Table of Content

24 July 2000, Volume 21 Issue 7

Previous Issue    Next Issue

Articles

Electrochemical Studies on the Interactions of the Complex of Co(phen)₂TATP³⁺ with DNA at Rotating Au Au Electrode

LI Hong, JIANG Xiong, WANG Lei, YE Bao-Hui, JI Liang-Nian

2000, 21(7):  995-998. 

Asbtract ( )   PDF (216KB) ( )  

Related Articles | Metrics

The interaction between complex Co(phen)₂TATP ³⁺ (phen=1,10 phenanthroline, TATP= 1,4,8,9-tetranitrogen-trisphene) and DNAhas been investigated by using rotating ring-disk electrode technique, and its models are discussed from the parameters obtained under diffusion and electrochemical control, respectively. It has been found that the values of the following electrochemical parameters: the apparent diffusion coefficient, transfer coefficient, rate constant at half-wave potential, collection coefficient, desorption efficiency etc., for the complex of Co(phen)₂TATP ³⁺ decrease significantly in the presence of DNAcompared with that in the absence of DNA. It is shown from the comparative studies of Co(bpy)₃³⁺ that, in the presence of DNA, significant differences exist in the change of transfer coefficient and collection coefficient between Co(bpy)₃³⁺ and Co(phen)₂TATP ³⁺ .

Studies on the Synthesis, Spectroscopy and Catalytic Properties of CrCoBEA Metallosilicate

WANG Ya-Jun, TANG Xiang-Hai, ZHU Rui-Zhi, PAN Lü-Rang 

2000, 21(7):  999-1004. 

Asbtract ( )   PDF (622KB) ( )  

Related Articles | Metrics

Metallosilicates with BEAstructure simultaneously containing chromium and cobalt have been hydrothermally synthesized for the first time under static conditions. By varying temperature, time as well as concentration of the starting materials, the optimal conditions for the synthesis of CrCoBEAmolecular sieve were deduced. The crystallinity, spectroscopic property and catalytic activity of CrCoBEAwere evaluated by means of XRD, FTIR, UV-Vis DRS, ESRand catalytic tests, respectively. The result reveals that crystallization with gel molar composition of TEOS∶0.017[Cr(acac)₃]∶0.017[Co(acac)₃]∶(0.580.64)TEAOH∶0.01Al(NO₃)₃∶(1620)H₂Oat 408428 Kafter 90150 h gave a high crystallinity, uni-phased Cr-CoBEAmolecular sieve. Both chromium and cobalt ions incorporated into the framework during crystallization were highly dispersed with multiple chemical status. The CrCoBEAmolecular sieve exhibited promising catalytic activities in the selective oxidation of cyclohaxene with dilute H₂O₂ and the decomposition of NO. The order of activity for selective oxidation of cyclohexene and decomposition of NOwere CrCoBEA>CoBEA>CrBEAand CrBEA>CrCoBEA>CoBEA, respectively.

Preparation, Crystal Structure and Thermal Decomposition Mechanisms of [Ni(CHZ)₃] (TNR)·5H₂O

LU Chun-Hua, ZHANG Tong-Lai, ZHANG Jian-Guo, CAI Rui-Jiao

2000, 21(7):  1005-1009. 

Asbtract ( )   PDF (243KB) ( )  

Related Articles | Metrics

The compound [Ni(CHZ)₃] (TNR)·5H₂Owas prepared by using nickel carbonate, the aqueous solution of styphnic acid and carbohydrazide as reagents. The crystal structure of [Ni(CHZ)₃] (TNR)·5H₂Owas determined by using single crystal diffraction analysis. Thermal decomposition mechanisms of the compound were studied by using TG DTG, DSCand IRtechniques. The crystalline was in triclinic system with space group P1 The unit cell parameters are as follows: a =1.04540(10) nm, b =1.1671(2) nm , c =1.2278(2) nm, α =109.190(10)°, β =121.168(12)°, γ =99.700(10)°, {V =}1.2613(3) nm³, Z =2, Dc=1.744 g/cm³, μ(Mo, Kα)=0.873 mm^-1 , F (000)=688, R =0.0419, R_w=0.1053. Carbohydrazide served as a bidentate, coordinating to nickel cation with its carbonyl oxygen atom and the first nitrogen atom so that a five membered chelating ring is formed. There are three such rings in the molecule. The coordination number is six and its configuration is deformed octahedral. The decomposition mechanisms confirm that the first dehydration process lost four water molecules, and the second step dehydrate one molecule. The residue is Ni₂O₃ at 500 ℃, finally.

Studies on Solvothermal Synthesis and Structure of a New Titanium Phosphate Large Single Crystal

GUO Yang-Hong, SHI Zhan, QU Xue-Jian, PANG Wen-Qin

2000, 21(7):  1010-1012. 

Asbtract ( )   PDF (182KB) ( )  

Related Articles | Metrics

The organically templated titanium phosphate [Ti₃P₆O₂₇ H₅] · [C₂H₉N₂]₅·2 [H₃O] has been synthesized by solvothermal method and its structure was determined by single crystal Xray diffraction. The crystal crystallizes in a orthorhombic system of the enantiomorphic space group P2₁2₁2₁ , with a = 1.0180(6) nm , b =1.5899(9) nm, c =2.3227(12) nm, V =3.7594(4) nm³, Z =4, D_c= 1.96 g/cm³ , F (000)= 2296 , R =0.0486, ωR₂=0.1257. The title compound contains chiral spirals formed from macroanionic chains of titanium oxygen octahedra bonded together by phosphate tetrahedral. These spirals are interconnected through hydrogen bonding in a manner to form unusual tunnels along the [001] direction in which H₂N(CH₂)₂NH₃⁺ cations are included. Second harmonics are generated in powdered sample.

