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    24 June 1998, Volume 19 Issue 6
    Articles
    Studies on Preparation and Properties of the Gas-sensing Semiconducting Material Cd2Sb2O6.8
    LIU Xing-Qin, LIU Ya-Fei, SHEN Yu-Sheng
    1998, 19(6):  837-842. 
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    A chemical coprecipitation method is developed to have successfully prepared the ultramicro powder of Cd2Sb2O6.8 pure phase with a defect pyrochlore structure. The effects of the coprecipitation conditions and calcining temperature on the phase compositions and structure are studied. The result shows that the pure Cd2Sb2O6.8 phase can be only obtained when n (Cd)/ n (Sb) molar ratio is kept as around 0.90, while other ratios (i.e. 0.85 and 1.00) lead to impure phases. The minimum calcining temperature for the pure phase formation is 750 ℃, which is lower than that for other methods reported in literature. Aformation procedure mechanism of the Cd2Sb2O6.8 phase is proposed in terms of high temperature ionic diffusion reaction: Cd ions diffuse into a kind of dehydrated antimony acid which possesses a defect pyrochlore structure, react and gradually form the ultramicro power of Cd2Sb2O6.8 . The gas sensing properties of the thick film gas-sensor elements made of this pure Cd2Sb2O6.8 powder are tested. Compared with the elements made of the powders by conventional solid state reaction method, the elements from this wet chemically prepared ultramicro powders show much improved gas sensing properties. The sensitivity to 1.0×10-4 C2H2 is even higher than that to 3.0×10-3 H2 or CO as well as 1.0×10-3 C2H4. The high sensitivity and good selectivity to C2H2 demonstrate it a promising acetylene gas sensing material .
    Synthesis, Properties and Crystal Structure of Organic-inorganic Radical Salt(DBTTF)6HPMo12 O40·2H2O
    CHEN Ya-Guang, LIU Jing-Fu, LIN Yong-Hua, XING Yan, JIA Heng-Qing
    1998, 19(6):  843-848. 
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    Organic inorganic radical salt(DBTTF)6PMo12O40 ·2H2O was synthesized by electrocrystallization and characterized by IR spectrum, electronic spectrum and ESR technology. Its magnetic property, conductivity and crystal structure were determined. The title compound crystallized in a triclinic system with P1 space group, a =1.3787(7), b =1.4204(2), c =1.5702(2) nm, α =104.57(1)°, β =103.41(2)°, γ =95.80(2)°, V =2.853(2) nm3, Z =1 and a final R =0.0727.
    Studies on the Stability of L-Threonic Acid-α-aminoacids(5-Substituted Phenanthrolines)-copper(Ⅱ) Ternary Complexes
    SUN Xiang-De, YIN Xiang-Chen, ZHU Shou-Rong, LIN Hua-Kuan, CHEN Rong-Ti, ZHANG Xing-Yuan
    1998, 19(6):  849-853. 
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    The formation constant of α-aminoacids(5 substituted phenanthrolines)-L-threonic-acid-copper(Ⅱ) ternary complexes were determined at 298 K, I =0.1 mol/L KNO3. The two biologically active ligand, α-aminoacid and L-threonic acid accommodate each other when coordinated to copper(Ⅱ) ion. The stability of ternary complex is larger than that of the corresponding binary complex. This result indicates that, as a ligand, L-threonic acid can serve as a carrier transport metal ions effectively in vivo. The percentage of ternary complex is obviously larger than that of binary complex in a wide pHrange. The formation constant of the ternary complexes linearly increase with the increase of protonation constant of α-aminoacid and the stability of its binary complexes. Linear free energy relationship(LFER) does exist in the presence of ternary system. Alcoholic proton in L-threonic acid was dissociated with a pKa larger than that in binary complex. In 5-substituted phenanthroline L-threonic acid-copper(Ⅱ) ternary system, the stability of the ternary complex decreases with the increase of protonation constant of 5-substituted phenanthroline due to d-p π back-bonding.
    Synthesis of Porphyrin Nanometer Material by a New Method
    WANG Xing-Qiao, GAO Shuang, YU Lian-Xiang, MIAO Chun-Jian, LI Hong-Bo, CAO Xi-Zhang, WANG Li Ping
    1998, 19(6):  854-857. 
