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    24 November 1991, Volume 12 Issue 11
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    Articles
    The Preparation of Co3O4Ultrafine Particles
    Wang Xiao-hui, Wang Zi-chen, Li Xi, Xu Bao-kun, Zhao Mu-yu
    1991, 12(11):  1421-1424. 
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    Co3O4ultrafine particles (UFP) were prepared from CoCl2by colloidal chemical method. The most favorable experiment conditions for the preparation of Co3O4UFP were studied. XRD, DTA, TG, IR and TEM examinations were used to discribe the characteristic of the sample. The spherical amorphous ultrafine Co3O4product has average diameters of 4. 0 nm, with good dispersity and transparency in many organic solvents. When heat-treated at 800 Kfor 3 hours, cubic crystal Co3O4UFPcan be obtained, the average crystal grain size is 6. 0 nm.
    Studies on the Synthesis, Structure and Properties of K10H3[Ln(SiMo11-nWnO3)2]·mH2O(n=5,7,9)
    Zhou Bai-bin, Shan Yong-kui, Liu Zong-xu, Zhang Xi-long
    1991, 12(11):  1425-1429. 
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    In this paper a synthetic method of K10H3[Ln(SiMo11-nWnO39)2·mH2O(n=5,7,9) (n=5,7,9;Ln=La3+,Ce3+,Pr3+,Nd3+,Sm3+,Eu3+,Gd3+,Dy3+,Yb3+)was studied. The crystal structure of K10H3[Pr(SiMo6W5O39)2]·30H2O was determined,the crystal adta are as follows;monoclinic,space group P21/n空间群,晶胞参数:a=1.7134(3)nm,b=2.6896(5)nm,c=2.1232(3)nm,β=103.60(3)°,Z=4. The characteristics of IR spectra, electronic spectra and X-ray powder diffraction of the of the new complexes were discussed. The investigation results of pyrolytic property proved that the pyrolysis temperature range of them was:n=5,250～300℃;n=7,300～350℃;n=9,350～400℃.
    Synthesis and Characterization of Complexes of Indium and Alkali Metal Halide with Crown Ethers
    Zhang Xian-xin, Zhou Zhi-xian
    1991, 12(11):  1430-1433. 
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    In the course of investigation on the extractions, ten novel solid complexes formed by combining the anions of tetrabromoindate(Ⅱ) or tetraiodoindate(Ⅱ) with the complex cations of potassium or sodium ion with benzo-15-crown-5 or dibenzo-18-crown-6 were synthesized. The complexes were characterized by elemental analyses, IR spectra and thermal analyses. In addition, in comparison with the relevant structural characters of the complexes of alkali metal pi-crates with crown ethers, some differences between the two types of the extraction systems were explanined reasonably.
    Syntheses and Characterization of Heteropoly Tungstosilicate Isomers of Lanthanide Elements
    Qu Lun-yu, Niu Zeng-yuan, Liu Jing-fu, Chen Ya-guang, Zhao Ben-liang, Peng Jun
    1991, 12(11):  1434-1436. 
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    The isomers of K13[Ln(α-,β2-SiW11O39)2]· xH2O(Ln=La,Ce,Pr,Nd,Sm,Gd,Er) were prepared, and characterized by elemental analysis, polarography, CV,UV,Vis,IR and 29SiNMR spectra, magnetic moments and thermal analysis. Their stabilities and relationship between the properties and structure are discussed.
    Synthesis and Spectral Studies of Cu(Ⅱ)-Zn(Ⅱ) Binuclear Complexes with N,N' -bis(2-aminopropyl)oxamido Copper(Ⅱ)
    Liao Dai-zheng, Bai Ling-jun, Li Li-cun, Wang Geng-lin
    1991, 12(11):  1437-1439. 
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    Three novel heterobinuclear complexes, [Cu(oxap)Zn(L)2(ClO4)2], where oxap=N,N' -bis(2-aminopropyl)oxamido, L=2,2' -bipyridyl(bpy), 1,10-phenathroline(phen) and 5-nitro-1,10-phenathroline(NO2-phen) were synthesized. ESR spectra of two complexes (L=phen, NO2-phen) in powder were studied at 77K.
