Loading...
CJCU

Table of Content

    24 January 2000, Volume 21 Issue 1
    Previous Issue    Next Issue
    Articles
    Studies on the Crystallization Mechanism of β Zeolite Synthesized with Nucleation Gel
    ZHOU Qun, QIU Shi-Lun, PANG Wen-Qin
    2000, 21(1):  1-4. 
    Asbtract ( )   PDF (566KB) ( )  
    Related Articles | Metrics
    Zeolite β was synthesized with a nucleation gel. The IR spectroscopic characterizations confirm the existence of the microcrystal nuclei in the nucleation gel. Chemical analysis of solid and liquid phases demonstrates that zeolite β can grow within a relatively narrow n(Si)/n(Al) ratio range. TGA analysis reveals that TEAOH only exists in the microcrystal nuclei formed in the nucleation gel. It was also found that the negative charges of the zeolite framework are actually balanced by the hydrated Na+ ions, which may direct the growth of zeolite β during the crystallization process.
    Syntheses and Crystal Structures of Transitional Metal Complexes with Polypyridines as Ligands
    YIN Ye-Gao, CHEUNG Kung-Kai, WONG Wing-Tak
    2000, 21(1):  5-9. 
    Asbtract ( )   PDF (205KB) ( )  
    Related Articles | Metrics
    The syntheses and crystal structures of transitional metal complexes of three substituted polypyridine ligands[4′-phenyl-2, 2′∶6′, 2″-terpyridine(L1), 4′, 4″-diphenyl-2, 2′∶6′, 2″∶6″, 2-quaterpyridine(L2)and 4′, 4Ê-diphenyl-2, 2′∶6′, 2″∶6″, 2Ê∶6Ê, 2″″-quenquepyridine(L3)] are reported in this work. Comparison of the structures of these complexes shows that the central metal ion has an inducing effect on the formation of the configuration of complexes.
    Studies on Chemical Preparation of Fe-P-B Ultrafine Amorphous Alloy Particles and the Interaction of the Components
    WU Yong, HU Zheng, PEI Hua-Xing, CHEN Yi
    2000, 21(1):  10-13. 
    Asbtract ( )   PDF (205KB) ( )  
    Related Articles | Metrics
    A series of Fe-P-B ultrafine amorphous alloy power samples, which can be expressed approximately as Fe82PxB18-x(2.4≤x≤10.1), have been chemically prepared. As the reaction temperature was raised from -7 ℃ to 28 ℃, the P contents decreased gradually from 10.1% to 2.4%, while the B contents increased gradually from 8.7% to 13.1%, Mssbauer experimental results indicates that there is a preferential bonding of Fe-P to Fe-B in the samples.
    Preparation of Pd-Y Alloy Membranes on Porous Alumina by MOCVD Using Mixed Metal β-Diketone as Precursors
    XIA Chang-Rong, GUO Xiao-Xia, WANG Xue-Jun, CHEN Chu-Sheng, PENG Ding-Kun, MENG Guang-Yao
    2000, 21(1):  14-17. 
    Asbtract ( )   PDF (291KB) ( )  
    Related Articles | Metrics
    A metal-organic chemical vapor deposition (MOCVD) process with metal β-diketone as precursor was applied to preparing Pd and Pd-Y alloy composite membranes on porous alumina substrates. A palladium phase membrane consisting of primary crystallites with dimension of around 30 nm×10 nm was deposited when a single Pd(AcAc)2 precursor was used. With a mixed precursor of 8Pd(AcAc)2+Y(AcAc)3, uniform and dense Pd-Y alloy membranes were reproducibly formed. The alloy membranes consisted of primary crystallites with a dimension of 21 nm×10 nm , which is much smaller than that of pure Pd membranes. XPS studies revealed that the content of Y in the Pd-Y alloy membranes was less than that in the mixed precursor. This goes along with the results of thermal gravimetric analysis of metal β-diketones, which showed that the volatility of Y(AcAc)3 was lower than that of Pd(AcAc)2. Hydrogen testing showes that the flux of a Pd-Y alloy membrane is much higher than that of a Pd membrane at the temperature investigated. And Pd-Y alloy membranes were more stable than Pd membranes.
    Synthesis and Structure of a Novel Supramolecular Complex with 1D Twisted Structure
    SUN Wei-Yin, FEI Bao-Li, SHU Mou-Hai, TANG Wen-Xia, YU Kai-Bei
    2000, 21(1):  18-20. 
    Asbtract ( )   PDF (179KB) ( )  
    Related Articles | Metrics
    A new bidentate ligand: 4,4′-bis(imidazol-1-ylmethyl)-2,2′-biphenyl(L) was designed and synthesized. Its Mn(Ⅱ) complex [(MnL3)(ClO4)2·2H2O]n crystallizes in orthorhombic system, space group Pca21 with a=3.392 1(11) nm, b=1.010 3(2) nm, c=1.791 5(4) nm, V=6.140(3) nm3, Z=4, Dc=1.334 g/cm3, F(000)=2 564, R=0.049 6, wR2=0.075 4, (Δρ)max=0.263×103e/nm3, (Δρ)min=-0.237×103 e/nm3. In the titled complex, each ligand L adopts a "Z" conformation and binds with two Mn(Ⅱ) ions and each Mn(Ⅱ) ion binds with six L ligands to give a one-dimensional twisted supramolecular complex.