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    Nanometer particles have tremendous application potency in the fields of photoelectricity conversion, information storage and photocatalysis, etc.. However, it has not been reported that preparation of nanometer material was carried out from porphyrin compounds with a structure which can be modulated and have a higher chemical activity. At present, the preparation methods of nanometer material include liquid-phase method, gas-phase method and physical method. The liquid phase method also covers coprecipatation method and solvent evaporation method. The coprecipatation method has some drawback, for instancd, being difficult to wash and filtrate and easy to retain entrained precipitant. For gas phase method, solvent evaporation method and physical method, it needs special equipment and exacting technology conditions, as well as a high processing temperature which results in decomposition of most organic compounds, including porphyrin compounds.In this work, a new method was used to synthesize porphyrin nanometer material. By using this simple method, liquid molecules can be easily embedded in the pores of diatomaceous earth pores. The synthesized porphyrin nanometer material was characterized by the methods of UV-Vis, IR, surface photovoltage spectroscopy and transmission electron microscope. According to the photograph of transmission elecrton microscope, the diameter of crystalline grain of porphyrin molecules aggregated in the pores of diatomaceous earth pores estimated to be 20 nm.
    Studies on the Rapid Preparation of Fullerols and Its Formation Mechanism
    LI Tian-Bao, HUANG Ke-Xiong, LI Xin-Hai, JIANG Han-Ying, LI Jing, YAN Xing-Zhong, LI Jun, ZHAO Shan-Kai
    1998, 19(6):  858-860. 
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    In this paper, we introduce a very rapid preparation method to produce water soluble C60 derivatives——fullerols by the reaction of C60 with aqueous NaOH and H2O2 in the presence of tetrabutylammonium hydroxide(TBAH) as the catalyst, and the reaction is accelerated very much and the reaction time is shortened from 1~3 d to 1~3 h by adding H2O2 to replace O2 in the air as the oxidant. FTIR, 1H NMR and MALDI-TOF-MS proved the multi hydroxy and C60 cage structure of the products. The hydroxylated fullerere epoxide——the intermediate which is very easy to hydrolyze to become fullerols was obtained, and the formation mechanism of fulleols was put forward.
    Studies of Matrix Modifiers in the Determination of Tin by GFAAS
    CHEN Shu-Yu, WU Rong-Hu, LIN Shu-Qin
    1998, 19(6):  861-865. 
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    In this paper, the mixed modifiers in the determination of tin by GFAASwere studied. The mechanisms of tin stabilized by two modifiers were inquired using X-ray diffraction analysis. The two modifiers can increase charring temperature up to 1400 ℃ and 1350 ℃, respectively. Mg(NO3)2 would form a higher background absorption in the determination process for tin. It has more advantages to use Ni+Vc, such as extremely increasing charring temperature, improving the determination sensitivity,decreasing the background absorption and the matrix interference. The measured results for the stream sediment samples are consistent with the certified value.
    The Research of Nitric Oxide Detection Using Nafion poly N ′, N ″-(1, 3-propanediyliene)bis(1, 2-benzene diamino N, N ′, N ″, N′″- Nickel Microsensor
    XIAN Yue-Zhong, YING Xiang-Yang, ZHANG Wen, LUO Min, JIN Li-Tong 
    1998, 19(6):  866-870. 
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    This report describes the development of a simple, easy to fabricate, sensitive, and stable nitric oxide sensor. The sensor is based on the N ′, N ″-(1, 3-proanediyliene)bis(1, 2-benzene diamino-N, N ′, N ″, N′″-nickel(Ni(Ⅱ)L) mediator is electropolymerized on a platinum, Nafion-modified microelectrode(diameter 15 μm). The detection of NOis based on the Ni(Ⅱ)Lcatalysis of NOoxidation at an anodic potential of +0.74 V. The electrocatalytic oxidation mechanism is also discussed. The Ni(Ⅱ)L modified microelectrode was used to monitor NOin human blood, the results suggest that the sensor can detect NOin vitro .
    Model Building with Neural Networks Based on Genetic Algorithms for Structure-activity Relationships of Pesticide
    SUN Wei-Guo, CHEN De-Zhao, CHEN Ya-Qiu, HU Shang-Xu
    1998, 19(6):  871-875. 
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    In this paper, a neural network based on genetic algorithms was proposed for a QSAR model building of herbicidal N-(1-methyl-1-phenylethyl)phenylacetamides. Since neural networks can express complicated structure-activity relationships, and the combination of Genetic Algorithms can help the networks to jump out of the local optimal points, thus, it's peeds up the covergence of the training. At the same time, it's prediction precision has been notably raised.
    Studies on Kinetics of Reaction Between Tb 3+ and Human Oxyhemoglobin by Stopped-flow Fluorometry
    CHENG Yi, LIN Hua-Kuan, WANG Kui
    1998, 19(6):  876-878. 