    Diester PVC Membrane Electrode for Quaternary Phosphonium and Quaternary Arsonium Cations
    Gong Ben-ling, Ji Hong, Hu Qi-zhi, Zhao Wen-kuan, Zhou Xing-yao
    1991, 12(11):  1440-1442. 
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    The quaternary phosphonium and quaternary arsonium ion-selective electrodes prepared with diesters as active substance and plasticizer were investigated. A PVC membrane electrode based on dioctylphtha.late exhibited a Nernstian response to ω-hydroxy-dodecyltriphenylphosphonium bromide and tetraphenylarsonium chloride. The response mechanism of the electrode was studied by using FTIRspectrometry. The response is caused by the secondary weak force between the positive charge center of quaternary phosphonium (or arsonium) and the electronegative benzene ring in diester.
    Determination of Components from Herba Cistanches by Analytical Supercritical Fluid Extraction with GC/MS
    Ma Xi-zhong, Yu Xiao-bing, Zheng Zhen-hua. Mao Jin-song
    1991, 12(11):  1443-1446. 
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    The determination of the components from Herba cistanches, a kind of Chinese medicine was carried oul by the analytical supercritical fluid extraction (SFE), followed by GC/ MS. The main factors affecting the extraction efficiency, including the use of modifier, are discussed. It has been demonstrated that the analytical SFE method has more advantages over the conventional techniques, and will be effectively used in the composition investigation of Chinese medicines.
    Investigations on Polarography with Linear Change Potential (XIX)--Theories of Convolution and Deconvolution Reversible-Adsorption Wave
    Chen Qiao, Zhang Zu-xun
    1991, 12(11):  1447-1451. 
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    In this paper, theories of convolution and deconvolution reversible-adsorption wave were described, the behavior of the wave had been studied also. Experimental results agree with the theoretical conclusions.
    Studies on Analytical Quantum Chemistry(Ⅱ)--The Protonation and Dissociation of a New Chromogcnic Reagent-Chlorophosphonazo-p-Methyl and Their Mechanism
    Zhou Wei-liang, Du Ying-xiang, Xu Zhong-jun, Pan Jiao-mai
    1991, 12(11):  1452-1454. 
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    The protonation and dissociation of chlorophosphonazo-p-methyl(CPApM) in aqueous solution have been studied spectrophotometrically. The protonation constant (lgKp) was found to be -0. 158±0. 005 and the dissociation constant (pKa)11. 41 ± 0. 03. The electronic structure of CPApM and microcosmic mechanism of protonation and dissociation of the reagent are interpreted by the calculation with quantum chemistry.
    Studies on Polarographic Adsorptive Complex Wave of Nickel with p-MPAQ
    Zhang Zheng-qi, Chen Zhao-peng, Huang Xin
    1991, 12(11):  1455-1456. 
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    In a pH 6.8 buffer solution containing 0. 0011% Triton X-100 the complex of the nickel( Ⅱ) with p-MPAQ shows a sensitive adsorptive complex wave at -0. 93 V, which can be used to determine trace amounts of nickel down to 5. 0×10-9mol/L. The proposed method has been applied to the determination of trace amounts of the nickel in aluminium alloy samples.
    Catalytic Spectrophotometric Determination of Ultratrace Amounts of Nitrite
    Zheng Zhao-sheng, Wu He-zhou, Zhao Wen-zhong
    1991, 12(11):  1457-1458. 
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    A new catalytic spectrophotometric method for determining ultratrace amounts of NO2- has been developed. The method is based on the catalytic oxidation of neutral red by potassium bromate in the solution of diluted H3PO4.The sensitivity of the method is 2. 6 ×10-12g/mLof nitrogen in NO2-(△A=0. 001, b=1 cm), the linear range of determination is 2. 0× 10-4-8.0×10-3pg/mLfor NO2-. The method has been used to determine trace NO2- in water samples.
    Investigation on Carbon Fiber Microelectrodes (Ⅴ)--The Kinetics of Ferrocene and Its Derivatives on Carbon Fiber Ultramicroelectrodes
    Chen Hong-yuan, Ju Huang-xian
    1991, 12(11):  1459-1461. 
