Table of Content

24 June 2003, Volume 24 Issue 6

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Preface

Rational Design and Synthesis Aided by Data Mining(Ⅰ)──Microporous Aluminophosphates with Specified Structure

LIU Xiao-Dong, XU Yi-Hua, YU Ji-Hong, LI Yi, ZENG Wei, CHEN Chao, LI Ji-Yang, PANG Wen-Qin, XU Ru-Ren, XU Ying

2003, 24(6):  949-952. 

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This work presents the data mining research on the synthesis database of microporous aluminophosphates through decision tree. The results show that the organic amine templates play an important role in the formation of a specified framework. The analysis of decision tree rules presents the defined synthesis conditions for microporous aluminophosphates. We predict the suitable templates for the formation of aluminophosphates with 12-membered ring channel structure in theory. Parts of our results have been supported by computational simulations and further proven by the experiment.

High Temperature Treatment and Characterization of Carbon Nanotubes

WANG Yao, HUANG Wei, WEI Fei, LUO Guo-Hua, YU Hao, AIHEMAI Ti-Jiang

2003, 24(6):  953-957. 

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Multi-walled carbon nanotubes(MWNTs) produced by the catalytic chemical vapor deposition(CCVD) method in a nano-agglomerated fluidized-bed reactor(NAFBR) have been treated in a vacuum furnace at the temperatures between 1 500 and 2 150 ℃. High resolution transmission electron microscopy(HRTEM), laser Raman spectroscopy, X-ray diffraction(XRD) and thermogravimetric analysis(TGA) were performed to characterize the annealed and purified MWNTs. The results reveal that the graphite layers of the tube-walls are more regular after the high temperature treatment, which can be characterized by Raman analysis. However, large defects in tube-walls can not be healed completely. Heating the nanotubes up to 1 800 ℃ essentially results in the removal of nanometer catalyst particles, and MWNTs with a purity of more than 99% can be obtained.

Synthesis and Crystal Structure of Drum Organooxotin Clusters from Hetero-aromatic Carboxylic Acid [PhCH₂Sn(O)(O₂CC₄H₃S)]₆·2CH₂Cl₂ and [PhCH₂Sn(O)(O₂CC₃H₂NO)]₆·2CH₂Cl₂

YIN Han-Dong, WANG Chuan-Hua, MA Chun-Lin, FANG Hai-Xia

2003, 24(6):  958-963. 

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Two novel drum organooxotin clusters [PhCH₂Sn(O)(O₂CC₄H₃S)]₆·2CH₂Cl₂(1) and [PhCH₂Sn(O)(O₂CC₃H₂NO)]₆·2CH₂Cl₂(2) were synthesized by the reaction of [(PhCH₂)₃Sn]₂O with 2-thiophenecarboxylic acid and 2-oxazoliylcarboxylcarboxylic acid in 1;2 molar ratio. Their crystal structures were determined by X-ray single crystal diffraction. Crystal 1 belongs to triclinic system with space group p1, a=1.276 0(3) nm, b=1.305 6(3) nm, c=1.334 3(3) nm, α= 105.65(3)°, β=96.27(3)°, γ=97.20(3)°, Z=1, V=2.099 7(7) nm³, D_c=1.809 g/cm³, μ=2.097mm^-1, F(000)=1 116, R=0.065 1, _wR=0.129 2. Crystal 2 belongs to triclinic system with space group p1, a=1.224 0(4) nm,b=1.367 3(4) nm, c=1.374 4(4) nm, α=107.760(4)°, β=98.069(5)°, γ=91.480(5)°, Z=2, V=2.163 1(12) nm³, D_c=3.373 g/cm³, μ=3.799mm^-1, F(000)=2 136, R=0.038 2, _wR= 0.079. Their structures show a distorted octahedron configuration with six-coordination for the central tin atoms. In crystal 1, the molecules are packed in the unit celLIn one-dimensional chain structure through weak interaction between the sulfur atom and one of the sulfur of an adjacent molecule.

Microstructure of Nanocrystalline Fe_0.5-xCo_xCu_0.5 Alloy Powders by Mechanical Alloying

TONG Fu-Qiang, WANG Chun-Zhong, LI Chang, CHEN Gang, YU Wen-Xue

2003, 24(6):  964-967. 

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A series of Fe _0.5-xCo_xCu_0.5 alloys were obtained by mechanical alloying with x=0, 0.1, 0.2, 0.3, 0.4 and 0.5. The microstructure of the samples with different milling times were measured and analyzed by the methods of XRD and DSC considering the transition temperature of γ phase. The results showed that the fcc phases of Fe _0.5-xCo_xCu_0.5 alloys for different compositions had been obtained under60 h milling. The average grain size, the average square root of second strain and the average value of the dislocation density of Fe_0.3Co_0.2Cu_0.5 alloy powders had a little relationship with the composition. ForCo_0.5Cu_0.5, the lattice parameter is smaller than that of pure Cu. The composition and microstructure of the samples with the same milling have a lot of effects on the transition temperature of γ phase and exothermic enthalpy.

A Study of the Phase Equilibrium for Quinary System Li⁺, Na⁺, K⁺//CO₃^2-, Cl^--H₂O at 298.15 K

ZENG Ying, YIN Hui-An, TANG Ming-Lin, FENG Xiao-Xiang

2003, 24(6):  968-972,988. 

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Zabuye Saline Lake, Tibet, P. R. China, is unrivalled in the world for its high concentration of chloride, sulfate, carbonate and borate of lithium, sodium and potassium. In accordance with the composition of the brine, the phase equilibrium of quinary system Li⁺, Na⁺, K⁺//CO₃^2-, Cl^--H₂O at 298.15 K were studied by isothermal method, from which the phase diagram (stereo-diagram and projected-diagram which were saturated with Li₂CO₃) were drawn. The phase diagram of this quinary system consists of seven crystallization fields, thirteen univariant curves and four invariant points. Seven crystallization fields correspond to six single-salt crystallization fields and one complex salt crystallization, that are LiCl·H₂O, NaCl, K₂Cl₂, Li₂CO₃, K₂CO₃·3/2H₂O, Na₂CO₃·10H₂O and complex salt NaKCO₃·6H₂O. The crystallization region of trona (Na₂CO₃·NaHCO₃·2H₂O) or solid solution is not found in this quinary system. The composition of equilibrium solid phase for four invariant points (K₁, K₂, K₃, K₄) is as follows: Li₂CO₃+NaKCO₃·6H₂O+Na₂CO₃·10H₂O+KCl for K₁, Li₂CO₃+NaKCO₃·6H₂O+K₂CO₃·3/2H₂O+KCl for K₂, Li₂CO₃+NaCl+KCl+LiCl·H₂O for K₃, Li₂CO₃+NaCl+Na₂CO₃·10H₂O+KCl for K₄, respectively.