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    The kinetics of reaction between Tb 3+ and human oxyhemoglobin was investigated by means of stopped flow fluorometry. The Tb 3+ ions quenched the intrinsic fluorescence of oxyhemoglobin within the first 100 ms. The rate constant of the reaction at various temperature and activation parameters were obtained. The results indicate that Tb 3+ binding to oxyhemoglobin is attributed to the second order reaction. The mechanism of the reaction was explored.
    The Spectrophotometric Determination of Proteins Using Zincon
    CHI Yan-Hua, LI Na, ZHUANG Jia, LI Ke-An, TONG Sheng-Yang
    1998, 19(6):  879-881. 
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    When BSA was added into zincon solution at pH 4.1, the purple colour was observed, which indicates the formation of zincon-BSA complex. The maximum absorption of complex was 564 nm and 594 nm with the apparent molar absorptivity of 1.5×106 L·mol-1 · cm-1 . The linear range of standard curve for BSAis 0~10 μg/mL, and the detection limit is 0.5 μg/mL. The basic reaction conditions were investigated. This proposed method was simple, sensitive, and reproducible. The analytical results of human serum albumin using this method is very satisfactory .
    Studies on Thickness-shear-mode Acoustic Wave Pyridine Sensor Coated with Calix [4]arenes
    CAO Zhong, LI Tong, YANG Xiao-Hai, WANG Ke-Min, LIN Hui-Gai, YU Ru-Qin
    1998, 19(6):  882-884. 
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    The frequency shift response characteristics for pyridine vapour by thickness shear-mode (TSM) acoustic wave sensors coated with three synthesized calix[4]arenes have been reported. It is shown that C-undecylcalix[4]resorcinarene(CUCRA) is the most efficient host-guest adsorptive material for sensing pyridine molecule. The CUCRA based TSM sensor possesses good reproducibility, high stability and short response time with a good linear determination range of 0.040~8.000 mg/Land a low detection limit down to 0.008 mg/Lof pyridine vapour while coating with 38 μg of CUCRA. The sensitivity is (54.63±2.35) Hz/(mg·L-1)(n =5, 25℃). There are some interference from alcohols, amines, carboxylic acid, heterocyclic and aromatic compounds. Compared with gas chromatographic method, the sensor can be used for the determination of pyridine vapour with recovery rate of 98.10%-103.92%.
    Studies on the Resolution of Racemic Amino Acid Esters by a New Resolving Agent R (-)Thiazolidine-2-thione-4-carboxylic Acid
    LI Ye-Zhi, GUO Chun-Xiao, LU Xiang-Yang, SHEN Li-Chun, HUNAG Hua-Min
    1998, 19(6):  885-889. 
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    Amino acid esters were resolved by a new resolving agent R (-)thiazolidine-2-thione-4-carboxylic acid R (-)TTCA . The optically active R (-)TTCA amino acid ester salts 1a_1f, [α]D20=-30.40°~-42.70° and optically active amino acid esters 2a_2f(e.e.: 35.40%~75.80%) were obtained. When 1a_1f reacted with aqueous NaOH, optically active amino acid esters 3a_3f(e.e : 39.50%~69.10%) were separated. The basicity of the amino group of amino acid esters and the formation heats of ammonium salts of amino acid ester have been studied using semiempirical quantum chemistry PM3 methods.
    The ESR Spin Trapping Studies of Reaction Between Ascorbic Acid with Hydrogen Peroxide
    BAI Ling-Jun, WANG Jian-Ying
    1998, 19(6):  890-894. 
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    Using 5,5-dimethyl-1-pyrroline N-oxide(DMPO) as a spin-trapping reagent, the oxidation reaction of ascorbic acid was studied. The radical generated in autoxidation process was ascorbate radical anion(A) only. In the presence of hydrogen peroxide, several radical intermediates were found and their structure were determined. The ESR parameters of A and DMPO/radical adducts were measured to be g =2.0056 and α H=0.17 mT for A, g =2.0059, αN=1.60 mT and αHβ=2.28 mT for DMPO/1, g =2.0059, αN=1.58 mT, αHβ=2.13 mT and αHγ=0.17 mT for DMPO/2, g =2.0059 and αN= αHβ=1.49 mT for DMPO/·OH, and g =2.0059 and αN=1.50 mT for DMPO/3(or 4). The mechanisms for the oxidation reactions of ascorbic acid were proposed on the basis of those observation.
    Synthesis and Biological Activities of Novel 2-Amino-5-benzylidene-4H-imidazolin-4-one Derivatives
    DING Ming-Wu, TU Hai-Yang, LIU Zhao-Jie, ZHUANG Nong-Bo
    1998, 19(6):  895-898. 
