检索结果-南通市图书馆

Effect of Temperature on the Deactivation of a Pd-Fe/α-Al_2O_3 Catalyst for CO Coupling to Diethyl Oxalate

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2003年第4期12卷 243-246页

作者： Jingang Fang, Zhenghua Li, genhui Xu, baowei wang, Tieli XiangKey Lab of Green chemical technology, School of chemical engineering, tianjin university, tianjin 300072. china Key Lab of Green chemical technology School of Chemical Engineering Tianjin University

Destructive tests of the catalyst was carried out to study the effect oftemperature on the catalytic activity of CO coupling to diethyl oxalate (DEO) over a Pd-Fe/Al_2O_3catalyst. It was found that a temperature jump could cause the deactivation of the Pd-Fe/α-Al_2O_3catalyst. The catalyst deactivated at different temperatures has different characteristics. Afterdeactivation the crystal structure of α-Al_2O_3 did not change, but the Pd particle size wasenlarged. Most of the Pd^0 were oxidized to Pd^(2+), and Fe^(2+) was oxidized to Fe^(3+) on thesurface of the deactivated catalyst. The catalyst could be regenerated, but its original activitycould not be recovered completely.

关键词： accelerating deactivation test diethyl oxalate palladium carbon monoxide

PLASMA technology APPLICATION IN NATURE GAS chemical engineering

在线全文

学校读者我要写书评

暂无评论

化工学报 2000年第S1期51卷 207-210页

作者： wang baowei and Xu genhui (School of chemical engineering, State Key Laboratory of C1 chemical technology, tianjin university, tianjin 300072.

Nature gas is not only an increasing important role in energy and chemicals supplies in 21st century but also the second most important of the anthropogenic greenhouse gases. This paper reviewed the plasma technology application in natural gas chemical engineering, pointed out the problem at present and forecasted plasma concerted catalysis technology will facilitate the nature gas directly conversion into more valuable chemicals supplies economically in short after time.

关键词： plasma technology natural gas application

Iron-Catalyzed Reductive C(aryl)—Si Cross-Coupling of Diaryl Ethers with Chlorosilanes

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2024年第6期42卷 578-584页

作者： Pei Liu baowei Wu Xuefeng Cong Jie Kong School of Chemistry and chemical engineering Northwestern Polytechnical UniversityXi'anShaanxi710072 China Institute of Molecular Plus Department of Chemistry and Haihe Laboratory of Sustainable Chemical TransformationsTianjin University92 Weijin RoadTianjin300072 China

The reductive cross-coupling between C(aryl)—O and Si—Cl bonds is of much importance as a valuable strategy for the construction of C(aryl)—Si bonds but has remained a great ***,we report a reductive cross-coupling of diaryl ethers and chlorosilanes via strong electrophilic C(aryl)—O and Si—Cl bonds cleavage by iron catalysis,which constitutes an efficient protocol for the synthesis of a range of functionalized *** combination of low cost FeCl2 as the precatalyst and iPrMgCl as the reductant shows high activity in the successive cleavage of unactivated C(aryl)—O bonds of diaryl ethers and strong electrophilic Si—Cl bonds of chlorosilanes,allowing their cross-coupling in a reductive *** low-valent iron species generated in situ by reduction of FeCl2 with iPrMgCl was proposed,which prefers to initially cleavage the C(aryl)—O bond of diaryl ethers with the chelation help of an o-amide auxiliary.

关键词： Cross-coupling Diaryl ethers Chlorosilanes C—O bond cleavage Iron catalyst 3d transition metals Selectivity Regioselectivity

Synthesis of Diethyl Oxalate by a Coupling-Regeneration Reaction of Carbon Monoxide

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2002年第Z1期 57-62页

作者： Fandong Meng,genhui Xu,baowei wang,Xinbin Ma1. School of chemical engineering and technology, tianjin university, tianjin 300072. china 2. Luoyang Petrochemical engineering Corporation, Luoyang 471003, china[Manuscript received March 13, 2002 revised Apr

This article describes a process for the synthesis of diethyl oxalate by a coupling reaction of carbon monoxide, catalyzed by palladium in the presence of ethyl nitrite. The kinetics and mechanism of the coupling and regeneration reaction are also discussed. This paper presents the results of a scale-up test of the catalyst and the process based on an a priori computer simulation.

