| Because of its certain acid and large specific surface, γ-Al2O3was often the preferred catalyst carrier. But when γ-Al2O3was used as the selective hydrogenation catalyst for dienes, the existence of certain acidity on the γ-Al2O3often made catalyst activity too high, even led to rapid coking and deactivation. If α-Al2O3obtained by conventional high temperature roasting method was used as carrier, the inert α-Al2O3had the capability of overcoming the rapid coke induced by carrier acid, but the specific surface area was too small,which would not only make the distribution of the metal active center greatly reduced, but also result in the reduction of catalyst activity. Therefore, the preparation of inert-Al2O3with high surface area had became the key to solving the diene selective hydrogenation.Inert-Al2O3with High specific surface area was prepared from Al(NO3)3·9H2O and CH4N2O by the microwave synthesis method, and preparation process were studied. Large specific surface of NiO/inert-Al2O3catalyst was prepared by the impregnation method, and its performance of selected hydrogenation for the diene in the model gasoline was evaluated by the micro-reactor device. The method of gas chromatographic analysis for reaction product was established. Large specific surface of Mo2C-Ni/inert-Al2O3catalyst was prepared by the impregnation-mixing-reduction method, its performance of selected hydrogenation for the diene in the model gasoline was evaluated. The high surface area of inert-Al2O3was modificated by the alkali metals, alkaline earth metals, the affects of different metal incorporation of inert-Al2O3was investigated. Furthermore, the modified inert-Al2O3carrier preparation catalyst for selective hydrogenation reaction was compared with the catalyst prepared by the inert-Al2O3without modification, the influence of change of the catalyst carrier was investigated. By the means of XRD, BET, NH3-TPD and SEM, the synthesized inert-Al2O3and its catalyst was characterized.The main results are as follows:1、High specific surface area inert-Al2O3with some α-Al2O3phase could be prepared from A1(NO3)3·9H2O and CH4N2O by precipitation with the microwave synthesis, the specific surface area was about200m2·g-1。The suitable conditions for synthesis were the mole ratio of2.5-3.0(Al(NO3)3·9H2O/Urea), the microwave power of600W, the radiation time about about3-4min. 2、The the amount of acid High specific surface area inert-Al2O3was0.0977mmol·g-1which is far less than γ-Al2O3, Whose amount of acid was0.5862mmol·g-1, and it didn’t have desorption peak of NH3. its morphology was the fragment shape.3、When the catalyst loaded about10%(weight) NiO on the inert-Al2O3and it was activated with H2, its hydrogenation percent conversion and selectivity for the diene in the model gasoline achieved both about100%under the atmosphere pressure, the temperature of80℃, the LHSV of6h-1,the H2/oil ration of100/1.4、The Mo2C-Ni/inert-Al2O3catalyst was prepared by inert-Al2O3. The Mo for loading amount was6%, The molar ratio of Mo/Ni is10/3. The optimum reaction conditions were the temperature of70℃, the LHSV of5h-1, the H2/oil ration of350/1.5、When inert-Al2O3was modified by mixing Alkali metal or alkaline earth metal in the materials directly, the product was amorphous alumina. The surface of product was modified by Rb is303.3m2·g-1. When Na, K, Mg, Ca, Ba was utilized to modify inert-Al2O3by impregnation method, the inert-Al2O3also had a phase, and the influence on surface area of inert was least by using Mg modifying, the result is107.8m2·g-1. |
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