Synthesis of Silicate Materials with Micro/Macroporous Bimodal Pore Systems

WANG Ya-Jun, TANG Yi, WANG Xing-Dong, YANG Wu-Li, NI Zheng, HUA Wei-Ming, YUE Ying-Hong, GAO Zi

2000, 21(7):  1013-1015. 

Asbtract ( )   PDF (212KB) ( )  

Related Articles | Metrics

Aseries of macroporous silicates with zeolitic microporous frameworks have been successfully prepared by self-assembly of discrete colloidal crystals of silicalite-1, titanium silicalite 1(TS-1) and ZSM-5 , using polystyrene(PS) spheres as templates. The properties of these novel materials were characterized by means of XRD, IR, SEM, ²⁹Si MAS NMRand N₂ adsorption/desorption measurements. These materials show ordered spheroidal voids, which are interconnected in three dimensions through windows. The ordering of the macropores are mainly affected by the particle size of the colloidal zeolites.

The Assembly of Tris(bipyridine)ruthenium(Ò) in MCM-48 and Photoluminescent Properties of Assembly Products

FANG Ming, ZHANG Ping, LI Shou-Gui, WANG Yue, XU Ru-Ren

2000, 21(7):  1016-1017. 

Asbtract ( )   PDF (242KB) ( )  

Related Articles | Metrics

Tris(bipyridine)ruthenium(Ò)(Ru(bpy)₃²⁺) was incorporated into mesoporous silicate MCM-48. Xray diffraction and emission spectroscopy were used to investigate the products, Ru(bpy) ₃²⁺/MCM-48. The emission spectra show that the wavelength of maximum intensity(λ_max) for Ru(bpy) ₃²⁺ increases with the increase of Ru(bpy)₃²⁺ loading level in MCM 48. The photoluminescent property of Ru(bpy)₃²⁺/MCM-48 was investigated. It was observed that the wavelength maximum intensity(λ_max) for Ru(bpy)₃²⁺/MCM-48 was red shifted when acetone vapor was introduced.

The Microstructure Analysis of Enzymes Immobilized by Sol-gel Method and Its Application in Phenol Optical Chemical Sensor

LI Jun, WANG Ke-Min, XIAO Dan, YANG Xiao-Hai

2000, 21(7):  1018-1022. 

Asbtract ( )   PDF (267KB) ( )  

Related Articles | Metrics

The external states of horseradish peroxidase(HRP) encapsulated membrane prepared by enclosed aging method and dip coating method are compared by common optical microscopy to clarify that the sol gel membrane prepared by enclosed aging method is no cracking. The transmission electron microscopy(TEM) is used to observe the character of the sol gel derived HRPmembrane. The TEMphotos show that enzyme can uniformly distribute in the gel as if in the solution and do not leach from the gel. This membrane can be used to fabricate a phenol optical sensor based on the decrease of chemiluminescence intensity. The response mechanism is discussed by compete reaction.

Quantitative Determination of Resveratrols in Wine by GC/MS and Elementary Study on Their Physiological Activity

MA Ting, LI Gong-Ke, LI Xiao-Dong, TIAN Xue-Mei, ZHANG Zhan-Xia, BAO Lun-Jun, ZHOU Hui-Tang

2000, 21(7):  1023-1027. 

Asbtract ( )   PDF (1108KB) ( )  

Related Articles | Metrics

C₁₈ SPEmethod was applied to the extraction of the resveratrols from Chinese wine. GC/MShas been used to analyze two isomers of resveratrol, cis- and trans-resveratrol in wine simultaneously. Identification was based on retention time and mass ion spectrum. These two compounds were quantitative determined. The precision of the method for the determination of cis and trans resveratrol was 4.48% and 5.23% of RSD, respectively. The recovery of cis and trans resveratrol was 94.4% and 97.6%, respectively. Twelve kinds of actual wine samples were determined. The elementary study was also performed for physiological activity of resveratrols. The effects of resveratrols on growth and reproductive activity of VSMC, LOVO, 3T3 cells of mouse were preliminary researched and the morphological change of these cells had been observed.

Advances of Miniaturized Total Chemical Analysis System and Its Techniques

XU Yi, Eijkel Jan-C. T. , Manz A.

2000, 21(7):  1028-1034. 

Asbtract ( )   PDF (657KB) ( )  

Related Articles | Metrics

Advances of miniaturized total chemical analysis system and μ-TAStechniques and applications were reviewed in this paper. The latest advances about the miniaturized capillary electrophoresis, DNAand biochemical analysis and combinatorial chemistry by microchip was specially discussed here.

A Miniaturization Solid-phase Extraction Technique Designed for Electrothermal Vaporization-Atomic Emission Spectrometry Determination

XIONG Hong-Chun, HU Bin, JIANG Zu-Cheng

2000, 21(7):  1035-1036. 

Asbtract ( )   PDF (296KB) ( )  

Related Articles | Metrics

Anew method of combination micro-column packed with 2-ethylhexyl hydrogen-2-ethylhexyl phosphonate(P₅₀₇ ) extraction resin with electrothermal vaporization inductively coupled plasma atomic emission spectrometry(ETV-ICP-AES) for separation and determination of trace rare earth elements(lanthanum, europium, yttrium and ytterbium) has been developed. Various influencing factors, such as the acidity of solution, flow rate and the volume of the sample, the length of the micro column on the separation and the preconcentration are examined in detail, the effect of the existence of organic matrix and the pre-ashing temperature on determination of rare earth elements by ETV-ICP-AES has also been studied.

Oscillographic Chronopotentiometry with Fourier Self-deconvolution

ZHENG Jian-Bin, ZHANG Hong-Quan, GAO Hong

2000, 21(7):  1037-1039. 

