检索结果-南通市图书馆

Theoretical study on the reaction mechanism of(CH_3)_3CO+CO

在线全文

学校读者我要写书评

暂无评论

Science China chemistry 2005年第1期48卷 18-24页

作者： ZHAO Hongmei1,2.3, SUN Chengke1,4, ZHANG Rongchang3, XI Hongmin3 & LI Zonghe1 1. department of chemistry, Beijing {2. University, Beijing 100875, China 2. The Laboratory of Molecular Reaction Dynamics, Institute of chemistry, Chinese Academy of Sciences, Beijing 100080, China 3. department of chemistry, Beihua University, Jilin 132.13, China 4. department of chemistry, qujing {2. University, Yunnan 655000, China 1. department of chemistry Beijing Normal University 100875 Beijing China 2. The Laboratory of Molecular Reaction Dynamics Institute of Chemistry Chinese Academy of Sciences 100080 Beijing China 3. department of chemistry Beihua University 132013 Jilin China 4. department of chemistry Qujing Normal University 655000 Yunnan China

The reaction mechanism of (CH3)3CO with CO has been theoretically investigated using density-functional theory (DFT) calculations at B3LYP/6-31G* level. In order to get more reliable energy values the single-point energy is evaluated at CCSD (T)/6-31++G** level. The results show that the reaction is multi-channel and the reaction of (CH3)3CO radical with CO mostly produces (CH3)3C + CO2. The reaction could play a role in eliminating air pollution.

关键词： DFT, B3LYP, (CH3)3CO, radical.

Approach to synthesis of novel chiral 3-chloro-2.5H)- furanone and its application in asymmetric reactions

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2000年第8期45卷 711-716页

作者： HUANG Hui & CHEN Qinghua1. department of chemistry, Tonghua Teacher’s {2., Tonghua 134002. China 2. department of chemistry, Beijing normal University, Beijing 100875, China department of chemistry Tonghua Teacher’s College Tonghua China department of chemistry Beijing Normal University Beijing China

The synthetic method of the novel chiral synthon, 5-/-menthyloxy-3-chloro-2.(5H)-furanone 5a and its application in asymmetric reactions were investigated. 5a is easily obtained in highly optical purity, and acts as a stable acceptor of Michael addition with oxygen nucleophiles in tandem double Michael addition / internal nucieophilic substitution to offer the spiro-cyclopropane derivative containing four stereogenic centers 8, which it is difficult to obtain by routine methods. The synthetic methods for 5a and 8 are reported in detail and the new compounds are identified on the basis of their analytical data and spectroscopic data, such as UV, IR, H NMR,13 C NMR, MS and elementary analysis. The absolute configuration of the interesting spiro-cyclopropanes, spiro [1-chloro-4-(/-menthyloxy)-5-oxo-6-oxa-biscyclo[3.1.0]hexane-2.3i(4’-/-menthyloxy-5’-/-menthyloxy- butyrolactone)] 8 was established by X-ray crystallography. This result can provide important synthetic strategy in synthesis of some complex

关键词： new chiral synthon. 5-l-menthyloxy-3-chloro-2.(5H)-furanone absolute configuration spiro-cyclopropane derivative containing multiple chiral centers.

Kinetic model of transesterification of diphenyl carbonate and 1,4-butyldiol

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas chemistry 2010年第4期19卷 436-440页

作者： Liping Wang1,2.3,4,Bin Xiao1,2.4,Gongying Wang1,2.1.Chengdu Institute of Organic chemistry,Chinese Academy of Science,Chengdu 610041,Sichuan,China 2.Changzhou Key Laboratory of Green and Technology,Changzhou Institute of chemistry,Changzhou 2.3164,Jiangsu,China 3.{2. of chemistry,qujing normal college,qujing 655000,Yunnan,China 4.Graduate School of Chinese Academy of Science,Beijing 100039,China [a] Chengdu Institute of Organic chemistry Chinese Academy of Science Chengdu 610041 Sichuan China [b] Changzhou Key Laboratory of Green and Technology Changzhou Institute of Chemistry Changzhou 213164 Jiangsu China [c] Department of Chemistry Qujing Normal College Qujing 655000 Yunnan China [d] Graduate School of Chinese Academy of Science Beijing 100039 China