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    The present paper reports the voltammetric behaviour of ferrocene and its five derivatives in various organic solvents, as well as the effects of scan rate of potential and supporting electrolyte on the currents investigated with both caron fiber ultramicroelectrode of radius 5 μm and glassy carbon electrode for comparison. The diffusion coefficients, electron transfer rate constants and half-wave potentials of the six compounds in different solvents were determined. The experimental results for the ferrocene in acetonitrile are in good agreement with those from literatures, but the most other data presented in this paper have not been reported yet in literatures.
    Studies on the Adsorptive Voltammetry of Estazolam
    Ji Gang, Li Qi-long
    1991, 12(11):  1462-1464. 
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    In 0. 1 mol/L NH3-NH4Cl buffer solution(pH9. 3), a sensitive reduction peak of es-tazolam was obtained by adsorptive voltammetry after accumulation on the surface of HMDE [initial potential -0. 80 V(w. Ag/AgCl), v=100 mV/s]. The peak potential was -1. 05 V. The linear range between ip and the concentration of estazolam is form 3. 0×10-9to 5.0×10-6mol/Lwith a detection limit of 1. 0×10-9mol/L. The electrochemical behavior of the system and its electrode reaction mechanism were studied by means of cyclic voltammetry, constant-potential coulometry, etc.. The electrode reduction process is irreversible with the adsorption characteristics. The adsorption of the system obeys Frumkin adsorption isotherm. The number of reduction electrons is 2 and the transfer coefficient a is 0. 77.
    Synthesis, Crystal Structure and Absolute Configuration of (+)-1R, 3R,5S-1,8,8-Trimethyl-3-Thio-3-(4-Methyl-Phenyloxo)-2,4,3-Diaza-Phosphabicyclo[3,2,1] Octane
    Liu Xiao-Ian, Miao Fang-ming, Liu Li-jian, Chen Ru-yu
    1991, 12(11):  1465-1468. 
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    The title compound was synthesized and its crystal and molecular structure was determined by X-ray diffraction analysis with CuKa radiation. The crystal data are as follows; Or-thorhombic system, space group P212121,a=0. 8365(3) nm, b=0. 8625(3) nm, c=2. 3512(2) nm, Z=4. The result of structure analysis shows there are three-membered ring structures in the molecular skeleton, the seven-membered ring is in a boat form and six-membered ring in a chair form including P(1) atom in the two rings, and the five-membered ring composed of carbon atoms is in an envelop form. In the molecule, S(1) is in an equatorial and O(1) in an axial position.Based on the appreciable anomalous scattering effect of Pand Satoms to the CuKa radiation, the absolute configuration of the molecule was established.
    Studies on the Chemical Components of Bupleurum Sibiricum Vest(Ⅱ)
    Song Zhi-zhong, Jia Zhong-jian, Zhu Qi-xiu
    1991, 12(11):  1469-1472. 
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    Five compounds, B1, B2, B3, B4, B5were obtained from the ether extract of Bupleu-rum Sibiricum Vest by means of silica gel, alumina and Sephadex LH-20 column chroma-tographies. The structures were elucidated on the basis of spectral analyses (IR, UV, CD, EIMS, 1HNMR and 13CNMR, DEPT, 1H-1H COSY, 1H-1HNOESY and single crystal X-ray analysis) and chemical reactions. The compounds were identified as : Z,Z' -6, 7,3',8' -dili-gustilide(B1), Z, Z' -6, 7, 3a', 6' -diligustilide (B2), cis-6, 7-dihydroxyligustilide (B3), preg-nenolone(B4) and vanillin(B5). Compound Bj is a new compound. The others four, B2,B3,B4, B5were isolated from the Bupleurum genus for the first time.
    The Synthesis of Indolyl-10H-Pyrido[1,2-a] Indolium Perchlorates
    Liu Zhi-jie, Jiang Lin, Zhang Jian-heng, Gong Yong
    1991, 12(11):  1473-1477. 
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    15 new 10H-pyrido[1, 2-a]indoliura perchlorates were synthesized by the reactions of 2,3,3-trimethyl-3H-indolium perchlorate with indolylchalcones or aryl vinyl ketones in iso-pen-tanol. The structures of the compounds were confirmed by spectral analysis. The reaction processes were rationalized from the structures. The substituent effects in 1H NMR were also studied.