    Synthesis of Highly Ordered Donut-like Mesoporous Silica SBA-15
    SUN Jin-Yu, ZHAO Dong-Yuan
    2000, 21(1):  21-23. 
    Asbtract ( )   PDF (496KB) ( )  
    Related Articles | Metrics
    Highly ordered hexagonal mesoporous silica SBA-15 with tunable morphology such as donut-like has been synthesized through the cosolvent approach. Donut-like SBA-15 prepared by using DMF cosolvent shows highly ordered circle channels and large mesopore size of 9.9 nm and pore volume of 1.45 cm3/g. Cosurfactant approach has also been used to control the morphology of SBA-15, resulting that highly ordered hard spheres (uniformed diameter—800 nm) mesoporous silica are formed. The morphology of mesoporous SBA-15 is much depended on the surface curvature energy of interface of inorganic silica and organic block copolymer species.
    Synthesis and Structure of Organophoryl Derivatives of Monovacant Polyoxometalates of General Formula [C6H5P(S)]2XW11O39(8-n)-(X=P5+, Si4+, B3+, Ga3+)
    SUN Zhen-Gang, YUE Shu-Mei, LIU Qun, LIU Jing-Fu
    2000, 21(1):  24-26. 
    Asbtract ( )   PDF (164KB) ( )  
    Related Articles | Metrics
    With Bu4NBr as phase-transfer agent, the monovacant polyoxometalates α-Xn+W11O39(12-n)-(X=P, Si, B, Ga) reacted in acetonitrile with electrophilic C6H5P(S)Cl2 to yield hybrid organic-inorganic species [C6H5P(S)]2XW11O39(8-n)- in satisfactory yield, which have been characterized by elemental analyses, IR and 31P, 183W NMR. The formulation of all tetrabutylammonium salts of [C6H5P(S)]2·XW11O39(8-n)- are in agreement with the results of elemental analyses, the hybrid anion consists of an α-Xn+W11O39(12-n)- framework on which are grafted two C6H5P(S) groups through P—O—W bridges. The spectroscopic data show that the [PhP(S)]2XW11O39(8-n)- compounds possess true Cs symmetry in acetonitrile and remain unsaturated.
    ss-DNA Immobilization and Hybridization on Nano-Gold/ 2-Aminoethane Thoil/Glassy Carbon Electrode
    MIAO Qian, JIN Bao-Kang, LIN Xiang-Qin
    2000, 21(1):  27-30. 
    Asbtract ( )   PDF (559KB) ( )  
    Related Articles | Metrics
    The modification of glassy carbon electrode(GCE) with nano-gold(NG) by chemical adsorption of 2-aminoethane thoil(AET) was achieved for the first time. On this electrode 15-mer ss-DNA was immobilized, then ss-DNA/NG/AET/GCE was formed. By using Co(bpy)33+, hybridization events of the immobilized ss-DNA was well detected. It was found that the NG could possibly cause a part of the ss-DNA to denature and bind Co(bpy)33+. However, soaking in pH 7.0 phosphate buffer solution, denaturization can be avoided and recognition ability of hybridization was enhanced. Cyclic voltammetric behavior of Co(bpy)33+/2+ bound to the ds-DNA/NG/AET/GCE was studied. It was found that the peak current(ip) showed a linear dependence on the potential scan rate up to 80 mV/s. It was demonstrated that GCE modified with NG by this method had higher stability and reliability.
    Studies on the Electrospray Ion Trap Mass Spectra of Roxithromycin and Its Metabolites
    ZHONG Da-Fang, TIAN Lei, LI Xue-Qing, XU You-Jun
    2000, 21(1):  31-35. 
    Asbtract ( )   PDF (283KB) ( )  
    Related Articles | Metrics
    To investigate the characteristics of mass spectra of roxithromycin and its metabolites, human urine samples which were collected from healthy volunteers after a single dose of 150 mg roxithromycin were analyzed using electrospray ion trap mass spectrometry in a multi-stage MS full scan mode performed on a Finnigan LCQ instrument. The mass spectrometry was operated in the positive mode. The obtained mass spectra were analyzed assisted with the software Mass Frontier 1.0 for their fragmentation passways. Besides roxithromycin, ten of its metabolites were identified in the urine samples by LC/MS. The full scan MS2 and MS3 spectra of each compound gave characteristic fragment ions of descladinose and dedesosamine respectively, and a series of dehydration ions were also found. The difference of fragmentation between the roxithromycin derivatives and the erythromycin oxime derivatives lied in the loss of different fragment ions containing nitrogen. These characteristics can be used for future structure elucidation in the studies of metabolism of roxithromycin and its analogues.
    Analysis of Biologically Active Compounds in Chinese Medicines by Molecular Biochromatography with Human Serum Albumin(HSA) Stationary Phase
    KONG Liang, ZOU Han-Fa, WANG Hai-Lin, NI Jian-Yi, ZHANG Yu-Kui
    2000, 21(1):  36-40. 