The transesterification of diphenyl carbonate （DPC） with 1,4-butyldiol （BD） was kinetically investigated in the presence of lithium acetate catalyst at 465 *** reaction was followed by the measurement of the quantity of phenol which was distilled from the *** experiments supported the assumption that the phenyl ester groups in DPC and phenyl hdroxybutyl carbonate （PHBH） had the same reactivity,and the transesterification obeyed first-order kinetics with respect to DPC and BD,and a rate equation was *** reaction rate was found to be first order with respect to the catalyst concentration as *** those data were incorporated in the rate equation,excellent agreement between calculated values and the observed ones was recognized over a wide range.

关键词： transesterification diphenyl carbonate 1,4-butyldiol lithium acetate kinetics

Electrochemical characteristics of CoSn_x alloy composite anode for lithium-ion rechargeable batteries

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2006年第z1期25卷 369-373页

作者： GUO Hong ZHAO Hailei JIA Xidi QIU Weihua School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China department of chemistry and Biology Qujing Normal University Qujing 655000 China School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

Nano/micro-scaled CoSnx alloy powders synthesized via carbothermal reduction at 800 ℃ with different compositions were characterized for anode materials in Li-ion battery. The synthesized spherical CoSnx particles show a loose nano/micro sized particle structural characteristic, which is apparently favorable for the improvement of cycling stability. The prepared CoSn3 alloy composite electrode exhibits a low initial irreversible capacity of ca.130 mAh·g-1 and a high specific capacity of ca.440 mAh·g-1 at constant current density of 100 mA·g-1. The relatively large particle size is considered to be the main reason for the lower irreversible capacity of CoSn3 electrode.

关键词： CoSnx composite anode materials carbothermal reduction Li-ion rechargeable batteries

Spectral anomalies and spectral switches of partially coherent and polychromatic light diffracted at an aperture

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2004年第1期47卷 24-35页

作者： Lü Baida1, 3 & PAN Liuzhan1, 2.1. Institute of Laser Physics and chemistry, Sichuan University, Chengdu 610064, China 2. department of Physics, Luoyang {2. college, Luoyang 47102., China 3. State Key Laboratory of Laser Technology, Huazhong University of Science and Technology, Wuhan 430074, China Correspondence should be addressed to L Baida (email: badalu@***) Received July 10, 2.03 1. Institute of Laser Physics and chemistry Sichuan University 610064 Chengdu China 2. State Key Laboratory of Laser Technology Huazhong University of Science and Technology 430074 Wuhan China 3. department of Physics Luoyang Normal College 471022 Luoyang China

Based on the propagation theory of partially coherent light in the space-frequency domain, the anomalous spectral behavior and spectral switches in the far field of partially coherent and polychromatic light diffracted at an aperture are studied. It is shown that, as compared with spatially fully coherent and polychromatic light whose spectral anomalies are induced only by aperture diffraction, the spectral anomalies and spectral switches of partially coherent and polychromatic light depend on the aperture diffraction, spatial correlationβ and bandwidth of the original spectrum. Detailed numerical calculations are made to illustrate the behavior of spectral switches of partially coherent and polychromatic light, and the results for spatially fully coherent and polychromatic light are treated as a special case ofβ=1 and included in our theory.

关键词： spectral anomaly spectral switch partially coherent and polychromatic light far field aperture diffraction

Stability and Instability of Solution for a Class of Nonlinear Differential Equations

在线全文

学校读者我要写书评

暂无评论

曲靖师范学院学报 2000年第6期 5-6+10页

作者： Liu Jun 1 Cui ping 1 Xun Fengxian 1 Li Jinhua 2. (1 department of Mathematics,qujing {2. college,qujing 655000,Yunnan Province 2. The Sixth Middle School of Qilin District,qujing 655000,Yunnan Province)

In this paper,the stability and instability of solution for a class of nonlinear differential equations are studied.

