In this study, Raney-Ni/Al_2O_3 catalysts were prepared from precursors which were calcined in different atmosphere(argon and air) and leached for different time. XRD, SEM, H_2-TPR and BET techniques were introduced t...In this study, Raney-Ni/Al_2O_3 catalysts were prepared from precursors which were calcined in different atmosphere(argon and air) and leached for different time. XRD, SEM, H_2-TPR and BET techniques were introduced to characterize the catalysts, and hydrogenation of unsaturated hydrocarbons, including vinyltoluene, dicyclopentadiene and indene, was used as probe reaction to evaluate the catalytic hydrogenation performance of the catalysts. The results demonstrated that the calcination atmosphere had noticeable effects on the compressive strength and hydrogenation performance of Raney-Ni/Al_2O_3. The catalyst calcined in argon exhibited better compressive strength and catalytic performance than the one calcined in air. The compressive strength and activity stability of catalyst were also determined by the leaching time. A too longer leaching time was not conducive to improving the compressive strength and catalytic performance of catalysts. When the precursor calcined in argon was treated in a 15%(by wt.) sodium hydroxide solution at 343 K for 5 h, a catalyst with higher compressive strength(at 26.10 N/mm) was obtained and the conversion of vinyltoluene, dicyclopentadiene(DCPD), and indene could amount to more than 87.5%, 99% and even 100%, respectively, under the reaction conditions covering a temperature of 493 K, a hydrogen pressure of 2.0 MPa, a LSHV of 3.0 h^(-1), and a hydrogen/oil ratio of 200:1.展开更多
Alkylation of toluene With 2-chloro-2-methylpropane （t-Bu-C1） to synthesize para-tert-butyltoluene （PTBT） was carded out in the presence of triethylamine hydrochloride-aluminum chloride ionic liquids used as the c...Alkylation of toluene With 2-chloro-2-methylpropane （t-Bu-C1） to synthesize para-tert-butyltoluene （PTBT） was carded out in the presence of triethylamine hydrochloride-aluminum chloride ionic liquids used as the catalyst. The ionic liquids were prepared with different molar ratios of Et3NHC1 to A1CI3, and the effect of the molar ratio between A1C13 and Et3NHC1, the reaction time, the reaction temperature, the ionic liquid dosage, as well as the molar ratio of toluene to chloro- 2-methylpropane on the alkylation reaction of toluene with chloro-2-methyl-propane was investigated. The test results showed that the acidic ionic liquids prepared with Et3NHC1 and A1C13 had good activity and selectivity for the alkylation reaction of toluene with alkyl chloride to produce PTBT. The optimal reaction conditions were specified at an A1C13 to Et3N- HCI ratio of 1.6, a reaction temperature of 20 ℃, a mass fraction of toluene to ionic liquid of 10%, and a chloro-2-methyl- propane to toluene molar ratio of 0.5. Under the suitable reaction conditions, a 98% conversion of chloro-2-methylpropane and an 82.5% selectivity of PTBT were obtained. Ionic liquids could be reused 5 times with its catalytic activity unchanged, and the regenerated ionic liquids can be recycled.展开更多
How to remove trace amount of sulfur in benzene is of significance,and deep desulfurization by Ni-containing absorbents is an efficient and promising method.In this paper,The Raney Ni/Al2 O3 adsorbent was prepared and...How to remove trace amount of sulfur in benzene is of significance,and deep desulfurization by Ni-containing absorbents is an efficient and promising method.In this paper,The Raney Ni/Al2 O3 adsorbent was prepared and its kinetic and thermodynamic characteristics on adsorptive desulfurization of benzene were studied.The results showed that Raney Ni/Al2 O3 adsorbent exhibited good adsorption performance.The equilibrium isotherms indicated that the adsorption of thiophene over the Raney Ni/Al2 O3 adsorbent complied with the Freundlich model.The results of adsorption kinetics studies showed that the pseudo-second-order kinetics equation was more advantageous than the pseudo-first-order kinetics equation in describing the adsorption kinetics of thiophene on Raney Ni/Al2 O3.The rate constant value(kp)was positively correlated with the temperature whereas the adsorption mass transfer process was mainly determined by the intraparticle and film diffusion.The adsorption thermodynamic analysis proved that△G^0<0,△H^0>0,and△S^0>0,implying that the adsorption was a spontaneous,entropy-increasing and endothermic process.展开更多
