[HSO_3-b-N(CH_3)_3]HSO_4/SiO_2催化剂上苯基羟胺Bamberg重排制备对氨基苯酚

SYNTHESIS OF p-AMINOPHENOL BY BAMBERG REARRANGEMENT OF PHENYLHYDROXYLAMINE OVER [HSO_3-b-N(CH_3)_3]HSO_4/SiO_2 CATALYST

在硝基苯加氢合成对氨基苯酚(PAP)过程的Bamberg重排反应中,采用酸性离子液体来替代硫酸催化剂。设计并合成了一种新型的含有—SO3H基团的季铵型酸性离子液体N,N,N-三甲基-N-磺丁基硫酸氢铵([HSO3-b-N(CH3)3]HSO4),并与另外3种离子液体1-磺丁基-3-甲基咪唑硫酸氢盐([HSO3-bmim]HSO4)、N,N-二乙基硫酸氢铵([(CH3CH2)2NH2]HSO4)及N,N,N-三甲基硫酸氢铵([(CH3)3NH]HSO4)的酸性质进行了对比,考察了这些离子液体在苯基羟胺Bamberg重排制备对氨基苯酚反应中的催化性能。为了减少离子液体的用量和便于回收催化剂,采用溶胶-凝胶法制备出负载型离子液体催化剂[HSO3-b-N(CH3)3]HSO4/SiO2,并对其催化性能进行了研究。结果表明,该催化剂在苯基羟胺Bamberg重排制备对氨基苯酚反应中具有较高的催化活性,在离子液体与苯基羟胺摩尔比为0.5、反应温度85℃、反应时间30 min的条件下,苯基羟胺转化率100%,对氨基苯酚选择性60.5%。

Acidic ionic liquid was used, instead of sulfuric acid, to catalyze the Bamberg rearrangement reaction in hydrogenation of nitrobenzene to p-aminophenol. A novel quaternary ammonium type of acidic ionic liquid N, N, N-trimethyl-N-sulfobutyl hydrogen sulfate, [HSO3-b- N（CH3）3 HSO4, containing-SO3 H was synthesized, and its acidity and catalytic activity were investigated, compared to that of the ionic liquids, such as 1-sulfobutyl-3 methylimidazolium hydrogen sulfate （[SO3 H-bmim] HSO4 ）, N, N-diethyl hydrogen sulfate （[ （CH3 CH2 ）2 NH2] HSO4 ） and N, N, N-trimethyl hydrogen sulfate （[（CH3）3NH] HSO4 ）. Supported ionic liquid catalyst [-HSO3-b-N（CH3）3 HSO4/SiO2 was prepared through sol-gel process to reduce the dosage of [HSO3-b-N（CH3 ）3 7 HSO4 in Bamberg rearrangement reaction and to make the catalyst be recovered easily. The evaluation results showed that the phenylhydroxylamine conversion and p-aminophenol selectivity were, respectively, 100% and 60.5% at conditions of 85℃, 30 min and the molar ratio of ionic liquid to phenylhydroxylamine of 0.5.