Table of Content

24 October 2000, Volume 21 Issue 10

Previous Issue    Next Issue

Articles

Preparation and Characterization of SAPO-34 and SAPO-44 Molecular Sieves Membranes

LIU Yun-Ling, WANG Xing-Dong, PANG Wen-Qin

2000, 21(10):  1451-1454. 

Asbtract ( )   PDF (234KB) ( )  

Related Articles | Metrics

Molecular sieve membranes consisting of SAPO-24 and SAPO-44 molecular sieve crystals have been hydrothermally prepared on the ceramic substrate in the Al₂O₃-SiO₂-H₃PO₄-H₂O-amine system. X-ray diffraction verified the presence of the pure molecular sieve phases on the substrate, and the SEMshowed that the SAPO-34 and SAPO-44 molecular sieve crystals had grown together to form a continuous molecular sieve layer. The influences of silica content, HFcontent, pHvalue in the memberanes formations have been studied.

Syntheses and Spectral Properties of Two Complexes of Isonitrosoacetylacetone- N -arylimine and Crystal Structure of PdCl(C₆H₅-IAI)(C₆H₅NH₂)

FENG Yun-Long, LIU Shi-Xiong

2000, 21(10):  1455-1458. 

Asbtract ( )   PDF (218KB) ( )  

Related Articles | Metrics

Two complexes of isonitrosoacetylacetone-N-arylimine, PdCl(C₆H₅—IAI)(C₆H₅NH₂)(1) and PdCl( p-CH₃C₆H₄—IAI)( p-CH₃C₆H₄NH₂)(2), were synthesized and characterized by IRand Raman spectroscopy. Complex 1 crystallizes in orthorhombic system, space group Pca 21, with parameters a =1.8587(4) nm, b =0.9380(2) nm, c =2.1237(4) nm, V =3.702(1) nm³, D_c=1.572 g/cm³, Z =8, F (000)=1760 , μ =1.160 mm^-1 . The final R₁ value is 0.0271 for 3592 observed reflections with I≥2σ(I) . The Pd(Ⅱ) ion has a distorted square-planar PdN₃Cl coordination composed of imino-nitrogen and oximo-nitrogen from the Schiff base ligand, amino-nitrogen from aniline and chlorine anion. The oxime group of the Schiff base ligand is coordinated to the Pd(Ⅱ) through its oximo-nitrogen atom, but not its oximo-oxygen-atom. The ν_C=O and ν_C=N bands display a shift to lower frequencies and ν_N-O bands to higher frequencies in IRand Raman spectra. There are π-π^* transition and d-π^* charge transfer transition in electronic spectra.

EXAFS Study of Ni/W/Zeolite/Al₂O3 Hydrocracking Catalyst Sulfurized with Different Modified Zeolites

ZHANG Jian, LU Hai-Long, SUN Jian-Wei, YAO Jian-Dong, LI Quan-Zhi, GUAN Ming-Hua, WANG Ji-Feng, DING Lian-Hui, YIN Ze-Qu, HU Tian-Dou, XIE Ya-Ning

2000, 21(10):  1459-1463. 

Asbtract ( )   PDF (445KB) ( )  

Related Articles | Metrics

Four hydrocracking catalysts supported on different kinds of modified Y zeolites were studied by utilizing EXAFS(Extend X-ray Absorption Fine Structure).The results show that the Ni and W in the catalysts have not been thoroughly sulfided. Apart from the sulfided state，the tungsten in the sulfided catalysts exists in a state of oxosulfided tungsten while some nickels exist in their oxide state. In addition，it also shows that there are NiWS species in the sulfided catalysts and the amount of which shows a good cor-relation with the Bronsted acid sites of the mixture supports of zeolites and γ-Al₂O₃.It means that the Ni-WS species maybe exist mainly in the cavities of the zeolites and the tungsten in micropore zeolites is more difficult to be sulfided than that on the surface of amorphous Al₂O₃.

Synthesis and Structure of Molybdenum citrato Cluster μ₂-S Bridge

LI Dong-Mei, LI Ya-Feng, XING Yong-Heng, WANG Ren-Zhang, LIU Shu-Qing, SUN Hao-Ran, WANG Tie-Gang, XU Ji-Qing, XING Yan, LIN Yong-Hua, JIA Heng-Qing

2000, 21(10):  1464-1467. 

Asbtract ( )   PDF (476KB) ( )  

Related Articles | Metrics

Anew molybdenum-citrato cluster containing [Mo₂O₂( μ-S)₂(C₆H₅O₇)(C₆H₄O₇)]^5- anion was synthesized and characterized by elemental analysis, IR, UV-Vis spectra, XPS and X-ray diffraction. The parameters of the crystal structure of the compound are monoclinic, space group P2₁/c, a =2.3766(5) nm, b =1.3274(3) nm, c =2.2471(5) nm, β =118.21°, V =6.247(2) nm³, Z=8, D_c=2.128 g/cm³, F(000)=3984, μ =1694 cm^-1 , R=0.0831 and R_2,w=0.1549. The anion is binuclear molybdenum citrato complex with μ₂-S bridge. Each molybdenum atom pocesesses a distorted octahedral struture, which is coordinated with a terminal oxygen, two sulfur atoms, three oxygen atoms of hydroxyl, α-carboxylate, β-carboxylate from citrate.

