The nucleophilic ring opening reaction of propargyl epoxides by amines based on a silver catalyst is presented, The reaction takes place under mild conditions and features a high regioselectivity to provide an effecti...The nucleophilic ring opening reaction of propargyl epoxides by amines based on a silver catalyst is presented, The reaction takes place under mild conditions and features a high regioselectivity to provide an effective method for the synthesis of 2-amino homopropargyl alcohols in moderate to high yields,展开更多
醇类化合物的碳-碳键官能团化反应一直是有机化学家们关注的焦点之一.由于醇类化合物O—H键键解离能比较高,约为440 k J/mol,使醇类化合物发生碳-碳键断裂并进行直接官能团化反应的方法目前在文献中还鲜有报道.上海科技大学物质科学与...醇类化合物的碳-碳键官能团化反应一直是有机化学家们关注的焦点之一.由于醇类化合物O—H键键解离能比较高,约为440 k J/mol,使醇类化合物发生碳-碳键断裂并进行直接官能团化反应的方法目前在文献中还鲜有报道.上海科技大学物质科学与技术学院左智伟课题组利用可见光催化的方法,顺利地实现了环醇类化合物的碳-碳键官能团反应.展开更多
Lanthanum-based oxides are promising candidates for low-temperature oxidative coupling of methane(OCM).To further lower the OCM reaction temperature,the Ce doped flower-like La_(2)O_(2)CO_(3)microsphere catalysts were...Lanthanum-based oxides are promising candidates for low-temperature oxidative coupling of methane(OCM).To further lower the OCM reaction temperature,the Ce doped flower-like La_(2)O_(2)CO_(3)microsphere catalysts were synthesized,achieving a significantly low reaction temperature (375℃) while maintaining high C_(2) hydrocarbon selectivity (43.0%).Doping Ce into the lattice of La_(2)O_(2)CO_(3)created more surface oxygen vacancies and bulk lattice defects,which was in favor of the transformation and migration of oxygen species at 350–400℃.The designed H_(2) temperature-programmed reduction (H_(2)-TPR) experiments provided strong evidence that the low reaction temperature of La_(x)Ce_(1-x)O_(1.5+δ)can be attributed to the transformation and migration of oxygen species,which dynamically generated surface oxygen vacancies for continuous oxygen activation to selectively convert methane.Moreover,designed temperatureprogrammed surface reaction (TPSR) clarified that two kinds of surface oxygen species in La_(x)Ce_(1-x)O_(1.5+δ)catalysts were concerned with catalytic performance,that is,the surface chemisorbed oxygen species for the activation of CH_(2)and the formation of CH_(2)·intermediates,surface La-Ce-O lattice oxygen species that caused the excessive oxidation of CH_(2)·intermediates.Finally,the factors affecting the transformation and migration of oxygen species were explored.展开更多
Cycloaddition of CO_(2) with aziridines is an important reaction to obtain high-value products.Porous MOFs can catalyze this reaction,but co-catalysts are still necessary to improve the catalytic performance.Such a re...Cycloaddition of CO_(2) with aziridines is an important reaction to obtain high-value products.Porous MOFs can catalyze this reaction,but co-catalysts are still necessary to improve the catalytic performance.Such a reaction catalyzed by MOFs-based materials without co-catalyst has not been reported hitherto.Herein,a porous and stable three-dimensional(3D)framework{[Ni(DCTP)]·6.5DMF}_(n)(1)with a large Langmuir surface area of 3,789 m^(2)/g was synthesized,which displayed high I2 adsorption ability up to 731.0 mg/g and could release it reversibly.Additionally,it exhibited a high CO_(2) adsorption capacity of 104.0 cm^(3)/g at 273 K.The investigation results revealed 1 could effectively catalyze the cycloaddition of CO_(2) and aziridines in the absence of additional co-catalyst,and it could maintain the catalytic activity after five cycles.Furthermore,1 also exhibited high catalytic activity for the gram-scale experiment.Importantly,it is the first MOF material as a heterogeneous catalyst for the conversion of CO_(2) and aziridines without co-catalyst.展开更多
Three types of ligands have been developed for copper-catalyzed Ullmann cross coupling reaction of bromaminic acid with amines in aqueous solution. Ligands with large steric hindrance and strong electron-donating capa...Three types of ligands have been developed for copper-catalyzed Ullmann cross coupling reaction of bromaminic acid with amines in aqueous solution. Ligands with large steric hindrance and strong electron-donating capacity were beneficial to the reaction. UV–Vis and CV analyses demonstrated that these ligands had strong coordination with copper(I), implying the effect of ligand coordination ability on the stability and catalytic activity of catalytic system.展开更多
通过微波辅助法制备了含氟的TS-1(F-TS-1-M),并与传统方法制备的氟改性TS-1(F-TS-1-T),微波处理的TS-1(TS-1-M)和未改性TS-1进行比较. XRD、 DR UV-Vis、 XPS表明F-TS-1-M和TS-1-M分子筛上的部分非骨架钛转变为骨架钛,这是由于微波的选...通过微波辅助法制备了含氟的TS-1(F-TS-1-M),并与传统方法制备的氟改性TS-1(F-TS-1-T),微波处理的TS-1(TS-1-M)和未改性TS-1进行比较. XRD、 DR UV-Vis、 XPS表明F-TS-1-M和TS-1-M分子筛上的部分非骨架钛转变为骨架钛,这是由于微波的选择性效应可以不同程度地活化Ti—O和Si—O键;^(19)F MAS NMR证实了F-TS-1-M分子筛中氟元素是以Si-F和SiF_6^(2-)的形式存在;^(29)Si MAS NMR表明F-TS-1-M分子筛的骨架缺陷位和表面羟基减少, Py-FT-IR结果表明F-TS-1-M的Lewis酸性和疏水性高于F-TS-1-T、 TS-1-M和TS-1.在环己酮氨肟化的反应中表现出优异的催化性能.展开更多
基金the National Natural Science Foundation of China(No. 21302095)Research Fund for the Doctoral Program of Higher Education of China(No. 20133221120003)+2 种基金Jiangsu Provincial NSFC(Nos. BK20130945, BK20130924)Top-notch Academic Programs Project of Jiangsu Higher Education Institutions (TAPP)Nanjing Tech University for financial support
文摘The nucleophilic ring opening reaction of propargyl epoxides by amines based on a silver catalyst is presented, The reaction takes place under mild conditions and features a high regioselectivity to provide an effective method for the synthesis of 2-amino homopropargyl alcohols in moderate to high yields,
文摘醇类化合物的碳-碳键官能团化反应一直是有机化学家们关注的焦点之一.由于醇类化合物O—H键键解离能比较高,约为440 k J/mol,使醇类化合物发生碳-碳键断裂并进行直接官能团化反应的方法目前在文献中还鲜有报道.上海科技大学物质科学与技术学院左智伟课题组利用可见光催化的方法,顺利地实现了环醇类化合物的碳-碳键官能团反应.