Asbtract ( )   PDF (178KB) ( )  

Related Articles | Metrics

The classical Fourier self deconvolution has the problem in selecting simulated function and filter function, so its application in resolving overlaped peaks is limited. In this paper, using coarser approximation obtained after wavelet transform as line shape function, a new electroanalytical method, Fourier self-deconvolution oscillographic chronopotentiometry is founded. Experimental results show that this method can not only improve the resolution power and sensitivity, but also make selection of parameters in the processing of Fourier self deconvolution easy and simple.

Studies on Non-protected Fluid Room Temperature Phosphorescence of Polycyclic Aromatic Hydrocarbon of Fluoren and Acenaphthene

LI Long-Di, MOU Lan, CHEN Xiao-Kang

2000, 21(7):  1040-1042. 

Asbtract ( )   PDF (331KB) ( )  

Related Articles | Metrics

Astrong and stable room temperature phosphorescence(RTP) signal of fluoren(Flu), acenaphthene(Ace) aqueous solution can be induced only by using Na 2SO₃ as oxygen scavenger and KIas heavy atom perturber. The maximum phosphorescence intensity wavelengths are λ_ex/λ_em=285/467, 286/493, 520 nm. The RTPintensity is very sensitive to the kind and amount of organic solvent added to the system. For a Flu(or Ace)/KI/Na 2SO₃ aqueous solution system containing 1.0% acetonitrile, the RTPintensity is linear to Flu(or Ace) concentration in the range of 8.0×10^-7 8.0×10^-6 mol/Land 8.0×10^-6 4.0×10^-5 mol/Lor 8.0×10^-7 2.8×10^-6 mol/Land 2.8×10^-6 4.0×10^-5 mol/L. The calculated detection limit by methodology of IUPACbased on three times the standard deviation of background is 8.6×10^-8 , 9.0×10^-8 mol/Lrespectively. The relative standard deviation( n =7) is 2.4% or 3.5% for the system containing 1.2×10^-5 mol/Lof Flu or Ace. The present work shows again that a protective medium is not necessary condition for the fluid RTPemission.

Synthesis and Characterization of Ether-bond RP-Packing

YU Xin, ZHAO Rui, LIU Guo-Quan

2000, 21(7):  1043-1044. 

Asbtract ( )   PDF (258KB) ( )  

Related Articles | Metrics

Asimple, practical and economical procedure has been developed to prepare novel C₁₈ ether-bond reversed phase packing. Asoft and long C₁₈ alkyl chain was coupled onto silica(Sinopak-S, particle size d=5 μm, pore diameter D_p=11 nm; and surface area S=170 m²/g) with γ-glycidoxypropyltrimethoxysilane as coupling agent. Chromatographic evaluation indicate that its reversed phase behavior was similar to ordinary ODS.

The Reaction of Iminoxy Radical with Phenols

HU Jia-Xin, JI Min, WANG Bing-Xiang, HU Yue-Fei, HU Hong-Wen

2000, 21(7):  1045-1047. 

Asbtract ( )   PDF (174KB) ( )  

Related Articles | Metrics

p-Chlorobenzaldoxime dehydrodimer, which decomposed to iminoxy radicals on heating, reacts with substituted phenols giving acetylamino, t-butyl, dimethyl, methoxy and phenyl substituted 2-(4'-chlorophenyl)benzoxazole derivatives. From 1-or2-naphthol, 8-hydroxyquinoline and bisphenol A,2-(4'-chlorophenyl)naphth[2,1-d]oxazole(6), 2-(4'-chlorophenyl)naphth[1,2-d]oxazole(5), 2-(4'-chlorophenyl)oxazolo[4,5-h]quinoline(7) and 2,2-bis[5'-(2'-(4"-chlorophenyl)benzoxazolyl)]-propane(8) were obtained. This is a new kind of radical substitution reaction. And a mechanism of the reaction is proposed.

Studies on the Biomimetic Catalytic Character of New Schiff Base Mono- and Di-nuclear Complexes

CHEN Xin-Bin, ZHU Shen-Jie, GUI Ming-De, YANG Yan

2000, 21(7):  1048-1051. 

Asbtract ( )   PDF (1219KB) ( )  

Related Articles | Metrics

This paper first reports the biomimetic catalytic character of new Schiff base mononuclear complexes MH₂L｛M = Mn(Ⅱ), Fe(Ⅲ)Cl, Cr(Ⅲ)Cl, Cu(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ); L = bis[N,N'-ethylene-2,2'-(phenylmethylene)bis(3,4-dimethylpyrrole-5-aldimino)]｝ and dinuclear complexes MnML[M = Mn(Ⅱ), Fe(Ⅲ)Cl, Cr(Ⅲ)Cl, Cu(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ)] for the monooxygenation of cyclohexane with PhIO. The results showed that the catalytic property of the dinuclear complex is better than that of the mononuclear complex, so we supposed that there is some cooperation between the two metals in these dinuclear complexes. It seems that this cooperation increases with the increase of the number of unpaired d electrons in the dinuclear complexes.

Synthesis of 1,2,4-Triazolo[3,2-d][1,5]benzoxazepine Compounds

LIU Xian-Jun, LIU Yi, DING Zong-Biao, WANG Quan-Rui

2000, 21(7):  1052-1055. 

Asbtract ( )   PDF (213KB) ( )  

Related Articles | Metrics

Azocarbenium ions 3, prepared in situ from 4-chromanone arylhydrazones 1, cycloadd readily to the triple bond of nitriles forming3-spiro substituted 1,2,4-triazolium salts 4. The initial cycloadducts 4 cannot be isolated but undergo consecutive reactions, e.g. [1,2]-shifts and ensuing ring enlargement to provide 1,2,4-triazolo[3,2-d][1,5]benzoxazepine compounds 5a—5k, a kind of novel tricyclic heterocycles.

Progress in the Study on Synthetic Method of Cyclopeptide

TANG Yan-Chun, TIAN Gui-Ling, YE Yun-Hua

2000, 21(7):  1056-1063. 