Synthesis and Structure Determination of Seven coordinate K[In^Ⅲ(Hdtpa)]·3.5H₂O

WANG Jun, MA Rui, GAO Jing-Qun, LIU Jian-Guo, SONG Xi-Ming

2000, 21(10):  1468-1470. 

Asbtract ( )   PDF (203KB) ( )  

Related Articles | Metrics

In this paper, the title complex K[In^Ⅲ(Hdtpa)]·3.5H₂O(dtpa=diethylenetriaminepentaacetic acid) was synthesized and its crystal structure was determined by single crystal X-ray structure analysis. The crystal belongs to monoclinic system, P2₁/ c (No.14) space group with a =0.9781(2) nm, b =0.7338(1) nm , c =2.9629(6) nm, β =91.81(3)°, V =0.2126(1) nm³, Z =4, M =606.31, D_x=1.895 g·cm^-3, μ =1.3821 mm^-1 , F (000)=1228, R =0.035 and R_w=0.041 for 2802 unique reflections. The complex anion [In^Ⅲ(Hdtpa)]^- has a pseudo-monocapped trigonal prismatic seven-coordination structure in which the seven coordinate atoms, three Nand four Oatoms, are all from a ligand dtpa. In addition, it can be seen that the complex anion [In^Ⅲ(Hdtpa)]^- can furnish a free carboxyl group(—CH₂COOH) being used for molecular embellishment to form the target diagnosis-and treat-drug of anticancer.

Controlled Synthesis of Semiconductor Nanocrystalline CdS by Living Biomembrane

WU Qing-Sheng, ZHENG Neng-Wu, DING Ya-Ping, LI Ya-Dong

2000, 21(10):  1471-1472. 

Asbtract ( )   PDF (158KB) ( )  

Related Articles | Metrics

Anew synthetical method for nanomaterials was developed, and the semiconductor nanocrystalline CdSwas fabricated through controlling of the living biomembrane in bean sprouts. The results indicated that approximately spherical CdSparticles about 5.1 nm, which has a cubic zinc-blende structure with a cell constant a =0.5818 nm, could be formed after the bean sprouts were successively soaked in 0.1 mol·L^-1 Na₂S and 0.1 mol·L^-1 CdCl₂ for 24 h. In addition, the tentative research for the reaction mechanism has been carried out.

Studies on Quantitative Structure-activity Relationships of Benzodiazepines Using Fuzzy Neural Networks

LIU Ping, CHENG Yi-Yu

2000, 21(10):  1473-1478. 

Asbtract ( )   PDF (274KB) ( )  

Related Articles | Metrics

In this paper, a new fuzzy neural network based on genetic algorithms is proposed for quantitative structure-activity relationship(QSAR) studies of benzodiazepines. The method based on GA+FL+NNallows supervised learning of fuzzy rules from significant examples and is affected unsusceptibly by the problem of local extremes. The network's knowledge base has a linguistic representation. This makes it easy for pharmaceutical chemists to understand and interpret. It is possible to introduce current knowledge acquired by researchers simply by adding one or more fuzzy rules to the network's knowledge base. Once the fuzzy knowledge base extracted from examples, it can predict the pharmacological activity of compounds at a high precision. The obtained fuzzy rules can also provide useful guidelines for synthesizing new compounds with a high pharmacological activity.

Three-dimensional Quantitative Structure-activity Relationship of the Opioid Antagonist with Potent Anorectant Activity of 3,4-Dimethyl-4-(3-hydroxyphenyl)piperidine

LI Hua, XU Lu, SU Qiang

2000, 21(10):  1479-1483. 

Asbtract ( )   PDF (1173KB) ( )  

Related Articles | Metrics

A series of 3,4-dimethyl-4-(3-hydroxyphenyl)piperidine opioid antagonists with varying substituents on the nitrogen were evaluated for their effect on food consumption in obese Zucker rats. In developing three-dimensional quantitative structure-activity relationship(3D-QSAR) studies for this series of opioid antagonists, different structure alignments have been tested to predict the anorectant activities. The interaction energies between molecules and the probe atom were then correlated with anorectant activity using partial least squares(PLS) method. The steric and electrostatic features of the 3D-QSAR were presented in the form of standard deviation coefficient contour maps of steric and electrostatic fields. The results showed that 3D-QSA Rresults are much better than the results obtained by 2D-QSAR.

The Analysis of Electrolysis Process of the Aniline Using Chemometrics Method

WANG Ya-Yun, LI Tong-Hua, CONG Pei-Sheng, ZHU Zhong-Liang

2000, 21(10):  1484-1487. 

