New Ti-incorporated MCM-36 as an efficient epoxidation catalyst prepared by pillaring MCM-22 layers with titanosilicate
Journal
Journal of Catalysis
Journal Volume
319
Pages
247-257
Date Issued
2014
Author(s)
Abstract
A new Ti-incorporated MCM-36 material (shortly termed Si/Ti-MCM-36) with bimodal pore structures was prepared through sequential steps. The hexadecyltrimethylammonium swollen MCM-22 precursor was pillared with titanosilicate formed via hydrolysis of an interlayer mixture of tetraethylorthosilicate (TEOS) and tetrabutylorthotitanate (TBOT). Hydrolyzation of TEOS and TBOT was a key step for intercalation efficiency. The X-ray diffraction (XRD) patterns and N2 sorption isotherm data confirmed the intercalation efficiency and the retention of basal layer MWW structure. A slightly ordered stacking of MWW sheets along c-direction was observed, generating mesopores of ca. 2 nm in diameter. Ti(IV) was well dispersed in the matrix of titanosilicate pillars, which expand the MWW layers apart. The Ti coordination environment examined by DR UV–Vis and Ti K-edge X-ray absorption spectroscopies was mainly in tetrahedral coordination. Post-treatment of the Si/Ti-MCM-36 materials with acid resulted in a new Ti-incorporated MCM-36 with good catalytic activities in cyclohexene epoxidation.
SDGs
Type
journal article