关键词： CO coupling diethyl oxalate kinetics and mechanism simulation scale-up test

Distribution of Electrical Field Energy for Conversion of Methane to C_2 Hydrocarbons via Dissymmetrical Electric Field Enhanced Plasma

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2006年第2期15卷 115-121页

作者： baowei wang genhui XU Hongwei Sun Key Laboratory for Green chemical technology School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China Research Institute of Petroleum Processing Beijing 100083 China

Direct conversion of methane into C2 hydrocarbons through alternating current electric field enhanced plasma was studied under room temperature, atmospheric pressure and low power conditions. The distribution of electrical field intensity and distribution of energy were calculated with software that was developed by us according to the charge simulation method. The results indicated that the energy of tip of electrode was 0.36 J/mm^3 and it was higher than the methane dissociation energy （0.0553 J/mm^3）. The methane located at this area can be activated easily. The higher-energy particles produced by dissociation collided with molecules around them and initiated consecutive reactions between free radicals and molecules. The method was proved to be valided and could be taken as a basis for the electrical field study concerned.

关键词： electrical field enhanced plasma intensity of electrical field distribution of energy

Conversion of CH4, steam and O_2 to syngas and hydrocarbons via dielectric barrier discharge

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2009年第1期18卷 94-97页

作者： baowei wang Xu Zhang Yongwei Liu genhui XU Key Laboratory for Green chemical technology of the Ministry qf Education School qf Chemical Engineering and Technology. Tianjin University Tianjin 300072 China

The conversion of CH4 with oxygen and steam in a dielectric barrier discharge （DBD） was studied in the paper to discuss the effects of different factors, such as the content of feed-in gas, the applied voltage and frequency. The results showed that a lower ratio of CH4 to O2 always resulted in a higher conversion of CH4. When it was 2, the conversion reached 32.43% without steam introduced into the system. The main effect of steam was increasing the selectivity to CO. The reaction was accelerated and the selectivities to CO and hydrocarbons were enhanced by increasing the applied voltage. It was also observed that a higher frequency led to a lower current and then restrained the reaction.

关键词： methane steam oxygen dielectric barrier discharges plasma

Synthesis of Methyl Glycolate by Hydrogenation of Dimethyl Oxalate over Cu-Ag/SiO_2 Catalyst

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2007年第1期16卷 78-80页

作者： baowei wang Qian Xu Hua Song genhui Xu School of chemical engineering and technology Key Lab for Green Chemical Technology Tianjin University Tianjin 300072 China

Methyl glycolate is a good solvent and can be used as feedstock for the synthesis of some important organic chemicals. Catalytic hydrogenation of dimethyl oxalate （DMO） over copper-silver catalyst supported on silica was studied. The Cu-Ag/SiO2 catalyst supported on silica sol was prepared by homogeneous deposition-precipitation of the mixture of aqueous euprammonia complex and silica sol. The proper active temperature of Cu-Ag/SiO2 catalyst for hydrogenation of DMO was 523-623 K. The most preferable reaction conditions for methyl glycolate （MG） were optimized： temperature at 468-478 K, 40-60 mesh catalyst diameter, H2/DMO ratio 40, and 1.0 h^-1 of LHSV.

关键词： dimethyl oxalate methyl glycolate ethylene glycol hydrogenation Cu-Ag/SiO2 catalyst

Effects of additive gases on dimethyl ether conversion through dielectric barrier discharge

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2009年第4期18卷 441-444页

作者： baowei wang Xiaolei Cao Yigang Yan genhui Xu Key Laboratory for Green chemical technology of Ministry of Education School of Chemical Engineering Technology 7ianjin University Tianjin 300072 China

Effects of additive gases on dimethyl ether （DME） conversion through dielectric barrier discharge （DBD） were investigated. Most of the additive gases tested in this work increased the conversion of DME, but decreased the yield of liquid product. However, the addition of O2 markedly increased both the conversion of DME and the yield of liquid product. The results show that when O2 volume fraction was 39.95%, the conversion of DME was close to 100% and the yield of liquid product reached 34.43%. Different additive gases resulted in different mass fractions variation of components in liquid products.

关键词： dielectric barrier discharge plasma dimethyl ether additive gas

Synthesis of Diethyl Oxalate by a Coupling-Regeneration Reaction of Carbon Monoxide

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2002年第1期11卷 57-62页

作者： Fandong Meng genhui Xu baowei wang Xinbin Ma School of chemical engineering and technology Tianjin University Tianjin 300072 China Luoyang Petrochemical engineering Corporation Luoyang 471003 China

关键词： CO coupling diethyl oxalate kinetics and mechanism simulation scale-up test