Asbtract ( )   PDF (208KB) ( )  

Related Articles | Metrics

In this paper using a variety of chemometrics methods such as PCA(Principle component analysis), HELP(Heuristic evolving latent projections), GA(Genetic algorithm) on the data matrix of the UV Vis spectra of mixture samples, we obtain the UV-Vis spectrum of one substance and the dynamic curve of another substance. We design a set of regressions to analyze this black system, and demonstrate in detail the unavoidable problem of the unique solution. With the simulated data the analytical results prove the correctness and accuracy of the regression. Finally a preliminary study was made on the electrolytic process of aniline, in which the UV-Vis spectra and the dynamic curves of aniline and intermediale are calculated.

The Relationship Between Resonance Scattering Intensity and the Size of Au Particles

JIANG Zhi-Liang, LI Fang, LI Ting-Sheng, LIANG Hong

2000, 21(10):  1488-1490. 

Asbtract ( )   PDF (921KB) ( )  

Related Articles | Metrics

Au particle of the size in the range of 10—189 nm has been prepared by sodium citrate procedure. The resonance scattering spectra of Au particle have been studied. The nanoparticle solutions of the size in the range of 10—95 nm exhibit red in colour. Their maxmum absorption wavelenth are in the range of 517.8—533.3 nm. The absorption peak shifts to the red with the size increasing. The maxmum resonance scattering peak is at 580 nm. The cube root of the intensity at 580 nm is proportional to the size of Au particles.

Analytical Application of Light Scattering Probe of Organic Dyes

WANG Ya-Ting , ZHAO Feng-Lin, LI Ke-An, TONG Shen-Yang

2000, 21(10):  1491-1497. 

Asbtract ( )   PDF (843KB) ( )  

Related Articles | Metrics

The application of light scattering probe with organic dyes to the determination of protein, nucleic acids and metal ions were reviewed on the basis of the work of our research group. The experimental phenomena were explained using the principle of light scattering and the theory of resonance enhanced light scattering of organic dyes. The structural characteristics of the potential dye-probes for protein analysis and nucleic acids analysis were foreseen.

Preparation of Novel pH Sensitive Phase Separating Polymers and Its Application in Fluorescence Immunoassay

YANG Huang-Hao, ZHU Qing-Zhi, LI Dong-Hui, CHEN Xiao-Lan, DING Ma-Tai, XU Jin-Gou

2000, 21(10):  1498-1500. 

Asbtract ( )   PDF (171KB) ( )  

Related Articles | Metrics

Poly( N-isopropylacrylamide methylacrylic acid)[P(NIP-co-MAA)], a linear water-soluble pHprecipitating synthetic polymer, was used as a novel separating carrier for the reactants in immunoassay. The P(NIP-co-MAA) precipitates out of water below a critical pH 5.6 at 37 ℃, and redissolved when the solution pHis above 6.1. This characteristic of the P(NIP-co-MAA) made it possible to carry out the immunochemical steps of the assay in true solution and then to quickly separate the resulting procucts from the reaction mixtures. The above approach was applied to an assay for the sandwich immunoassay of hepatitis Bsurface antigen(HBsAg). Sensitivity of this method was close to that of traditional ELISAusing same reactants. However, the assay was much faster(assay time decreased from 100—120 min to 45 min). This method has been applied to the determination of the HBsAg levels in human blood serum with satisfactory results. This general technique may also be used for a wide variety of separation processes in addition to immunoassay, in which a specific component is to be isolated for analysis, recovery, or disposal.

Synthesis of 1-(2'-Alkylthioethoxyl)methyl Uracil and Its Oxidation Products

LIU Xue-Jun, CHEN Ru-Yu 

2000, 21(10):  1501-1505. 

Asbtract ( )   PDF (249KB) ( )  

Related Articles | Metrics

As a continuation to our projects of searching for new anticancer and antiviral agents, the series of novel 1-(2'-alkylthioethoxy)methyl uracils have been synthesized in overall yields of 70.4%_74.9% in three steps from uracil, and they have been smoothly oxidized into corresponding sulfoxides in yields of 88.5%_94.4% by NaIO₄ in ethanol/water. Corresponding sulfones were obtained in yields of 86.2% _93.5% from sulfides and sulfoxides by means of 30% H₂O₂ /DEAD(diethyl diazodicarboxylate) as oxidation reagent in methanol or THF. All the new compounds have been characterized by ¹H NMR, IRspectrum and elemental analysis. The literature procedure of synthesizing the key intermediate(1,4 bistrimethylsilyluracil) was improved by hexamethyldisiylazane(HMDS)/trimethyl chloride(TMSCl) as substituent of HMDS/(NH₄)₂SO₄, and reaction time was shortened so much from 12 h to 3 h in new procedure. The experimental results indicated that the conversion of sulfides and sulfoxides to the corresponding sulfones was very slow and in low yields(42.5% and 47.3%), when only 30% H₂O₂ was used as the oxidation reagent. After addition of DEADinto the reaction mixture, the reaction could be considerably accelerated, and conversion rates of the reaction were raised (86.2%_93.5%). The anticancer and antiviral activities of the compounds 4, 5, 6 are being testing.