Asbtract ( )   PDF (819KB) ( )  

Related Articles | Metrics

The synthetic method and strategy of cyclopeptide were presented, some efficient coupling reagents were introduced, and different influence factors such as the concentration of reaction solution, structure of linear peptide precursor, conformation etc, were discussed.

Two New Methods for Synthesis of 4β-Amino-4-deoxypodophyllotoxin and 4β-Amino-4'-demethyl-4-deoxypodophyllotoxin

CHEN Shao-Yuan, YU Yong-Ping, YOU Jin-Zong, CHEN Yao-Zu

2000, 21(7):  1064-1066. 

Asbtract ( )   PDF (308KB) ( )  

Related Articles | Metrics

Two new methods for synthesis of 4β-amino-4-deoxypodophyllotoxin and 4β-amino-4'-demethyl-4-deoxypodophyllotoxin have been developed. These compounds were synthesized by reduction of the corresponding₄β-anzido-podophyllotoxin derivatives with SmI₂ or HCO₂NH₄/Pd-Cin excellent yields under mild conditions with convenient manipulation.

Reaction of Electron Transfer from Methionine-containing Dipeptides to Triplet 4-Nitroquinoline 1-Oxide

XU Ye-Ping, SONG Qin-Hua, YU Shu-Qin, CHEN Cong-Xiang, MA Xing-Xiao, LIN Wei-Zhen, YAO Si-De

2000, 21(7):  1067-1069. 

Asbtract ( )   PDF (179KB) ( )  

Related Articles | Metrics

Photochemical reactions of 4-nitroquinoline 1-oxide(4NQO) with methionine-containing dipeptides Met-Met, Ala-Met, Met-Lue and Met-Gly have been studies by using 248 nm laser flash photolysis. The formation of α-alkyl radicals was observed, and their rate constants of formation were obtained. The reaction mechanism that the α-alkyl radicals produced via an electron transfer process between triplet 4NQO and methionine-containing dipeptide was proposed.

Studies on the Synthesis of New Sulfonylamide Ligand, Crystal Structure and Asymmetric Hydrogen Transfer Reaction of Acetophenone

DONG Chun-E, ZHANG Jun-Long, ZHENG Wei-Zhong, ZHI Yong-Gang, ZHANG Liang-Pu, YU Zuo-Long

2000, 21(7):  1070-1072. 

Asbtract ( )   PDF (399KB) ( )  

Related Articles | Metrics

The new ligand(1R, 2R)(+)N,N'-bis(8-quinolinesulfonylamino)-1,2-diphenylethylene diamine(BQSDA) was synthesized. The 1∶1 chiral crystal was formed from BQSDAwith acetone. The crystal belongs to monoclinic, space group P2₁, a=0.9717(2) nm, b=0.9495(10) nm, c=1. 7542(3) nm, α=γ=90°, β=97.130°, V=1.606(5) nm³, D_c=1.35 g/cm³. There is a hydrogen bond N1—H…O5 between BQSDAand acetone. The ligand has been used as the chiral catalyst in asymmetric hydrogen transfer reaction of acetophenone in a high yield with e. e.up to 66.5%.

Reduction of Diphenyldiselides with Cp₂TiCl₂/BuⁱMgBr/THF

XU Xin-Hua, HUANG Xian

2000, 21(7):  1073-1074. 

Asbtract ( )   PDF (568KB) ( )  

Related Articles | Metrics

The reduction of diaryldiselenides by Cp₂TiCl₂/BuiMgBr/THFled to arylselenium complex of titanocene [Cp₂TiSeAr]. This species reacted smoothly with electrophilic substrates such as acylhalides, α-bromocarbonyl compounds, diaryliodonium salts, α,β-unsaturated carbonyl compounds to afford the corresponding organic selenides in high yields.

Photoelectrochemistry of CdS/Zn²⁺-TiO₂ Composite Semiconductor Nanoporous Films Sensitized by Ru(bpy)₂(NCS)₂ Dye

ZHANG Li, WANG Yan-Qin, YANG Mai-Zhi, GAO En-Qin, CAI Sheng-Min

2000, 21(7):  1075-1079. 

Asbtract ( )   PDF (262KB) ( )  

Related Articles | Metrics

The Zn²⁺-doped TiO₂ nanoparticles were prepared with hydrothermal method. The photoelectrochemical properties of Zn²⁺-doped TiO₂ nanoporous film electrode sensitized by Ru(bpy)₂·(NCS)₂, and Zn²⁺-TiO₂/CdScomposite semiconductor nanoporous films sensitized by Ru(bpy)₂(NCS)₂ were studied respectively. Doping, sensitizing and forming composite semiconductor particles produced red-shifts on the photocurrent action spectra. The conversion efficiency of light to electricity for the Zn²⁺-TiO₂/CdScomposite semiconductor nanoporous films was greatly improved and reached maximum.

Theoretical Study of the Structures, Spectra, Nonlinear Second-order Optical Properties and Photoisomerization Process of the Spiroconjugated Compound 1',3',3'-Trimethyl-6- hydroxyspiro[2H-1-benzopyran-2,2'-indoline]

SUN Xiu-Yun, FENG Ji-Kang, REN Ai-Min, SU Zhong-Min, FU Wei, JIN Hong-Wei

2000, 21(7):  1080-1085. 

Asbtract ( )   PDF (1850KB) ( )  

Related Articles | Metrics

The structures and electronic spectra of the spiropyran molecule 1',3',3'-trimethyl-6-hydroxyspiro[2H-1-benzopyran-2,2'-indoline](HBPS) and its photoisomerization products have been studied by means of AM1 and ZINDOmethods. The mechanism of the photoisomerization has also been studied thoretically, and based on this study, the nonlinear optical susceptibility has been calculated using sum-over-states(SOS) formula with the program designed by us.

