Novel efficient synthesis of β-naphthyl methyl ether using sulfated mesoporous molecular sieve Al-MCM-41

The mesoporous molecular sieve Al-MCM-41 and sulfated Al-MCM-41 were prepared and characterized with various techniques: XRD, ICP-AES, BET, (27)Al and (29)Si MAS-NMR, FTIR, TPD of ammonia and N(2) adsorption isotherms. Impregnation of Al-MCM-41 with sulfuric acid results in the decrease of crystallinity, surface area, pore volume and the expelling of aluminum from the AI-MCM-41 framework, with concomitant increase of the Lewis acidity. P-Naphthyl methyl ether was synthesized from P-naphthol and methanol at 200 degrees C and 35 bar over Al-MCM-41 and sulfated Al-MCM-41 in a batch autoclave reactor. The catalytic results were compared with those obtained by using sulfuric acid, amorphous silica-alumina, gamma-alumina, USY and H-ZSM-5 zeolites. The sulfated AI-MCM-41 catalyst forms the exclusive product of beta-naphthyl methyl ether and has much higher yields than other catalysts except USY. The non-framework aluminum existing in the intrachannel space of Al-MCM-41 probably causes the enhancement of catalyst activity. The catalytic results are correlated to the acidity, the surface area and the pore size of the catalysts. (C) 1999 Elsevier Science B.V. All rights reserved.