The phosphorus tungsten(PW) heteropoly acids were immobilized on the mesoporous molecular sieves(MCM-41) by wet impregnation. The prepared catalysts were characterized by X-ray powder diffraction, TG and DTA,FTIR. The alkylation of p-cresol with isobutylene was carried out over the PW /MCM-41 catalysts. The influences of various reaction parameters such as reaction temperature, time, PW loading, and catalysts amount on the conversion of p-cresol and the products selectivity were also investigated. Under the optimized reaction conditions of 90 °C,PW loading of 10%, catalyst amount of 1.5%, p-cresol conversion was found to be 93.89% with product rate to 2-tert-butyl-p-cresol 51.29%, 2,6-di-tert-butyl-p-cresol 42.48% and tert-butyl-p-tolyl ether 0.12%, responding to selectivity of 2, 6-di-tert-butyl-p-cresol 45.24%.

No abstract

Amino functional silica gel was synthesized by in-situ hydrolysis method in the present of silane coupling agent. Then dendrimer-like polyamidoamines based on the silica gel surface (PAMAM-SG) were prepared using Micheal addition of the amino and methyl acrylate, and ester-exchange of ethylene diamine and the ester group. The effects of solution pH, concentration and temperature on the adsorption capacity of PAMAM-SG for Cr3+were studied. The optimum pH range is 4.0-7.0. The adsorption rate decreased with increasing the time, but increased with increasing the temperature. The adsorption capacity increased with increase of the concentration until the adsorption reached equilibrium. The adsorption capacity increased with the generations of PAMAM-SG.