Synthesis and Crystal Structure of Bis(tetrahydrofurfurylindenyl) Lanthanide Chlorides

CHENG Jian-Hua, CUI Dong-Mei, CHEN Wen-Qi, HU Ning-Hai, TANG Tao, HUANG Bao-Tong

2003, 24(6):  973-976. 

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Lanthanocene chlorides (C₄H₇OCH₂C₉H₆)₂ LnCl[Ln=Y(1); Ln=Gd(2)] were synthesized by the reaction of tetrahydrofurfurylindenyl lithium(in situ) with corresponding anhydrous lanthanide chorides in THF. The crystal structures of these two complexes were determined by X-ray diffraction and they were unsolvated monomeric complexes. They were stable in the air for several hours. Complexes 1 and 2 belong to the same crystal system(orthorhombic) and space group(P2₁2₁2₁). The unit cell dimensions of complex 1 were a=1.042 52(9) nm, b=1.474 55(12) nm, c=1.497 99(13) nm, Z=4, D c=1.508g/cm³; The unit cell dimensions of complex 2 were a=1.037 01(10) nm, b= 1.472 33(12) nm, c=1.513 54(14) nm, Z=4, D c=1.699 g/cm³. They have the same structure and different space configurations. The central metal atom is coordinated by two indenyl, two oxygen of the tetrahydrofurfuryl and one chlorine atom to form a distorted trigonal bipyramid.

Morphological Modification of Large Crystal TS-1 by Ion Etching

GUO Hong-Chen, LIU Na, ZHOU Jun-Cheng, GUO Ming-Xing, WANG Xiang-Sheng, CHEN Li-Xing, ZOU Long-jiang

2003, 24(6):  977-979. 

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A post-synthesis modification method, named ion etching, is proposed to adjust the morphology of titanium silicalite TS-1 for a better catalytic activity. The new method mainlYINvolves treating titanium silicalite TS-1 with an ammonia-containing aqueous solution in autoclave under the conditions of ca. ammonia aqueous solution concentration 0.5-14 mol/L NH₃, volume ratio of liquid/solid 20-100, hydrothermal temperature 100-180 ℃ and contact time 24-500 h. According to the characterizations by SEM, XRF, XRD, FTIR and UV-Vis, the modification can transform a well-defined large crystal TS-1[1 μm×2 μm×6 μm, n(Si)/n(Ti)=53.62] into fine grains which can avoid falling off from the matrix if the conditions of the treatment are properly controlled. The effect of ion etching upon TS-1 morphology is attributed to the OH -ion(derives from NH₃·H₂O) catalyzed hydrolysis of the T-O-T bridge bond of the silicic zeolitic framework. Its main advantages over mechanical ball-millingthe conventional zeolitic morphology modification method, include actually fully retained crystallinity and almost intact coordination state of the active Ti sites of the remained framework, as confirmed by XRD, FTIR and UV-Vis. Probe reaction shows that, the large crystal TS-1 modified by the present method at 170 ℃ for 129 h, when used as the catalyst for epoxidation of propylene, could be operated at propylene weight hourly space velocity of 0.5h_-1, and 97.85% hydrogen peroxide conversion and 96.87% propylene oxide selectivity were obtained. However, to reach comparative hydrogen peroxide conversion, the intact zeolite could only be operated under propylene weight hourly space velocity of 0.2h_-1. The remarkable increase of the catalytic activity of the modified TS-1 may be attributed to the improved intra-crystal diffusivity and the excellent preservation of the crystallinity and active Ti sites by the present modification.

Synthesis and Characteristic of 3-D Inorganic-organic Hybrid Framework Microporous Material [Co₃(BDC)₃(EG)₄]·2DMF

FANG Qian-Rong, SHI Xin, XIN Ming-Hong, WU Gang, TIAN Ge, ZHU Guang-Shan, LI Ya-Feng, YE Ling, WANG Chun-Lei, ZHANG Zhen-Dong, TANG Lu-Lu, QIU Shi-Lun

2003, 24(6):  980-982. 

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A 3-D inorganic-organic hybrid framework microporous material [CO₃(BDC)₃(EG)₄]·2DMF was synthesized under mild conditions and its crystal structure was determined bYUsing single crystal X-ray diffraction. The crystal structure was solved by a direct method and refined by full-matrix least-square method. The crystaLIs the triclinic system and belongs to space group P-1 with a=9.978(2) nm, b=11.223(2) nm, c=11.283(2) nm, α=102.26(3)°, β=113.52(3)°, γ=92.73(3)°, V=6.329(2) nm³, Z=1, D_c=1.565 Mg/m³, M_r=1 063.59, μ=1.183mm^-1, F(000)=541, GOF=1.024, R=0.044 2, _wR=0.124 9.

Preparation and Crystal Structure of Cobalt(Ⅱ) Complex with 3,5-Pyridinedicarboxylic Acid

QU Xiong-Wei, LIU Gang, ZHANG Liu-Cheng, LI Lin, HU Huai-Ming

2003, 24(6):  983-985. 

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The title coordination compound of cobalt(Ⅱ) ion with 3,5-pyridinedicarboxylic acid(Pydc) acid was synthesized and its crystal structure was determined. It crystallizes in triclinic system, P-1 space group, a=0.684 93(14) nm, b=0.939 69(19) nm, c=0.981 7(2) nm, α=90.96(3)°, β= 91.72(3)°, γ=99.82(3)°, Z=2. Cobalt(Ⅱ) ion coordinates with the N atom of 3,5-Pydc and five O atoms of water molecules in octahedral geometry. A 3-dimesional framework is formed by hydrogen bonds between carboxylic O atoms of 3,5-Pydc and O atoms of water.

Solvothermal Synthesis of Nanostructured Cobalt Fiber Under Microemulsion Media

ZHAO Yong-Nan, CHEN Xiang-Ming, LI Xiu-Hong, WANG Yong, WANG Chao-Ying, LI Ming, MAI Zhen-Hong

2003, 24(6):  986-988. 

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BYUsing the combination of solvothermal and microemulsion methods, hierarchical cobalt nanorods with 70 nm width and 3₉ mm length have been prepared under mild conditions. The nanorods are composed of a bundle of ²0 nm wide whiskers, which are composed of spherical nanoparticles(5 nm). It is suggested that the co-operation of the reduction of Co²⁺ and the transition from sphericalmicelles into hexagonal rod-like micelles lead to the formation of the nanostructured cobalt filaments.

Synthesis and Characterization of a Novel 1-D Hybrid Zinc Phosphate (2,2′-bipy)₂Zn₂(PO₄H)(PO₄H₂)₂

YAO You-Wei, YANG Guo-Yu 

2003, 24(6):  989-991. 