Transfer Rule of Equivalent Circuits of Similar Plots on the Impedance Complex Plane and on the Capacitance Complex Plane for an AC Impedance Measurement(Ò) Transferring of the Equivalent Circuits Containing the Warburg Impedance

ZHANG Ya-Li, SUN Dian-Ting, GUO Guo-Lin, GUI Lin-Lin

2000, 21(7):  1086-1092. 

Asbtract ( )   PDF (196KB) ( )  

Related Articles | Metrics

The AC impedance technique is one of the important methods for electrochemical study. We have discovered that there is a certain transformation relationship between the equivalent circuits for similar plots on an impedance complex plane and on a capacitance complex plane. The transfer rule for an equivalent circuit being composed of the resistance and the capacitance has been given in our previous papers. Herein we give the transfer rule for an equivalent circuit including Warburg impedance as follows: for the equivalent circuit involving Warburg impedance, if we make the following transformation, (1) a resistance is substituted for a capacitance, and a capacitance for a resistance, (2) a Warburg impedance is changed to a Warburg transform, and a Warburg transform is changed to a Warburg impedance(the Warburg transform is expressed by a parallel connection of a resistance and a capacitance subjecting to the prerequisite of ωRC=1, R=Wω^-1/2 and 1/(ωC)=Wω^-1/2, here constant Wis the proportional factor), and (3) a parallel connection is changed to a series connection, and a series connection to a parallel connection, then the plot on the ZdZc plane for the original equivalent circuit and the plot on the CdCc plane for the transferred one, or the plot on the CdCc plane for the original equivalent circuit and the plot on the ZdZc plane for the transferred one are similar, respectively. This means that impedance of the original equivalent circuit has the similar expression with capacitance of corresponding transferred one. Using the transfer rule the study results on a plot on one complex plane can be directly used to a similar plot on another complex plane. Therefore, the transfer rule is a useful tool for the ACimpedance study.

Supersonic Jet-cooled Laser-induced Fluorescence(LIF) Spectrum of Biacetyl

PEI Lin-Sen, CHEN Yang, JIN Jin, GAO Yi-De, DAI Jing-Hua, CHEN Cong-Xiang

2000, 21(7):  1093-1097. 

Asbtract ( )   PDF (245KB) ( )  

Related Articles | Metrics

The laser-induced fluorescence(LIF) excitation spectra of biacetyl in the range of 432—451 nm were obtained under the supersonic jet condition. Three weaker peaks, which are at 0, 87 and 98 cm^-1, respectively(related to 22182 cm^-1) were observed in a high sensitivity spectrum at red-hand of 22336 cm^-1 peak which was assigned as band origin previously. The tunnel splits for 87 and 97 cm^-1 peaks were observed in the hyperfine spectra. They are 1.04 cm^-1 and 1.68 cm^-1 for 87 cm^-1 peak and 97 cm^-1 peak respectively. These values are in agreement with calculated values very well. The band origin of S₁←S₀ transition is now determined at 22182 cm^-1. Acomplete assignment of biacetyl LIFspectrum is done for the first time. The frequency of torsion mode is determined to be 91.1 cm^-1 , and the enharmonic constant is 4.875 cm^-1.

The New Catalyst for the Elimination of Hydrogen from CO₂ Feed Gas in the Production of Urea

HAO Zheng-Ping, AN Li-Dun, WANG Hong-Li

2000, 21(7):  1098-1100. 

Asbtract ( )   PDF (820KB) ( )  

Related Articles | Metrics

An idea for designing new catalyst for hydrogen elimination from CO₂ feed gas in urea synthesis was suggested. The excellent catalyst with a high activity for H₂-O₂ and CO-O₂ reaction, good resistance to sulfur poisoning and good performance for energy saving was designed and prepared. This catalyst is superior to other industrial catalysts in catalytic activity and can offer resistance to sulfur poisoning and shows a continuously increasing and more extensive application prospects.

Synthesis, Characterization of Cr-HMS and the Application in Catalytic Oxidation

YUE Hong-Yong, HUA Wei-Ming, TANG Yi, YUE Ying-Hong, GAO Zi

2000, 21(7):  1101-1104. 

Asbtract ( )   PDF (416KB) ( )  

Related Articles | Metrics

Aseries of chromium containing mesoporous molecular sieves Cr-HMSwith various chromium content were synthesized and characterized. It was found that the incorporation of chromium into HMSleads to the decrease of their structural order as well as the uniformity of their mesopores. The catalysts exhibit good activities for both the oxidation of cyclohexane and the hydroxylation of benzene. The conversions of benzene and cyclohexane versus the chromium content in the catalysts show typical volcano shapes. In the case of the oxidation of cyclohexane which is easier to be oxidized, pretreating Cr-HMSby reduction in H₂ can not only retain its relatively high activity, but also acquire a relatively high stability.

Mechanismic Studies on the Selective Reduction of NO by CH₄ over an In/HZSN-5 Catalyst

WANG Xiao-Dong, MA Lei, ZHANG Tao, BAO Xin-He, SUN Xiao-Ying, LIANG Dong-Bai, LIN Li-Wu

2000, 21(7):  1105-1107. 

Asbtract ( )   PDF (412KB) ( )  

Related Articles | Metrics

CH₄ oxidations in CH₄+O₂, NO+CH₄(+O₂) and NO₂+CH₄(+O₂) reaction systems over the catalyst of indium impregnated on HZSM-5(In/HZSM-5) were studied. The efficacies of O₂, NOand NO₂ for CH₄ oxidation were evaluated. The dramatically different conversions of CH₄ in these different reaction systems suggested that NO₂ played a key role in CH₄ conversion. TPDstudies of CH₄, O₂, NOand NO₂ on HZSM-5 and In/HZSM-5 were also investigated. It was found that only NO_x could absorb on the samples and the chemisorbed amount of NO₂ was much larger than that of NO. This illustrated that the absorbed NO₂ species were very important in the CH₄-SCRprocess. Our TPDresults and IRresults from the literatures both indicated that not only the acid sites but also the In sites in the In/HZSM-5 catalyst facilitated the formation of NO₂. Moreover, the reaction between NO₂ and CH₄ took place on the In sites.