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    The carbodiimide 2, which was obtained from aza Wittig reaction of vinyliminophosphorane with aromatic isocyanate, reacted with nucleophiles to give ten novel 2-amino-5-benzylidene 4H-imidazolin-4-one derivatives. The reactivity of carbodiimide 2 towards various nucleophiles was studied and a gualidene like intermediate 3i was isolated from the reaction mixture.Preliminary evaluation of the biological activities of compound 4 was made.
    Studies on Bio rational Design of Photosystem Ⅱ Inhibitors(Ⅱ) ——The Crystal and Molecular Structure of Ethyl 3-Benzylamino-2-cyano-3-methylthioacrylate
    LIU Hua-Yin, YANG Guang-Fu, LU Rong-Jian, TAN Hui-Fen, YANG Hua-Zheng, LAI Lu-Hua
    1998, 19(6):  899-902. 
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    Based on the structure of D1 protein of photosystem Ⅱ of Pisum sativum, the title compound with good Hill reaction inhibition was designed and synthesized, and its structure was confirmed by X-ray diffraction. It was found that the CH2 group between phenyl and amino is important for compound's inhibition, and there is no H-binding in the molecule.
    Studies on Synthesis and Bioactivity of Pinacolone (or 1-Arylethanone) Containing 1H-1,2,4-Triazole Group and Their Reduced Products
    ZHOU Zheng-Hong, ZHAO Jun, LIAO Xiang-Jun, ZHANG Zu-Xin, PENG Yong-Bing, ZHAO Guo-Feng
    1998, 19(6):  903-907. 
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    Thirty three new compounds containing 1H-1,2,4 triazole group were synthesized through Calkylation of α-(1H-1,2,4-triazol-1-yl) pinacolone (or 1-Arylethanone) with aryloxyalkyl bromide and their structures were confirmed by 1H NMR spectra and elementary analysis. Preliminary bioassays showed that the synthesized compounds exhibited some fungicidal activity and plant growth regulating activity.
    Synthesis and Physical Properties of TCNQ Charge-transfer Salts of Transition-metal Pyridine Complex Cations
    LI Jin-Shan, FENG Yi-Si, WANG Zhe-Fu, MEN Zhen-Yu
    1998, 19(6):  908-912. 
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    Eight TCNQ charge-transfer salts of transition metal pyridine complex cations with the general formula [M(Py)m]n (M=Mn, m =4; M=Co, Ni, Cu, m =2; TCNQ= 7,7,8,8 tetracyanoquinodimethane, n =2,3) have been synthesized and characterized by elemental analysis, IRspectrum, ESR spectrum, X-ray photoelectron spectrum, magnetic susceptibility and electrical conductivity. The results indicate that there are TCNQ- and TCNQ0 in the molecules of these charge transfer salts; TCNQ- interacts with TCNQ0 to form a structural unit [TCNQ]n2-(n =2,3); these structural units stack along with one dimension direction to form molecular column; it leads the metals of these compounds to mixed valence state because partial charges transfer from [TCNQ]n2- to [M(Py)m]2+ ; three of these charge transfer salts show a good electrical conductivity.
    Synthesis of Cyclic Glycerophospholipid Conjugates of Adenosine
    ZHANG Cheng-Xiang, ZHANG Zhong-Biao, TANG Chu-Chi, CHEN Ru-Yu
    1998, 19(6):  913-916. 
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    New structural liponucleoside prodrugs were prepared in which 5-benzoyladenosine was covalently attached to five and six-membered cyclic phospholipids. In the strategy for the synthesis, hexaethyl phosphorous triamide, activated by a catalytic amount of iodine, was used as the phosphorylating reagent in a one-pot reaction resulting in a number of phospholipid-adenosine conjugates.
    Studies on Biologically Active Organotin Compounds Containing Silicon
    XIE Qing-Lan, LIU Hua
    1998, 19(6):  917-920. 
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    The development of the organotin compounds containing silicon in recent years was reviewed in this paper. It was shown that the biological activity depends mainly on the substituents on the silicon atom in the following order: (Me3SiCH2)3SnY>>(PhMe2SiCH2)3SnY>(Ph2MeSiCH2)3SnY, (PhCH2Me2SiCH2)3SnY.
    Studies on the Thermostability and Conformation of Thermostable α-Amylase from Bacillus Licheniformis A.4041
    ZHAO Ying, DONG Qing-Chu, MA He-Wen, YAN Bao-Shan, FEI Xiao-Fang, WANG Guo-Yan
    1998, 19(6):  921-923. 