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Trying to transgraft the idea of adjusting polyoxometallates′ micro-structures by rationally designing structure building units composed of ligand and "secondary metal" to the synthesis of open-framework zinc phosphate results in a novel 1-D hybrid zinc phosphate, (2,2′-bipy)²Zn²(PO₄H)·(PO₄H₂)²(FJ-10: Fujian Institute of Research on the Structure of Matter). X-ray single crystal analysis reveals FJ-10 belongs to a triclinic crystal system, space group P-1, a=1.038 18(6) nm, b= 1.230 41(7) nm, c=1.234 81(7) nm, α=97.207 0(10)°, β=109.411 0(10)°, γ=113.081 0(10)°, V=1.307 79(13) nm³, R¹=0.039 9, _wR₂=0.101 3. The topology structure of FJ-10′s framework is characterized by PO³(OH) bridged 4-rings. FJ-10 exemplifies firstly the π-π stacking of hybrid chains whose structure-building units are involved in ZnO³N². FJ-10 predicts the novel hybrid transition phosphates.

Layer-by-layer Assemblies Consisting of Vandium-substituted Keggin Type Heteropolytungstate Anions and Their Electrocatalytic Behavior

ZHAI Sheng-Yong, LIU Jian-Yun, JIN Yong-Dong, DONG Shao-Jun

2003, 24(6):  992-995. 

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Vanadium-substituted heteropolytungstate anions(H₃PW₆V₆O₆-40, denoted as PW₆V₆)-containing multilayer films have been fabricated on the 4-aminobenzoic acid(4-ABA) modified GCE surface by alternating deposition with a quaternized poly(4-vinylpyridine) partially complexed with osmium bis(2,2-bipyridine)(denoted as QPVP-Os). Surface plasmon resonance(SPR) spectroscopy and cyclic voltammetry(CV) have been used to characterize the growing behavior of the as-prepared multilayer films. It is shown that the multilayer films are uniform. The average thickness for a bilayer of QPVP-Os/PW₆V₆ in the multilayer films is 2.88 nm. The electrocatalytic activities of the multilayer films for the reduction of BrO₃^- and NO₂^- have been investigated.

Determination of High Polymerization Degree Dextran by Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry(MALDI -TOFMS) and Comparison of Matrix Effects in the Determination

DENG Hui-Min, ZHANG Zhen-Ying, ZHA Qing-Min, DENG Qin-Ying, ZHAO Shan-Kai

2003, 24(6):  996-999. 

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A dextran sample with a high polymerization degree(n>100) was directly determined by the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOFMS) without being further fractionated and the molecular weight of the dextran up to more than 18 000 had been detected. The effects of matrixes 2,5-dihydroxybenzoic acid(DHB), 1-hydroxyisoquinoline(1-HIQ), 3,4-dihydroxycinnamic acid(caffeic acid, CA) and binary matrixes DHB+1-HIQ, DHB+CA were tested and compared. The results showed that the larger mass range could be obtained when matrix DHB was used, the dextran molecules were desorbed and ionized more efficiently and the reproducibility of spectra was enhanced when binary matrixes DHB+ 1-HIQ and DHB+CA were used, also the resolution of spectra were increased when binary matrixes DHB+1-HIQ were used.

Studies on Distribution of Al Species Using Ion-exchange Microcolumn Combined with ICP-AES

CHEN Jie, WU Yi-Wei, HU Bin, JIANG Zu-Cheng

2003, 24(6):  1000-1004. 

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The distributions of Al species in different Al-ligands solutions were studied systematically bYUsing a microcolumn packed with weakly acidic cation-exchange resins coupled with ICP-AES. At pH=6.0, all labile monomeric Al species were retained on the microcolumn while non-labile monomeric Al species were directly passed through the column. The Al-ligands systems studied include Al-fluoride, Al-phosphate, Al-citrate, Al-oxalate and Al-EDTA. The effects of different Al-to-ligand molar ratios on the speciation were studied at a certain pH value, and some practised rules were obtained.

Electrochemical and Spectroelectrochemical Study of m-Phenylenediamine

JIAO Kui, Gang, YANG Tao, WU Jun-Feng

2003, 24(6):  1005-1008. 

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Electrochemical and spectroelectrochemical properties of m-phenylenediamine(MPD) were studied by means of cyclic voltammetry and UV-Vis thin-layer spectroelectrochemistry. The cyclic voltammogram of MPD at gold disc electrode has an oxidative peak as well as a reductive peak. But at SnO₂;F film electrode, it has only an oxidative peak, which is an irreversible process. Potential-controlled UV-Vis thin-layer spectra of MPD at SnO₂;F film optically transparent electrode were recorded and a double logarithmic method was applied to treat the spectroelectrochemical data. From the double logarithmic plot, the kinetically modified formal potential E⁰=0.766 and αn=0.41 were obtained.

A Preprocessing Method Applied in Multi-dimension Data──NOSC

HUANG Jian-Rong, LI Tong-Hua, CHEN Kai, QI Yun-Peng

2003, 24(6):  1009-1012. 

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Orthogonal signal correction(OSC) is a novel spectral preprocessing method, which is based on the orthogonal projection. This pre-processing way removes from the spectral vector or matrix(X) only the part that definitely is unrelated to Y-vector or Y-matrix. Due to the merits of OSC, much interesting is focus on it, and several modified algorithms have been presented to improve it. In this paper, we present a modified multi-dimension method, named NOSC, which is applied in preprocessing three-dimension data. The three-dimension data is the measurement of a drug mixture by HPLC-DAD, in which there are three components, that are enoxacin, norfloxacin, and ciprofloxacin. Compared with those only processed by NPLS, the multi-dimension data preprocessed by NOSC have an optimal analytic result, and the covariance sauqre root is 0.33, 0.21 and 0.16 for enoxacin, norfloxacin, and ciprofloxacin respectively. NOSC was recommended for processing multi-dimension data with NPLS, PRFA and GRAFA, etc..

A Phenomenon of Negative Peak Appeared in Kinetic Ultraviolet Absorb Curve of Initial Biomineralization

HUANG Zhao-Long, ZHANG Wei, CUI Fu-Zhai, CAI Qiang

2003, 24(6):  1013-1015. 

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The ultraviolet photometry is an effective method to investigate the kinetic process of biomineralization because it can be used to monitor the reaction in real time without disturbance. This paper reports an interesting phenomenon in experiment on collagen mineralization. An abnormal negative peak was found in kinetic ultraviolet absorb curve of collagen/calcium phosphate biomineralization system in Tris-HCl buffer(pH=7.4). Influence of several experiment conditions on the negative peak was studied. SEM observation of the sample before and after the negative peak revealed that the crystals morphology and the aggregation of the mineralized collagen fibers are different. It indicated that the negative peak in the kinetic curve is an optical phenomenon related to the compositional and structural change of the mineral, which are the important elements in biomineralization mechanism study.

Rapid on-site Determination of the Toxicity of Organophosphates and Carbamates in Vegetables by Enzyme Catalytic Dynamic Photometry with Handheld Pesticide Analyzer

ZOU Ming-Qiang, YANG Rui, ZHAO Li-Li, YU Ai-Min, JIN Qin-Han

2003, 24(6):  1016-1018. 

