以N,N-二甲基甲酰胺(DMF)及杂环氮碱为添加剂,研究了有机碱对芳香羧酸氧钒催化过氧化氢氧化茴香脑制备茴香醛的调变作用.考察了催化剂性质、添加剂种类、DMF用量和反应时间等因素对茴香脑选择氧化的影响,发现DMF作为温和的Lewis碱与pH值调节剂,对茴香脑的转化及主产物茴香醛的选择性具有明显的调控作用.结果表明,以化学计量的过氧化氢(H2O2∶茴香脑=2∶1)为氧化剂,0.5%邻苯二甲酸氧钒配合物(OPC)作催化剂,在DMF-CH3CN(6%v/v)介质中30℃反应5 h,底物转化率与茴香醛选择性分别为97%和89%.
The modification effect of organic bases on the oxidation of p-propenylanisole to anisaldehyde with H2O2 catalyzed by oxovanadium aromatic carboxylates was studied using N,N-dimethylformamide(DMF) and heterocyclic nitrogen bases as additives.The effects of catalyst property,additive type,DMF amount and reaction time on the reaction were investigated.It was found that DMF can serve as a mild Lewis base and a pH value modifier in remarkably tuning the conversion of p-propenylanisole and the selectivity for anisaldehyde.The results showed that 97% conversion of p-propenylanisole and 89% selectivity for anisaldehyde were achieved over 0.5% oxovanadium(IV) phthalate complex(OPC)(IV) in DMF-CH3CN(6% v/v) with stoichiometric amount of H2O2(H2O2 ∶ p-propenylanisole = 2∶1) after 5 h reaction at 30 ℃.