TS－1分子筛催化苯羟基化反应

STUDY ON HYDROXYLATION OF BENZENE WITH HYDROGEN PEROXIDE CATALYZED BY TITANIUM SILICALITE 1

ＴＳ－１分子筛对苯羟基化反应有着较高的催化活性及选择性．在反应体系中加入适量的无机酸，可提高反应的选择性；增加催化剂ＴＳ－１及Ｈ２Ｏ２的加入量，由于转化率的提高，反应选择性略有下降，而产物分布中苯酚的含量减少，苯醌的含量增大．ＴＳ－１催化苯羟基化反应是一个复杂的串连反应过程，即首先是苯氧化为苯酚，然后苯酚进一步氧化为苯二酚（对苯二酚为主），苯二酚再进一步氧化为醌．提高反应温度，Ｈ２Ｏ２的转化率和选择性随之提高，并且产物分布中苯酚的含量增大，醌的含量减少。

Benzene can be oxidized catalytically and selectively to phenol and p quinone by hydrogen peroxide in the presence of TS 1 molecular sieve. Addition of small amount of inorganic acid in reaction medium can improve the selectivity for phenol. Increasing the amount of TS 1 catalyst or H 2O 2 concentration, the selectivity for phenol decreases, however, the selectivity for p quinone increases due to the increase of H 2O 2 conversion. The catalytic reaction may suffer following procedure: benzene is first hydroxylated to phenol and then the phenol is further oxidized to hydroquinone and catechol which are easily oxidized to p quinone and tar. The H 2O 2 conversion and selectivity for phenol are also increased with the increase of reaction temperature.