New supported Raney-Cu catalyst was prepared from pseudo-boehmite powder and copper aluminum alloy powder. It could be used in a continuous-flow fixed-bed reactor and it was also a good catalyst for hydrogenolysis of ...New supported Raney-Cu catalyst was prepared from pseudo-boehmite powder and copper aluminum alloy powder. It could be used in a continuous-flow fixed-bed reactor and it was also a good catalyst for hydrogenolysis of glycerol to propylene glycol after the two raw materials were processed by the following procedures: molding, drying, calcination, and leaching. XRD, H2-TPR, as well as SEM technique were employed to study the physicochemical properties of the catalysts, and the hydrogenolysis of glycerol to 1,2-propylene glycol (1,2-PDO) was used as a probe to evaluate the performance of supported skeletal copper catalysts. The test result indicated that CuAl2 was the main crystal phase of precursor after the dried strips were calcined at 850 °C in air. A part of CuAl2 was oxidized to α-Al2O3, which was the main contributor to the strength of Raney-Cu/Al2O3, while the remaining CuAl2 was converted to active skeletal copper after the leaching process. The effects of reaction temperature, hydrogen pressure, LHSV, hydrogen-oil ratio, glycerol concentration, and alkaline additives on the catalytic performance were studied in water or ethanol, respectively. Conversion of glycerol and selectivity of 1,2-PDO were 30.9% and 91.4% in water, or 99.0% and 73.6% in the ethanol system, respectively, when the reaction was performed at a temperature of 215 °C, a H2 pressure of 3 MPa, a LHSV of 1.0 h-1, a hydrogen-oil ratio of 500, and a glycerol concentration of 20%(ethyl alcohol solution).展开更多
Supported nickel-based catalysts were prepared by the incipient wetness impregnation method for the selective hydrogenation of methyl isobutyl ketone to methyl isobutyl carbinol in a fixed-bed reactor. The effects of ...Supported nickel-based catalysts were prepared by the incipient wetness impregnation method for the selective hydrogenation of methyl isobutyl ketone to methyl isobutyl carbinol in a fixed-bed reactor. The effects of the nickel source,Ni loading, calcination time, and calcination temperature on the hydrogenation performance were studied. The experimental results showed that the Ni/γ-Al_2O_3 catalyst demonstrated the highest catalytic performance under the preparation conditions by using nickel nitrate as the nickel source with a NiO loading of 20%, followed by calcination at 440°C for 5h. In addition,this catalyst showed the largest specific surface area, best crystal structure, highest active component content, smallest particle size, and uniform distribution of NiO on the surface of the carrier. The nickel-based catalyst prepared using the optimized conditions exhibited a 96.1% conversion of methyl isobutyl ketone, with a methyl isobutyl carbinol selectivity of 99.6%. The described procedure is very effective for the preparation of methyl isobutyl carbinol using methyl isobutyl ketone as the feedstock.展开更多
基金the Beijing Municipal Commission of Education for funding (PXM2013-014222)
文摘In this study, Raney-Ni/Al_2O_3 catalysts were prepared from precursors which were calcined in different atmosphere(argon and air) and leached for different time. XRD, SEM, H_2-TPR and BET techniques were introduced to characterize the catalysts, and hydrogenation of unsaturated hydrocarbons, including vinyltoluene, dicyclopentadiene and indene, was used as probe reaction to evaluate the catalytic hydrogenation performance of the catalysts. The results demonstrated that the calcination atmosphere had noticeable effects on the compressive strength and hydrogenation performance of Raney-Ni/Al_2O_3. The catalyst calcined in argon exhibited better compressive strength and catalytic performance than the one calcined in air. The compressive strength and activity stability of catalyst were also determined by the leaching time. A too longer leaching time was not conducive to improving the compressive strength and catalytic performance of catalysts. When the precursor calcined in argon was treated in a 15%(by wt.) sodium hydroxide solution at 343 K for 5 h, a catalyst with higher compressive strength(at 26.10 N/mm) was obtained and the conversion of vinyltoluene, dicyclopentadiene(DCPD), and indene could amount to more than 87.5%, 99% and even 100%, respectively, under the reaction conditions covering a temperature of 493 K, a hydrogen pressure of 2.0 MPa, a LSHV of 3.0 h^(-1), and a hydrogen/oil ratio of 200:1.
基金the financial support from the Beijing University of Chemical Technologythe Key Laboratory of Advanced Chemical Engineering and Technology, Beijing Institute of Petrochemical Technology, for the analysis of samples
文摘Alkylation of toluene With 2-chloro-2-methylpropane （t-Bu-C1） to synthesize para-tert-butyltoluene （PTBT） was carded out in the presence of triethylamine hydrochloride-aluminum chloride ionic liquids used as the catalyst. The ionic liquids were prepared with different molar ratios of Et3NHC1 to A1CI3, and the effect of the molar ratio between A1C13 and Et3NHC1, the reaction time, the reaction temperature, the ionic liquid dosage, as well as the molar ratio of toluene to chloro- 2-methylpropane on the alkylation reaction of toluene with chloro-2-methyl-propane was investigated. The test results showed that the acidic ionic liquids prepared with Et3NHC1 and A1C13 had good activity and selectivity for the alkylation reaction of toluene with alkyl chloride to produce PTBT. The optimal reaction conditions were specified at an A1C13 to Et3N- HCI ratio of 1.6, a reaction temperature of 20 ℃, a mass fraction of toluene to ionic liquid of 10%, and a chloro-2-methyl- propane to toluene molar ratio of 0.5. Under the suitable reaction conditions, a 98% conversion of chloro-2-methylpropane and an 82.5% selectivity of PTBT were obtained. Ionic liquids could be reused 5 times with its catalytic activity unchanged, and the regenerated ionic liquids can be recycled.