    Asbtract ( )   PDF (1701KB) ( )  
    Related Articles | Metrics
    A strategy for analysis of bioactive compounds in traditional Chinese medicine was first proposed by molecular biochromatography with human serum albumin(HSA) stationary phase. Separation of active compounds in four kinds of traditional Chinese medicine(TCM) was compared on the HSA column, and found that different TCM show different characteristic of chromatogram patterns. The effects of extracting solutions(water/methanol/ethanol) and extracted time on the amount of bioactive compounds in Angelica sinensis(Oliv.) Diels were examined, and a quality control method was also developed based on this technique, which is able to simultaneously determine the concentrations of ferulic acid and liguistilide in extracted solutions of Angelica sinensis(Oliv.) Diels by water and methanol.
    Studies on the QSPR Between Charged Partial Surface Area and lgP of Organic Compounds Using Genetic Algorithm and Neural Network
    GUO Ming, LIU Wen-Jie, XU Zun
    2000, 21(1):  41-44. 
    Asbtract ( )   PDF (192KB) ( )  
    Related Articles | Metrics
    The original calculation methods of Charged Partial Surface Area(CPSA) are very complex because of considering many factors of environment, the calculation about the contribution in surface area of atom to molecular in these methods are solvent accessible area. In this paper, we improved the algorithm of CPSA and calculated the “nickel” surface area of atom using molecular mechanics and the CPSA of compounds by quantum chemistry. The satisfactory result of correlation analyze between lgP and improved CPSA of alcohol demonstrates that our algorithm is simple and effective, both genetic algorithm and neural network are well used in this research.
    Adsorption Characteristics of Fullerene-extracted Soots and Its Application for Collecting Volatile Organic Compounds in Ambient Air
    CHEN Jian-Xin, CHEN Cai, SHENG Guo-Ying, WANG Xin-Ming, FU Jia-Mo, LIU ZiYang, LIU Shu Ying
    2000, 21(1):  45-48. 
    Asbtract ( )   PDF (1057KB) ( )  
    Related Articles | Metrics
    Fullerene-extracted soots which are the by-product of producing fullerenes(C60/C70) can adsorb organic vapors efficiently. Breakthrough volumes(maximum sample volumes, Vmax)and specific retention volumes(20 ℃)of 17 VOCs(volatile organic compounds)are measured. The recoveries of adsorption/thermal desorption of Fullerene-extracted soots adsorbent tubes ranged from 40.8% to 117%, most of which are (100±20)%. Fullerene-extracted soots is cheap and can be used in environmental analysis for trapping and enriching traces of VOCs in ambient air.
    Application of Linear Neural Network to Simultaneous Determination of Four B-group Vitamins
    YIN Chun-Sheng, SHEN Yang, LIU Shu-Sheng, LI Zhi-Liang, PAN Zhong-Xiao
    2000, 21(1):  49-52. 
    Asbtract ( )   PDF (199KB) ( )  
    Related Articles | Metrics
    Simultaneous determination of the multicomponents of four B-group vitamins with a novel Linear Neural Network (LNN) algorithm was reported. Based on the data correlation coefficient and standard deviation, 11 representative wavelength points were selected from the original UV spectral data (240 points) as the original input patterns for FLN to build an NN model. The results obtained by LNN is satisfactory, with a correlation coefficient 0.999 83 and a standard deviation 0.113 01.
    A Novel Method of Extracting Weak Signal
    WANG Li-Ya, CAI Wen-Sheng, YIN Chun-Sheng, PAN Zhong-Xiao
    2000, 21(1):  53-55. 
    Asbtract ( )   PDF (359KB) ( )  
    Related Articles | Metrics
    A novel method for extracting weak signal based on the theory of stochastic resonance was proposed. It was implemented by using the cooperative effect of noise instead of adding noise to a weak signal. The previous studies show that several disadvantages exist in the adding noise method. Due to the fact that adding noise to the weak signal will decline the signal-noise-radio(SNR) of the input of the nonlinear system, it will lower the detection effect. Additionally, the resonance point is determined manually, and also obvious offset of the peak position may occur in the result analyzed. Here the novel method was applied to analyze the weak laser-Raman spectrum of a CCl4 sample (liquid in capillary) which was measured with SPEX-1403 laser-Raman-spectrometer from 250 cm-1 to 418 cm-1 on 5 mW (output power of laser). The spectrum was analyzed with the novel method by varying the data to [-4.13, 3.50] and declining μ from 2.0 and compared with the result acquired by wavelet analysis. The results show that the novel method can greatly increase the SNR of input signal easily to detect the weak signal. With the deep research of the theory of stochastic resonance and improvement of the new method, it will probably become a power tool to analyze spectrum.
    Determination of Amines by Capillary Electrophoresis with Pulse Voltammetric Detector
    WANG Li-Shi, YANG Xiao-Yun, MO Jin-Yuan
    2000, 21(1):  56-58. 
    Asbtract ( )   PDF (173KB) ( )  
    Related Articles | Metrics
    The determination of five aromatic amines was studied using capillary electrophoresis with pulse voltammetric detector. The D/A converter at an EVOC PLC-711B Card was used to generate the pulse electrode potential waveform. The A/D converter acquired the electrode current at the last one millisecond of every pulse. Good reproducibility and low limit were obtained. The results shown that pulse voltammetric detection has the advantages of elimination of charge current and direct identification of unknown chemicals.
    Studies of the New Chemiluminescence System-NaIO4-H2O2-Trace Cyclohexane-Polyhydrophenols and Its Application
    YE Lei, ZHANG Guo-Fang, CHEN Hong-Yuan
    2000, 21(1):  59-61. 
