摘要:

AbstractThe kinetic behaviour of aluminum naphthenate/benzene system in the process of gelation and degradation was systematically studied. The results obtained from the kinetic experiments indicated that the gelation stage was in accordance with a kinetic model of an auto‐catalytic first‐order reaction, and the degradation stage was a simple first‐order reaction. The rate constants in these two stages at various temperaturs were measured. And the determined apparent activation energies for the gelation stage and for the degradation stage are 27.5±2.0 and 37.7±2.3 kJ/mol, respe

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090101

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY

摘要:

AbstractThe reaction of TbCl3with K[2,4‐(CH3)2C5H5] at 0°C in THF followed by crystallization at −90°C led to a pale yellow hexagonal prismatic crystalline product [2,4‐[CH3)2‐η5‐C5H5]3‐Tb·1/2THF, which is highly sensitive to air and water and rapidly efflorescent at ambient temperature. The single crystal X‐ray diffraction data of the compound have been collected at low temperature (‐60°C) and the crystal structure has been solved by heavy atom method. It belongs to triclinic system, space groupP1 with lattice parameters α=8.477Å,b=12.583Å,c=12.858Å, α=118.08°, β=91.38°, γ=108.75°,V=1120.36Å3andZ=2. Least‐squares refinement converged to a final valueR=0.043. The compound possesses an idealizedC3hsymmetry with three 2,4dimethylpentadienyl ligands bound to the central terbium atom in a pentahapto mode (η5). Each unit cell contains two molecules of [2,4‐(CH3)2‐η5‐C5H5]3Tb and one molecule of solvent THF, of which the role in

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090102

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY

摘要:

AbstractCyclic voltammetric studies of clusters (C5H5‐C2C6H4‐R‐p)Co2(CO)6‐n Ln[n=0,2; L=PPh3, P(OEt)3] and (RCH2C)2Co2(CO4) (PPh3)2on Pt electrode are described. The primary reduction (0 / −1) and oxidation (+ 1 / 0) steps are considered as a mono‐electron process for all clusters. For the clusters (C5H5C2C6H4‐R‐p)Co2(CO)6, a good linear relation between reduction potentialEpredand Hammett constant σpof R in the clusters is found. For the clusters (RC2R')Co2(CO)4L2, their radical anions are extremely unstable at room temperature and fragment into a series of mononuclear species, one of which is (RC2R')Co(CO)2PPh3. The reaction of radical anions of (RC2R')Co2(CO)6–n(PPh3)n(n=0,2) with PPh3also produces mononuclear species (RC2R')Co(CO)2PPh3which has been detected by means of cyclic voltammetry and ESR. The influence of R on redox properties of clu

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090103

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY

摘要:

AbstractThe possibility of co‐depostion of Li (I) with RE (I) has been investigated. The influences of temperature and concentration of chlorides on the deposition potential have been studied. Linear scanning voltammetry, cyclic voltammetry and current reversal chronopotentiometry were used to study the co‐deposition process. Both the electrochemical and electrolytic results clearly showed that Li (I) and RE (I) could co‐deposit on the aluminum‐copper electrode under selected conditions. Small amount of rare earth element behaved excellently as grain refiner in aluminum—lith

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090104

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY

摘要:

AbstractThe light beating technique (intensity correlation algorithm) was employed to analyze the Rayleigh scattering from the roughened Ag electrode in very dilute (10−4M) pyrazine, pyridine and piperidine aqueous solutions containing KC1 (0.1 M). The relaxation time is longer when the applied voltages are between −0.4 V and −0.8 V (vs. SCE) where the Raman effect also shows greater surface enhancement. Also observed was that for the piperidine case the relaxation time reaches its maximum at the more negative applied voltage. The origin of the relaxation is attributed mainly to the desorption process of the pyrazine, pyridine and piperidine molecules off the roughened Ag electrode. An electrostatic model was also proposed for the interpretation of these experimental observa

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090105

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY

摘要:

AbstractThe potentiostatic deposition of cadmium‐rich CMT films onto Ti, Mo, Ni substrates from an aqueous bath was carried out. The photoelectrochemical properties of film electrodes were investigated when used in a solid‐liquid junction photoelectrochemical cell (PEC). A.C. capacitance was determi

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090106

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY

摘要:

AbstractThe behavior of 4‐aryl‐1(2H)‐phthalazinones (1a—c) toward some electrophilic and nucleophilic reagents has been described with the aim of preparing some new phthalazinone derivatives of the expected pharmacological or biological act

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090107

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY

摘要:

AbstractPhotolysis of 4‐acetyl‐4‐ethoxyformylcyclohexanone, 4‐acetyl‐4‐phenylcyclohexanone and 1‐acetyl‐1‐phenylcyclohexane in deuteriochloroform using a high pressure Hg—Xe lamp showed unusual polarizations. The results are explained by the formation of a singlet exciplex of the ketone with deuteriochloroform and the photoaddition of deuteriochlor

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090108

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY

摘要:

AbstractEthyl (Z)‐α‐formylamino‐β‐arylacrylates were obtained in good yields by the condensation of ethylN, N‐diformylamino acetate and aromatic aldehydes in the presence of sodium ethoxide in ethanol. The structure of ethyl α‐formylaminocinnamate was characterized by single crystal X‐ray diffrac

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090109

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY

摘要:

AbstractIn order to investigate the structure‐odor relationship of odoriferous compounds and search for new aroma chemicals, seven acetals of 4‐trimethylsilyl‐3‐cyclohexenone and their carbon counterparts were synthesized by Birch reduction of 4‐substituted anisoles and then acetalization. Seven acetals of 4‐trimethylsilylcyclohexanone and their carbon counterparts were synthesized similarly. Structures of all new compounds were determined by MS, IR and1H NMR, and their characteristic odors were evaluated as well.The characteristic odors of the acetals formed by 4‐substituted‐3‐cyclohexenone and 1,2‐diols are fruity and woody. The acetals formed from 1, 3‐diols are woody, and formed with 1, 4‐diols are very faint in odor. Odors of acetals of 4‐substituted cyclohexanone are all very weak. As a whole, odors of organosilicon compounds are weaker, but somewhat more delicate than

ISSN:1001-604X    

DOI:10.1002/cjoc.19910090110

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1991

数据来源: WILEY