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A simple, convenient and on-site determination method and the corresponding handheld analyzer for monitoring toxicity of organophosphates and carbamates in vegetables were developed based on enzyme catalytic dynamic photometry. Variousexperimental parameters were studied and optimized. The toxicity level can be judged according to the enzyme inhibition rate directly displayed on the analyzer. The method is rapid, with an average analysis time of 6-8 min for per sample. It is of practicality and great value, and can effectively be applied for monitoring the toxicity of pesticides, such as organophosphates and carbamates, commonlYUsed for vegetables.

Total Synthesis of (±)-Nimbonone and (±)-12-Ethyl-13-methoxy-8,11,13-podocarpatriene

ZHANG Cheng-Lu, BIE Ping-Yan, PENG Xuan-Jia, PAN Xin-Fu

2003, 24(6):  1019-1022. 

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BYUsing α-cyclocitral(1) as the A ring synthon, and triphenyl phosphonium chloride(2) as the C ring synthon, the keYINtermediate 5 was obtained after the condensation and intracyclization reactions. In order to introduce the ethyl substituent, Fiedel-Crafts acetylation had been first employed to synthesize compound 6, and then the carbonyl group in compound 6 was protected with 1,2-ethanedithiol to afford compound 7. Compound 7 was oxidized to afford compound 8. Desulfurization of compounds 7 and 8 with Raney Ni gave the desired products (±)-nimbonone (9) and (±)-12-ethyl-13-methoxy-8,11,13-podocarpatriene (10) respectively.

Isolation and Identification of a Novel Cembrane-type Diterpenoid from the Soft Coral Sarcophyton crassocaule

XU Xiao-Hua, KONG Chui-Hua, LIN Chang-Jiang, WANG Xin, LU Jian-Hua

2003, 24(6):  1023-1025. 

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A novel cembrane-type diterpenoid was first isolated from the soft coral Sarcophyton crassocaule collected from the Xisha Islands in the South China Sea. Its structure was determined on 2D-NMR, HRMASS and IR techniques and the relative configuration was confirmed by NOESY and X-ray diffraction. The crystaLIs monoclinic, space group P2₁ with cell dimensions of a=0.890 00(10) nm, b=0.638 0(10) nm, c=1.169 670(2) nm. α=90°, β=92.470(10)°, γ=90°, V=0.926(3) nm³, D=1.192 4 g/cm³, Z=2, R=0.057 8, ^wR=0.138 0. The new compound was named as Sarcocrassolide B. It exhibited a strong cytotoxicity against P388 cell line with IC₅₀ value of 1.5 μg/mL.

Preparation of 4-Aminopyridine Imprinted Polymer-based Monolithic Capillary Column and Evaluation of Electrochromatography

YAN Wei-Ying, ZHANG Zhi-Chao, GAO Ru-Yu, WANG Qin-Sun

2003, 24(6):  1026-1030. 

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The 4-aminopyridine(4-AP) molecularly imprinted polymer(MIP)-based monolithic capillary column was prepared by an in situ thermal-initiated polymerization process; the preparation process is simple and quick. The MIP was covalently linked to the inner wall of fused silica capillary. The performance of the column was evaluated by capillary electrochromatography(CEC). Under the optimal CEC conditions, the resolution of 4-AP and 2-AP was 2.5 on the 4-AP MIP based monolithic column, while only 0.35 on the reference column without any imprint of 4-AP. The recognition ability of MIP for 4-AP was influenced by a lot of factors including pH, sort of buffers, ionic strength and the content of organic modifier in the mobile phase. The recognition of the MIP was enhanced with decreasing the salt concentration of the buffer or increasing the acetonitrile content in the mobile phase. The phenomena are ascribed to the reduction in the amount of cationic ions in the mobile phase, which compete with 4-AP in combination with carboxyLIn the cavity of MIP, and weaken the specific affinity of the imprint cavity for the imprinted molecule. The effect of the sort and pH of buffer on the recognition of the MIP is complicated. For phosphate buffer, the effect of pH is parabolic, giving the best recognition at pH=5, while for acetate buffer, increase in pH benefits the recognition.

Synthesis of a Dimer-VB₁₂ Model Molecule and Stability of Co-N Bond

FENG Ya-Qing, ZHANG Xiao-Dong, MENG Shu-Xian, ZHOU Li-Shan

2003, 24(6):  1031-1033. 

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Vitamin B 12 model molecule, dicyano cobyric mono acid hexamethylester 2f was synthesized from Vitamin B 12 by alcoholysis and acidic hydrolysis. Dicyano-a,b,c,d,e,g-α-f-N-(3-imidazoly) propylamido cobyrinate 3f was synthesized by the reaction between 2f and 3-imidazolylpropylamine hydrochloride. Compound 3f was treated with trifluoroacetic acid to give dimer-vitamin B 12 model molecule 5f. Compound 5f was treated with acidic buffers in methanol and the ring of 5f was opened to give compounds 6f. UV-Vis spectra were determined in buffers with different pH values. The equilibrium constants of Co-N bonds were calculated. K-value of 5f was 552×10³, which is much greater than that of monomer vitamin B₁₂ 4f. The strength of coordination bonds between the N atom in the side chain of cobyrinate and the Co atom in 5f was much weaker than that in monomer-vitamin B₁₂ 4f.

Synthesis and Characterization of 2-Chloro-2-oxo-1,3,2-dioxaphospholanes Containing Hydroxyl Group and Corresponding Phosphorylcholines

WANG Ling, YANG Zhi-Mou, CHEN Lin, XU Jian-Min, SHEN Jian, LIN Si-Cong

2003, 24(6):  1034-1036. 

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In order to construct the zwitterionic structure of phosphorylcholine onto the surface of biomaterials, five novel phospholanes containing hydroxyl group were synthesized from the corresponding diol and 2-chloro-2-oxo-1,3,2-dioxaphospholane in the presence of THF. Then, five novel phosphorylcholines containing hydroxyl group were prepared by the corresponding phospholane and anhydrous trimethylamine in the presence of acetonitrile. Their structures were characterized by FTIR, ¹HNMR and elemental analysis.

Synthesis of a Novel Antigen Containing P

XIE Gui-Yang, CHEN Liu-Min, CHEN Jia-Hua, JIN Sheng

2003, 24(6):  1037-1039. 

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It is of great importance to study the catalytic antibody that catalyzes the hydrolysis of peptide bond. The synthesis of a new kind of antigen(10) containing phosphorus was reported in this paper, which was designed and synthesized according to hippuryl phenylalanine, a substrate of carboxypeptidase A(CPA). To mimic the structure of the substrate, the free C-terminal carboxylic group was remained. However, it was not easy to synthesize the phosphonamide peptide hapten(7) directly, so compound 5 was synthesized firstly, after the catalytic hydrogenolysis it was coupled with p-nitrobenzoyl chloride to get compound(7). The synthesis of antigen and further preparation of antibody will be a good foundation for the activity study of the antibody.