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    The influence of heat on the conformation and stability of α-amylase α-Ⅲ fraction from Bacillus Licheniformis A.4041 was studied by means of the fluorescence and CDspectra. Heated at 80 ℃ for 15 min, the enzyme hardly lost its activity. At the same time, a considerable change of its fluorescence and CDspectra was observed. It was shown that, comparing with the whole conformation of the enzyme molecule, the active site has a relative stability. Heated at 90 ℃ for 15 min, the conformational and active changes resulted by Ca 2+ and starch were different. The Ca2+ mainly affects the whole enzyme molecular conformations, whereas the substrate is important to sustain the activity. It indicates that the structure of enzymatic active site plays an important role to the thermostability of the α-Ⅲ.
    A New Method for Synthesis of N,2-Diaryl Diazenecarboxamide
    WANG Yu-Lu, WANG Xiao-Yang, LI Jian-Ping, WANG Cai-Lan, WANG Hong, MA Dong-Lan
    1998, 19(6):  924-925. 
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    By using N-bromosuccinimide(NBS) and pyridine as the oxidation reagents for dehydrogenating aryl substituted semicarbazide to form azo compounds is described for the first time. Eight azo compounds have been prepared in excellent yields under mild condition. This method only needs simple instrument and short reaction time. The structures of these azo compounds were identified by elemental analysis, IR, 1H NMR and MS spectra.
    The Role of CO in the Synthesis of Methanol from the Hydrogenation of Carbon Dioxide
    LI Ji-Tao, Au-Chak-Tong, CHEN Ming-Dan, ZHANG Wei-De
    1998, 19(6):  926-929. 
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    The effect of adding COto the raw gases for methanol synthesis from the hydrogenation of carbon dioxide over the CuO/ZnO/Al2O3 catalysts has been reported. Small amount of CO in the raw gases can increase the selectivity and yield of methanol by 38% and 25%, respectively. TPD MSand TPSR MS results indicate that COcan suppress the adsorption of CO2 on the sites, which bring about the reverse water gas shift reaction and hence promote the selectivity of methanol.
    Quantum-chemical Calculation for Fluorine Ion Influence on Double Four-membered Ring of Zeolite Molecular Sieves Structure
    LI Bao-Zong, XU Wen-Guo, QIU Shi-Lun, PANG Wen-Qin, XU Ru-Ren
    1998, 19(6):  930-933. 
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    On the full optimization of geometry, the eight model clusters(including F- held in the double four-membered ring and no F-) have been peformed by using semi-empirical quantum-chemical PM3 method to obtain their geometric, electronic structures and stability. The influence of fluorine ion on structures and properties of four-membered ring has been examined. The stabilities of full Si, P-Al and P-Ga forming four-membered rings were found to be gradually increased with F- encapsulation. However, the forming four membered ring for the Si-Al cluster is unstable. The calculated results show that the distances between F- locating in the four-membered ring and framework elements are in agreement with the experimental values.
    The Synthesis and Crystal Structure of Novel Heteropoly Complex K3H2 GeW8Mo3VO40 ·4H2O
    WU Qing-Yin, WANG Xiao-Fang, SONG Yu-Lin
    1998, 19(6):  934-937. 
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    K3H2 GeW8Mo3VO40·4H2O, a novel crystal was synthesized by the stepwise acidification and the stepwise addition of materials. The crystal structure was determined from single crystal X-ray diffraction at room temperature. The complex crystallizes in the space group C2 (monoclinic), with a =1.8944(4) nm, b =3.2920(7) nm, c =1.2494(2) nm, β =90.25(3)°, V =7.792(4) nm3, Z =6. The final discrepancy factor was R=0.063, RW=0.067.
    Studies on Thermokinetic Method(Ⅱ)——Theory and Method of Flow-mixed Method
    LIU Yi, TAN Xiao-Feng, WANG Cun-Xin, YAN Cheng-Nong, SONG Zhao-Hua, QU Song-Sheng 
    1998, 19(6):  938-941. 
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    By analyzing the physical model of flowing system, the relationship between heat power and flow rate was deduced, in which the sample was input by flow-mixed method with LKB 2277 Bioactivity Monitor. By using linear analysis method, reaction enthalpy and rate constant can be calculated simultaneously. This method was applied to ethyl acetate saponification reaction, and a significant result was obtained.
    A Study of Coordination Behaviour of RECl3 with Serine
    LI Zhong-Jin, JI Mian, LIU Jian-Rui, GAO Sheng-Li
    1998, 19(6):  942-945. 
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    Under the guide of phase equilibrium results, 20 solid complexes RE(Ser)Cl3·3H2O and RE(Ser)2Cl3·5H2O(RE=La—Nd, Sm—Gd, Dy, Yb, Y) have been prepared in water, and characterized by chemical analysis, molar conductivity, IR, UV, FS, X-ray diffraction and TG-DTG.