    Studies on the Synthesis and Insecticidal Activities of S-Alkyl O-Aryl Thiophosphoric Derivatives
    Tang Chu-chi, Wu Gui-ping, Zhang Gen-zhu, Chen Xue-ren, Bi Fu-chun, Wang Wen-li, Zhu Lan-hui
    1991, 12(11):  1478-1482. 
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    Forty-two compounds, among them thirty-four new compounds of S-alkyl O-aryl thiophosphoric derivatives have been synthesized by using a new convenient method which is based on the isomerization-chlorination of O,O-dialkyl O-aryl phosphorothionate with phosphoryl chloride to give S-alkyl O-aryl thiophosphorochloride. Then, this thiophosphorochloride reacts with various nucleophiles, e. g. alcohol, phenol, mercaptan, thiophenol, ammonia, amine, in the presence of acid-binding agent to obtain S-alkyl O-aryl thiophosphoric derivatives, e. g. S-alkyl O-alkyl (or aryl) O-aryl phosphorothiolate, S-alkyl S-alkyl (or aryl) O-aryl phospho-rodithiolate, S-alkyl O-aryl phosphorothiolamide. The insecticidal activities of the compounds prepared towards bean aphid (Aphis laburni), cotton red spider (Tetranychus telarius), army worm(Leucania separata) and house fly (Musca domestica) have also been tested.
    Synthesis, Crystal Structure and Absolute Configuration of (+)-1R,3R,5S-1,8,8-Trimethyl-3-Methylthio-3-Oxo-2,4,3-diaza-Phosphabicyclo[3,2,1] Octane
    Liu Xiao-Ian, Miao Fang-ming, Liu Li-jian, Chen Ru-yu
    1991, 12(11):  1483-1485. 
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    The title compound was synthesized and its molecular structure was determined by X-ray diffraction analysis with Cu Ka radiation. The crystal belongs to space group P21 and the crystal cell parameters are:α=0. 7566(1) nm, b=0. 7708(2) nm, c=1. 0255(1) nm,β=98. 60(1)°, V=0. 5913 nm3, Z=2. The molecular skeleton is composed of three rings, the sev-en-membered ring containing phosphorous and nitrogen atoms in boat conformation, in which the bond P-Sis in equatorial and P-Oin axial position; the six-membered ring and five-mem-bered ring are in chair form and envelop form, respectively. The absolute configuration was established by using the approciable anomalous scattering effect of Pand Satoms.
    Bishomoscalarane Sesterterpenes from the Sponge Phyllospongia Foliascens
    Fu Xiong, Zeng Long-mei, Su Jing-yu, Chen Shao-xing, Snyder John K.
    1991, 12(11):  1486-1487. 
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    Two sesterterpenes, which belong to the scalarane class of sesterterpenes with a 20, 24-bishomo-tetracyclic skeleton, have been isolated from the South China Sea sponge Phyl-lospongia Foliascens. The structures of phyllohemiketal Aand Bwere determined as 1 and 2 on the basis of spectral data.
    Oligofurostanosides from Smilax Nigrescens
    Ju Yong, Jia Zhong-jian
    1991, 12(11):  1488-1489. 
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    Four furostanol glycosides were isolated from 70% EtOH extract of the roots of Smi-lax Nigrescent Wang et Tang. Their structures were established on the basis of spectral and chemical methods. One of the glycosides is a new oligofurostanoside 26-O-β-D-glucopyranosyl-(25R)-furost-5, 20 (22)-diene-3β, 26-diol-3-O-[α-L-rhamnopyranosyl (1-2)]-β-D-glucopyra-noside and the others are, 26-O-β-D-glucopyranosyl-22-methoxy-(25R)-furost-5-ene-3.26-diol-3-O-[α-L-rhamnopyranosyl (1-2)]-β-D-glucopyranoside, methyl protodioscin and pseudopro-todioscin.
    Studies on Chemical Ingredients of Delphinium lliense Huth
    Dong Ying, Wang Rui, Chen Yao-zu
    1991, 12(11):  1490-1492. 