A New Route for the Synthesis of Grapholitha Molesta Sex Pheromone

LIU Fu-Chu, LI Yan-Wu, LIN Jun, ZHU Hong-You, LI Quan, ZONG Qian-Shou

2003, 24(6):  1040-1042. 

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The sex pheromone of grapholitha molesta 8(Z/E)-dodecen-1-ol acetate (6) was synthesized bYUsing oleic acids as the raw material. 1,8(Z)-Heptadecadiene (2) was obtained from the decarbonylation reaction of oleic acid (1) in the presence of palladium complexes catalyst. Selective hydroboration and oxidation of 2 by Ca(BH₄₂2O₂ system gave 8(Z)-heptadecen-1-ol (3), which then was acetylized by treatment with Ac 2O/pyridine to afford 8(Z)-heptadecen-ol acetate(4). The compound 4 was ozonized to form the keYINtermediate 8-acetoxyoctanal (5), then compound 5 was coupled with the Wittig regents to obtain the title compound 8(Z/E)dodecen-1-ol acetate (6), Z/E molar ratio is 25;75. The overall yield was 45%. The structures of all the compounds were confirmed by IR, MS and NMR spectra.

Structure and Catalytic Activities of Magnesia Supported Molybdovanadophosphoric Acid Catalysts

ZHOU Guang-Dong, CHENG Tie-Xin, ZHUANG Hong, LIU Yan, LI Wen-Xing, BI Ying-Li, ZHEN Kai-Ji

2003, 24(6):  1043-1047. 

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MgO supported copper salts of molybdovanadophosphoric acid H₄PMo₁₁VO₄0 catalysts were prepared in alcohol by impregnation, and its catalytic activities for the reaction of n-hexanol conversion towards n-hexanal exhibit a higher selectivity(>93% in all case). Chemical nature and texture of MgO were not damaged in the alcohoLImpregnation solution. The measurements of IR, XRD, UV-DRS, NMR, DTA-TG and BET surface area showed that the copper salts of molybdovanadophosphoric acid monolayer dispersed on the surface of MgO and the Keggin type structure of the heteropoly acid salts only partly decomposed. It is observed that the Keggin type structure could be renewed after the catalytic reaction, and an activity phase was formed.

Mesoscopic Simulation on the Interaction Between Polymer PVP and Surfactant AOT

YUAN Shi-Ling, LIU Cheng-Bu, XU Gui-Ying, CAI Zheng-Ting

2003, 24(6):  1048-1051. 

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The interaction between polyvinylpyrrolidone (PVP) with sodium bis(2-ethylhexyl) sulfosuccinate (AOT) has been studied by dissipative particle dynamics (DPD) simulation. With the increase of surfactant concentration, the mean square end-to-end distance <r²> of polymer chain firstlYINcreased, then reduced, and increased again. The analysis of structure shows that the dihedral of polymer chain changed if AOT was added in the polymer system. It indicates that the interaction between polymer and surfactant occurs. And the aggregates of polymer and surfactant can be shown bYUsing the DPD simulated cell. One conclusion is that molecular simulation can be considered as an adjunct to experiments.

Rheological Properties of Mixed Suspensions Containing Oppositely Charged Colloidal Particles

GUO Pei-Zhi, SUN De-Jun, JIN Zhi-Lin, ZHANG Chun-Guang

2003, 24(6):  1052-1055. 

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The rheological properties of single-component clay dispersions and clay/MMH mixed dispersions containing oppositely charged colloidal particles have been investigated. As the clay concentration is increased, the clay suspensions develop from the newtonian form of flow behavior to a yielding type of response. At^w(clay) is between 2%-4%, upon addition of MMH to clay dispersions, the magnitude of yield value and storage modulus increase monotonically, indicating enhanced gel strength. Adding NaCl to clay/MMH mixed suspensions causes the decrease of storage modulus, yield values and apparent viscosities. In the structural recovery measurements, the time dependence of viscoelastic properties of clay/MMH mixed dispersions shows only very small variations of the storage moduli over 3 h, in contrast to unusual thixotropic properties of aqueous single-component dispersions of laponite or MMH. The above results are interpreted based on attractive electrostatic interactions between clay and MMH particles due to their opposite charges, similar to the edge(+)/face(-) interactions in single-component clay dispersions under a low pH value.

SERS Study of the Adsorption of Benzene on Rhodium Electrode

GU Ren-Ao, LIU Guo-Kun, REN Bin, TIAN Zhong-Qun

2003, 24(6):  1056-1058. 

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The Raman spectra of benzene electrochemical adsorption on a roughened Rh electrode have been studied successfully by proper electrode treatment process. The results show that, there is a great difference between the Raman spectra of pure benzene liquid and that of benzene molecule adsorbed on the roughened Rh electrode. It is indicated that the geometry and electron structures have changed greatly after benzene molecule was adsorbed on the roughened Rh electrode. Benzene molecule may be adsorbed on the surface of the roughened Rh electrode with a structure like 1,3-cyclohexadiene. The dependence of benzene electrochemical adsorption on the electrode potential and the electrolyte has been studied in this paper.

DFT Study of Reaction CH₃O₂^&#183;+NO→CH₃O^&#183;+NO₂ in Gas Phase

FU Qiang, CHEN Li-Li, PAN Xiu-Mei, LI Ze-Sheng, SUN Jia-Zhong

2003, 24(6):  1059-1062. 

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The mechanism of the reaction CH₃O ₂^·+NO CH₃O ·+NO₂ in gas phase has been studied bYUsing density functional theory. The geometries of reactants, transition states, intermediates and products have been optimized by B3LYP/6-31G ^* and HF/6-31G^* basis set. Transition states and intermediates have been verified by frequency analysis. The reaction path has been traced by Fukui′s theory of intrinsic reaction coordinate(IRC), with the change of geometry parameter being computed. In order to obtain credible energy, single points energy has been calculated by QCISD methods using the 6-311G^** basis set with zero-point energy correction done by B3LYP method. The isomerizations of the intermediates and the charge densities have been analyzed. The results show that the whole reaction comes through many courses, and it is an endothermic reaction with 50.93 kJ/mol endothermic value calculated. Among the three reaction paths proposed, the triplet state reaction is the most probable one with the lowest activation energy of 163.31 kJ/mol. This work will provide the important theoretical foundation for protecting theozonosphere and atmosphere.

Preparation of Carbon Nanotubes by Catalysis-assisted Detonation

LU Yi, ZHU Zhen-Ping, WU Wei-Ze, LIU Zhen-Yu

2003, 24(6):  1063-1066. 