Synthesis and Biological Activities of O-Aryl-O-alkyl-O-(1-methylthioethylideneamino)phosphates

WANG Su-Hua, TANG Guo-Zhi, XING Xiao-Dong 

2000, 21(10):  1506-1509. 

Asbtract ( )   PDF (675KB) ( )  

Related Articles | Metrics

The synthesis of 22 novel title compounds was reported. Their structures were identified by EA, IR, ¹H NMRand MS. The preliminary bioassy showed that many of these compounds have good insecticidal activities. Especially, the killing mortality of compounds 3, 6, 13 on mosquitoes Culex pipiens pallens, oriental army worms Mythimna sepatata and bean aphids Aphis laburni was 100% at 0.001%, 005%, 0.025% , 0005% mass fraction of the compound respectively.

Studies of Quinazolone Analogues Containing Phosphorus and Their Reaction with Aldehydes

HUANG Jun-Min, CHEN Ru-Yu

2000, 21(10):  1510-1514. 

Asbtract ( )   PDF (380KB) ( )  

Related Articles | Metrics

Aseries of 1-methoxycarbonylmethyl 2-(1-substituted hydroxymethyl) 3-benzyl 2,4-dioxo-1,3,2-benzodiazaphosphorins 2 or Ò and their rearrangement reaction products 3 or Ó have been synthesized by the reaction of aldehydes and P_Hreagent. Their structures were confirmed by elemental analysis, NMR, IRand MS. On the basis of NMRanalyses, we studied the diastereoisomerism phenomenon of the products 2 or Ò and the rearrangement reaction by which the products 3 or Ó were formed. The results of preliminary bioassay show that some of the target compounds have good in vitro activity against HSV-1 and (or) excellent fungicidal activity.

Studies on Silicon-containing Fragrance Odor Raw Materials (Ⅵ) ——Synthesis of cis(trans)-1-Substituted-3-trimethylsilylcyclohexanols, ¹³C NMR and Odor Evaluation

LIU Zhong-Jie, CAO Yu-Rong 

2000, 21(10):  1515-1519. 

Asbtract ( )   PDF (265KB) ( )  

Related Articles | Metrics

Seven pairs of cis(trans) isomers of 1-substituted-3-trimethylsilylcyclohexanols were synthesized. The structures were determined by ¹H NMR, ¹³C NMR, MSand GC. The configurations of cis(trans) isomers were determined by ¹³C NMR. The increments caused to the carbons of the cyclohexyl ring by substituents were discussed. Their characteristic odors were evaluated. Most of the title compounds are sweet or sweet and woody.The odor of trans-1-n-butyl-3-trimethylsilylcyclohexanol is sweet and woody, penetrating, lasting, superior.

Synthesis of 2-Pyrazoyl-5-substituted-1,3,4-oxadiazoles and Their Biological Activities

CHEN Han-Song, LI Zheng-Ming, LI Jia-Feng

2000, 21(10):  1520-1523. 

Asbtract ( )   PDF (1468KB) ( )  

Related Articles | Metrics

Aseries of 2-pyrazolyl-5-substituted-1,3,4-oxadiazoles were synthesized starting from 5-pyrazole formic acid hydrazide and carboxylic acid by one pot method in the presence of phosphorus oxychloride. Two 1-benzoyl-2-pyrazolylhydrazines were prepared from 5-pyrazole hydrazide. Preliminary bioassay indicated that some compounds showed certain fungicidal and herbicidal activities.

Preparation of a Polymer Supported BINOL-Ti Catalyst and Its Application in Asymmetric Addition of Diethylzinc to Aldehydes

WANG Heng-Shan, SU Wu, LIU Da-Xue, YANG Xiao-Wu, DA Chao-Shan, WANG Rui 

2000, 21(10):  1524-1526. 

Asbtract ( )   PDF (188KB) ( )  

Related Articles | Metrics

Anew polymer supported BINOLligand(4) was prepared by means of anchoring binaphthyl molecule(3) to aminoethylated polystyrene through a procedure of solid phase peptide synthesis. The key compound (R)-2,2'-dihydroxy 1,1'-binaphthyl-3-carboxylic acid(3) was prepared from R BINOLby protection of hydroxyl groups and then reaction with n-butyllithium followed by carboxylation. By controlling the amount of BuLi, (3) was obtained in 55% overall yield. Ligand (4) was prepared through condensation of (3) with aminoethylated polystyrene in the presence of DCCand HOBt and found to have a loading of 0.40 mmol/g (by mass increase). The linkage between binaphthyl and aminoethylated polystyrene was indicated by a new absorption in IRspectrum of (4) at 1644 cm^-1 in comparing with what of the polystyrene. By mixing (4) with Ti(OiPr)₄ in dry CH₂Cl₂, a complex was easily prepared and this complex was found to be an efficient heterogeneous catalyst in asymmetric addition of diethylzinc to aldehydes. Optical active alcohols with up to 82% ee were obtained from the asymmtric addition with high chemical yields when 20% of (4) was used. And when benzaldehyde was used as substrate, we found that enantioselectivity increased obviously when the amount of (4) used in reaction increased from 5% to 20%;decreased the load of BINOLin ligand (4) reduced the ee of addition product; and Rform of products was resulted.