    Asbtract ( )   PDF (162KB) ( )  
    Related Articles | Metrics
    The chemiluminescence (CL) generated from the hydrogen peroxide oxided by periodate could be enhanced differently by polyhydrophenols, such as pyrogallol, phloroglucinol, pyrocatechol, resorcinol and parodioxybenzene. Furthermore, the CL could be improved in the presence of the trace non-polar organic solvent, the possible mechanism was proposed. Based on which a sensitive CL method for polyhydrophenols has been built. The linear ranges of determination for pyrogallol, phloroglucinol, pyrocatechol, resorcinol and parodioxybenzene were 1×10-5～2×10-7mol/L, 1×10-3～1×10-5mol/L, 1×10-4～6×10-6mol/L, 1×10-3～2×10-5mol/L and 1×10-3～6×10-5 mol/L, respectively, and their detection limits were 7.2×10-8mol/L, 6.8×10-6 mol/L, 2.1×10-6mol/L , 7.1×10-6mol/L and 2.2×10-5mol/L respectively.
    Immobilization of STI on Polymerized Liposome by Inter Arm and Its Affinity Adsorption for Trypsin
    ZHANG Wen-Tao, YU Kai, SUN Yan
    2000, 21(1):  62-65. 
    Asbtract ( )   PDF (202KB) ( )  
    Related Articles | Metrics
    Soybean trypsin inhibitor(STI) was immobilized on polymerized liposome of pentacose-10,12-diene-1-ol-phospho ethanolamine by diglycolic anydride, glutaraldehyde and 1,4-butanediol diglycidyl ether. In the course of precipitation, 20% to 60% trypsin does cleavage from PL-STI and shows PL-STI can be used as the affinity precipitation adsorbent of enzyme.
    Determination of One-electron Reduction Potentials of Podophyllotoxin and Its Derivatives by Pulse Radiolysis
    WANG Shi-Long, WANG Mei, SUN Xiao-Yu, ZHANG Chao-Jie, MA Xiu-Wen, NI Ya-Ming, YAO Si-De, WANG Wen-Feng
    2000, 21(1):  66-69. 
    Asbtract ( )   PDF (494KB) ( )  
    Related Articles | Metrics
    One-electron reduction potential is one of the important parameters of radiosensitive compound with a high electron affinity. In this work one-electron reduction potentials of podophyllotoxin and its derivatives were determined by pulse radiolysis using duroquinone as references. The one-electron reduction potentials of podophyllotoxin, 4'-demethylepipodophyllotoxin(DMEP) and etoposide (VP-16) are -310 mV, -339 mV, -334 mV, respectively.
    Studies on Carbohydrates(ⅩⅩⅪ)——Synthesis of Spacer-armed Lactoses and Their Dimers
    LI Qing, CAI Meng-Shen, LI Zhong-Jun, ZHOU RouLi
    2000, 21(1):  70-73. 
    Asbtract ( )   PDF (325KB) ( )  
    Related Articles | Metrics
    Octaacetyllactose was used as glycosylation donor which reacted with diethylene glycol or triethylene glycol to give corresponding spacer-armed lactoses and dimers 2, 3, 6, 7, then they were deprotected to give target compounds 4, 5, 8, 9 which can be used for studies on anti-tumor metastasis as well as relationship of structure-activity.
    A Facile Synthesis of Dallacker Bislactone
    FU Bin, ZHAO Chen, ZHANG Pang
    2000, 21(1):  74-78. 
    Asbtract ( )   PDF (1297KB) ( )  
    Related Articles | Metrics
    Dihydro-9,9,10,10-bis(propiono-γ-lactono)-phenanthrene was synthesized by five steps of reaction with an overall yield of 24%, 7% better than Dallacker synthesis in eight steps. Ethyl 3-(o-iodobenzoyl)propionate was also synthesized from o-iodobenzoyl chloride and triethyl ethane-1,1,2-tricarboxylate in two steps of reaction with an overall yield of 43%, 13% better than the above synthesis. The acylation of triethyl ethane-1,1,2-tri-carboxylate by diphenoyl chloride was also studied and reasonably good yields obtained.
    Reductive Cyclization Initiated by an NAD(P)H Model——Synthesis of 2,2-Disubstituted Indanes
    WANG Hong-Yi, LIU You-Cheng, GUO Qing-Xiang
    2000, 21(1):  79-81. 
    Asbtract ( )   PDF (378KB) ( )  
    Related Articles | Metrics
    A facile synthesis of 2,2-disubstituted idanes was achieved by the reductive cyclization of 1-(o-bromomethylphenyl)-2,2-disubstituted-ethylenes(electron-withdrawing substituents) with an NAD(P)H model, 1-benzyl-1,4-dihydronicotinamide, in yields from moderate to good. The study revealed that 1-benzyl-1,4-dihydronicotinamide can be used in synthetic organic chemistry as an effective reductant.
    Studies on the Metallothionein Polymerization in Different Buffers
    HOU Ting-Jun, AN Yu, BI Ru-Chang, RU Bing-Gen, XU Xiao-Jie
    2000, 21(1):  82-84. 
