该方法适用于精致苯中已知杂质浓度的测定,以及在生产苯或在制造工艺中使用苯时作为整体质量的控制工具。一般用于C9或小于C9非芳、甲苯、C8芳烃和1,4二噁烷(二氧杂环己烷)等杂质的测定。目前车间使用ASTM D 4492-96用气相色谱法对苯分...该方法适用于精致苯中已知杂质浓度的测定,以及在生产苯或在制造工艺中使用苯时作为整体质量的控制工具。一般用于C9或小于C9非芳、甲苯、C8芳烃和1,4二噁烷(二氧杂环己烷)等杂质的测定。目前车间使用ASTM D 4492-96用气相色谱法对苯分析的标准测定方法。其方法对于内标物加入量规定应与被测物质量分数接近。此次试验目的为了能找到是测量数据结果更准确并且更有利于制备样品的内标物含量。展开更多
The scarcity and weak durability of metal,especially precious metal catalysts are big obstacles for their large-scale application in many reactions.The state-of-the-art of the catalytic science prefers such type of ca...The scarcity and weak durability of metal,especially precious metal catalysts are big obstacles for their large-scale application in many reactions.The state-of-the-art of the catalytic science prefers such type of catalysts,which can replace metal-based catalysts to alleviate energy and environmental crises and exhibit catalytic performance comparable to or even exceeding these metal catalysts.Herein,we report that N-doped porous carbon(NKC)derived from cheap and abundant radish can be employed as versatile and efficient bifunctional catalysts in both the catalytic reduction of 4-nitrophenol(NRR)and oxidation of styrene(SOR).The series of NKC catalysts were prepared with a simple and facile one-pot strategy by coupling the N-doping,carbonization and KOH activation processes.These catalysts show hierarchical porosity,with the specific surface area,total pore volume and N-doping content ranging from 918.9-3062.7 m^2 g^-1,1.01-2.04 cm^3 g^-1 and 1.29-15.3 at%,respectively.Interestingly,our finding suggests that the catalytic performance is not directly related to these parameters but correlates positively with the content of graphitic N dopants,which is the dominant contributor for impelling both the NRR and SOR.Another intriguing finding is that for both reactions,the optimal catalyst was found to be the NKC-3-800 which possesses the highest graphitic N content of 3.13 at%.In addition,to gain insight into the catalytic behavior,analyses of kinetics and thermodynamics were performed,and the catalytic mechanisms were postulated.This work paves the way for the construction of biomass-derived N-doped carbon catalysts for bi-or even multi-functional applications in various organic reactions.展开更多
Effect of doping cerium in the support on the catalytic activity and side product of the reaction in the oxidative carbonylation of phenol to diphenyl carbonate (DPC) over the catalyst Pd-Co/Cu-Co-Mn mixed oxides was ...Effect of doping cerium in the support on the catalytic activity and side product of the reaction in the oxidative carbonylation of phenol to diphenyl carbonate (DPC) over the catalyst Pd-Co/Cu-Co-Mn mixed oxides was studied. The specific surface areas, crystal phase, valency, and content of the element on the surface of the catalysts were determined, and the products were detected by gas chromatograph/mass spectrometry (GC-MS). It is found that the catalyst without Ce shows higher activity than that with Ce, and the yields of DPC for the two cata-lysts can reach 30% and 23%, respectively. However, doping cerium can prevent the formation of 2-hydroxyphenyl benzoate and p-bromophenyl phenyl carbonate.展开更多
文摘该方法适用于精致苯中已知杂质浓度的测定,以及在生产苯或在制造工艺中使用苯时作为整体质量的控制工具。一般用于C9或小于C9非芳、甲苯、C8芳烃和1,4二噁烷(二氧杂环己烷)等杂质的测定。目前车间使用ASTM D 4492-96用气相色谱法对苯分析的标准测定方法。其方法对于内标物加入量规定应与被测物质量分数接近。此次试验目的为了能找到是测量数据结果更准确并且更有利于制备样品的内标物含量。
文摘The scarcity and weak durability of metal,especially precious metal catalysts are big obstacles for their large-scale application in many reactions.The state-of-the-art of the catalytic science prefers such type of catalysts,which can replace metal-based catalysts to alleviate energy and environmental crises and exhibit catalytic performance comparable to or even exceeding these metal catalysts.Herein,we report that N-doped porous carbon(NKC)derived from cheap and abundant radish can be employed as versatile and efficient bifunctional catalysts in both the catalytic reduction of 4-nitrophenol(NRR)and oxidation of styrene(SOR).The series of NKC catalysts were prepared with a simple and facile one-pot strategy by coupling the N-doping,carbonization and KOH activation processes.These catalysts show hierarchical porosity,with the specific surface area,total pore volume and N-doping content ranging from 918.9-3062.7 m^2 g^-1,1.01-2.04 cm^3 g^-1 and 1.29-15.3 at%,respectively.Interestingly,our finding suggests that the catalytic performance is not directly related to these parameters but correlates positively with the content of graphitic N dopants,which is the dominant contributor for impelling both the NRR and SOR.Another intriguing finding is that for both reactions,the optimal catalyst was found to be the NKC-3-800 which possesses the highest graphitic N content of 3.13 at%.In addition,to gain insight into the catalytic behavior,analyses of kinetics and thermodynamics were performed,and the catalytic mechanisms were postulated.This work paves the way for the construction of biomass-derived N-doped carbon catalysts for bi-or even multi-functional applications in various organic reactions.
文摘Effect of doping cerium in the support on the catalytic activity and side product of the reaction in the oxidative carbonylation of phenol to diphenyl carbonate (DPC) over the catalyst Pd-Co/Cu-Co-Mn mixed oxides was studied. The specific surface areas, crystal phase, valency, and content of the element on the surface of the catalysts were determined, and the products were detected by gas chromatograph/mass spectrometry (GC-MS). It is found that the catalyst without Ce shows higher activity than that with Ce, and the yields of DPC for the two cata-lysts can reach 30% and 23%, respectively. However, doping cerium can prevent the formation of 2-hydroxyphenyl benzoate and p-bromophenyl phenyl carbonate.
