金属改性固体超强酸催化剂的制备及催化性能研究

Study on preparation and isomerization performance of solid super acid catalyst modified by metal

合成了大孔径球形Al2O3载体,并采用一步水热法,以正丁醇锆为锆源制备了ZrO2-Al2O3复合载体,以过硫酸铵为硫源,制备了不同过渡金属M(Ni、Zn、Fe、Mn)改性的M-S2O82-/ZrO2-Al2O3催化剂。采用BET、XRD、SEM、FT-IR对催化剂进行了表征,结果表明:制备的4种催化剂均形成了固体超强酸结构,其中Ni-SZA-R催化剂的四方晶相晶粒尺寸最小,比表面积最大。考察了不同过渡金属制备的催化剂对正戊烷异构化性能的影响,结果表明:4种催化剂异构化活性由大到小依次为Ni-SZA-R,Zn-SZA-R,Fe-SZA-R,Mn-SZA-R。在反应温度220℃、反应压力2.0 MPa、氢气与正戊烷物质的量比4∶1、质量空速(WHSV)1.0 h-1的条件下,Ni-SZA-R催化剂催化正戊烷异构化反应,异戊烷收率为69%。

The spherical Al2O3 carrier with large aperture is prepared,and then using zirconium n-butanol as zirconium resource,ammonium persulfate as sulfur resource,the ZrO2-Al2O3 complex carrier is prepared,furthermore the M-S2O82-/ZrO2-Al2O3 catalysts modified by different transition metals M(Ni,Zn,Fe,Mn)are prepared by one step hydrothermal method.The catalysts are characterized by BET,XRD,SEM and FT-IR,and the results show that all of the four prepared catalysts have solid super acid structure,among them,Ni-SZA-R catalyst has the smallest grain size of tetragonal crystalline phase,and the largest specific surface area.The effects of the catalysts with different transition metals on the performance of isomerization of n-pentane are investigated,and the results show that the sequence of isomerization activities from strong to weak is Ni-SZA-R,Zn-SZA-R,Fe-SZA-R,Mn-SZA-R.Under the conditions of reaction temperature 220℃,pressure 2.0 MPa,ratio of hydrogen to n-pentane 4∶1 and weight hourly space velocity(WHSV)1.0 h-1,the yield of i-pentane can reach 69%by using Ni-SZA-R catalyst.