    Asbtract ( )   PDF (160KB) ( )  
    Related Articles | Metrics
    In this paper, the naturally occurred polymerization for rabbit metallothionein monomers has been studied in different milieu, while leaves out the aggregation caused by the oxidation of cysteine, since the latter circumstance was the result of purification lapsus. After the purification of metallothionein monomers, dynamic light scattering technique is used to detect the polymerized states of rabbit liver metallothionein Ⅰ and Ⅱ in different buffers, which is the first systematical detection of polymerized states of MTs in solutions. The effects of different factors contributing to methothionein aggregations have been investigated by computational simulations. The calculation results showed that the metallothionein polymerization would be regulated by many factors including electrostatic interactions, hydrophobic interactions and different ions in buffers. A molecular recognition mechanism of MTs' polymerization in solutions is proposed on the bases of experimental results and theoretical calculations.
    The Influence of Water Molecules in the Structure-activity Relationship Study of Sulfonylurea Molecules
    MA Yi, LIU Jie, LI Zheng-Ming
    2000, 21(1):  85-87. 
    Asbtract ( )   PDF (167KB) ( )  
    Related Articles | Metrics
    A study of some sulfonylurea molecules with consideration of water molecules as its solvent was undertaken. The influence of the water molecules on the structure-activity relationship of the 35 sulfonylurea molecules was discussed . By supper-imposition of structural sulfonyl molecules, a molecular RMS was correlated with pI50, which denotes that the configuration difference in water solution is one of the reasons which causes the difference in bioactivity.
    Studies on the Optical Stability of Chiral Compounds in EI Mass Spectrometry Process
    WU Yi-Nan, PAN Yuan-Jiang, CHEN Yao-Zu
    2000, 21(1):  88-90. 
    Asbtract ( )   PDF (159KB) ( )  
    Related Articles | Metrics
    The optical stability of chiral 2-hydroxy-2-phenylacetic acid in electron ionization mass spectrometry(EIMS) process has been detected directly by deuterium labelling technique. From the EI mass spectrum of deuterated 2-hydroxy-2-phenylacetic acid, the major characteristic fragment ion at m/z 108(the capture of the carbonyl group) and the corresponding isotopic ion(13C) at m/z 109 can be observed, and the ratio of m/z=109 to m/z=108 is about 8%(the calculated value is 7.8%). As enolization of deuterated 2-hydroxy-2-phenylacetic acid in mass spectrometry can yield the characteristic fragment ion at m/z 109 and results in much higher ratio of 109/108 than 8%; this study shows that no enolization takes place during the EI-MS process of 2-hydroxy-2-phenylacetic acid. This results can be concluded that these compounds are optically stable in the process of instantaneous vaporization at high temperature and electron impact ionization.
    Enhancement Effect of Hydrophilic Au and Hydrophobic SiO2 Nanoparticles on Glucose Biosensor Sensitivity
    TANG Fang-Qiong, WEI Zheng, CHEN Dong, MENG Xian-Wei, GOU Li, RAN Jun-Guo
    2000, 21(1):  91-94. 
    Asbtract ( )   PDF (433KB) ( )  
    Related Articles | Metrics
    The construction of glucose biosensor by immobilization of glucose oxidase(GOD) on the surface of hydrophilic Au and hydrophobic SiO2 nanoparticles is reported, and polyvinyl butyral(PVB) is used as auxiliary immobilization enzyme matrix. The data of the current response of enzyme electrodes containing hydrophilic Au and hydrophobic SiO2 nanoparticles to glucose are obtained. The experiments show that the nanoparticle would have a very strong enhancement effect on the GOD electrode response sensitivity. A mechanism for the behavior of the different kind of nanoparticles is proposed. The experiment and theory proved the function of nanoparticles in immobilization enzyme. This report provides experimental and theoretical basis for preparing the useful glucose biosensor.
    Textural Characterization of SiO2-PEG Xerogels
    SUN Ji-Hong, GONG Yan-Jun, FAN Wen-Hao, WU Dong, SUN Yu-Han
    2000, 21(1):  95-98. 
    Asbtract ( )   PDF (555KB) ( )  
    Related Articles | Metrics
    The porous SiO2 xerogels with controlled structure were obtained from TEOS in the presence of PEG by sol-gel method. The results showed that PEG restrained the hydrolysis reaction of TEOS, and then modified the surface of sol particle to form the PEG-clusters (i.e. the ring-like networks in short order). As a result, the addition of PEG could adjust the texture properties of SiO2 xerogels. It has been found that the SiO2 xerogel has a stronger flexible skeleton, narrower pore distribution, and higher thermal stability with the removal of the residue organic(such as PEG and so on) by vacuum heat-treatment.
    High Level Ab Initio MO Study on the H2O Interacting with N2
    ZHANG Yu, WANG Yi-Bo, SUN Ze-Min, TIAN An-Min
    2000, 21(1):  99-104. 
    Asbtract ( )   PDF (2404KB) ( )  
    Related Articles | Metrics
    Ab initio molecular orbital calculations including MP2 correlation energy have been employed to optimize the geometries of the H2O and N2 complexes by using 6-311++G(3d,3p) basis set. It was found that a stable minimized structure has a nearly linear hydrogen bonded geometry, the binding energy of which was calculated by use of MP2, MP4SDTQ and CCSD(T) methods by using 6-311++G(3d,3p) basis set adding mid-bond function (3s3p2d1f). The calculated binding energy is -5.061 kJ/mol at the MP4SDTQ and -4.715 kJ/mol at the CCSD(T) level.
