乙醇气相氧化羰化合成碳酸二乙酯I.催化剂的制备及反应性能

制备了系列乙醇气相氧化羰化合成碳酸二乙酯(DEC)的催化剂,在固定床反应装置上评价了其反应性能.考察了催化剂活性组分及其负载量、载体、助剂等因素对催化剂活性的影响.结果表明:负载在活性炭上的单一金属氯化物催化剂的活性比较低,双金属催化剂Pd(PPh_3)_2Cl_2-CuCl_2/AC可明显提高碳酸二乙酯的产率;活性炭是较好的载体,助剂KCl能提高催化剂的反应活性.当Cu的负载量在9.0%,Pd的负载量控制在0.5%时,催化剂的催化活性达到比较好的效果.在优化的催化剂制备条件下,乙醇的转化率达到33%,DEC的选择性达到95%,同时DEC时空产率达到129g/(L.h).

Synthesis of diethyl carbonate by vapor phase oxidative carbonylation of ethanol I. Preparation of catalysts and reaction performance

A series of catalysts were prepared, and their catalytic performances for the synthesis of diethyl carbonate (DEC) by gas-phase oxidative carbonylation of ethanol were evaluated in a fixed-bed reactor. Effects of the catalyst preparation parameters, active components and their loading amount, supports and promoters, on the performances of catalysts were investigated. The results showed that the activity of the activated carbon supported single metal chloride catalysts were relatively low, and the activated carbon supported bimetallic chloride catalysts, such as Pd (PPh_3))2Cl_2CuCl_2/AC, could greatly increase the space time yield of DEC; the activated carbon was better support than other several supports and KC1 promoter could improve the reactivity of catalyst. The activated carbon supported catalyst Pd (PPh_3)_2Cl_2CuCl_2-KCl/AC with Cu 9.0% and Pd 0.5% by mass showed high activity, with this catalyst ethanol conversion of 33%, DEC selectivity of 95%, and DEC space time yield of 129 g.L~(-1).h~(-1) were obtained.