基金financially supported by the Importation and Development of High-Caliber Talents Project of Beijing Municipal Institutions(CIT&TCD 20130325)the Project of Construction of Innovative Teams and Teacher Career Development for Universities and Colleges under Beijing Municipality(IDHT20180508)。
文摘How to remove trace amount of sulfur in benzene is of significance,and deep desulfurization by Ni-containing absorbents is an efficient and promising method.In this paper,The Raney Ni/Al2 O3 adsorbent was prepared and its kinetic and thermodynamic characteristics on adsorptive desulfurization of benzene were studied.The results showed that Raney Ni/Al2 O3 adsorbent exhibited good adsorption performance.The equilibrium isotherms indicated that the adsorption of thiophene over the Raney Ni/Al2 O3 adsorbent complied with the Freundlich model.The results of adsorption kinetics studies showed that the pseudo-second-order kinetics equation was more advantageous than the pseudo-first-order kinetics equation in describing the adsorption kinetics of thiophene on Raney Ni/Al2 O3.The rate constant value(kp)was positively correlated with the temperature whereas the adsorption mass transfer process was mainly determined by the intraparticle and film diffusion.The adsorption thermodynamic analysis proved that△G^0<0,△H^0>0,and△S^0>0,implying that the adsorption was a spontaneous,entropy-increasing and endothermic process.
基金financially supported by the Importation and Development of High-Caliber Talents Project of Beijing Municipal Institutions(CIT&TCD20130325)the Project of Construction of Innovative Teams and Teacher Career Development for Universities and Colleges under Beijing Municipality (IDHT20180508)
文摘New supported Raney-Cu catalyst was prepared from pseudo-boehmite powder and copper aluminum alloy powder. It could be used in a continuous-flow fixed-bed reactor and it was also a good catalyst for hydrogenolysis of glycerol to propylene glycol after the two raw materials were processed by the following procedures: molding, drying, calcination, and leaching. XRD, H2-TPR, as well as SEM technique were employed to study the physicochemical properties of the catalysts, and the hydrogenolysis of glycerol to 1,2-propylene glycol (1,2-PDO) was used as a probe to evaluate the performance of supported skeletal copper catalysts. The test result indicated that CuAl2 was the main crystal phase of precursor after the dried strips were calcined at 850 °C in air. A part of CuAl2 was oxidized to α-Al2O3, which was the main contributor to the strength of Raney-Cu/Al2O3, while the remaining CuAl2 was converted to active skeletal copper after the leaching process. The effects of reaction temperature, hydrogen pressure, LHSV, hydrogen-oil ratio, glycerol concentration, and alkaline additives on the catalytic performance were studied in water or ethanol, respectively. Conversion of glycerol and selectivity of 1,2-PDO were 30.9% and 91.4% in water, or 99.0% and 73.6% in the ethanol system, respectively, when the reaction was performed at a temperature of 215 °C, a H2 pressure of 3 MPa, a LHSV of 1.0 h-1, a hydrogen-oil ratio of 500, and a glycerol concentration of 20%(ethyl alcohol solution).
基金financially supported by the National Natural Science Foundation of China (91634101)the Project on Construction of Innovative Teams and Teacher Career Development for Universities and Colleges under Beijing Municipality (IDHT20180508)
文摘Supported nickel-based catalysts were prepared by the incipient wetness impregnation method for the selective hydrogenation of methyl isobutyl ketone to methyl isobutyl carbinol in a fixed-bed reactor. The effects of the nickel source,Ni loading, calcination time, and calcination temperature on the hydrogenation performance were studied. The experimental results showed that the Ni/γ-Al_2O_3 catalyst demonstrated the highest catalytic performance under the preparation conditions by using nickel nitrate as the nickel source with a NiO loading of 20%, followed by calcination at 440°C for 5h. In addition,this catalyst showed the largest specific surface area, best crystal structure, highest active component content, smallest particle size, and uniform distribution of NiO on the surface of the carrier. The nickel-based catalyst prepared using the optimized conditions exhibited a 96.1% conversion of methyl isobutyl ketone, with a methyl isobutyl carbinol selectivity of 99.6%. The described procedure is very effective for the preparation of methyl isobutyl carbinol using methyl isobutyl ketone as the feedstock.