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Carbon nanotubes can be synthesized via the detonation of the mixture of picric acid, cobalt acetate and phenanthrene at an appropriate molar ratio in a sealed stainless steel pressure vessel. TEM result shows that the carbon nanotubes present an appearance of entangled morphologies with outer diameters of 20-40 nm. The average lengths of the nanotubes between the two entangled points range from several to 40 μm. HRTEM result reveals the multi-wall structure of the obtained nanotubes. The in situ formed cobalt catalysts validated by XRD and TEM are crucial to the carbon nanotubes formation during the detonation. The abundance of nanotubes depends critically on the loading density of picric acid, under the experiment conditions and a high loading density is preferable to the preparation of nanotubes-rich products. Under an optimal condition(0.2 g/cm³ loading density), the purity of as-synthesized nanotubes can be up to 70%, as confirmed by the combination of investigations of TEM and TG.

DFT Study of the Intermolecular Interaction of Hydrazinium Nitroformate Ion Pair

JU Xue-Hai, XIAO Ji-Jun, XIAO He-Ming

2003, 24(6):  1067-1071. 

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Two fully optimized geometries of hydrazinium nitroformate(HNF) ion pairs have been obtained with DFT method at the B3LYP/6-31+G^** level. The binding energies of ion pairs are corrected for the basis set superposition errors(BSSE) and for the zero-point energies(ZPE). The corrected binding energy of the most stable ion pair is predicted to be -420.03 kJ/mol, which can compensate for the totaLIonization energy needed for the ionization of hydrazine and trinitromethane. The intermolecular bonds between ion pairs primarily consist of Coulomb interaction and, judged by the electron densities at the bond critical points, the covalent interactions also make a remarkable contribution to the bonding. Based on statistical thermodynamics, the thermodynamic properties of the related systems have been calculated. The changes of the enthalpy and Gibbs free energy on going from the ions to the most stable ion pair are predicted to be -419.72 and -376.61 kJ/mol at 298.2 K, respectively.

Ab initio Calculation Investigation on the Molecular Conformation of Aza-bridged Bis-phenanthroline Macrocyclic Compound

LIU Hai-Yang, XU Zhi-Guang, XU Xuan, YING Xiao, WU Ting-Wan, ZHANG De-Cong, HU Xi-Ming, WANG Wen-zhu

2003, 24(6):  1072-1075. 

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The ¹HNMR chemical shifts of aza-bridged bis-phenanthroline macrocycle(H₂HAPP) in d-TFA solvent, with C_2h and C_2h symmetric conformation, have been calculated at RHF/6-31G^** and B3LYP/6-31G^** level bYUsing ab initio GIAO method. The calculated chemical shifts of protonized H₄HAPP²⁺ species with C_2h symmetric conformation are in good agreement with the experimental data, and the C_2h symmetric conformation optimized at B3LYP/6-31G^* leveLIs preferable. The calculated results of the harmonic vibration frequency of C_2h and C_2h geometries optimized at B3LYP/6-31G * leveLIndicate that C_2h conformation is stable and C_2h is not stable. The electronic spectrum of protonized species H₄HAPP²⁺ has also been calculated bYUsing ab initio TDDFT method. TheoreticaLInvestigation suggests the protonized species H₄HAPP²⁺ is of C_2h symmetry.

Comparative Molecular Field Analysis of Tyrosine Kinase Inhibitors

PENG Tao, PEI Jian-Feng, ZHOU Jia-Ju

2003, 24(6):  1076-1079. 

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Three-dimensional structure-activity relationships of some tyrosine kinase inhibitors were studied bYUsing CoMFA technique. The model can not only be used to predict the compounds in the training set but also the compounds in the test set. The CoMFA contour plots were used to identify several key features including steric and electrostatic fields, which were valuable for us to get insight into the potential mechanism of the intermolecular interactions between inhibitor and the receptor. Suitable steric and electrostatic effects are required for a higher activity.

Studies on the Erosion Mechanism of Kapton and Its Protective Effect

ZHANG Lei, YAN Chuan-Wei, SUN Gang, TONG Jing-Yu, LI Jin-Hong, CAO Chu-Nan

2003, 24(6):  1080-1084. 

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Kapton HN(PMDA-ODA, polyimide) has many applications in aerospace technology as solar cell blanket and thermal blanket. But Kapton is susceptible to atomic oxygen(AO) erosion. Exposure experiment ground-based simulation facilitYINdicate that it undergoes mass loss and surface degradation. XPS was used to characterize the chemical and physical change of the surface of Kapton after AO irradiation. Strong oxidative degradation of Kapton and substantial changes in surpermolecular organization and morphology of its surface layer were observed after AO irradiation. The results suggest that AO not only reacts with Kapton surfaces, but also the transfer of the energy of particle collisions of chain macromolecules in surface layer aids in the development of physicochemical reaction processes. It is evident that siloxane coatings have excellent properties for anti-AO effects.

Effect of Length of Substituted Alkyl Chain on 2-D Nanostructure

XU Shan-Dong, ZENG Qing-Dao, QIAO Ying-Hong, WANG Chen, WAN Li-Jun, BAI Chun-Li

2003, 24(6):  1085-1088. 

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A series of alkyl-substituted 1,3,5-triphenols were synthesized, and their adsorption and assembling behavior on a highly oriented pyrolytic graphite(HOPG) surface were studied by scanning tunneling microscopy(STM) under ambient conditions. A characteristic stripe-like structure was observed from these samples. In high-resolution STM images of the molecules with shorter chains, we found that two parallel alkyl chains were arranged side by side on one side of the phenylring, another alkyl chain was arranged on the other side and the alkyl chains interdigitate to form a uniform alkane lamella. The high stability and close-packed assembly were interrupted with increasing the chain length, and the co-existing self-assembly structure of the single molecule and dimmer was formed. This result is attributed to Van der Waals interactions between the alkyl chain-alkyl chain and the alkyl chain-substrate. This observation illustrates that changing alkyl chain length is an effective method for obtaining various two-dimensional molecular assemblies.

Template Synthesis and Photocatalytic Activity of TiO₂ Nanowires Array Film

GAO Yuan, MA Yong-Xiang, LI Hu-Lin

2003, 24(6):  1089-1092. 

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TiO₂ nanowires array film was prepared within the pores of anodic aluminum oxide(AAO) template bYUsing sol-gel chemistry. This method was suitable for solving the problems caused by the generallYUsed sol-gel method, i.e. the agglomeration between particulates of the catalyst film in the burning process and the catalyst from the supports in the reaction. Anatase crystal form of TiO₂ nanowires film was shown through XRD characterization and the diameter was determined by the pore size of the AAO template bYUsing AFM image, respectively. The photocatalytic activity of TiO₂ nanowires array film measured bYUsing an acridine dye solution as a modeLIs higher, compared with that of TiO₂/glass film.

Studies on Photocatalytic Degradation of Rhodamine B on Fe³⁺-TiO₂/SiO₂ Coating Film

WANG Jian-Qiang, XIN Bai-Fu, YU Hai-Tao, REN Zhi-Yu, QU Peng-Fei, FU Hong-Gang

2003, 24(6):  1093-1096. 