    Improvement of Fitting Calculation About Shil'nikov Chao
    LU Ling, LI Cheng-Ren
    2000, 21(1):  105-107. 
    Asbtract ( )   PDF (180KB) ( )  
    Related Articles | Metrics
    Fitting calculation about Shil'nikov chaotic behavior of system performed on electrodissolution of Cu in a H2SO4/NaCl solution is improved, and the Lyapunov index is obtained. It is proved that there exists a chaotic attractor in this system. The chaotic attractor of the numerical simulation is consistent with the experimental one.
    Oxidation of Naphthol with Hydroperoxide Catalyzed by Metalloporphyrins(Ⅱ) ──Mechanism for Preparation of 2-Hydroxy-1,4-naphthaqinone
    YAN Yan, TONG ShanLing, GUO Kui, ZHENG GuoDong, ZHEN KaiJi, FANG Chi-Guang, CHANG Xin, LI Qing
    2000, 21(1):  108-111. 
    Asbtract ( )   PDF (547KB) ( )  
    Related Articles | Metrics
    With hydrogen peroxide as oxidant, we got a high selectivity of 2-hydroxy-1,4- naphthaqinone from 1- and 2-naphthol in methanol solution containing sodium hydroxide at low temperature. A series of tetraphenylporphyrin ferron chloride and its corresponding substitutes are employed as catalysts. By determination of UV-Vis and EPR spectra in situ, a probable mechanism model was established.
    Isomerization of n-Butane over the Catalysts of SO4/ZrO2-Al2O3 and Pt-SO4/ZrO2-Al2O3
    ZHANG Yu-Ling, BI Ying-Li, CHUI Xiang-Hao, CHENG Tie-Xin, LI Wen-Xing, ZHEN Kai-Ji
    2000, 21(1):  112-115. 
    Asbtract ( )   PDF (250KB) ( )  
    Related Articles | Metrics
    The effects of the conditions such as calcination time and temperature for preparing solid superacid catalysts, SO4/ZrO2-Al2O3(SZA) and Pt-SO4/ZrO2-Al2O3, on their surface structure and crystallizability were studied. The reaction performance of the catalysts mentioned above for isomerization of n-butane was examined using pulse technique. The results showed that addition of Al2O3 could increase the catalytic activity and selectivity, and decrease the reaction temperature for getting the same activity; addition of Pt to SZA could increase the catalyst catalytic activity and stability more effectively.
    Studies of Peroxodisulfated Zirconia Solid Superacid
    ZHANG Li, WANG Lin, CHEN Jian-Min
    2000, 21(1):  116-119. 
    Asbtract ( )   PDF (996KB) ( )  
    Related Articles | Metrics
    The preparation of peroxodisulfated zirconia(PSZ) solid strong acid catalysts is introduced. It showed more active than sulfated zirconia (SZ) for n-butane isomerization at ambient temperature. Peroxodisulfate is the first type of nonhalide found to be more efficient than sulfate which so far has been found the best one promoted zirconia. The optimum calcination temperature is 600 ℃, which is 50 ℃ lower than that of SZ. The conversion of n-butane over PSZ was 50.4% during 20 h and at 35 ℃, and 36.7% over SZ under the same condition. According to X-Ray differential, TEM, BET and chemical analysis, it can be concluded that the formation of superacids over PSZ is similar to that over SZ. It is worth to point out the particle sizes of PSZ calcined between 500 ℃ and 800 ℃ are in the range of nanometers, and the optimum PSZ has both tetragonal and limited monoclinic zirconia.
    Studies on Coupling of Methane under Pulse Corona Plasma(Ⅲ)——Heterogeneous Catalysis of Metal Oxides
    ZHU Ai-Min, ZHANG Xiu-Ling, GONG Wei-Min, ZHANG Bao-An
    2000, 21(1):  120-123. 
    Asbtract ( )   PDF (1486KB) ( )  
    Related Articles | Metrics
    Under pulse corona plasma, heterogeneous catalysis of metal oxides upon the dehydrogenative coupling of methane was examined. In the presence of pulse corona plasma, the tested materials show various catalytic activities and adjust distribution of C2 products to a certain extent. Comparing the results with a blank γ-Al2O3 carrier, the C2 yield of a loaded γ-Mn2O3/γ-Al2O3 catalyst under plasma is nearly three times as large as the former and the C2 selectivity increases over 30 percent. Combined pulse corona plasma with it, the energy efficiency increases by a factor of 3 at least. Finally, a tentative model for the dehydrogenative coupling of methane under plasma over the catalyst is proposed.
    An ESR Investigation of the Intermediate Obtained from Oxidation of Sodium Hypophosphite in the Process of Electroless Nickel Deposition
    KUANG Ya-Fei, WANG Mei-Yuan, LI Guo-Xi, HUANG Shu-Kun
    2000, 21(1):  124-126. 
