Chapman Stephanie, O'Malley Alexander J, Miletto Ivana, Carravetta Marina, Cox Paul, Gianotti Enrica, Marchese Leonardo, Parker Stewart F, Raja Robert
Department of Chemistry, University of Southampton, University Road, Southampton, SO17 1BJ, UK.
UK Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UK.
Chemistry. 2019 Jul 25;25(42):9938-9947. doi: 10.1002/chem.201901188. Epub 2019 Jul 2.
Soft templating with siliceous surfactant is an established protocol for the synthesis of hierarchically porous silicoaluminophosphates (HP SAPOs) with improved mass transport properties. Motivated by the enhanced performance of HP SAPOs in the Beckmann rearrangement of cyclohexanone oxime to the nylon 6 precursor ϵ-caprolactam, an integrated theoretical and empirical study was carried out to investigate the catalytic potential of the siliceous mesopore network. Inelastic neutron scattering (INS) studies, in particular, provided unique insight into the substrate-framework interactions in HP (Si)AlPOs and allowed reactive species to be studied independent of the catalyst matrix. The spectroscopic (INS, FTIR spectroscopy, MAS NMR spectroscopy) and computational analyses revealed that in the organosilane-templated SAPO, the interconnectivity of micro- and mesopores permits cooperativity between their respective silanol and Brønsted acid sites that facilitates the protonation of cyclohexanone oxime in a physical mixture at ambient temperature.
使用硅质表面活性剂进行软模板法是一种成熟的合成具有改善传质性能的分级多孔硅铝磷酸盐（HP SAPOs）的方法。受HP SAPOs在环己酮肟贝克曼重排制备尼龙6前体ε-己内酰胺中增强性能的启发，开展了一项综合理论与实证研究，以探究硅质介孔网络的催化潜力。特别是非弹性中子散射（INS）研究，为HP（Si）AlPOs中的底物-骨架相互作用提供了独特见解，并使反应物种能够独立于催化剂基质进行研究。光谱分析（INS、傅里叶变换红外光谱、固体核磁共振光谱）和计算分析表明，在有机硅烷模板化的SAPO中，微孔和介孔的互连性允许其各自的硅醇和布朗斯台德酸位点之间协同作用，从而在室温下促进物理混合物中环己酮肟的质子化。