Synthesis and Characteristics of Thienyltrifluroacetone-acylpyrazolone-phenanthroline-europium Chelate

ZHU Wei-Guo, YUAN Tong-Suo, WEI Xiao-Qiang, LU Zhi-Yun, HUANG Yan, LIU Yu, XIE Ming-Gui

2000, 21(10):  1527-1529. 

Asbtract ( )   PDF (305KB) ( )  

Related Articles | Metrics

Anovel chelate Eu(TTA)₂(PMTBBP)Phen, which contained ligand 1-pheny-3-methyl-4-(4'-t-butylbenzoyl)-5-pyrazolone(HPMTBBP), 4,4,4-trifluro-1-(2-thienyl)-1,3-butandione(HTTA) and phenanthroline(Phen), was synthesized. Its chemical structure was elucidated by IR, UV, ¹H NMR, MS, DSCand elementary analysis. The influence of acylpyrazolone on fluorescent intensity of the new chelate was studied. The results showed that Eu(TTA)₂(PMTBBP)Phen had more excellent PLproperties and better film formation than that of Eu(TTA)₃Phen.

Effect of TiO₂ Nanoparticles on the Luminescence Properties of PPV

ZHANG Jing, AI Xi-Cheng, LI Qian-Shu, ZHANG Bao-Wen, WANG Bo-Jie

2000, 21(10):  1530-1533. 

Asbtract ( )   PDF (226KB) ( )  

Related Articles | Metrics

Aseries of poly(phenylenevinylene)(PPV)/ TiO₂ nanocomposites were prepared from the mixtures of PPVprecursor and TiO₂ sol by employing a sol-gel process. The luminescent properties of the PPV/TiO₂ nanocomposites were dependent on the mass ratio of TiO₂ to PPV. When the mass ratio of TiO₂ to PPVwas 1/9, the resultant TiO₂ nanoparticle quenched the luminescence of PPV. However, when the mass ratio of TiO₂ to PPVwas 1/1, the PPV/TiO₂ nanocomposites showed enhanced luminescence. In this paper, the relationships between the luminescent properties and structures of PPV/TiO₂ nanocomposites were investigated by FT-IR, UV-Vis, FLspectra and TEM.

Photoelectrochemical Behavior of 3d Transition Metal Nanostructured film Electrode Doped with TiO₂

LI Wei-Hua, QIAO Xue-Bin, GAO En-Qin, YANG Mai-Zhi, HAO Yan-Zhong, CAI Sheng-Min

2000, 21(10):  1534-1538. 

Asbtract ( )   PDF (263KB) ( )  

Related Articles | Metrics

The 3d transition metal ions [Cr(Ⅲ), Fe(Ⅲ), Mn(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Cu(Ⅱ), Zn(Ⅱ)] nanocrystalline doped with TiO₂(abbr. m^3d-TiO₂) were characterized by AFMand XRD. The m^3d-TiO₂ nanostructured film electroede was prepared and investigated with photoelectrochemical techniques. The results show that the size of m^3d-TiO₂ nanocrystalline particles was quite uniform and the radii were about 15 nm. The m^3d-TiO₂ nanocrystalline particles were a mixture of brookite and anatase crystal forms. Of all the m^3d-TiO₂ investigated in this paper, however, the photocurrent intensity of Zn²⁺-TiO₂ nanostructured film electode was higher than that of the electrode undoped with TiO₂. The phenomenon of p-n type inversion was observed in certain wavelength range, which was caused by 3d transition ions doping.

Photocatalytic Degradation of Acetophenone Mediated by TiO₂ Under Different Experimental Conditions

XU Yi-Ming 

2000, 21(10):  1539-1542. 

Asbtract ( )   PDF (697KB) ( )  

Related Articles | Metrics

The photocatalytic degradation of acetophenone in TiO₂ aqueous suspension has been studied with the light irradiation of wavelength λ ≥350 nm under different conditions of light intensity, initial concentration, pHand temperature. 2-Hydroxylacetophenone was identified as the main intermediate, which experienced a simultaneous photodegradation in the system. The measured pseudo-first-order rate constant was found to decrease gradually with the initial concentration of acetophenone, but the raw data fitted the Langmuir-Hinshelwood kinetic equation very well. The degradation rate was larger in a basic medium, and got increased as well under the light irradiation of higher intensity. The apparent Arrehenius activation energy was also evaluated to be 4.2—6.4 kJ/mol.

Photoelectrochemical Studies on the TiO₂ Nanostructured Porous Film Sensitized by Pentamethylcyanine Dye

ZHANG Li, YANG Mai-Zhi, GAO En-Qin, QIAO Xue-Bin, HAO Yan-Zhong, WANG Yan-Qin, CAI Sheng-Min, MENG Fan-Shun, TIAN He

2000, 21(10):  1543-1546. 

