改性ZSM-5催化剂的制备及其在甲醇氢氯化合成氯甲烷中的应用

Preparation of Modified ZSM-5 Catalysts and Application in Sythesis of Chloride Methane from Methanol and Hydrogen Chloride

采用等体积浸渍法制备了系列SiO2改性的ZSM-5催化剂,通过程序升温脱附法(NH3-TPD)和微型固定床反应器法分别研究其表面酸性和催化活性,并考察了反应温度、氯化氢与甲醇物质的量之比和空速对反应的影响。结果表明:当SiO2的用量为1.0%时,SiO2/ZSM-5(50)分子筛表现出了较高的催化活性;在反应温度为230℃,甲醇与氯化氢物质的量之比为1:1,空速为724.4 h-1时,氯甲烷收率最高达到95%;反应115 h后,催化剂性能有所下降,利用空气氧化法对催化剂进行再生后,可使催化剂性能基本恢复。

HZSM-5 catalysts modified by SiO2 were prepared by the iso-volumetric impregnation method and the acidity was studied by NH3 temperature programmed desorption（NH3-TPD）. The catalysts were evaluated in a fixed bed reactor and the effects of reaction temperature, ratio of hydrogen chloride to methanol, and residence time on the catalytic performance of the catalysts were investigated. The results showed that ZSM-5（50） modified by SiO2（mass fraction of SiO2 1.0%） exhibited excellent reaction activity. The yield of chloride methane reached up to 95% under the conditions of reaction temperature 230℃, molar ratio of hydrogen chloride to methanol 1：1, space velocity 724.4 h-1. The catalytic life reached 115 h and the catalyst activity could be recovered by air oxidation method.