    Asbtract ( )   PDF (164KB) ( )  
    Related Articles | Metrics
    The radical intermediate, which is produced in the process of electroless nickel plating, was detected in the presence of water-soluble trap α-4-pyridy1-N-tert-buty1 nitrone(POBN) or α-phenyl-tert-buty1 nitrone(PBN) by electron spin resonance(ESR) spectroscopy. The results obtained indicated that a 16-line(g=2.006 1, aβC—H=1.98×10-4 T, aγP—H=3.32×10-4 T, aN=aP=15.93×10-4 T) or a 18-line (g=2.004 9, aβC—H=aγP—H=2.38×10-4 T, aP=17.72×10-4 T, aN=16.20×10-4 T) ESR spectrum was observed in the process of electroless nickel plating when spin trap PBN or POBN was added. The spectra-line patterns and hyperfine coupling parameters were greatly indentical with those in the solution composed of Ti3+(0.01 mol/L)+H2O2(0.05 mol/L)+H2PO2-(0.01 mol/L)+POBN or PBN(0.01 mol/L). Therefore, the spin adducts formed in the process of electroless nickel plating could be ascribed to the adducts belonging to HPO2-· and POBN or PBN and it follows that the anion radical HPO2-·was really produced from the oxidation of sodium hypophosphite in the process of electroless nickel plating.
    Quantum Chemical Study on The Thermolyses of o-Aminobenzoyl Azide and Its Derivatives
    XU Wen-Yuan, HONG San-Guo, TANG Zhi-Gang, LI Yong-Hong
    2000, 21(1):  127-129. 
    Asbtract ( )   PDF (1182KB) ( )  
    Related Articles | Metrics
    UHF/AM1 method has been applied to study the thermolyses of o-aminobenzoyl, o-amino-p-methylbenzoyl, o-amino-p-formalbenzoyl azides. The results obtained show that these reactions proced through various competing routes yielding to different products, and the activation energy of the rate-determining steps of routes (2)—(4) are lower than that of route(1).
    Molecular Thermodynamic Model of Polyelectrolyte Solutions Without Adding Salt
    CAI Jun, LIU Hong-Lai, HU Ying
    2000, 21(1):  130-132. 
    Asbtract ( )   PDF (796KB) ( )  
    Related Articles | Metrics
    A molecular thermodynamic model for polyelectrolyte solutions without the added salt has been developed in this work. It includes three contributions. The first term is the contribution from the mixture of charged hard spheres which is determined by using Blum′s MSA model. The second term is that from bonding of polyion segments which is calculated through two-particle cavity correlation function accounting for the correlation in the nearest-neighbour segments of polyion. The third term accounts for the stickiness between the polyion and its counterions beyond the territorial binding. Thermodynamic properties of polyelectrolyte solution can be described satisfactorily.
    Direct Electrochemical Synthesis of Metal Alkoxides
    CHU Dao-Bao, ZHOU Xing-Fu, LIN Chang-Jian, TAN Jian-Guang
    2000, 21(1):  133-135. 
    Asbtract ( )   PDF (436KB) ( )  
    Related Articles | Metrics
    The direct electrochemical synthesis of metal alkoxides [Ti(OEt)4, Ti(OPr-#em/em#)4, Ti(OBu)4, Ti(OEt)2(acac), Cu(OEt)2, Cu(OBu)2, Mg(OEt)2 and Ni(OEt)2] were studied by anode dissolution of metals in absolute ethanol in the presence of a conductive additives. The anodic behaviour of Ti electrode in ethanol was investigated by using cyclic voltammetry(CV). These metal alkoxides were characterized by FTIR spectra. The results show that direct electrochemical synthesis of metal alkoxides have a high current efficiency and electrolysis yield. These alkoxides have a high purity and can be directly used as the precursor of nanosize oxides prepared by sol-gel procedure. The anodic behaviour of Ti electrode in alcohol is markedly the feature of the pitting corrosion. The passivation of Ti anode would occur in the presence of trace water.
    Studies of Phase Behavior in Blends of PS/PMMA/SAN By Using Flory′s Equation of State Theory
    TANG Ping, LI Guang-Xian
    2000, 21(1):  136-139. 
    Asbtract ( )   PDF (1502KB) ( )  
    Related Articles | Metrics
    Modified Flory′s equation of state theory(EOS) was extended to study the phase behavior of ternary blends PS/PMMA/SAN containing a copolymer. EOS parameters(the characteristic parameters) for copolymer SAN were evaluated from those for the constituent monomer segments by using proper combining rules, and binary segmental interaction energy density parameters between homopolymer and copolymer were computed by using simple binary interaction model. The phase behavior of the ternary blend PS/PMMA/SAN was predicted overa wide temperature range and the calculated Spinodal curves agreed satisfactorily with the experimental data.
    Synthesis and Characterization of Poly(tetrahydrofuran) Triol
    XU Yi-Jin, PAN Cai-Yuan
    2000, 21(1):  140-143. 
    Asbtract ( )   PDF (204KB) ( )  
    Related Articles | Metrics
    New oxacarbenium perchlorate, C2H5C(CH2OCH2CH2CO+ClO4-)3, was synthesized and used in the preparation of poly(tetrahydrofuran) (PTHF) triol. The product structure was determined by 1H NMR and FTIR. GPC curves show that the cyclic oligomers were negligible. Molecular weight and distribution of branch chain were obtained by analyzing the hydrolyzed products of PTHFs. All the results demonstrate that PTHF triol was obtained, both inter- and intra-molecular chain transfer reactions were negligible and molecular weight could be controlled.
    Preface
    Studies on Microemulsion formed by Polymer Surfactants Based on Carboxy Methyl Cellulose
    YU Xiao-Qiang, LI Yao-Xian, WANG Jing-Yuan, LI Feng, MENG Yan, TANG Xin-Yi, SUN Chia-Chung
    2000, 21(1):  144-146. 