Asbtract ( )   PDF (344KB) ( )  

Related Articles | Metrics

The photoelectrochemical behavior of the TiO₂ nanostructured porous film sensitized by pentamethylcyanine dye was investigated. The ground state level and the excited state level of the dye were determined by using the cyclic voltammetry and the optical absorption spectroscopy. The results showed that the excitation state level matched the conduction band edge of TiO₂ nanoparticle. Therefore, the sensitization of this dye can increase the photocurrent intensity of TiO₂ nanostructured electrode obviously and results in a red shift of optical absorption from the ultra violet region to the visible and near infra red region. As a result, the light-to-electricity conversion efficiency was improved evidently.

Heterogeneous Photocatalytic Reaction of Cr(Ⅵ) Reduction on Nanosized Titania

ZHANG Qing-Hong, GAO Lian, GUO Jing-Kun

2000, 21(10):  1547-1551. 

Asbtract ( )   PDF (451KB) ( )  

Related Articles | Metrics

The influences of the pH value of solutions, initial concentrations of chromate, purged gas and photocatalysts loading on clean-up efficiency for Cr(Ⅵ) have been investigated. In order to study the influence of phase and size effect on the photocatalytic activities, anatase and rutile TiO₂ nanocrystallites were prepared, whose particle size is 9.5 nm(BETsurface area 133.4 m²/g) for anatase phase and 7.5 nm(BET surface area 167.6 m²/g) for rutile phase, respectively. The results of the photocatalytic reactions indicate that the phtocatalytic activity of anatase crystallite is higher than that of rutile crystallite, however, both anatase and rutile nanosized TiO₂ powders have higher photocatalytic activities than those of commercial TiO₂ powder.

Ion-gate Response of Glutathione Self-assembled Monolayer Modified on a Gold Electrode on the Activation of Surfactants

WANG Jun, ZENG Bai-Zhao, FANG Cheng, ZHOU Xing-Yao 

2000, 21(10):  1552-1554. 

Asbtract ( )   PDF (513KB) ( )  

Related Articles | Metrics

Glutathione(GSH) was prepared on a gold electrode by self-assembled procedure. Cyclic voltammetry was used to investigate the electrochemical behavior of GSH self-assembled monolayer modified on a gold electrode on the activation of surfactants in potassium ferricyanide and benzoquinone(BQ) solution. It was found that GSH monolayer showed an ion-gate behavior in the presence of cationic surfactants and the electron transfer was improved with the increase of the concentration of cationic surfactants, which results from the fact that the interaction between the monolayer and surfactant changes the conformation of GSHmonolayer. Anionic surfactant showed some inhibition to electron transfer at GSHmonolayer modified gold electrode.

The Crystal Structure of Ultra-fine CaCO₃ and Its Thermal Decomposition

YUE Lin-Hai, SHUI Miao, XU Zhu-De, LU De-Yi

2000, 21(10):  1555-1559. 

Asbtract ( )   PDF (471KB) ( )  

Related Articles | Metrics

The thermal decomposition of three ultra-fine CaC03 having different particle sizes and agglom-eration states was investigated.The kinetic parameters obtained by using the contracting volume mecha-nism R3 and Coats and Redfern's equation were in good agreement with those using Kissinger non-mecha-nism equation. Furthermore，the result showed that a considerable diminution of the activation energy Ea up to 60~80 kJ·mol^-1 is observed in the case of ultra-fine calcite. The Voigt analysis of the X-ray diffrac-tion data for the samples showed that abnormally large strain existed in the lattice of these samples. We suggest that this may be the reason of their abnormal decomposition behavior. At the same time，we ob-served that the conglomeration states revealed by TEM and SEM images result in the minute difference be-tween those ultra-fine CaCO₃.

The Dynamic Model of the Coating Process of Silicon Dioxide Nonafilm on Titanium Dioxide Particles

CUI Ai-Li, WANG Ting-Jie, JIN Yong

2000, 21(10):  1560-1562. 

Asbtract ( )   PDF (859KB) ( )  

Related Articles | Metrics

Asol gel mechanism is proposed in this research for the process of silicon dioxide film coating on Titanium dioxide particles. The dynamic process of film forming on the particle surface is researched. The influence of temperature and concentration on film formation rate is researched. The dynamic equation of the film formation of silicon dioxide is obtained from the experiments. The theoretically calculation results are consistent with the experimental results.

Preparation, Photochromic Properties of Keggin Type Tungstophosphoric Acids Based on Polyacrylamide

FENG Wei, ZHAGN Tie-Rui, LIU Yan, LU Ran, ZHAO Ying-Ying, YAO Jian-Nian

2000, 21(10):  1563-1565. 

Asbtract ( )   PDF (410KB) ( )  

Related Articles | Metrics

A new photochromic complex of Keggin type Tungstophosphate acid/polyacrylamide system was prepared in aqueous solution, and its thin films was made by the dip-coating technique. Their properties were investigated by FT-IR, UV-Vis, as well as TG-DTA measurement. The results showed that this type of system had different properties in solution and in thin films. ESRspectra g values for the one-electron blues were the characteristic of tetragonal W⁵⁺ complex in aqueous solution and thin films. The formation of a radical signal of ESRspectra indicated that polyacrylamide was a proton donor, the reversibility for photochromism was relative to the presence and diffusion of oxygen in polymeric network.