关键词： Nonlinear Differential Equation Motive Stability Theory Stability

Synthesis and 183W NMR Characterization of α-K7GaW11（TiO2.O39·11H2. Heteropolyanion

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2001年第8期12卷 731-732页

作者： Xiao Peng ZHAN2. Lu MENG1* 1Faculty of chemistry, Northeast normal University, Changchun 13002. 2.2. of chemistry, Yangzhou college of Education, Yangzhou 2.5002 department of chemistry Yangzhou College of Education Yangzhou 225002 China Faculty of chemistry Northeast Normal University Changchun 130024 China

The peroxotitanium-substituted heteropolytungstate (-K7GaW11(TiO2.O39(11H2. has been synthesized and characterized by elemental analysis, IR, UV, 183W NMR and electrochemistry. 183W NMR spectrum consists of six lines with intensity ratio 2.2.1:2.2.2. indicated that the TiO2.occupied the empty octahedral site of the GaW11 anion forming a polyanion with Cs symmetry. The characteristic charge-transfer absorption band O2.-?Ti at 385 nm occurs in the UV spectrum. The polarographic reduction potential of O2.- at ca.+0.87 V has been found.

关键词： Peroxotitanium gallatotungstate Keggin structure 183W NMR.

Correlation between the Standard Formation Enth alpy and the Path Index of Pyridine Derivatives

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Wuhan University Journal of Natural Sciences 2000年第2期5卷 229-232页

作者： LI Liang chao 1 ,LIAO Gui ying 1,2.,JIANG Sheng bin 2.,WANG Ying xi 2.,SUN Ju tang 3 1. Departmnt of chemistry, Jingzhou normal {2., Jingzhou, China, 434100 2. Hubei, Research Institute of chemistry, Wuhan, China, 430074 Jingzhou normal college Department of Chemistry Jingzhou China Jingzhou normal college Department of Chemistry Jingzhou China Hubei Research Institute of Chemistry Wuhan China Hubei Research Institute of Chemistry Wuhan China Wuhan University College of Chemistry Wuhan China (GRID:grid.49470.3e) (ISNI:***)

A formulated as △fH m ? (PPDs,g)=a+ΣbiPi + cifi is put forward for estimating standard formation enthalpies of pyridine-derivatives (PDDs), in which,P i is path index andc i f i is an amended term of interaction between substituent and N atom on pyridine ring. The Calculations based on the model were carried out for some pyridine-derivatives. The values of standard formation enthalpy calculated are consistent with those in literature.

关键词： Key words pyridine derivatives standard formation enthalpy path index

Kinetics and mechanism of the reaction between thiourea and iodate in unbuffered medium

在线全文

学校读者我要写书评

暂无评论

Science China chemistry 2004年第6期47卷 480-487页

作者： WANG Shun1,2. LIN Juanjuan1, CHEN Fan1, HU Maolin1, HU Xingen1, HAN Yiping1 & GAO Qingyu2.1.department of chemistry and Material Science, Wenzhou {2. college, Wenzhou 32.02., China 2. college of Chemical Engineering, China University of Mining and Technology, Xuzhou 2.1008, China 1. department of chemistry and Material Science Wenzhou Normal College 325027 Wenzhou China 2. college of Chemical Engineering China University of Mining and Technology 221008 Xuzhou China

The reaction between iodate and thiourea has been studied in an unbuffered acidic medium. In excess iodate the reaction shows not only oligooscillations in pH, Pt potential and the concentration of iodide ion, [I?], but also an initial induction period which has the linear relation with initial pH. At the end of the induction period, [I?] decreases sharply and a yellow coloration (due to iodine) appears transiently. While in excess thiourea iodine is produced and finally con- sumed, leaving milky deposits (due to sulfur) at the end of the reaction. The induction period from the start of the reaction to the maximum of [I2. is also directly proportional to initial pH. A 14-step mechanism, including a H+-mediated preequalibrium, Dusman reaction, iodine-sulfur reactions and sulfur-sulfur reactions, is proposed. Computer simulations using this mechanism give good agreement with experiments.

关键词： oligooscillations, pH dynamics, thiourea, iodate, complex reaction mechanism, dynamic simulation.