Direct Synthesis of 2D-Hexagonal Mesoporous Iron Silicate and its Catalytic Activity for Selective Friedel-Crafts Alkylation

ABSTRACT

2D-hexagonal mesoporous iron silicate (HMFeS) has been synthesized hydrothermally in the presence of a mixture of an amphiphilic triblock copolymer, pluronic F127 and 1,2,4-trivinylcyclohexane (TVCH) as swelling agent under acidic aqueous conditions. The direct incorporation of iron(III) into 2D-hexagonal silicate framework can be monitored in a optimized molar ratio of water and hydrochloric acid. The mesophase of the materials was investigated by using small-angle powder X-ray diffractions (PXRD), transmission electron microscopy (TEM) image analysis and nitrogen adsorption/desorption studies. TEM image and PXRD revealed that the material had 2D-hexagonal mesoporous architecture. The morphology of the material was investigated by using scanning electron microscope (SEM) and framework bonding by utilizing FT IR spectroscopy. The atomic absorption spectrophotometer (AAS) was used to estimate the incorporated iron sites within the silicate framework. BET surface area (780 m2g-1) and peak pore size of HMFeS (10.07 nm) is much higher than the pure silica SBA-15 (611 m2g-1 and peak pore size of 9.09 nm). This mesoporous material (HMFeS) acts as a very good catalyst in the Friedel Craft benzylation and benzoylation reactions of arenes under optimized reaction condition using benzyl chloride and benzoyl chloride as the bezylating and benzoylating agents, respectively.

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