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Fe³⁺-doped titanium dioxide films coated on silica(Fe³⁺-TiO₂/SiO₂) were prepared by sol-gel method and characterized by means of SEM, Raman and DRS technologies. The activity of the prepared photocatalysts was investigated by the degradation reaction of Rhodamine B radiated with visible light(Xe lamp), and the results indicate that the presence of Fe³⁺ ion in photocatalyst accelerates the degradation reaction rate of Rhodamine B. Moreover, the effects of the pH value and initial concentration of Rhodamine B in solution on the photocatalytic reaction were discussed.

Preparation of Core-shell Titania Spheroid with Mesoporous Structure and the Application in Synthesis of Glutaraldehyde

GUO Chang-Wen, DAI Wei-Lin, CAO Yong, FAN Kang-Nian

2003, 24(6):  1097-1099. 

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A novel process for preparation of micrometer-scale functional materials without organic templates has been demonstrated. Titania spheroid with a tailored core-shell structure and high ordered mesoposity has been manipulated in the ethanol hydrothermal system containing ammonia sulfate as a dispersant. Titania spheroid with a mean diameter of 3.6 μm and a high specific surface area of 266 m²/g has been synthesized by precipitating titanium tetrachloride with ammonia gas released from hydrolysis of urea at a high temperature. A special core-shell structure with a 100 nm thin shell and a 300 nm spacing strip interiors has been characterized by SEM & TEM. The catalytic performance of the titania spheoid supported WO₃ catalyst for the selective oxidation of cyclopentene(CPE) to glutaraldehyde(GA) has been investigated. The WO ₃/TiO₂ spheroid catalyst displays an exciting prospect for good selectivity(72.9%) toward GA and a high GA yield(about 70%) for the titled reaction using aqueous H₂O₂ as the oxidant.

Immobilization and Catalytic Property of α-Chymotrypsin in the Channel of Silica Mesoporous Material SBA-15

GAO Bo, ZHU Guang-Shan, FU Xue-Qi, XIN Ming-Hong, QIU Shi-Lun

2003, 24(6):  1100-1102. 

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The hexagonal silica mesoporous material SBA-15 with ordered 2-dimensional channel structure was used as a suppport to the immobilization of emzyme. α-Chymotrypsin, an enzyme, was assembled in the channel of SBA-15 by immersion method. The absorbed amount of enzyme in SBA-15 and the activity of the immobilized enzyme were studied. It was found that there was more absorbed enzyme in SBA-15 than in other carrier and the activity of the immobilized α-chymotrypsin was increased compared with the free enzyme. It suggests that silica mesoporous material SBA-15 is a good support for immobilization of enzyme.

Hydrothermal-fluid Drying Synthesis of New V-O-Al Catalyst for the Dehydrogenation of Isobutane

MA Hong-Chao, WANG Zhen-Lü, ZHU Wan-Chun, WANG Guo-Jia

2003, 24(6):  1103-1105. 

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The V-O-Al catalyst was prepared by hydrothermal-fluid drying synthesis method and was tested in the dehydrogenation of isobutane to isobutene. The catalysts were characterized by means of XRD, ESR, TPR and BET. The V-O-Al catalyst, derived from hydrothermal synthesis and possessing a higher vanadia dispersion in the alumina and larger surface area, especially showed a better catalytic activity and marked stability than the supported vanadium oxide catalyst.

Preparation of Etherified β-Cyclodextrin and SelectivitYIN Its Blend Membrane for Xylene Isomers

QIAN Jin-Wen, WANG Li-Na, AN Quan-Fu, CHEN Huan-Lin

2003, 24(6):  1106-1109. 

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Etherified β-CD was synthesized bYUsing benzyl chloride(PhCH₂₂Cl).The influences of etherification conditions on the reaction conversion and the degree of substitution of etherified β-CD were investigated. The reaction conversion increases with increasing molar ratio of PhCH₂₂Cl to β-CD and the concentration of β-CD. The most proper temperature and time for the reaction conversion are 90 ℃ and 12 h, respectively. The degree of substitution of etherified β-CD increases greatly with increasing molar ratio of PhCH₂₂Cl to β-CD, but there is no significant change for the degree of substitution when temperature, time and concentration of β-CD increased. Meanwhile, the pervaporation performance of PVB membrane containing 25%(mass fraction) etherified β-CD for 10%(mass fraction) PX in PM/MX mixture were measured, and the separation factor α=1.16, permeation flux J=70.57 g/(m²·h) at 30 ℃ were obtained.

The Sensitization on Photoconductivity of Bisbenzimidazole Perylene with 5,10,15,20-Tetraphenylporphyrin in Dual-layer Photoreceptor

YANG Xin-Guo, SUN Jing-Zhi, WANG Mang, CHEN Hong-Zheng, HUANG Ji

2003, 24(6):  1110-1113. 

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The xerographic properties of dual-layer photoreceptors containing 5,10,15,20-tetraphenylporphyrin(H₂TPP) and bisbenzimidazole perylene(Im-PTC) composite were described. H₂TPP/Im-PTC composite was dispersed by ball-milling in polymers and dual-layer photoreceptors were prepared by coating. Photoreceptors containing H₂TPP/Im-PTC composites exhibited a better photosensitivity than that containing Im-PTC. When irradiatied with 500 nm monochromatic light of 12.5 μW/cm², photosensitivity(E_1/2<>^-1) of 5%/40%Im-PTC composite was increased from 0.163 3μJ^-1·cm² to 0.571 4μJ^-1·cm². In addition, the initial potential of photoreceptors increased and the residual potential decreased drastically. Photovoltaic response of H₂TPP/Im-PTC composite was stronger than that of Im-PTC and showed H₂TPP/Im-PTC composite had higher charge photogeneration and separation ef ficiency. The photoinduced electron-transfer process between H₂TPP and Im-PTC contributes to the enhancement of photosensitivity of composite photogeneration materials.

A Study of the Chain Motion in STVPh/PEO System by ESR Spin Label

TAN Li, CHEN Shi-Ming, YAN Xiao-Min, PING Zheng-Hua, SHEN Yi-Min

2003, 24(6):  1114-1117. 

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The electron spin resonance(ESR) spectra of PEO end labeled with nitroxide groups were recorded over a temperature range for the bulk polymer and for(1;3 by mass ratio) blends with styrene-vinylphenol copolymer(STVPh) containing different hydroxyl groups. For SLPEO, ESR spectra are composed of a single component, indicating the spin label locating in a single environment. For SP-1, SP-9 and SP-26 blends, two spectral components with different rates of motiona "fast" component and a "slow" component are observed in the experimental temperature range. It can be concluded that the fast and slow components should be attributed to micro heterogeneitYIN the blends: nitroxide radical trapped in the PEO rich and STVPh rich regimes in the blends, respectively. The miscibility of the blends increases with increasing hydrogen bonding density due to the specific interaction between hydroxyl groups in STVPh and the ether oxygen in PEO. Accordingly, the T_5mT, E_a, τ_c values are increased owing to the decrease of the SLPEO mobility of chain motion with increasing hindrance of physical cross-linking density.

