论文部分内容阅读
采用浸渍法制备了不同负载量的Al2(SO4)3/SiO2催化剂.使用BET、XRD、FT-IR、异丙醇探针反应、NH3吸附量热和NH3吸附红外等手段对催化剂进行了表征,并测试了其在甲醇脱水合成二甲醚反应中的活性.BET、XRD和FT-IR结果表明,载体SiO2的表面积较高,随着Al2(SO4)3负载量的增加,样品的表面积逐渐降低,当Al2(SO4)3负载量高于20%时,样品表面开始出现晶相Al2(SO4)3.NH3吸附量热和NH3吸附红外结果表明,载体SiO2的酸性很弱,负载了Al2(SO4)3后,样品酸性大大增强,且酸性随着Al2(SO4)3负载量的增加先增强后减弱.样品表面同时存在B酸中心和L酸中心,但以B酸中心为主.Al2(SO4)3负载量为3%的样品的表面酸性最强,因而在甲醇脱水反应中表现出最高的反应活性,533K,甲醇转化率为83.5%,二甲醚选择性100%.
Al2 (SO4) 3 / SiO2 catalysts with different loadings were prepared by impregnation method.The catalysts were characterized by BET, XRD, FT-IR, isopropanol probe reaction, NH3 adsorption calorimetry and NH3 adsorption infrared spectroscopy, The results of BET, XRD and FT-IR indicated that the surface area of SiO2 was higher, and the surface area of sample was decreased with the increase of Al2 (SO4) 3 loading , The crystal phase Al2 (SO4) began to appear on the surface of the sample when the loading of Al2 (SO4) 3 was above 20%. The adsorption heat of NH3 and the adsorption of NH3 by NH3 showed that the SiO2 of the support was weakly acidic and supported Al2 (SO4 ) 3, the acidity of the sample increases greatly, and the acidity first increases and then decreases with the increase of Al2 (SO4) 3 loading.The B acid sites and L acid sites exist on the surface of the sample, ) 3 The sample with 3% loading showed the strongest surface acidity and therefore showed the highest reactivity in the methanol dehydration reaction at 533K with a methanol conversion of 83.5% and a dimethyl ether selectivity of 100%.