    Asbtract ( )   PDF (359KB) ( )  
    Related Articles | Metrics
    Polymeric surfactants were prepared by ultrasonic copolymerization of carboxy methyl cellulose (CMC) and alkyl poly(etheroxy) acrylate. The polymeric microemulsion was prepared by mixing polymeric surfactants aqueous solution, toluene and alcohol at given ratios. The results of dynamic laser scattering indicated that the microemulsion droplets have almost same size and conformation, and the size of polymeric microemulsion particles, which is much bigger than that of low molecular weight surfactants, is beyond the limit of microemulsion definition. But the systems are still thermodynamically stable. The results of isotope tracer analysis indicated that more and more alcohol molecules insert to the interface of oil and water, changes the interfacial structure of phases and finally help microemulsion formed. The whole structure of microemulsion is oil core surrounded by water. The formation of reverse micelles is shown to be unlikely even in toluene-rich region.
    Articles
    Emulsion Copolymerization of MMA/BA in the Presence of Surface Active Monomers(Ⅱ)——Kinetics and Polymerization Mechanism
    ZHANG Mao-Gen, WENG Zhi-Xue, HUANG Zhi-Ming, PAN Zu-Ren
    2000, 21(1):  148-151. 
    Asbtract ( )   PDF (1752KB) ( )  
    Related Articles | Metrics
    The effects of the amount of surface-active monomers [sodium sulfonated lauryl(allyl glyceryl) succinate, ZC-L] on the polymerization rate and latex particle size in MMA/BA emulsion copolymerization were investigated. The change of average particle size and particle size distribution during the polymerization process was determined with Coulter LS 230 laser particle size analyzer, and compared with those of MMA/BA emulsion polymerization in the presence of sodium dodecyl benzene sulfonate and MMA/BA emulsifier-free emulsion polymerization. The nucleation mechanism is believed to be homogeneous nucleation when [ZC-L]<CMC, and the particles formed are stabilized by the coagulation of the particles each other to increase the surface charge density; the nucleation mechanisms include homogeneous nucleation and micelle nucleation when [ZC-L]>CMC, and the particles are stabilized by absorption of surfmers from the system.
    Emulsion Copolymerization of MMA/BA in the Presence of Surface Active Monomers(Ⅲ)——Latex Stability
    ZHANG Mao-Gen, WENG Zhi-Xue, HUANG Zhi-Ming, PAN Zu-Ren
    2000, 21(1):  152-155. 
    Asbtract ( )   PDF (1855KB) ( )  
    Related Articles | Metrics
    The latex stabilities of MMA, BA and MMA/BA emulsion polymerization in the presence of two homemade surface-active monomers(Surfmers) [sodium sulfonated lauryl(allyl glyceryl) succinate(ZC-L) and sodium sulfonated lauryl(methacryloyl glyceryl) succinate(ZD-L)] were investigated. Excellently stable PMMA, PBA and P(MMA/BA) latexes with no free emulsifiers and solid content over 40% were prepared.
    Studies on Particle Size Distribution and Nucleation Mechanism of St/BA Miniemulsion Polymerization with Redox Initiators
    ZHANG Hong-Tao, TAN Bi-En, HU Fang, LI Jiang-Zong
    2000, 21(1):  156-159. 
    Asbtract ( )   PDF (449KB) ( )  
    Related Articles | Metrics
    Miniemulsion copolymerization of styrene/butyl acrylate was investigated by redox initiator(NH4)2S2O8/NaHSO3 at lower temperature and contrasted it to convention emulsion polymerization. Monomer droplet of the former is several ten times of microns(5~20 μm), and that the latter is in the range of submicron(100~400 nm). The change of particle size and distribution in polymerization process were determined in miniemulsion polymerization process. It is fuond that the particle size decreased with increasing of surfactant, cosurfactant, initiator concentration, but the distribution became wider. In addition, it is bigger than convention emulsion polymerization. The changes rule of particle number and the surfactant-covering ratio were calculated. The effects of initiator and emulsifier on polymerization process and the difference of nucleation mechanism between miniemulsion and conventional emulsion were discussed.
    Studies on Microemulsion formed by Polymer Surfactants Based on Carboxy Methyl Cellulose
    CAO Ya, LI Hui-Lin
    2000, 21(1):  160-164. 
    Asbtract ( )   PDF (1632KB) ( )  
    Related Articles | Metrics
    Polymeric surfactants were prepared by ultrasonic copolymerization of carboxy methyl cellulose (CMC) and alkyl poly(etheroxy) acrylate. The polymeric microemulsion was prepared by mixing polymeric surfactants aqueous solution, toluene and alcohol at given ratios. The results of dynamic laser scattering indicated that the microemulsion droplets have almost same size and conformation, and the size of polymeric microemulsion particles, which is much bigger than that of low molecular weight surfactants, is beyond the limit of microemulsion definition. But the systems are still thermodynamically stable. The results of isotope tracer analysis indicated that more and more alcohol molecules insert to the interface of oil and water, changes the interfacial structure of phases and finally help microemulsion formed. The whole structure of microemulsion is oil core surrounded by water. The formation of reverse micelles is shown to be unlikely even in toluene-rich region.
Special Issues
More...
Download
More...
Links
More...