    Microcalorimetric Studies of Surface Acidity and Basicity of Metal Oxides
    TU Mai, LI Da-Tang, SHEN Jian-Yi, CHEN Yi
    1998, 19(6):  946-949. 
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    Microcalorimetric adsorption was used to determine quantitatively the number and strength of acid/base sites on the oxide samples of Eu2O3, CeO2, MgO, ZnO, Al2O3 and NiO. The initial heats of NH3 and CO2 adsorption were found to be proportional to Sanderson electronegativities of the samples.
    Energy Transfer of Excited Normal Modes in H2X(X=O, S)
    LI Shen-Min, WANG Ming-Liang, CONG Yao, YANG Zhong-Zhi
    1998, 19(6):  950-954. 
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    Qausiclassical trajectories QCThave been used to investigate energy transfer of various excited H—X(X=O,S) stretching and H—X—H bending normal modes in H2O and H2S, respectively. Average energy in each normal mode as a function of time is obtained. The results demonstrate that only those modes with frequencies close to or with the same vibrational symmetry as that of the excited mode participate in the energy transfer.
    Studies on the Reaction and Quantum Chemistry of Thiazolidine 2-thione and (R) Thiazolidine-2-thione-4-carboxylic Ethyl Ester with α-Bromopropylchloride
    LI Ye-Zhi, GUO Chun-Xiao, TIAN Yan-Qing, ZHAO Xiao-Gang, HUANG Hua-Min
    1998, 19(6):  955-958. 
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    Thiazolidine-2-α-bromopropyonyl thiol ester 2a and optically active (R)-thiazolidine-4-ethoxy carbonyl-2-α-bromopropyonyl thiol ester 2b were perpared by the reaction of α-bromopropyonyl chloride with thiazolidine-2-thione and (R) thiazolidine-2-thione-4-carboxylic ethyl ester. The electronic structures of products and reactants were studied by molecular orbital PM3 method. The reaction enthalpies of products and the transition state of reactant 1a were obtained.
    High Temperature and High Pressure Extraction of Lanthano-fullerenes by Using Different Solvents
    LIU Bing-Bing, LIU Zi-Yang, XU Wen-Guo, YANG Hai-Bin, GAO Chun-Xiao, LI Dong-Mei, YANG Yu-Kun, LIU Shu-Ying, ZOU Guang-Tian
    1998, 19(6):  959-960. 
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    The traditional Soxhlet extraction of lanthanofullerenes was improved and the high temperature and high pressure method with different extraction solvents was used. It's found that La@C2n can be efficiently extracted with toluene and pyridine from the insoluble part of the soot after the toluene Soxhlet extraction. Pyridine can more efficiently and selectively extract lanthofullerenes, especially La@C82, while toluene can extract La@C74, which is a new member added to the soluble species to lanthanofullerenes.
    Temperature Programmed Decomposition of NO over Er2O3/Bi2O3 Catalysts
    ZHANG Wei-De, LI Ji-Tao, GU Ping-Ying, WAN Hui-Lin, AU Chak-Tong
    1998, 19(6):  961-963. 
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    The face centered cubic(fcc) phases of n (Er2O3)/ n (Bi2O3)=5%~40%, molar fraction) which is an oxygen ion conductor were prepared. The decomposition of NOover these Er2O3/Bi2O3 catalysts was examined by means of temperature programmed surface reaction. The results showed that the surface adsorbed NO decomposed to N2 and O2 at ca. 600 ℃. The plot of NO conversion and Er composition showed that there was an optimum decomposition rate at ca. 23%(molar fraction). Comparing to the data of conductivity, one can conclude that the rate of NO decomposition increases with the increase in the number of oxygen vacancies. This has been contributed to the similar electronic structure between O2 and NO.
    Methane Aromatization in the Absence of Oxygen over the Fourth Period Transitional Metal Ion Exchanged H-ZSM-5 Catalysts
    LI Shuang, ZHANG Chun-Lei, YUAN Yi, WU Tong-Hao, XU Zhu-Sheng, LIN Li-Wu 
    1998, 19(6):  964-966. 
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    The catalytic performance of methane aromatization in the absence of oxygen over Mo based catalysts using the fourth period transitional metal ions exchanged HZSM-5 as the supports have been studied in the paper. Moreover, the activity of the catalysts was correlated with the amount of deposited carbon over the catalysts after reaction. By introduction of transitional metal ions to the exchanged sites of H-ZSM-5, the metal ions acted as the promoters and controlled the production of deposited carbon, so enhanced activity and stability of the catalysts to some extent. Among the ions exchanged MoO3/MHZSM 5 catalysts, those exchanged with Cu2+, Fe3+, VO2+ and Mn2+ have a relatively high activity and stability .