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    From the underground part of Delphinium Iliense Huth collected from Yili Region of Xinjiang of China, eight compounds were isolated by extraction, liquid chromatography and re-crystallization. On the basis of Chemical and spectral(UV.IR,1H NMR,13C NMR and MS) evidences, they were identified as lappaconitine, N-deacetyllappaconitine, ranaconitine, aconorine, diethylamine hydrochloride.octacosanoic acid,β-sitosterol and N-acetylanthranilic acid.
    Catalytic Action of Binuclear Ti-H Complexes in Hydrogenation of Diphenyl Ethyne
    Xuan Zhen-ai, Liu Yi-yin, Han Ke-fei, Chen Shou-shan, Chen Mei-wen
    1991, 12(11):  1493-1494. 
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    In this paper, we have investigated the catalytic action of a few binuclear Ti-Hcomplexes on the hydrogenation of diphenyl ethyne in order to study the effects of the structures of the catalysts. It was found that the binuclear Ti-Hcomplexes can also catalyze the hydrogenation of diphenyl ethyne. The catalytic action of binuclear Ti-Hcomplexes is similar to that of the mononuclear ones and relates to their structures.
    Ab Initio Studies on the Interaction of Formaldehyde with Acetaldehyde, Methyl Ether and Nitromethane
    Cai Guo-qiang, Yu Qing-sen, Zong Han-xing, Dong Nan
    1991, 12(11):  1495-1498. 
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    Athereoretical study on the interaction of formaldehyde with acetaldehyde, methyl ether and nitromethane was carried out by STO-3Gand 6-31G. By fully geometry of geometry optimized at 6-31Glevel, the most stable geometries of all complexes are coplanar cyclic structures containing two hydrogen bonds C-H-O. The distances of H-Oare between 0.228 and 0. 264 nm. The interaction energies are between -17. 31 and -24. 29 kJ/mol, which are in the same order as the binding energy of water dimer. The stabilities of complexes depend mainly on the abilities of electron with drawing substituents linking to methyl and the strain of hydrogen bond in cyclic structures. The results of STO-3Gunderestimate the binding energies and are not fully consistent with those of 6-31Gin geometries of the complexes.
    An Investigation on the Photochemical Reactions (Ⅰ)--The Photochemical Reactions of Sulfur Dioxide and 1-Hexene
    Du Yao-guo, Zhao Xiao-ming, Guo Hai-chen
    1991, 12(11):  1499-1502. 
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    The photochemical reactions of sulfur dioxide and 1-hexene in the presence or absence of oxygen systems were studied by GC and GC-MS methods. We found the formation of aerosol and a series of products such as aldehydes, ketones, acids, esters and organic sulfur compounds which condensed on the inner-surface of silica bottle. According to the characteres of such compounds and chemical kinetic theories, we suggested the mechamisms of these photo-chemical reactions. These results are very important to the chemistry of air pollution.
    Effect of Trace Modifier Sr on Solidification Process of Al-Si Alloys
    Wang Zi-chen, Wang Xiao-hui, Zhang Li-hua, Zhao Mu-yu
    1991, 12(11):  1503-1506. 
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    The influence of Sr on the solidification process of Al-Si alloys was systematically investigated by differential thermal analysis. The results obtained show that Sr in the meit raised the primary α-Al nucleation temperature and the temperature of eutectic solidification, and retarded the primary silicon nucleation. It is, therefore, possible that rich Al phase is the leading crystallization phase during the Al-Si eutectic alloys solidification.
    Studies on the Kinetics of Digestion Process of Synthetic Gibbsite by DSC
    Yin Ai-jun, Chen Qi-yuan, Zhang Ping-min
    1991, 12(11):  1507-1509. 
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    The kinetics of the digestion process of synthetic gibbsite was studied by DSCin the solution of sodium hydroxide, and the mechanism of the process was discussed. Aset of non-isothermal reaction kinetic models was presented, and it could interpret the results from DSCwell.
    A Development of Fiber-Optic Spectroelectrochemical Cell and Its Preliminary Application
    Zhu Yuan-bao, Xie Qing-ji
    1991, 12(11):  1510-1512. 
