反应蒸馏在苯直接羟基化制备苯酚中的应用

Application of reactive distillation in direct hydroxylation of benzene to phenol

在催化剂存在下,以H_(2)O_(2)直接羟基化苯制备苯酚是一种简单、经济和绿色的方法。但传统的壶式反应装置,存在产物与催化剂、反应物分离复杂,苯酚收率和选择性低等不足。采用改进的反应蒸馏装置,并运用正交试验法对反应影响因素进行优化。反应蒸馏装置的运用,强化了反应中的传质和传热过程,明显提升苯酚的收率和选择性;在H_(2)O_(2)进样速度为0.2 mL/min,催化剂粒度为20-40目,催化剂床层厚度为3 cm,反应温度为333 K,再沸器温度为358 K和n(H_(2)O_(2))/n(苯)为2.5时,苯酚的收率和选择性分别达到94.86%和100.0%。该方法不仅是一种绿色、高效的合成的苯酚新方法,而且对有限石化资源的应用及加工提供了新的思路及理论依据。

The direct hydroxylation of benzene with H_(2)O_(2)at the presence of catalyst is a simple,economical and green rout to prepare phenol.However,the traditional method using pot-type reactor involves many disadvantages,such as the complex separate process of products from catalyst and reactant,the low yield and selectivity of phenol etc.An improved catalytic reactive distillation reactor was proposed,and the affecting factors were optimized by orthogonal experiment.The reactive distillation device intensified process of mass and heat transfer,and significantly improved the yield and selectivity of phenol in the goal reaction.Under the flow rate of H_(2)O_(2)was 2.0 mL/min,the size of catalyst was 20-40 mesh,the bed thickness of catalyst was 3 cm,the reaction temperature was 333 K,and the reboiler temperature was 358 K and the molar ratio of hydrogen peroxide to benzene was 2.5,the yield and selectivity of phenol reached 95.61%and 100.0%respectively.It is a new,green and efficient method for synthesis of phenol,and provides a new idea and theoretical basis for the application and processing of limited petrochemical resources.