The catalytic hydrogenation of 2-nitro-4-acetylamino anisole(NMA)is a less-polluting and efficient method to produce 2-amino-4-acetamino anisole(AMA).However,the kinetics of catalytic hydrogenation of NMA to AMA remai...The catalytic hydrogenation of 2-nitro-4-acetylamino anisole(NMA)is a less-polluting and efficient method to produce 2-amino-4-acetamino anisole(AMA).However,the kinetics of catalytic hydrogenation of NMA to AMA remains obscure.In this work,the kinetic models including power-law model and Langmuir-Hinshelwood-Hougen-Watson(LHHW)model of NMA hydrogenation to AMA catalyzed by Raney nickel catalyst were investigated.All experiments were carried out under the elimination of mass transfer resistance within the temperature range of 70–100°C and the hydrogen pressure of 0.8–1.5 MPa.The reaction was found to follow 0.52-order kinetics with respect to the NMA concentration and 1.10-order kinetics in terms of hydrogen pressure.Based on the LHHW model,the dual-site dissociation adsorption of hydrogen was analyzed to be the rate determining step.The research of intrinsic kinetics of NMA to AMA provides the guidance for the reactor design and inspires the catalyst modification.展开更多
Selective hydrogenation over earth-abundant metal catalysts is challenging but particularly valuable for practical applications in heterogeneous catalysis.Herein,we demonstrate that the catalytic selectivity of the co...Selective hydrogenation over earth-abundant metal catalysts is challenging but particularly valuable for practical applications in heterogeneous catalysis.Herein,we demonstrate that the catalytic selectivity of the commercial Raney nickel catalyst can be greatly tuned by modulation of the nickel surface by silica.Using quinoline hydrogenation as a model,we show that the silica-modified Raney nickel catalysts exhibit good activity,excellent selectivity,and long stability,whereas the undesired over-hydrogenation reactions are effectively hindered.In contrast,the pristine Raney nickel catalyst shows inferior selectivity for the targeted product.Mechanistic studies confirm a positive role of silica to facilitate the desorption of 1,2,3,4-tetrahydroquinoline from the catalyst surface,thus enhancing the product selectivity.展开更多
基金the National Natural Science Foun-dation of China(22022802 and 22288102).
文摘The catalytic hydrogenation of 2-nitro-4-acetylamino anisole(NMA)is a less-polluting and efficient method to produce 2-amino-4-acetamino anisole(AMA).However,the kinetics of catalytic hydrogenation of NMA to AMA remains obscure.In this work,the kinetic models including power-law model and Langmuir-Hinshelwood-Hougen-Watson(LHHW)model of NMA hydrogenation to AMA catalyzed by Raney nickel catalyst were investigated.All experiments were carried out under the elimination of mass transfer resistance within the temperature range of 70–100°C and the hydrogen pressure of 0.8–1.5 MPa.The reaction was found to follow 0.52-order kinetics with respect to the NMA concentration and 1.10-order kinetics in terms of hydrogen pressure.Based on the LHHW model,the dual-site dissociation adsorption of hydrogen was analyzed to be the rate determining step.The research of intrinsic kinetics of NMA to AMA provides the guidance for the reactor design and inspires the catalyst modification.
基金the National Key Research and Development Program of China(2022YFA1503502)National Natural Science Foundation of China(U21B20101,21932006,and 22202175)China Postdoctoral Science Foundation(2021M700119).
文摘Selective hydrogenation over earth-abundant metal catalysts is challenging but particularly valuable for practical applications in heterogeneous catalysis.Herein,we demonstrate that the catalytic selectivity of the commercial Raney nickel catalyst can be greatly tuned by modulation of the nickel surface by silica.Using quinoline hydrogenation as a model,we show that the silica-modified Raney nickel catalysts exhibit good activity,excellent selectivity,and long stability,whereas the undesired over-hydrogenation reactions are effectively hindered.In contrast,the pristine Raney nickel catalyst shows inferior selectivity for the targeted product.Mechanistic studies confirm a positive role of silica to facilitate the desorption of 1,2,3,4-tetrahydroquinoline from the catalyst surface,thus enhancing the product selectivity.
