Acylation of 5-methyl-3-hydroxyisoxazole (1) with 3-substituted cyclopropanecarboxylic chlorides (3) in the presence of triethylamine (TEA) in acetonitrile yields predominantly O-acylated products (4).The N-acyl isome...Acylation of 5-methyl-3-hydroxyisoxazole (1) with 3-substituted cyclopropanecarboxylic chlorides (3) in the presence of triethylamine (TEA) in acetonitrile yields predominantly O-acylated products (4).The N-acyl isomers (5) are afforded regiospecifically using trimethylsilyl ether of 3-hydroxyisoxazole (2).展开更多
Mn-based catalysts have exhibited promising performance in low-temperature selective catalytic reduction of NOx with NH_(3)(NH_(3)-SCR).However,challenges such as H_(2)O-or SO_(2)-induced poisoning to these catalysts ...Mn-based catalysts have exhibited promising performance in low-temperature selective catalytic reduction of NOx with NH_(3)(NH_(3)-SCR).However,challenges such as H_(2)O-or SO_(2)-induced poisoning to these catalysts still remain.Herein,we report an efficient strategy to prepare the dual single-atom Ce-Ti/MnO_(2)catalyst via ball-milling and calcination processes to address these issues.Ce-Ti/MnO_(2)showed better catalytic performance with a higher NO conversion and enhanced H_(2)O-and SO_(2)-resistance at a lowtemperature window(100−150°C)than the MnO_(2),single-atom Ce/MnO_(2),and Ti/MnO_(2)catalysts.The in situ infrared Fourier transform spectroscopy analysis confirmed there is no competitive adsorption between NOx and H_(2)O over the Ce-Ti/MnO_(2)catalyst.The calculation results showed that the synergistic interaction of the neighboring Ce-Ti dual atoms as sacrificial sites weakens the ability of the active Mn sites for binding SO_(2)and H_(2)O but enhances their binding to NH_(3).The insight obtained in this work deepens the understanding of catalysis for NH_(3)-SCR.The synthesis strategy developed in this work is easily scaled up to commercialization and applicable to preparing other MnO_(2)-based single-atom catalysts.展开更多
文摘Acylation of 5-methyl-3-hydroxyisoxazole (1) with 3-substituted cyclopropanecarboxylic chlorides (3) in the presence of triethylamine (TEA) in acetonitrile yields predominantly O-acylated products (4).The N-acyl isomers (5) are afforded regiospecifically using trimethylsilyl ether of 3-hydroxyisoxazole (2).
基金We gratefully acknowledge the financial supports from the National Natural Science Foundation of China(Nos.52070180,51938014,and 21802054)the Science Research Project of the Ministry of Education of the Heilongjiang Province of China(No.145109102)+2 种基金the Beijing Chenxi Environmental Engineering Co.,Ltd.Z.Z.thanks the financial support of Guangdong Key discipline fund for this collaborationY.J.thanks the financial supports from the Outstanding Youth cultivation program of Beijing Technology and Business University(No.19008021144)Research Foundation for Advanced Talents of Beijing Technology and Business University(No.19008020159).
文摘Mn-based catalysts have exhibited promising performance in low-temperature selective catalytic reduction of NOx with NH_(3)(NH_(3)-SCR).However,challenges such as H_(2)O-or SO_(2)-induced poisoning to these catalysts still remain.Herein,we report an efficient strategy to prepare the dual single-atom Ce-Ti/MnO_(2)catalyst via ball-milling and calcination processes to address these issues.Ce-Ti/MnO_(2)showed better catalytic performance with a higher NO conversion and enhanced H_(2)O-and SO_(2)-resistance at a lowtemperature window(100−150°C)than the MnO_(2),single-atom Ce/MnO_(2),and Ti/MnO_(2)catalysts.The in situ infrared Fourier transform spectroscopy analysis confirmed there is no competitive adsorption between NOx and H_(2)O over the Ce-Ti/MnO_(2)catalyst.The calculation results showed that the synergistic interaction of the neighboring Ce-Ti dual atoms as sacrificial sites weakens the ability of the active Mn sites for binding SO_(2)and H_(2)O but enhances their binding to NH_(3).The insight obtained in this work deepens the understanding of catalysis for NH_(3)-SCR.The synthesis strategy developed in this work is easily scaled up to commercialization and applicable to preparing other MnO_(2)-based single-atom catalysts.
