Study On Catalyst For Alkylation Of Toluene With Tert-butyl Alcohol

A series of zeolite catalysts, including mordenite zeolite(HM), Beta zeolite(Hβ), ZSM zeolite(HZSM-5),were prepared by exchanging NH4+ methods. Their physicochemical properties such as the pore structure, acid property and acidity were characterized by X-ray diffraction (XRD), pyridine infrared spectroscopy (Py-IR) and ammonia program temperature desorption (NH₃-TPD) techniques. Based on the characterizations, the catalytic performances of catalysts in the alkylation of toluene with tert-butyl alcohol were investigated in a batch reactor. The relations between the physicochemical properties of catalysts and their activity and selectivity had been discussed in liquid phase alkylation of toluene with tert-butyl alcohol.(1) The various zeolite catalysts. Catalytic performances of HM, USY, Hβand HZSM-5 were investigated in the alkylation of toluene with tert-butyl alcohol in a 100ml stainless steel batch reactor equipped with a stirrer, and their physical chemical properties were characterized by XRD, NH₃-TPD and Py-IR techniques. Both acid type and pore structure of the zeolites are the key factors influencing the catalytic behavior. The active centers with weak and medium acid strength and 12-membered ring open pore structure facilitate the catalytic activity in the reaction. The Lewis acid sites in catalysts mainly act as the active centers for the tert-butylation of toluene, and the strong acid sites do not favor the target product.(2) Ultra stable Y zeolite catalyst. It shows high catalytic conversion and selectivity in the tert-butylation of toluene because of its unique pore structure and acid property. It is revealed that the conversion of toluene 47.15%, the selectivity of tert-butyltoluene (TBT) 97.44% and the selectivity of para-tert-butyltoluene (PTBT) 65.62% are obtained for the appropriate conditions, what is calcined temperature of catalyst 623K, reaction temperature 180℃, initial pressure 0.6MPa and the molar ratio of tert-butyl alcohol to toluene 2, w(material): w(catalyst) =10, the molar ratio of cyclohexane as solvent to toluene 10, reaction time 5h.(3) mordenite zeolite catalyst. Their physical chemical properties of catalysts under...