ZrO_2/TiO_2催化剂上一步法合成乙二醇二甲醚

采用共沉淀法制备了ZrO2/TiO_2催化剂,在固定床反应器上考察其催化二甲醚(DME)与环氧乙烷(EO)一步法合成乙二醇二甲醚(DMG)的性能,并采用X射线衍射(XRD)、氮气吸附(BET)、氨气化学吸附和氨气傅立叶红外(NH_3-FTIR)等对催化剂进行表征。结果表明,当ZrO_2质量分数为25%时,催化剂呈现无定形态,最可几孔径分布为7.5 nm,NH_3吸附酸量670μmol/g,表面分布B酸与L酸。在反应温度80℃,压力0.6 MPa,DME与EO物质的量之比为3,气体空速(GHSV)为1 800.0 h~(-1)的条件下,EO转化率100.0%,DMXG(乙二醇二甲醚、二乙二醇二甲醚和多乙二醇二甲醚)选择性89.5%以上。催化剂连续使用720 h,EO转化率99.7%,DMG选择性为71.7%。

One-Step Synthesis of Dimethoxyethane over ZrO2/TiO2 Catalyst

The catalyst ZrO2/TiO2 was prepared by co-precipitation method. The catalytic performance of the one-step synthesis of dimethoxyethane using dimethyl ether (DME) and ethylene oxide (EO) as raw material was investigated in the fixed bed reactor. The catalysts were characterized by X-ray diffraction (XRD), nitrogen physical adsorption (BET), ammonia chemical adsorption and ammonia Fourier transform infrared (NH3-FTIR). The results showed that when the mass fraction of ZrO2 was 25%, the catalyst exhibited amorphous morphology, and the maximum pore size distribution was 7.5 nm, NH3adsorption acid content was 670 μmol/g, and theB acid andL acid distributed on its surface.Under the conditions ofreaction temperature 80℃, reaction pressure 0.6 MPa, the mass ratio of DME to EO 3, gas hourly space velocity (GHSV) 1800.0 h-1, conversion of EO was 100.0% and selectivity of DMXG (ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, polyethylene glycol dimethyl ether) was above 89.5%. When the catalyst was continuously used for 720 h, the conversion of EO was 99.7 % and the selectivity of DMG was 71.7 %.