Biosynthesis of Lipid by Mortierella Isabellina Grown on Hexadecanol

XIAN Mo, ZHEN Ming, KANG Yi-Jian, ZENG Qing-Xin, BI Ying-Li, ZHEN Kai-Ji

2000, 21(7):  1108-1109. 

Asbtract ( )   PDF (686KB) ( )  

Related Articles | Metrics

Mortierella isabellina was found to accumulate lipid with 2% hexadecanol and 1% yeast extract as the growth substrates. The amount of lipid reached 64.5% of dry mycelia, and unsaturated acids accounted for 97.05% of the total fatty acids. Mean while, 75% of hexadecanol in medium was converted to lipid. The biosynthetic route from hexadecanol to linoleic acid was presumed as follows: Hexadecanol——C_18∶0(Steric acid)——C_18∶1(Oleic acid)——C_18∶2(Linoleic acid)

Effects of Structure on Electrochemical Properties of Pyrolytic Carbon Anodes

XIE Zhong-Wei, ZHANG Xi-Yan, TIAN Yu-Mei, GONG-Jian, QU Xiao-Guang, QU Lun-Yu

2000, 21(7):  1110-1112. 

Asbtract ( )   PDF (186KB) ( )  

Related Articles | Metrics

Carhons were prepared at different temperatures by pyrolytic treatment of phenolformaldehyde resin molded with ZnCl₂ in advance. X-ray structure analyses have shown that these carbon are essentially amorphous with rather loose structure of molecular size order with an interlayer distance of 0.36—0.37 nm. Using electrochemical methods, we have studied the insertion of lithium within these materials. Resole resins, heated to 580 ℃, have a reversible capacity of about 400 mA·h/g, which is beyond the theoretical capacity of graphite(372 mA·h/g) and discover that carbons with a smaller crystallite size and large interlayer distance have the larger discharge capacity.

A Novel Catalyst of MoO₃/MCM-49 over Nonoxidative Aromatization of CH₄

XU Ning, KAN Qiu-Bin, ZHANG Ji, LI Xue-Mei, JI Liang, WU Tong-Hao

2000, 21(7):  1113-1114. 

Asbtract ( )   PDF (214KB) ( )  

Related Articles | Metrics

MoO₃/MCM-49 has been synthesized under the special condition and it shows a high activity and selectivity for nonoxidative aromatization of methane with a long lifetime and extreme capacity of anti-coking. MoO₃/MCM-49 is considered as a very promising catalyst for the title reaction.

Formation of Needle-like CdS Nanoparticles on DNA Template

CHEN Xia, JIN Jian, YANG Wen-Sheng, GUO Zhong-Man, JIANG Lin, YANG Bai-Quan, XU Li, WEI Li, LI Tie-Jin, ZHENG Da-Fang

2000, 21(7):  1115-1117. 

Asbtract ( )   PDF (331KB) ( )  

Related Articles | Metrics

Monolayer of octadecylamine(ODA) and salmon sperm DNAor salmon sperm DNA-Cd complex were studied on air-water interface by π-Aisotherm. After being co-transferred onto substrates by Langmuir-Blodgett technique, atomic force microscope(AFM) measurements show the DNAmolecules are packed into lines in the film, due to the interactions between the ODAand DNAmolecules. By exposing the ODAand DNA-Cd complex LBfilm to H₂S, needle-like CdSnanoparticles were formed along the DNAlines as characterized by transmission electron microscope(TEM). Electron diffraction(ED) image indicates that the so prepared needle-like CdSis a new kind of nanostructured materials.

The Experiential Modification of Mulliken's Overlap Population as the Judgment of Bond Strength

LI Xin-Hua, ZHU Long-Guan, YU Qing-Sen

2000, 21(7):  1118-1120. 

Asbtract ( )   PDF (992KB) ( )  

Related Articles | Metrics

We modified Muliken's overlap population n(A, B)= and obtained an experiential formula N(A,B)=N_A(A,B)+N_B(A,B) of judging bond strength, where N_A(A, B)={Z_A/N_A², N_B(A, B)=Z_B/N_B². Twenty-eight bonds calculated by IEHMmethod and 11 monohydrides calculated by using₆-31G^** basis sets at Hartree-Fock level, electronic correlation effects are also considered through MP₂/6-31G^**, were used to verify our experiential formula. Compared with the judgment of chemical bond strength by means of Muliken's overlap population, our experiential formula has a more obvious improvement as a judgment of bond strength than Muliken's overlap population. As a judgment of chemical bond strength between atoms in molecules, the experiential formula has conquered some limitations of Muliken's overlap population, and accorded with the experimental results.

A New “Green” Route to the Synthesis of Adipic Acid

GONG Hong, JIANG Heng, LU Zhen-Bo

2000, 21(7):  1121-1123. 

Asbtract ( )   PDF (354KB) ( )  

Related Articles | Metrics

In this paper, a new “green” route to the synthesis of adipic acid is reported. This environmentally benign synthesis of adipic acid involves in the direct oxidation of cyclohexene catalyzed by Na₂WO₄·2H₂Owith 27.5% aqueous hydrogen peroxide using alkyl ammonium sulfate as a phase transfer agent. The results show that N,N-dimethyl-dodecylammonium sulfate, dodecylammonium sulfate and tri-n-octylammonium sulfate can be used as efficient phase transfer agents for this reaction under refluxing temperature. After the reaction is stopped, the homogeneous solution was cooled to 0 ℃ for 12 h. Then the crystalline product was collected by filtration and dried in air, a colorless, analytically pure product adipic acid was obtained in_52.1%—94.1% yields. The catalyst in concentrated filtrate can be reused.