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    A new-type spectroelectrochemical cell--Fiber-optic Spectroelectrochemical cell(FOSECC) was developed. Using this cell, we investigated the absorption spectra of Fe(CN)63-/Fe(CN)64- with the changes of the applied potentials. The formal potentials and the numbers of electrons transferred at various temperatures were determined and the thermodynamic functions of this electrochemical systems were derived from the results obtained. The sensitivity of this cell expressed with molar absorbance/potential ratio was worked out. All the results were satisfactory.
    Identification of Mechanism Function and Investigation on the Kinetics of Thermal Decomposition of MnC2O4
    Li Jing-hua, Zhang Gui-en, Huang Shan
    1991, 12(11):  1513-1516. 
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    The thermal decomposition of MnC2O4was studied by means of thermogravimetry both at the constant temperature and linearly increasing temperature. Three-stage identification of the function depending on the mechanism is suggested. The experimental results and theoretical analysis show that the thermal decomposition of MnC2O4is dominated by an A3mechanism. The activation energy E=103. 95 kj/mol, the frequency factor A=4. 448×108min-1. Its kinetic compensation effect is: lgA=0. 09661E-1. 2856.
    The Self-Consistent Field Method of Bonded Tableaux
    Wu Wei, Zhang Qian-er
    1991, 12(11):  1517-1521. 
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    The self-consistent field calculation for the bonded tableau unitary group approach (BTUGA) is disscused. The bonded tableau interaction(BTI) and the multi-bonded-tableau self-consistent field (MBTSCF) method are established. It is found that BTUGA can be widely applied to quantum chemistry calculation of practical molecular systems by using the self-consistent field method presented in this paper.
    Titration Calorimetry Study on the Protonation Reaction of α-Carboxyl Group of Ammo Acids
    Zhang Bao-lin, Wang Wen-qing, Li Zhong, Tao Zu-yi
    1991, 12(11):  1522-1523. 
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    The thermodynamic functions of protonation reactions of α-carboxyl group of twelvekinds of amino acids--alanine?valine, lysine, leucine, phenylalanine, methionine, trypto-phan, threonine, serine, arginine, glutamic acid and glycine, have been determined by titration calorimetry combined with computer fit program. The differences between △H, AG, lgK, △Sof the protonation reactions of amino acids have been reported. By comparison with pHtitration method, it is simple, rapid and would be obtained simultaneously the total thermodynamic functions-IgK, △H, △G and △S.
    The Evaluation of Copper Stearate LB Films by Angle-Resolved XPS
    Chen Hui-juan, Chai Xiang-dong, Wei Quan, Li Tie-jin
    1991, 12(11):  1524-1525. 
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    In this article, angle-resolved XPS was used for the evaluation of copper stearate LB films. At the different take-off angles, the ratios(r) of carboxyl C1sintensities to that of the total carbon in the sample are different. Comparing the powder sample with the disordered structure, we got the relationship between the difference of r and the quality of LBfilms. Such a method was found to evaluate the quality of LBfilm with carboxyl hydrophilic head.
    Effects of Properties of Solvents on the Structure and the Stability of Lamellar Liquid Crystal
    Guo Rong
    1991, 12(11):  1526-1528. 
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    The measurements of 2H NMR gave three reasons for the decrease of the stability of lamellar liquid crystal in SDS/C10OH/solvents when formamide was used as the solvent instead of waters the order parameter of SDS and C10OH decreased, the degression of order parameter of SDS and C10OH along the carbon chain increased and the compatibility of SDS with C10OH decreased. The low angle X-ray measurements show that the permeability of the solvent in the lamellar liquid crystal was increased when water was replaced by formamide so that the interlayer spacing d decreased at a certain weight ratio of C10OH/SDS and the dependence of the interlayer spacing d on the weight ratio of SDS/C10OH changed.
    Studies on Cytochrome C by Thin-Layer Spectroelectrochemistry
    Wu Xia-qin, Akio Ichimura, Ge Jin, Zhang Zong-rang
    1991, 12(11):  1529-1531. 
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    The electrochemical behavior of horse heart Cytochrome Cwas investigated in the presence of 4,4' -Dithiodipyridine as an electron transfer promoter on the gold minigrid optical transparent thin-layer electrode (Au-OTTLE). The formal potential E0' and electron transfer number n of the redox reaction of Cytochrome Cwere measured as 50 mV(vs. Ag/AgCl) and 1 respectively by thin-layer spectroelectrochemistry on Au-OTTLE. These data were also compared with the cyclic voltammetric results observed on Au-OTTLE > Au-microdisk electrode, and Au-disk electrode.
