Characterization and Catalytic Properties of Al-MCM-41 Mesoporous Materials Grafted with Tributyltin Chloride

Abstract

Surface organometallic chemistry (SOMC) is a recently developing research field. It is of great significance for the quantitative modification, restoration of solid surface, identification of the physical and chemical nature of surface and the preparation of new catalyst. The production of R3Sn-O-MCM-41 (R3SnM) was obtained by heating tributyltin chloride and Al-MCM-41 mixture at 170 °C for 5 h under stirring in nitrogen atmosphere. The composition, structure and surface physical and chemical properties of the samples were characterized by inductively coupled plasma mass spectrometry (ICP-MS), 13C, 119Sn, 29Si and 27Al solid state NMR (nuclear magnetic resonance) spectra, in-situ pyridine infrared spectroscopy (Py-IR), N2 adsorption-desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), etc. The results of ICP and organic elemental analysis shows that the grafting yield wSn was 6.46% for R3SnM. H0 (the negative logarithm of the acid concentration) and the number of acid sites for R3SnM respectively were 2.77–0.99 and 4.8 mmolg−1 by the Hammett method. N2 adsorption-desorption, XRD, TEM analysis showed that R3SnM with ordered hexagonal mesopore structure, resulted in the decease of surface areas and pore size as well as the increase of mesoporous volume and surface acidity, as compared to Al-MCM-41. R3SnM was used in the synthesis of isoamyl acetate. The yield of isoamyl acetate was 96% when n(isoamyl alcohol): n(acetic acid) 1.0:1.0, wR3SnM = 5%, 138°C for 5 h. The catalyst can be reused and the yield of 86% can be attained when catalyst was reused five times at the same catalytic conditions.