The Structure Study of the β-Cyclodextrin Inclusion Complexes

YONG Guo-Ping, LI Guang-Shui, ZHENG Fei, ZHOU Hui-Shun

2000, 21(7):  1124-1126. 

Asbtract ( )   PDF (264KB) ( )  

Related Articles | Metrics

The inclusion complexes of β-cyclodextrin(β-CD) with vanillin, sebacic acid and cholesterol were prepared. DSCanalysis showed that the optimum qualitative ratio of three inclusion complexes was 1∶1, 2∶1, 3∶1, respectively. XRDresults of β-CDand its inclusion complexes indicate that the crystals of three inclusion complexes belong to an obvious channel-type packing structure, and the axial structure period is two times of the height of β-CDtorus. The structural models of three inclusion complexes were proposed according to "head-head" alignment of β-CDs, molecular size match and polarity. Aspecific peak in XRDspectra indication of forming inclusion complex can be identified at 12 nm(about 7 degrees).

Theoretical Studies on the Stabilities of Some C₆₀ Bis-adducts

CHEN Zhong-Fang, WANG Gui-Chang, ZHAO Hong-Xi, ZHAO Xue-Zhuang, TANG Au-Qing

2000, 21(7):  1127-1129. 

Asbtract ( )   PDF (1280KB) ( )  

Related Articles | Metrics

The quantum chemical investigations of some representative bis-adducts of C₆₀, C₆₀O₂, C₆₀(NH)₂, C₆₀(CH₂NHCH₂)₂ and C₆₀(SO₄)₂ have been carried out at the AM1 and PM3 semi-empirical molecular orbital levels. The relative energies of various isomers of these C₆₀ bis-adducts have been calculated. For C₆₀O₂ and C₆₀(NH)₂ with the sterically non-demanding addends, cis-1 isomer resulted from 1,2-additions to adjacent 6/6 ring fusion is the lowest energy structure; for C₆₀(CH₂NHCH₂)₂ and C₆₀(SO₄)₂ with sterically demanding addends, the most energetically preferred structure is e isomer. This is consistent with and enhances the general rule for regio-selectivity of fullerene C₆₀ established by Hirsch, though Hirschs rule is summarized on the basis of methanofullerenes. The thermodynamic analysis is not significant to explain the experimentally observed regiochemistry for C₆₀ bis-adducts, and the kinetic reasons or mechanisms may dominant in determining the regioselectivity of fullerene bis-adducts. Further addition patterns for multiple addition were also discussed.

Melting and Crystallization Behavior of Poly(ether ether ketone)/Poly(ether ether ketone ketone) Blends

RUAN Ru-Xiang, JIANG Zhen-Hua, WANG Gui-Bin, ZHANG Li-Mei, MA Rong-Tang, WU Zhong-Wen

2000, 21(7):  1130-1133. 

Asbtract ( )   PDF (472KB) ( )  

Related Articles | Metrics

Blends of poly(ether ether ketone ketone)(PEEKK) with poly(ether ether ketone)(PEEK) were prepared by melting mixing. The thermal and crystallization behaviors were characterized by DSC. The Avrami exponent is almost independent on composition and crystallization temperature, but the crystallization rate constant decreases as PEEKis in major phase. The melting point of blends decreases with increasing PEEKcontent but the equilibrium melting point is not affected by composition.

Synthesis and Characterization of Affinity Adsorbents for N-Demethylvancomycin

ZHAO Qing-Xiang, YAN Hu-Sheng, CHENG Xiao-Hui, HE Bing-Lin

2000, 21(7):  1134-1137. 

Asbtract ( )   PDF (428KB) ( )  

Related Articles | Metrics

Copolymer of N,N-dimethylacrylamide and N,N′-ethylene bisacrylamide was partially hydrolyzed to introduce the carboxyl groups onto the copolymer. Amino acids were introduced onto the carboxyl group-containing copolymer by coupling the methyl ester of the amino acids with the copolymer and then saponifying the ester. In this way, three analogues(—Gly, —Gly-D-Ala, —Gly—D-Ala—D-Ala) of the cell wall mucopeptide of Gram-positive bacteria were introduced onto the copolymer and three affinity adsorbents (Adsorbents Ⅰ, Ⅱ and Ⅲ) for vancomycin group of antibiotics were synthesized. The results showed that the adsorption capacities of adsorbents Ⅱ and Ⅲ for N-demethylvancomycin were 0. 80 and 0.86 mmol/g, respectively. The optimal pHfor the adsorption was about 6. The effect of the salt(NaCl) concentration in the solution on the adsorption capacities of adsorbents Ⅰ and Ⅱ indicated that the capacity of adsorbent Ⅰ decreased markedly with increasing the salt concentration, while the effect of the salt concentration on the capacity of adsorbent Ⅱ was relatively slight. The result suggested that the affinity interaction contributed to the adsorption of adsorbent Ⅱ was greater than that of adsorbent Ⅰ. The adsorbed N-demethylvancomycin was completely desorbed by 0.4 mol/L Na₂CO₃(pH9.5)/CH₃CN(7/3 in volume ratio).

The Curing Theory of A_f Type Free Radical Homopolymerization(Ⅲ) The Defects of Polymer Gel Network

WANG Hai-Jun, ZHAO Min, BA Xin-Wu, LI Ze-Sheng

2000, 21(7):  1138-1141. 

Asbtract ( )   PDF (1335KB) ( )  

Related Articles | Metrics

The defects in the polymer gel network produced by polymerization is universal, which, in general, affects the physical and chemical properties of polymer materials. In present paper, we obtain the probability and the number of dangling loop——a kind of polymer network defect by analyzing the growth of polymer network with the aid of polymer statistical theory.