    The Deposition and Characterization of Langmuir-Blogett Films of Mono-crown Ether Substituted Unsymmetrical Phthalocyanines
    LI Xi-You, XU Hui-Jun
    1998, 19(6):  967-969. 
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    The mono-layers and Langmuir-Blogget films forming properties of three novel unsymmetrical phthalocyanines bearing one crown ether ring and three alkoxyl chains have been studied. Inspection of the π-A isotherms indicates that they form stable and well distributed mono-layers on water subphase. The mono-layers can be transferred to CaF2 substrates. UV-Vis spectroscopic studies show that the absorbance varies linearly with the number of layers. Compounds a and b gave rise to Ytype deposition while compound c deposited in Ytype over the first few dipping cycles with subsequent Z-type deposition on the following cycles. The molecular packing of the films has been probed by polarized UV-Vis spectroscopy and low-angle X-ray diffraction methods. The results show that the phthalocyanine macrorings of compounds a, b and c inclined to the substrates' surface with an angle of 39°, 57° and 47°, respectively. The thickness of the corresponding films was estimated to be 1.9, 2.2 and 2.9 nm, respectively.
    Separation of Ce(Ⅳ) and RE(Ⅲ) with Hollow Fiber Membrane based Extraction
    WANG Yu-Jie, ZHANG Shu-Min, LI De-Qian
    1998, 19(6):  970-972. 
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    Separation of Ce(Ⅳ) and RE(Ⅲ) was investigated by hollow fiber membrane based extraction with contercurrent recirculating operation. The mass transfer coefficients of Ce(Ⅳ) and RE(Ⅲ) and the effective factors to them were tested. The results show the mass transfer coefficient of Ce(Ⅳ) is larger than that of RE(Ⅲ), and their mass transfer mechanism is different. The mass transfer of Ce(Ⅳ) was controlled by the resistance in water critical layer due to its more rapid interfacial reaction rate and larger distribution coefficient, which was different from RE(Ⅲ) mass transfer with a slow interfacial reaction rate and small distribution coefficient. Ce(Ⅳ) was separated from the mixed solution of Ce(Ⅳ) and RE(Ⅲ) by means of the difference of their mass transfer rates.
    Epitaxial Crystallization of sPP on the (100) Lattice Plane of HDPE Crystals
    YAN Shou-Ke, YANG De-Cai, Petermann J.
    1998, 19(6):  973-976. 
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    Crystallization behavior of syndiotactic polypropylene(sPP) on the (100) lattice plane of high-density polyethylene(HDPE) crystals was studied by means of transmission electron microscopy and electron diffraction. The results indicate that sPPcrystals can grow epitaxially on the (100) PElattice plane with their chain directions ±37° apart from the chain direction of the HDPEsubstrate. The contact planes are (100) lattice planes for both polymers. This kind of epitaxy is explained in terms of parallel alignment of HDPEchains along the rows formed by the {CH3,CH2,CH3} groups in the (100) lattice plane of the sPPcrystals. This implies that in the epitaxial crystallization of sPPwith fiber oriented HDPEsubstrate, not only the (110) but also the (100) HDPE lattice planes can act as the oriented nucleation sites. Furthermore, according to the poor matching between HDPEchains in the (100) lattice plane and the {CH3,CH2,CH3} group rows in the (100) lattice plane of the sPPcrystals, it is concluded that the geometric matching is not the only controlling factor for the occurrence of polymer epitaxy.
    A Study of the Kinetics of Pulsed Laser-initiated Radical Polymerization
    YAN De-Yue, ZHANG Ming-Fu
    1998, 19(6):  977-983. 
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    This paper dealt with the kinetics of radical polymerization initiated by pulsed laser in the absence of chain transfer reaction. The rigorous expressions of the number-and weight average degrees of polymerization for resulting polymer were derived. In the meantime, the normalized molecular weight-distribution functions for chain radicals, terminated species and total polymer were obtained respectively. Numerical calculation shows that the values of various molecular parameters, such as number-and weight- average molecular weights and polydispersity index, periodically vibrate between maxima and minima, and the amplitude of vibration decreases with increasing monomer conversion. The molecular weight distribution curves consist of some characteristic peaks, and the number of peaks increases with the decreasing of concentration of the primary radicals formed at the beginning per laser pulse. Comparing with disproportionation termination, combination termination leads to a narrower molecular weight distribution of resultant polymer.
