文献类型：期刊文献

英文题名：Conquering the solubility barrier of di-n-octylamine as structure-directing agent in hierarchical silicoaluminophosphate synthesis by using phase-transfer synthesis

作者：Yang, Fan[1];Zhou, Qiuming[2,3];Wang, Jia[1];Ding, Hongxin[4];Zhu, Xuedong[1];Zhu, Kake[1];Fan, Weibin[2]

机构：[1]East China Univ Sci & Technol, State Key Lab Chem Engn, UNILAB, Shanghai 200237, Peoples R China;[2]Chinese Acad Sci, Inst Coal Chem, State Key Lab Coal Convers, Taiyuan 030001, Peoples R China;[3]Univ Chinese Acad Sci, Beijing 100049, Peoples R China;[4]Fudan Univ, Dept Chem, Shanghai 200438, Peoples R China

年份：2023

卷号：461

外文期刊名：CHEMICAL ENGINEERING JOURNAL

收录：;EI(收录号：20230813615502);WOS:【SCI-EXPANDED(收录号:WOS:000946596100001)】；

基金：KZ is grateful for the financial support from National Natural Science Foundation of China (21878079) and the Foundation of State Key Lab- oratory of Coal Conversion (Grant No. J19-20-603) . The authors thank Research Center of Analysis and Test of East China University of Science and Technology for the help on the characterizations.

语种：英文

外文关键词：Organic structure -directing agent; Di; n -octylamine; Silicoaluminophosphate; Hydrophobic; SAPO-31; Hydroisomerization; N-dodecane

摘要：Silicoaluminophosphates (SAPOs) are a class of microporous solids employed as solid acid catalysts or adsorbents in petrochemical and coal chemical processes, which are often generated in hydrothermal synthesis using watersoluble organic structure-directing agents (OSDA), resulting in the formation of micron sized, rod-like crystals running along pore-channel direction for unidimensional SAPOs. The use of a low-cost, barely soluble di-noctylamine (DOA) as OSDA in a water/toluene biphasic media to crystallize SAPO-31 is reported. The product is disclosed to be a hierarchically porous material built up of self-assembled nanocrystals (similar to 110 nm) with enhanced diffusion property and preserved acidity comparable to that of a standard sample derived using di-nhexylamine as OSDA. The formation is mediated by the formation of a Pickering emulsion structure that favors crystal nucleation over growth, thus overcoming the solubility barrier of candidate OSDA. The obtained material exhibited higher isomer yield in catalytic hydroisomerization of n-dodecane compared to the control sample. Product distribution analysis discloses that mono-branched isomers are generated mainly inside the micropores, while di-branched isomers are produced via key-lock catalysis on pore-mouth sites. The increase in isomerization selectivity is attributed to the formation of more mono-branched isomers and their lowered cracking probability associated with enhanced diffusion property. This new synthetic protocol expands the toolkit of candidate OSDAs towards hydrophobic molecules and exemplifies porogen-free fabrication of hierarchical SAPOs. The uncovered origin of shape-selectivity offers a guidance towards manipulating hydroisomerization product slates.