基金the Shanxi Science and Technology Department bidding project(No.20191101012)the autonomous research project of SKLCC(No.2020BWZ003)for providing financial support。
文摘Lanthanum-based oxides are promising candidates for low-temperature oxidative coupling of methane(OCM).To further lower the OCM reaction temperature,the Ce doped flower-like La_(2)O_(2)CO_(3)microsphere catalysts were synthesized,achieving a significantly low reaction temperature (375℃) while maintaining high C_(2) hydrocarbon selectivity (43.0%).Doping Ce into the lattice of La_(2)O_(2)CO_(3)created more surface oxygen vacancies and bulk lattice defects,which was in favor of the transformation and migration of oxygen species at 350–400℃.The designed H_(2) temperature-programmed reduction (H_(2)-TPR) experiments provided strong evidence that the low reaction temperature of La_(x)Ce_(1-x)O_(1.5+δ)can be attributed to the transformation and migration of oxygen species,which dynamically generated surface oxygen vacancies for continuous oxygen activation to selectively convert methane.Moreover,designed temperatureprogrammed surface reaction (TPSR) clarified that two kinds of surface oxygen species in La_(x)Ce_(1-x)O_(1.5+δ)catalysts were concerned with catalytic performance,that is,the surface chemisorbed oxygen species for the activation of CH_(2)and the formation of CH_(2)·intermediates,surface La-Ce-O lattice oxygen species that caused the excessive oxidation of CH_(2)·intermediates.Finally,the factors affecting the transformation and migration of oxygen species were explored.
基金This work was supported by the Natioanl Natrual Sciencce Foundation of China(21625103,21971125,21801183)China Postdoctoral Science Foundation(2019M660978,2020T130319),and the 111 Project(B12015).
文摘Cycloaddition of CO_(2) with aziridines is an important reaction to obtain high-value products.Porous MOFs can catalyze this reaction,but co-catalysts are still necessary to improve the catalytic performance.Such a reaction catalyzed by MOFs-based materials without co-catalyst has not been reported hitherto.Herein,a porous and stable three-dimensional(3D)framework{[Ni(DCTP)]·6.5DMF}_(n)(1)with a large Langmuir surface area of 3,789 m^(2)/g was synthesized,which displayed high I2 adsorption ability up to 731.0 mg/g and could release it reversibly.Additionally,it exhibited a high CO_(2) adsorption capacity of 104.0 cm^(3)/g at 273 K.The investigation results revealed 1 could effectively catalyze the cycloaddition of CO_(2) and aziridines in the absence of additional co-catalyst,and it could maintain the catalytic activity after five cycles.Furthermore,1 also exhibited high catalytic activity for the gram-scale experiment.Importantly,it is the first MOF material as a heterogeneous catalyst for the conversion of CO_(2) and aziridines without co-catalyst.
基金Supported by the National Natural Science Foundation of China(21176038,21576044,21536002)the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(21421005)the Dalian University of Technology Innovation Team(DUT2013TB07)
文摘Three types of ligands have been developed for copper-catalyzed Ullmann cross coupling reaction of bromaminic acid with amines in aqueous solution. Ligands with large steric hindrance and strong electron-donating capacity were beneficial to the reaction. UV–Vis and CV analyses demonstrated that these ligands had strong coordination with copper(I), implying the effect of ligand coordination ability on the stability and catalytic activity of catalytic system.
基金The financial supports from the National Natural Science Foundation of China(Project NO.21403135)Shanxi provincial key research and development plan project(NO.201603D121018-1)
文摘通过微波辅助法制备了含氟的TS-1(F-TS-1-M),并与传统方法制备的氟改性TS-1(F-TS-1-T),微波处理的TS-1(TS-1-M)和未改性TS-1进行比较. XRD、 DR UV-Vis、 XPS表明F-TS-1-M和TS-1-M分子筛上的部分非骨架钛转变为骨架钛,这是由于微波的选择性效应可以不同程度地活化Ti—O和Si—O键;^(19)F MAS NMR证实了F-TS-1-M分子筛中氟元素是以Si-F和SiF_6^(2-)的形式存在;^(29)Si MAS NMR表明F-TS-1-M分子筛的骨架缺陷位和表面羟基减少, Py-FT-IR结果表明F-TS-1-M的Lewis酸性和疏水性高于F-TS-1-T、 TS-1-M和TS-1.在环己酮氨肟化的反应中表现出优异的催化性能.