钠催化氧化环己酮反应12 h,制得的己二酸的最大产率仅为71.8%。而磷钨酸作催化剂反应8 h,己二酸的最大产率高达95.1%。同时,不用酸性配体,磷钨酸对环己酮或环己酮/环己醇混合液也表现出很高的催化活性,在优化条件下己二酸产率可达87.5%或82%。

Cyclohexanone or the mixture of cyclohexanone and cyclohoexanol can be directly oxidized to adipic acid with 30% H2O2 in the presence of Na2WO4 ·2H2O or H7 [P（W2O7）6 ]·xH2O without any phase transfer catalyst and organic solvent. The effects of amount of 30% H2O2, reaction time, temperature, amount of the catalyst, proportion of cyclohexanone to cyclohoexanol and Oxalic acid on the oxidation reaction are investigated. The yield of adipic acid is 71. 8% with Na2WO4·2H2O as catalyst and oxalic acid as ligand at 90℃. When using H7 [P（W2O7 ）6 ] ·xH2O as catalyst, 95.1%. yield of adipic acid can be reached at 90℃. In the absence of acidic ligand, H7 [ P（W2O7 ）6 ]·xH2O can still perform very well in the oxidation of cyclohexanone or the mixture of cyclohexanone and cyclohoexanol. The yield of adipic acid can reach 87.5 % or 82 % under optimum conditions.