Novel PdCl₂(RuCl₃)/ZrO₂-SO₃ Catalysts for Synthesis of Carbamates by Oxidative Carbonylation of Amines

SHI Feng, SIMA Tian-Long, DENG You-Quan

2000, 21(10):  1566-1568. 

Asbtract ( )   PDF (175KB) ( )  

Related Articles | Metrics

Novel combined PdCl₂(RuCl₃) with ZrO₂-SO₃ catalysts were developed for the synthesis of carbamates by oxidative carbonylation of aliphatic and aromatic amines. At 170 ℃ and 4.0 MPa, oxidative carbonylation of aromatic amines to the corresponding carbamates over this catalyst system could be proceeded with a high conversion and selectivity. Especially when β-naphthylamine was used as the substrate, 100% conversion and 95% selectivity were obtained in only 15 min. The catalytic performance of PdCl₂/ZrO₂-SO₃ was better than that of RuCl₃/ZrO₂-SO₃ for such oxidative carbonylation reaction. Possible role of ZrO₂-SO₃ as co catalyst was also conjectured.

Morphologically Selective Synthesis of Nanocrystalline SnO₂

LIU Yang, YANG Guo-Cheng, ZHANG Xin-Tong, BAI Yu-Bai, LI Tie-Jin

2000, 21(10):  1569-1571. 

Asbtract ( )   PDF (182KB) ( )  

Related Articles | Metrics

In this paper, we report our research on morphologically selective synthesis of nanocrystalline SnO₂ by the combination of hydrothermal preparation and calcinated process. We firstly prepared SnO₂ nanocrystals by the hydrothermal method at 140 ℃ for 3 h, using SnCl 4 as the reactant. With the initial pHof 1.8 or 1.34, we prepared uniform and well dispersed SnO₂(tetragonal) nanocrystals, with similar size of about 3 nm, as determined by TEM. However, after being calcinated at 500 ℃ for 2 h, specimen₁ prepared at pH=1.8 showed the rod like shape with an average size of 5 nm×20 nm, while the other one(specimen 2) prepaed at pH=1.34 showed a granular shape with an average size of 10 nm. XRDexperiments showed that specimen₁ had a new diffraction peak after calcination, which was contributed by the (023) face of orthorhombic SnO₂. The experiment results indicated that the morpholgy of SnO₂ nanocrystals after calcination was closely related to the initial acidity of the reaction solution, possibly due to the difference in surface properties, e.g. the difference in crystalline faces exposed to the surface of particals, under different hydrothermal conditions.

A Study of Solubilities and Physico chemistry Properties of Equilibrium Solutions in the Reciprocal Quaternary System Li⁺, K⁺/Cl^-, CO₃^2--H₂O at 298 K

DENG Tian-Long, YIN Hui-An, TANG Ming-Lin

2000, 21(10):  1572-1574. 

Asbtract ( )   PDF (1000KB) ( )  

Related Articles | Metrics

Zabuye Saline Lake, Tibet, China, is unrivalled in the world for its very high salinity, in particular, for the very high concentration of ions of lithium, potassium, and boron in the brine. It belongs to alkaline and carbonate borate type salt lake. As a part of the study on phase equilibrium of the 6-component subsystem Li⁺, Na⁺, K⁺/Cl^-, CO₃^2-, B₄O₇^2--H₂O of the brine system, a study on the reciprocal quaternary system Li⁺, K⁺/Cl^-, CO₃^2--H₂O at 298 Kwas done with isothermal dissolution equilibrium method in the present work. The phase equilibrium of the reciprocal quaternary system Li⁺, K⁺/Cl^-, CO₃^2--H₂O at 298 Kwas studied with isothermal dissolution method in this work. The physico-chemistry properties of the corresponding equilibrium solutions such as densities, viscosities, refractive index, conductivities and pHvalue were determined. The dried salt diagram of the system consists of four crystallization fields (KCl, Li₂CO₃, LiCl·H₂O, K₂CO₃·3/2H₂O) and five isothermal solubility curves. There are no double slat or solid solution found. Pitzer's model of the electrolyte solution theory was used for parameterization from the results of solubility determination for subsystems and the prediction of solubilities for the reciprocal quaternary system was made. The solubility data of the experiment are in agreement with those calculated.

Studies on the Stability of Aluminium Magnesium Hydroxide Positive Sol

YU Yue-Qin, WU Yu-Min, HOU Wan-Guo, ZHANG Chun-Guang, WANG Guo-Ting

2000, 21(10):  1575-1577. 

