微乳液法制备Pt-S2O82-/ZrO2-Al2O3型固体超强酸催化剂及其异构化性能

采用微乳液法负载Pt制备了Pt-S2O82-/ZrO2-Al2O3(Pt-SZA-M)固体超强酸催化剂, 以正戊烷异构化反应为探针, 对比了微乳液法和浸渍法负载Pt制备的催化剂(Pt-SZA)的异构化性能, 并采用XRD, FTIR, BET, TG-DTA, TPR和TEM对催化剂进行了表征. 结果表明, 与Pt-SZA催化剂相比, Pt-SZA-M催化剂中Pt粒子的粒径更小(4.5 nm)且尺寸更均一; Pt-SZA-M催化剂的比表面积(109.6 m2/g)比Pt-SZA催化剂(95.0 m2/g)增加了15.4%. Pt-SZA-M催化剂的初始还原温度比Pt-SZA催化剂降低了10~20℃, 表明微乳液法负载Pt可以提高催化剂的氧化活性, 提高氢分子在催化剂上的吸附解离能力. 异构化活性实验结果表明, 与Pt-SZA催化剂相比, Pt-SZA-M催化剂的低温活性得到明显改善, 在反应压力为2.0 MPa、 氢烃摩尔比为4: 1、 质量空速为1.0 h-1的条件下, Pt-SZA-M催化剂在反应温度为230℃时活性达到60.8%, 在100 h内异戊烷的收率可稳定在58.0%左右, 选择性在95.0%以上.

Preparation of Pt-S2O82-/ZrO2-Al2O3 Catalyst by Microemulsion Method and Its Performance for Isomerization

Pt-S2O2-8/ZrO2-Al2O3(Pt-SZA-M) solid superacid catalyst was prepared by microemulsion method.The isomerization performance of catalysts prepared with the microemulsion method and dipping method was compared with n-pentane isomerization as a probe reaction.The catalysts were characterized by XRD,FTIR,BET,TG,TPR and TEM.The results showed that compared with the Pt-SZA catalyst,the Pt particles on Pt-SZA-M were smaller(4.5 nm) and more uniform;the specific surface area of Pt-SZA-M was 109.6 m2/g,which was 15.4% higher than that of Pt-SZA(95.0 m2/g).The initial reduction temperature of Pt-SZA-M was decreased by 10—20 ℃ compared with that of Pt-SZA,which indicated that loading Pt by microemulsion method could improve the oxidative activity of catalyst and enhance the dissociation adsorption ability of H2 on the surface of catalyst.The activity test of isomerization performance indicated that compared to the Pt-SZA,the activity of isomerization of the Pt-SZA-M under low temperature was significant improved,at reaction temperature of 230 ℃,pressure of 2.0 MPa,hydrogen/hydrocarbon molar ratio of 4∶ 1 and weight hourly space velocity(WHSV) of 1.0 h-1,the isopentane yield was 60.8%.The isopentane yield was stabilized in ca.58.0% and the selectivity was higher than 95.0% within 100 h.