    A Study of the Topological Properties on the Molecular Cylinder and MÖbius Strip with Three-Rung and Four-Rung Ladder
    Qiu Wen-yuan
    1991, 12(11):  1532-1534. 
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    The novel topology of the molecular cylinder and MÖbius strip with three-rung and four-rung ladder is discussed. Some novel results in the low dimensional topology deriving from consideration of topological symmetry of the molecular graphs defined by the subject compounds are also discussed. The Hiickel-type molecules with the even number of twists and the MÖbius-type molecule with the odd number of twists are defined. It is shown that for the Hiickel-type and MÖbius-type molecules with vertices and edges of constitutionally equivalent or nonequiva-lent, the topological symmetry is topological invarants(homeomorphic), while Tof the number of twist are not isotopic variable. The topological chirality of these molecules, which is an interesting problem, has been solved with the invention of the topological symmetry concept applied to molecular structures. In order to completely characterize a molecule it is useful to understand the symmetries of its molecular graph in3-space. For this purpose the topological equivalent graph and topological symmetry are said to be rigid.
    The Effect on Zeolite Properties by Combined Modification
    Zhan Bi-zeng, Zeng Zhao-huai
    1991, 12(11):  1535-1536. 
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    The effects on the properties of ZSM-5 zeolite modified by steam. H3PO4and Mg(Ac)2were studied. It is shown that middle strong acid sites were the active sites for ethyla-tion of toluene with ethanol. It is possible to cover the external surface acid sites selectively and keep the channel structure essentially by depositing an adequate amount of Pand Mg on the steam-treated zeolite. This is assumed in favour of increasing the shape-selectivity .to remain the activity as the unmodified zeolite. In this case,the so called "opposite effect" may be overcome. The modified catalyst P1Mg1HZ is stable at an average activity of 16.5% with the 85% p-selectivity and >97% alkylation selectivity for 100 hours on streaming.
    Studies on Monolayer Properties of Star-Shaped Graft Copolymer Based on St-DVB Microgel/MMA
    Zhang Xi, Cha Xiao, Shen Jia-cong
    1991, 12(11):  1537-1539. 
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    The behavior of this new kind of star-shaped amphiphilic polymeric monomolecuar layer membrane was studied by the surface pressure-area(π-A) curves. It is found that the π-Acurves can be influenced by many factors such as the floating plate vertical or parallel to the compression direction, different diffusing time, and repeat compression times. We also studied stearic acid amphiphile plasticized the GPSMA monolayer.
    Identification of the Configurations of dl and meso-diethyl-2,3-dicyano-2,3-diphenyl Succinates and Its p-(X)-Substituted Phenyl Derivatives by FAB-B/E Link Scan Metastable Ion Spectrometry
    Li Hai-quan, Zhao Fan-zhi, Zai Jian-jun, Chen Neng-yu, Qi Chen-ze, Yang Di-lun, Liu You-Cheng
    1991, 12(11):  1540-1541. 
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    In this paper, three pairs of dl and meso-diethyl-2,3-dicyano-2,3-diphenyl succinate and its derivatives of p-(X)substituted phenyl succinates(X=H,CH3,OCH3) were analyzed by using FAB-B/Elinked scan metastable ion spectrometry. The effect and applicability of this method in identification of the configuration of these isomers were discussed.
    Synthesis of Perovskite-type Nanocrystalline Material Complex Oxide LaFeO3by Citrate Process
    Li Xi, Zhao Mu-yu, Wang Zi-chen, Xu Bao-kun
    1991, 12(11):  1542-1544. 
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    The precursors of LaFeO3were prepared by cifrnle process and nanocrystals of LaFeO3were synthesized by a solid phase reaction at 400-500℃ for 2 h. The nanocrystalline material of LaFeO3was obtained at 0. 5 GPa. The characterization of the samples was carried out by XRD and TEM. The size of the crystals is about 12. 4 nm by TEM. The diffracted X-ray intensity of the compact sample was attributed to the contribution from the LaFeO3nanocrystals and the interfaces.