Studies on Butadiene/Styrene/4-Vinyl Pyridine Copolymer-montmorillonite Intercalated Hybrid

WANG Yi-Zhong, ZHANG Li-Qun, YU Ding-Sheng

2000, 21(7):  1142-1145. 

Asbtract ( )   PDF (639KB) ( )  

Related Articles | Metrics

Anew method to prepare polymer-montmorillonite hybrid was developed. Montmorillonite could be dispersed in water as exfoliated layers, then when it was blended with the butadiene/styrene/4-vinyl pyridine copolymer emulsion, the latex particle was interpenetrated with the layer of montmorillonite during the blending process. When the blend was coagulated by hydrochloric acid, the pyridine group reacted with H⁺, so the copolymer with positive charge could intercalate the layer of montmorillonite that had negative charge. There was some strong bonding between copolymer and montmorillonite in the hybrid. The extracting experiment showed that montmorillonite absorbed some copolymer. It was found that the layer structure of montmorillonite was swollen and became chaos by means of XRD. TEMshowed that the layer dispersed uniformly in the copolymer matrix and the distance between the layers was more than 6 nm. Copolymer molecule intercalated montmorillonite layer, so it's motion was confined by the layers. DSCshowed that the T_g of copolymer in hybrid had been changed. The mechanical properties of hybrid had been improved greatly after it was vulcanized, the layer could act as a good reinforcing agent for the composites.

Monte Carlo Simulation on Living Radical Polymerization with RAFT Process

LI Li, HE Jun-Po, YANG Yu-Liang

2000, 21(7):  1146-1148. 

Asbtract ( )   PDF (480KB) ( )  

Related Articles | Metrics

Monte Carlo simulation is applied, with a high effectiveness and versatility, to the studies on the kinetics and chain length distribution in radical polymerization with RAFTprocess. The results show that the molecular weight the resulting polymers increase linearly with monomer conversion, and the polydispersity is lower than 1.1, a typical feature of living polymerization. The simulation results are in consistent with the experimental results in literature. Additionally, that the molecular weight is proportional to the initial concentration of dithioester, [DSE]₀, and the polymerization rate is [DSE]₀-independent, could be of great help for controlling molecular weight in experiment.

Free Radical Ternary Copolymerization of C₆₀ with Styrene and Maleic Anhydride

GUAN Wen-Chao, LEI Hong, LIAO Dao-Xun

2000, 21(7):  1149-1150. 

Asbtract ( )   PDF (127KB) ( )  

Related Articles | Metrics

Anovel C₆₀-styrene-maleic anhydride copolymer was prepared with radical polymerization. 50 mg of C₆₀ and 1 g of styrene and 1 g of maleic anhydride were dissolved in₂₀ mLof o-dichlorobenzene, then was initiated by 200 mg of BPOat 70 ℃ under the protection of Ar for 32 h. The copolymer was obtained as a brown solid. The structure of copolymer was characterized by UVand FTIR. GPCanalyses shows that its average molecular weight M_w is 13000. The copolymer is soluble in THF, DMSOand water. The surface tension of 0.5% of copolymer aqueous solution was determined to be 54.6×10^-3N/m(20 ℃). TEManalyses shows that the copolymer is a kind of water-soluble nanosphere with the average diameter of about 60 nm.

Synthesis and Characterization of Novel Liquid Crystalline Epoxy Resin Containing Ester Mesogen

LIU Wei-Chang, WANG Xiao-Gong, ZHOU Qi-Xiang, LIU De-Shan

2000, 21(7):  1151-1153. 

Asbtract ( )   PDF (197KB) ( )  

Related Articles | Metrics

Anew kind of epoxy resins with ester mesogen was synthesized and characterized by means of IR, ¹H MMR, DSCand POM. It was testified to be an epoxy-terminated oligomer containing di(p-hydroxyl benzoic acid) hydroquinone ester as mesogenic unit. The numger average molecular weight was measured by end-group analysis and the effect of reaction ratio on the molecular weight equivalent and the liquid crystalline properties of the products was also discussed.

Effect of Solvents on the Morphology and Properties of SBS Solution Cast Films

WANG You, DONG Yao, SHEN Jing-Shu, LONG Cheng-Fen

2000, 21(7):  1154-1156. 

Asbtract ( )   PDF (184KB) ( )  

Related Articles | Metrics

The effect of solvents on the morphology and properties of styrene-butadiene-styrene(SBS, {M_n=}99575, M_w/M_n=1.3, S/B=3∶7) triblock copolymer films was studied in this paper. The solvents used in the study are: ethylmethylketone, a preferential solvent for the PSblock; toluene, a non-preferential solvent for both the PSand the PBblocks; and mixed hexane/cyclohexane(2/5, in volume ratio), a preferential solvent for the PBblock. The morphology of samples cast from solutions from different solvents and then stained by RuO₄ was observed by TEM. Moreover, the tensile properties and deformation recovery behavior for these samples were measured and the results are explained according to the microstructures observed.

Studies on Synthesis of P(S-b-Me-OXZ) Block Copolymers

LIU Yan-Fei, WAN Xiao-Long, YING Sheng-Kang

2000, 21(7):  1157-1159. 

Asbtract ( )   PDF (275KB) ( )  

Related Articles | Metrics

The halogen-terminated polymers (PS—X) were obtained by living free radical polymerization. Through the end-group transformation action of AgClO₄, poly(styrene-b-2-methyl-2-oxazoline) block copolymer [P(s-b-Me-OXZ)] was synthesized by transforming the living free radical polymerization into ring-opening polymerization of 2-methyl-2-oxazoline.The obtained copolymers were characterized by SEC, IRand ¹H NMR. The suitable polymerization conditions for block copolymer synthesis were studied.