Wu Shiyu, Yi Yufu, Liao Shengliang, Si Hongyan, Yang Yuling, Fan Guorong, Wang Peng
College of Forestry, Jiangxi Agricultural University; National Forestry and Grassland Bureau Woody Spice (East China) Engineering Technology Research Center, Nanchang 330045, China.
Langmuir. 2021 Jan 19;37(2):957-968. doi: 10.1021/acs.langmuir.0c03356. Epub 2021 Jan 5.
We described the comprehensive synthesis, characterization, and catalytic performance of a novel type of the ordered cubic 3̅ supermicroporous silicas by using tetraethyl orthosilicate as a silicon source and a hydroxyl-functionalized quaternary ammonium salt as a template under alkali conditions. The effects of various reaction conditions on the pore structure and morphology of the silica materials were thoroughly investigated. Our results showed that under a wide range of reaction conditions, supermicroporous silicas with a highly ordered cubic 3̅ structure can be produced with a large BET specific surface area of 1741 m/g, high pore volume of 0.91 cm/g, concentrated pore size at 19.1 Å, and crystalline morphology. After Al doping, the obtained aluminosilicates preserved a highly ordered cubic supermicroporous structure. By using the H-form aluminosilicates as catalysts, we selectively dimerized β-pinene. The catalysts exhibited an excellent catalytic activity for β-pinene dimerization with a conversion yield up to 100%. Compared with conventional mesoporous H-form Al-MCM-48 catalysts, the prepared supermicroporous catalysts exhibited superior catalytic performance due to their excellent shape-selective properties, producing the β-pinene dimer in a yield up to 72.4% with dimer/oligomer ratios in the range of 7.5-10.1. This study featured a detailed preparation and characterization of supermicroporous silica with novel microstructures and showed its utility in catalytic dimerization.