    Studies on the Coking Inhibitors of Hydrocarbon Pyrolysis
    Luo Qing-jin, Wang Zong-xiang
    1991, 12(11):  1545-1546. 
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    The effects of both alkali-metal salts such as potassium carbonate and organic sulfide-phosphate compounds such as CRShave been investigated on the pyrolysis of light gas oil with a continous flow laboratory pyrolysis unit. The effects of operating conditions such as temperature and the ratio of steam to oil etc. have also been investigated. The results show that the apparent rate of coke formation decreases by 30-70 percent by coating the inner wall of the reactor with 0. 002-0. 010 kg per square meter of potassium carbonate. If we add 0. 0001-0. 0005 kg/kg CRS in the feedstock, not only the rate of coke formation decreases by 20-50 percent, but also the state of deposited coke becomes fragible, and the yields of ethylene and propylene increase. In addition, according to the experimental results and some concepts from referenc articles, the mechanism of coking inhibition by inhibitors such as potassium carbonate and CRS has been discussed in detail.
    Effect of Content of Hard Segment on Structures and Properties of RIM Crossl inking Polyurethanes
    Zhang Jian-yuan, Wang De-ning, Li Mai-jin, Hu Chun-pu, Ying Sheng-kang
    1991, 12(11):  1547-1550. 
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    The effect of content of hard segment on the structure and properties of RIM crosslinking polyurethane(l-MDI/l, 4-BDO/PPO-EO) has been studied. The results of equilibrium swelling, ATR-FTIR and DSC show that increasing the content of hard segment increases the degree of linkage,and decreases the degree of microphase separation and ordering in the hard rich domains. By TEM, the phase separation phenomena on different levels, namely, macrophase separation and microphase separation were observed.
    Studieson Pyrolytic Products of Para-cresol-Formaldehyde Resin
    Xie De-min, Hou Wan-ling, Wang Rong-sun
    1991, 12(11):  1551-1554. 
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    The structural characteristic of products obtained from the pyrolysis of para-cresol-formaldehyde resin in the temperature range of 500 to 1000' Cis discussed in detail on the basis of elemental analysis, IR, X-ray diffraction and ESR spectra. The results of the analyses show that all the samples appear as black powder, which are insoluble and infusible, and have a wide range of electrical conductivity, X-ray diffraction measurements show all of the peaks are broadened, indicating that these samples are amorphous. The interlayer distances (dc) almost do not vary with an increase in Tp. The crystallite sizes (Lc) are larger than phenol-formaldehyde resins. These results show that all of the samples have slightly aligned crystallites or local molecular orientations which contain four to five fragmental layers stacked on average along the c-axis of each crystallite. Electron spins with a π-nature exist in all the pyrolyzed samples. The ESRlinewidth and the spin concentration of the samples vary with TP. The spin concentration becomes maximum and the linewidth is minimum at Tp=600℃.
    Esterification and Transesterification Catalyzed by Lipase in Organic Solvents
    Cao Shu-gui, Liu Zhan-bin, Feng Yan, Ding Zhong-tian, Cheng Yu-hua
    1991, 12(11):  1555-1557. 
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    Esterification and transesterification catalyzed by porcine pancreatic lipase in organic solvents are studied. The activity of lipase is dependent upon the pHof powdered lipase, the nature of organic solvents, temperature, water content, carbon chain length and branch of substrates. In addition, a rose-fragrant terpene alcohol ester was produced by using lipase with geraniol and carboxylic acid(lauric or octanoic acid).
    Studies on Polymerization of a -Pinene Initiated by a New System AlCl3/Activator/Donors(Ⅱ)--Studies on Polymer of α-Pinene and Polymerization Mechanism
    Deng Yun-xiang, Lin Hua-yu, Ma Qing-yun, Fan Shi-yan, Higashimura T.
    1991, 12(11):  1559-1561. 
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    The characteristic of polymerization of a-pinene initiated by a new initiating system AlCl3/SbCl3/Donor was studied by several spectroscopies, and they were compared with that obtained under the varied polymerization conditions. The results indicate that the product with a high molecular weight is obtained with different molecular structure units. According to the experimental data, the ring-opening polymerization mechanism of a-pinene polymerization initiated with this system is put forward.
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