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合成了固体超强酸催化剂 Zr O2 - Dy2 O3/ SO42 - ,并将其负载于分子筛 HZSM- 5上 ,制成复合型固体超强酸催化剂 Zr O2 - Dy2 O3/ SO42 - - HZSM- 5 (以下简称催化剂 ZDSH) .采用 Hammett指示剂法、吸附吡啶的 TPD法 ,考察催化剂 ZDSH的酸强度及其分布 ;通过热重分析 (TGA)、差热分析 (DTA)方法 ,考察镝对催化剂 ZDSH稳定性的作用 ;运用红外光谱 (IR)法 ,分析催化剂 ZDSH表面 SO42 -的结构 .结果表明 ,催化剂 ZDSH能催化柠檬酸与正丁醇的酯化反应 ,转化率达 97.6 7% ,反复使用 5次后 ,转化率仅下降 4.41% ;镝对催化剂 ZDSH的酸强度和酸量具有较大的调变作用 ,且能降低催化剂表面的积炭量 ,并且能通过形成镶嵌式结构抑制 SO42 -的流失 ,显著提高催化剂 ZDSH的稳定性 .
The solid superacid catalyst Zr O2 - Dy2 O3 / SO42 - was synthesized and supported on molecular sieve HZSM - 5 to make the composite solid superacid catalyst Zr O2 - Dy2 O3 / SO42 - HZSM-5 (hereinafter referred to as catalyst ZDSH) .Thymmett indicator method was used to adsorb pyridyl TPD method to investigate the acidity and distribution of the catalyst ZDSH. The effect of dysprosium on the stability of ZDSH catalyst was investigated by thermogravimetric analysis (TGA) and differential thermal analysis (DTA) The structure of SO42 - was analyzed by infrared spectroscopy (IR). The results showed that the catalyst ZDSH could catalyze the esterification of citric acid with n-butanol at a conversion of 97.6 7%. After repeated use for 5 times, The rate is only decreased by 4.41%; dysprosium has a greater modulation effect on the acid strength and acidity of the catalyst ZDSH, and can reduce the amount of carbon deposition on the surface of the catalyst, and can inhibit the loss of SO42 - by forming a mosaic structure, ZDSH stability.