Electrodepositing Polyaniline by Pulse Galvanostatic Method

JIAO Shu-Qiang, PENG Xia-Hui, ZHOU Hai-Hui, CHEN Jin-Hua, KUANG Ya-Fei

2003, 24(6):  1118-1121. 

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A new method, pulse galvanostatic method(PGM) is proposed to synthesize polyaniline(PANI) films in 0.2 mol/L aniline and 0.5 mol/L H₂SO₄ aqueous solution. Cyclic voltammogram in 0.5 mol/L H₂SO₄ solutions show that the films of PANI obtained by PGM are more electroactive than those by galvanostatic method(GM). The micrograph of polyaniline films has been investigated by scanning electron microscopy. The nano-fibrous structure can be observed for the polyaniline films by PGM, while the polyaniline films by GM show a granular structure. Additionally, the influence of t_on/t_off and frequency of PGM on the properties of polyaniline has also been discussed. Electrochemical research shows that the anodic peak current of CVs has a maximum value in the plot of peak current density relating to t_on/t_off. Meanwhile, the peak current increases with the imcrease of frequency.

Studies on Degradation Behaviour of Poly(ethyleneglycol)-b-poly (butylene terephthalate) Copolymers

ZHANG Ai-Ying, FENG Zeng-Guo, ZHANG Yong, BA Jian-Hua

2003, 24(6):  1122-1125. 

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The degradation behavior of the copolymers are investigated by immersing the copolymer film into PBS(pH=7.4) at 37 ℃ in a shaking bath .The influence of the copolymer composition on physical properties, including the swelling ratio, the weight loss, the inherent viscosity, the surface morphology of polymer films, as well as the degree of crystallization is discussed. The experimental results reveal that the degradable profiles can be controlled by changing the copolymer composition.It is shown that the intial degradation of copolymer comes from the cleavage of the ester bonds between hydrophilic PEG and hydrophobic PBT.

CMC_o of Nonylphenol Polyoxyethylene Ethers in Oil Phases and the Problems Concerned

WANG Hai-Bo, LIU De-Shan

2003, 24(6):  1126-1130. 

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Critical micelle concentration (CMC) is a verYUseful parameter in the study of emulsions. And there are some interesting relations between CMC and the molecular structure of surfactant. Although surfactant molecular is composed of hydrophilic part and lipophilic part, the common point of view about CMC is still focused on CMC_of surfactant in aqueous solution(CMC_w). Because of the lack of CMC_o (CMC_of surfactant in oil phase) in the study on emulsion, it is impossible to explain the function of surfactant in the emulsification completely by CMC_w. And because of the importance of CMC_o is often ignored, the information of CMC_o is not easily available at present. In this paper, simple method was designed to determine the ranges of CMC in oil phases of some common surfactants. The relationship between CMC in oil phases and the molecular structure of surfactants was also investigated. The solubility of surfactant in oil phase is the key factor influencing CMC_o. Through the analysis about the change interface tension between water and oil phases. It was found that the best result of the decrease in the interface tension was caused by the suitable CMC_w and CMC_o simultaneously. CMC_w and CMC_o could be used to determine the situations of surfactant molecules in the systems correctly. The useful conclusion means that the relationship between CMC_w and CMC_o could be used to evaluate the effectiveness of surfactants in different systems. And the importance of CMC_o in the study of emulsion could be clearly seen.

Characterization of the Disinfection Process Using Quaternary Ammonium Salts Grafted Cellulose Fiber

ZHOU Xuan-Rong, LU Dian-Nan, SHAO Man-Jun, XING Xiao-Dong, WANG Xiao-Gong, LIU Zheng

2003, 24(6):  1131-1135. 

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Characterization of disinfection process using quaternary ammonium salts grafted cellulose fiber was carried out with E.coli as a model bacteria. A rapid adsorption of E.coli. on the grafted fiber was identified, as indicated by the dramatic reduction of the concentration of viable cells in the suspensions. The adsorption as function of the fiber input indicates the dominating role of the electrostatic interaction between the fiber and E.coli. cell surface. The determination of oxygen uptake rate (OUR) was introduced to characterize the growth of E.coli. on the fiber surface. The adsorption of E.coli. on the fiber surface was observed with scanning electron microscope(SEM), which showed the lysis of cell envelope along with the processing. The results obtained in the present study show that the disinfection process is composed by two steps, in which the first step, i.e., the adsorption of E.coli. on the fiber surface driven by electrostatic interaction, is a fast reaction. While cell lysis, the second step, is a relatively slow reaction. The present study also shows the potential of OUR and SEM as fundamental tools in the development of antibacterial materials.

Preparation and Characterization of Orderly Alternating TiO₂/CTAB Multilayer Film

ZHANG Sheng-Mao, ZHANG Zhi-Jun, DANG Hong-Xin, LIU Wei-Min, XUE Qun-Ji

2003, 24(6):  1136-1138. 

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The composite thin film of TiO₂/CTAB was prepared on quartz substrate bYUsing super-molecular self-assembly method. The structure of the thin film was characterized by means of X-ray diffraction and UV-Vis absorption spectrum. The results of UV-Vis absorption spectrum indicate that the diameter of the TiO₂ nanoparticles is 2 nm. The results of X-ray diffraction indicate that the thin film is composed of organic and inorganic layers in alternately orderly arrangement. The distance between the organic layer and inorganic layer is 4.61 nm. The thicknesses of organic layer and inorganic layer are 2.58 and 2 nm, respectively.

Grafting of Dendritic Polyesters onto Nanometer Silica

GUO Zhao-Xia, LI Ying, YU Jian

2003, 24(6):  1139-1141. 

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Dendritic polyesters bearing COOH groups at the focal points were grafted onto nanometer silica premodified with 3-aminopropyltriethoxysilane by N,N′-dicyclohexylcarbodiimide mediated amidation. The products were characterized qualitatively by FTIR, TGA and elemental analysis. It was shown that a significant grafting (10%-15% net grafting for this reaction) was obtained despite the steric hindrance of the dendrons.

Elastomeric Stamp Made by the Silicon Rubber Modified with Montmorillonite

JIN Bang-Kun, WU Xiao-Song, CHEN Da-Zhu, HE Ping-Sheng

2003, 24(6):  1142-1144. 

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The polydimethylsilicone(PDMS) rubber, a material generallYUsed to make the elastomeric stamp in soft lithography, was modified by the organic montmorillonite(MMT). The cure behavior and the modular change of the nanocomposite were monitored with the resin curemeter. The results showed that after the intercalation of montmorillonite, the nanocomposite cure faster and the modulus of compound increased obviously. Especially, the elasticity and fitness of the PDMS/MMT nanocomposite were enhanced, also the nanocomposite had better mechanical properties and stronger solvent resistance. The results suggest that this nanocomposites is more suitable for preparing elastomeric stamps in soft lithography.