钨酸催化氧化环己酮合成己二酸

以钨酸-有机酸性添加剂为催化体系,在无有机溶剂和相转移剂的情况下,催化30%过氧化氢氧化环己酮合成己二酸。当钨酸∶有机酸性添加剂∶环己酮∶过氧化氢=11∶4∶01∶76(摩尔比,钨酸用量为2.5mmol)时,使用有机酸性添加剂来调节钨酸催化活性,结果表明以钨酸-磺酸水杨酸氧化环己酮效果最优,反应8h时己二酸分离产率达86.8%、纯度为99.9%;以间苯二酚或邻苯二酚为添加剂时,己二酸分离产率分别达到85.9%和84.5%,纯度约为100%;而不使用任何添加剂时,己二酸分离产率只有68.1%、纯度为95.2%。当使用磺酸水杨酸、草酸等为有机酸性添加剂时,随反应时间的延长,己二酸分离产率均升高。当磺酸水杨酸用量为2.5mmol时,己二酸分离产率和纯度均较高。钨酸-磺酸水杨酸和钨酸-草酸催化体系重复使用5次后,己二酸分离产率仍分别可达80.2%和80.9%。

Tungstic Acid Catalyzed Oxidation of Cyclohexanone to Adipic Acid in the Presence of Organic Additives

Without organic solvent and phase-transfer reagent,the catalytic oxidation of cyclohexanone to adipic acid with aqueous 30% hydrogen peroxide can be achieved in the presence of tungstic acid-acidic additive.When the molar ratio of tungstic acid to acidic organic additive to cyclohexanone to hydrogen peroxide is 1∶1∶40∶ 176(tungstic acid is 2.5 mmol),and the tungstic acid-resorcinol is used as catalyst,the isolated yield of adipic acid is up to 86.8% for 8 h.When 2-aminophenol or resorcinol is used as an additive,the isolated yield of adipic acid is up to 85.9% and 84.5% respectively,of which the purity is about 100%.If the tungstic acid alone is used as catalyst,the isolated yield of adipic acid is only 68.1%,and the purity of product is low.It is proved that the acidic effect and coordination effect of additives play the same important role in the reactions.With sulfosalicylic acid,oxalic acid and so on used as additives,the isolated yield of adipic acid increased with increasing reaction time.The yield and purity of adipic acid are very high when the amount of sulfosalicylic acid is 2.5 mmol in the reaction medium.Tungstic acid-sulfosalicylic acid catalyst and tungstic acid-oxalic acid can be reused five times and the isolated yield of adipic acid is still 80.2% and 80.9% respectively.