甲醇-水体系中苯羟基化制苯酚的研究

多步法合成苯酚中需加入酸及有机试剂,容易造成环境污染。在TS-1分子筛与过氧化氢形成的体系中苯一步羟基化合成苯酚的方法,由于反应条件温和,绿色环保,引起了研究者的关注,但目前的文献报道都基于单一溶剂体系,研究结果各有差异。在甲醇-水两元混合体系中,通过改变两者比例来调整溶液极性,采用TS-1分子筛为催化剂,双氧水为氧化剂,研究了TS-1分子筛直接催化苯羟基化制苯酚的反应。结果表明,当n(水)∶n(甲醇)=0.78、反应时间4h、催化剂用量TS-1/苯为17.5g/mol、n(过氧化氢)∶n(苯)=4.76、反应温度为60℃,苯酚的收率在甲醇-水体系中明显优于单一溶剂,并在此条件下,加入冰醋酸量为n(冰醋酸)∶n(苯)=0.31时,苯酚收率可达12.82%。

Hydroxylation of Benzene to Phenol Catalyzed by TS-1 Molecular Sieve in Methanol-water System

The multi-step way of producing phenol can easily cause a series of environment pollution because in this process many kinds of acid and organic reagents were adopted.One-step hydroxylation of benzene to phenol in molecular sieve/H2O2 system has caused extensive concern because of the advantages of mild reaction conditions and green environmental protection.However different results were shown in literature at present based on single solvent systems.The hydroxylation of benzene to phenol in methanol-water double components system using TS-1 molecular sieve as the catalyst and H2O2 as the oxidant was studied,and the solution polarity was adjusted through changing the ratio of methanol and water.When n(water)∶n(methanol)=0.78,reaction time 4 h,dosage of catalyst=17.5 g/mol,n(H2O)∶n(benzene)=4.76,reaction temperature 60℃,the phenol selectivity in methanol-water system is superior than in single solvent.Under these conditions,with the acetic acid dosage of n(acetic acid)∶n(benzene)=0.31 the phenol selectivity of 12.82% is obtained.