Phenyl-amino sulfonic solid acid-MCM-41 complex: A highly active and selective catalyst for the synthesis of mono-alkylated products in the solvent free tert-butylation of phenol

A simple post synthesis route was established for heterogenizing 3-(3-aminophenylamino)propane-1-sulfonic acid onto functionalized mesoporous MCM-41 to give an inorganic-organic hybrid, MCM-3-NHPhSO3H. The XRD analysis of the hybrid material exhibited three well-resolved diffraction peaks for the (1 0 0), (1 1 0) and (2 0 0) planes, which indicates the retention of the mesostructure. The C-13 CP-MAS NMR spectroscopy of the hybrid material showed four intense carbon peaks from 107 to 131 ppm, corresponding to the aromatic ring of the grafted ligand. Surface properties of the material revealed a pore size of 1.84 nm and a specific surface area of 572 m(2) g(-1). The TEM images of the hybrid showed a well-ordered honey-comb structure after the series of modifications. The catalytic performance of MCM-3-NHPhSO3H resulted in 99% conversion of tert-butylphenol (TBA) with selectivity to only mono-alkylated products. The initial selectivity yield of 98% tert-butylphenol ether (TBPE) had decreased until a product distribution of 64% 2-(tert-butyl)phenol (2-TBP), 32% 4-(tert-butyl)phenol (4-TBP), 3% (TBPE) and 1% isobutene (IBE) was obtained. The catalyst could be regenerated without significant loss in reactivity. (C) 2013 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.