Al-SO_3H-SBA-15孔径可控制备及其对醋酸与异丁烯加成酯化的催化性能

Pore controlled preparation of Al-SO_3H-SBA-15 for the addition of acetic acid and isobutylene

以均三甲苯为调节剂,采用一步共缩合法制备一系列孔径可调(3.71~4.76 nm)、高比表面积、Al掺杂且磺酸嫁接的介孔分子筛SBA-15(x-AS-SBA-15)。通过小角度X线衍射(SAXRD)、N_2吸附-脱附、热分析(TG)、NH_3程序升温脱附(NH_3-TPD)、傅里叶变换红外光谱(FT-IR)、紫外-可见光谱(UV-Vis)和扫描电子显微镜(SEM)等手段对x-AS-SBA-15的结构、酸量等理化性质进行表征。结果表明:x-AS-SBA-15仍然留有六方介孔的相结构,但是随着x值的增大,有序介孔分子筛的孔径减小,有序度有所降低。同时研究了x-AS-SBA-15在醋酸与异丁烯无溶剂加成酯化反应中的催化性能,结果表明:50-AS-SBA-15具有最优的催化活性和产物选择性。50-AS-SBA-15用量为醋酸的5%、反应温度为30℃、烯酸摩尔比为3∶1时,醋酸转化率为93.5%,醋酸叔丁酯选择性为94.0%。催化剂拥有良好的稳定性,重复利用5次催化活性依旧保持稳定。

The modified SBA-15 materials（ x-AS-SBA-15） with Al ions and organo-sulfonic acid were synthesized in a one-pot approach of co-condensing inorganic-organic reagents in the presence of different amounts of trimethylbenzene（ TMB）. The obtained materials was characterized by small angle X-ray diffraction（ SAXRD）,N2 adsorption-desorption,thermal analysis（ TG）,temperature programmed desorption of NH3（ NH3-TPD）,Fourier transform infrared spectroscopy（ FT-IR）,ultraviolet-visible spectroscopy（ UV-Vis） and scanning electron microscope（ SEM） techniques. Results showed that x-ASSBA-15 had typically mesoporous structure with tunable pore size of 3. 71-4. 76 nm and huge specificsurface area. However the pore size and the specific pore volume decreased with the increase of TMB amount. The activity of x-AS-SBA-15 in the additive reaction of acetic acid with isobutene was investigated. It turned out that the 50-AS-SBA-15 had the best catalytic activity and the product selectivity.The conversion of acetic acid could reach 93. 5% with the selectivity of tertiary butyl acetate as high as 94. 0% over 50-AS-SBA-15,using a catalyst loading of 5% and isobutene/acetic acid molar ratio of 3 ∶1 under 30 ℃.The 50-AS-SBA-15 catalyst could be reused up to five times without significant loss of catalytic activity.