    The Synthesis and Characterization of the Novel Poly(aryl ether ketone)s with Liquid Crystallinity
    ZHANG Shan-Ju, ZHENG Yu-Bin, WU Zhong-Wen, TIAN Ming-Wen, YANG De-Cai
    1998, 19(6):  984-988. 
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    The novel poly(aryl ether ketone)s with liquid crystallinity were synthesized by nucleophilic substitution reactions of 4,4′-biphenol and substituted hydroquinone with 4,4′-difluorobenzophenone and their thermotropic liquid crystalline properties were characterized by DSC, PLMand WAXD. The copolymers containing 70% biphenol formed nematic phase while the copolymer containing 50% biphenol exhibited smectic texture. The banded textures were formed after shearing the sample in the nematic liquid crystalline state. The identification of the structures in each mesogenic phase has been carried out by combining WAXD with PLM and DSC.
    Solid State Structure and Properties of Chitin/Chitosan
    MO Xiu-Mei, WANG Peng, ZHOU Gui-En, XU Zhong-De
    1998, 19(6):  989-993. 
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    During the preparation of different deacetylated degrees of chitin from 4.5% to 95%, it has been found that the deacetylation rate varied with the pieces size of chitin and the reaction time. The chitosan membranes prepared by coating its solution on a glass plate and drying it at different temperatures show different crystal structures and mechanical properties under the measurement of PLM, XRDand DSC. XRDmeasurement also gives the difference between chitin and chitosan as well as the similarity of chitin films separately coated from crab chitin, silkworm chitin and squid chitin. The crystal cell of chitosan fiber is determined as a =0.987 nm, b =0.924 nm, c =1.031 nm and β =83.29 °.
    Preparation and Application of Magnetic Affinity Adsorbent Based on Magnetic Cellulose Bead
    LI Xin, LI Chao-Xing, HE Bing-Lin
    1998, 19(6):  994-999. 
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    In this paper,the reversed phase suspension and embedment techniques were adopted of preparing the paramagnetic cellulose beads (MCBs). While the viscose suspended in oil phase was heated at 90 ℃ for 40 min, cellulose might be regenerated from cellulose xanthate,and the γ-Fe2O3 superfine powder(φ<300 nm) dispersed in the viscose was wrapped up among the regenerated cellulose chains, then the MCBs were obtained whose mean size might be less than 300μm, and its distribution was narrow.Moist MCBs have the porosity more than 85%. Their magnetizability was of the order of magnitude of 10-3 emu/g. These MCBs can be activated by many kinds of common methods, and can be applied to immobilizing different bioactive ligands to obtain various magnetic affinity adsorbents(MAA). We activated the MCBs in a 35 mmol/L sodium periodate solution, and immobilized the human chorionic gonadotropin(hCG) on them to obtain the MAAwith 300 IUhCG/g content. This kind of MAA could specifically adsorb anti-hCG antibody from murine ascites supernatant.
    The Influences of Solid Surface Modification on the Crystallizability of Polypropylene
    SUN Jing-Zhi, WANG Jing-Yuan, SONG Bo, XU Bing, WANG Yong, TANG Xin-Yi
    1998, 19(6):  1000-1003. 
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    The polypropylene was modified with solid surface modification method. The effects of reaction conditions on the gel fraction in the system were discussed. IR, WAXD, DSCand DMA were used to characterize the influences of modification on the crystallizability of polypropylene. The results show a surface-to-core modification process.
    ESR Study on the Interfacial Interaction Between Metal Oxide and Poly(N,N-dimethylaniline)
    ZHENG Hai-Peng, ZHANG Rui-Feng, SHEN Jia-Cong
    1998, 19(6):  1004-1006. 
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    The interfacial interaction between several metal oxides and poly(N,N-dimethylaniline)(PDMA) was investigated by ESR. Especially in Fe2O3/PDMA system, it is shown obviously that an electron-transfer process occurred from nitrogen atoms of PDMAto Fe2O3 which made PDMA form more stable radical cations and Fe(Ⅲ) turn into Fe(Ⅱ).
    The Conductive Properties of ER Suspensions Containing Chitosan Particles
    WU Shui-Zhu, ZENG Fang, SHEN Jia-Rui
    1998, 19(6):  1007-1009. 
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    In this paper, the electrorheological(ER) suspensions containing chitosan particles and silicone oil were prepared with glycerin as activator. The conductive properties of these suspensions and their influencing factors, such as field strength, particle concentration, activator content, temperature and shear rate were investigated as well. The results show that the suspension system′s conductive property is enhanced as the field strength, concentration, activator content or temperature increases; while with the increasing shear rate, the system′s conductive property decreases.