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Well hexagonally ordered CrSBA-15 catalysts synthesized by different hydrothermal methods were used, for the first time, for the selective synthesis of benzophenone (BP O) by liquid-phase oxidation of diphenylmethane (DPM) under various reaction conditions. To investigate the leaching of chromium species on the surface of silica networks, the results of original and reusable Cr-containing mesoporous silica catalysts were correlated and compared, and the catalytic activity of washed CrSBA-15(8) was also demonstrated. Based on the all catalytic results for this reaction, CrSBA-15(8) was found to be a highly active and an environmentally friendly solid catalyst and has superior catalytic activity than other Cr-containing mesoporous catalysts.

Highly ordered two-dimensional SnSBA-15 molecular sieve catalysts with different concentrations of tin species have been synthesized using Pluronic P123 as a structure directing agent under pH-adjusting direct hydrothermal method and have been used for synthesis of nopol by Prins condensation of β-pinene with paraformaldehyde. The influence of various reaction parameters on this reaction has been investigated. The Prins condensation reaction has also been carried out with different solvents for finding the best solvent with a good catalytic activity. In addition, the Prins condensation of β-pinene with paraformaldehyde in the presence of propyl cyanide with water has been carried out for the synthesis of nopol, and in this condition the catalytic activity of the catalyst used was not seriously affected. On the basis of all catalytic results, SnSBA-15(5) is found to be a highly active, water-resistant and recyclable heterogeneous catalyst for selective synthesis of nopol.

t-Butylation of toluene with t-butylalcohol (t-BuOH) as alkylating agent was conducted under liquid phase reaction conditions over Al-MCM-41 with different Si/Al ratios for highly selective synthesis of 4-t-butyltoluene. For the reactions, the influences of various reaction parameters such as reaction temperature, time and t-BuOH to toluene ratio are discussed. With increasing the Si/Al ratios of Al-MCM-41 catalysts from 21 to 104, the conversion of toluene, and the yield and selectivity of 4-t-butyltoluene decreased because the number of Bronsted acid sites in Al-MCM-41catalysts is found to decrease almost linearly with increasing ratios of Si/Al. The conversion and selectivity is increased in Al-MCM-41(21) with each cycling of reaction. The Si/Al ratio of 21 is found to be more suitable for the t-butylation of toluene to highly selective synthesis of 4-t-butyltoluene. Thus the selectivity of 4-t-butyltoluene is higher in Al-MCM-41(21) than that in other Al-MCM-41 samples.

The mesoporous molecular sieves Al-MCM-41 with Si/Al ratios equal to 21, 42 and 83 were synthesized under hydrothermal conditions using cetyltrimethylammonium (CTMA + ) surfactants as template in the absence of auxiliary organics. The same ratios of Al-MCM-41 materials were impregnated using sulfuric acid; the materials are sulfated Al-MCM-41 (SO 4 2− /Al-MCM-41). The mesoporous SO 4 2− /Al-MCM-41 materials were characterized using several techniques, e.g. CP–AES, Nephelometer, XRD, FTIR, thermogravimetric–differential thermal analysis (TG/DTA), 27 Al -MAS-NMR, nitrogen adsorption and pyridine acidity (TPD and FTIR) measurements. Crystallinity, surface area, pore diameter and pore volume of SO 4 2− /Al-MCM-41 decreased on expelling the aluminum from the Al-MCM-41 framework and the Lewis acidity increased. The Bronsted, Lewis acidity and total acidity of the SO 4 2− /Al-MCM-41 materials were determined by FTIR-pyridine and TPD-Pyridine acidity measurements. The catalytic results were compared with those obtained by using Al-MCM-41, sulfuric acid, amorphous silica-alumina, H-β, USY and H-ZSM-5 zeolites. The SO 4 2− /Al-MCM-41 catalysts were found to be more effective in the ethoxylation of hydroxyl biaromatics, for example, in the production of ethyl β-naphthyl ether (neroline) from β-naphthol using ethyl acetate as the ethoxylating reagent. The SO 4 2− /Al-MCM-41 catalyst exclusively forms the product of ethyl β-naphthyl ether and has much higher selectivity than any other catalysts except USY.

Mesoporous silica molecular sieves MCM-41 containing zinc and aluminum ions (Zn-Al-MCM-41) with Si/(Zn + Al) ratio equal to 340 and 380 and only aluminum ions with Si/Al ratio equal to 93 and 104, respectively, were synthesized under hydrothermal conditions using cetyltrimethylammonium (CTMA + ) surfactants as template in the absence of auxiliary organics. The mesoporous materials, viz. Zn-Al-MCM-41 and Al-MCM-41 were characterized using several techniques, e.g. powder X-ray diffraction (XRD), nitrogen adsorption measurements, Fourier transform-infra red spectroscopy (FT-IR) and thermogravimetric–differential thermal analyzer (TG–DTA). XRD studies indicated that the calcined materials had the standard MCM-41 structure. Nitrogen adsorption was used to determine specific surface area, pore volume, and pore size distribution in the Zn-Al-MCM-41(340), Zn-Al-MCM-41(380), Al-MCM-41(93) and Al-MCM-41(104) mesoporous molecular sieves. FT-IR studies showed that Zn and Al ions were incorporated into the hexagonal mesoporous structures of Zn-Al-MCM-41 and Al-MCM-41. The thermal stability of the as-synthesized materials was studied using TG–DTA. The effect of reaction temperature, WHSV and isopropanol:toluene ratios on the selectivity of p-cymene were studied. The Zn-Al-MCM-41(340) catalyst containing larger pore size and higher number of Bronsted acid sites was found to be more effective in the alkylation of alkyl aromatics, for example, in the production of p-cymene from toluene, using 2-propanol as the alkylating reagent. The selectivity of p-cymene under varying experimental condition, viz. effect of reaction temperature, WHSV and ratio of isopropanol:toluene for the various catalysts follows the sequence Zn-Al-MCM-41(340 )> Al-MCM-41(93 )> Zn-Al-MCM-41(380 )> Al-MCM-41(104). © 2002 Elsevier Science B.V. All rights reserved.