Asbtract ( )   PDF (242KB) ( )  

Related Articles | Metrics

The potential equation in the positive sol of aluminium magnesium hydroxide was deduced according to the model of constant surface charge density, and the potential curves in the NaBr solution were obtained. The studies of coagulation kinetics showed that the coagulation process of monovalent anions may be divided into a rapid and slow coagulation. The efficiencies in causing coagulation for monovalent anions followed the order Br^->I^->NO₃^->Cl^-, which didn't correspond to the lyotropic series. The coagulation value of polyanion had a discrepancy with Shulze-Hardy law. The higher the cation valent was, the stronger the stabilization of sol was.

Photocatalytic Degradation Properties Studies of A New Nanocrystalline TiO₂ Coating Film

WU Feng-Qing, RUAN Sheng-Ping, LI Xiao-Ping, GAO Wei, XU Bao-Kun, ZHAO Mu-Yu

2000, 21(10):  1578-1580. 

Asbtract ( )   PDF (410KB) ( )  

Related Articles | Metrics

The TiO₂ powder was prepared by a stearic acid gel method. XRDcharacterization indicated that the crystal form was anatase. The grain size, given out by Sherrer formula, is 19 nm. With polystyrene dissolved in toluene as binder, TiO₂ adhered to the glassfibre substrate. By this method, the powder was immobilized and the crystal form, grain size and photocatalysis activities were well maintained. Photocatalysis degradation properties were investigated by putting the TiO₂ immobilization film in the methyl orange aqueous system. The results indicated that the differences of degradation rate between the TiO₂ immobilization film and powder were not obvious, which made waste water treatment using photocatalysis degradation technique possible in the practical application.

Electrochemical Properties and Energy Band Structure of Pyrazoline Derivatives

WU Fang, TIAN Wen-Jing, FAN Yu-Guo, ZHANG Lian-Qi, ZHANG Bao-Wen, CAO Yi

2000, 21(10):  1581-1583. 

Asbtract ( )   PDF (176KB) ( )  

Related Articles | Metrics

The band gap( E_g) and HOMOlevel of pyrazoline derivative were obtained by UV-Vis absorption spectra and electrochemical cyclic voltammetry methods. The effect of the molecular structure of pyrazoline on the energy band structure was investigated. It was indicated that the HOMOlevel changed from -5.56 eVto -5.10 eVwhile the LUMO level changed from -2.68 eVto -2.36 eVwith different substituents in pyrazoline derivatives. The results obtained showed that the energy band structure of pyrazoline derivatives could be adjusted through changing the molecular structure.

The Relationship Between Chain Structure and Phase Structure and Tensile Stress-Strain Behavior of Copolymer Polypropylene with Low Ethylene Content

MA De-Zhu, CHEN Wei-Guo, HAO Wen-Tao, ZHANG Zhong-Ping, LUO Xiao-Lie

2000, 21(10):  1584-1588. 

Asbtract ( )   PDF (689KB) ( )  

Related Articles | Metrics

In our published works, it has been proved that the impact copolymer polypropylene(ICPP) has characteristic chain structure and phase structure which make CPPexhibit excellent low-temperature impact strength. The tensile stress-strain behavior at low-temperature of impact copolymer polypropylene strongly discloses the structure nature why impact copolymer polypropylene has so excellent low-temperature impact strength and comprehensive mechanical properties. The dependence of Young′s modulus, stress yield and the elongation at break on the variation of the temperature can be explained by the characteristic chain structure and characteristic phase structure of the impact copolymer polypropylene. The difference of the elongation at break between the homopolymer and copolymer indicates that ethylene-propylene rubber acts as the toughening phase in the impact copolymer polypropylene. The difference of stress yield between the two-copolymer polypropylenes comes from the difference of the adhesion between the rubber particles and the matrix PP. The Young′s modulus is closely related to the crystallinity of the matrix PP, the size of the spherulite and the size distribution, and the glass transition temperature of both ethylene-propylene rubber and PPmatrix can also give important influence on it.

Solvothermal Preparation of Mn₃O₄ Nanoparticles and Effect of Temperature on Particle Size

GUO Rong, FU Qing-Hong, ZHANG Xiao-Hong

2000, 21(10):  1589-1592. 

Asbtract ( )   PDF (295KB) ( )  

Related Articles | Metrics

In the lamellar liquid crystal(LLC) phase of NaOL/hexadecane/AHD-ol/H₂Osystem, the small X-ray diffraction measurements show that hexadecane was solubilized in the oil layer, while AHD-ol, commoner in the amphiphile layer. Copolymerization of the double bonds in the middle hydrocarbon chain of NaOLand in the three double bonds of ADH-ol took place in each amphiphile layer of LLCphase. The polymer with LLCstructure and surface activity was obtained at 72 ℃.

Synthesis of Polypropylene-b-syndiopolystyrene Block Copolymers with Titanocene Activated with Modified MAO

CHEN Rui, WU Qing, ZHU Fang-Ming, LIN Shang-An 

2000, 21(10):  1593-1597. 

Asbtract ( )   PDF (259KB) ( )  

Related Articles | Metrics

Polypropylene b syndiopolystyrene block copolymers were synthesized by sequential addition of two monomers with Cp^*Ti(OBz)₃ catalyst activated with modified methylaluminoxane(MAO) and triisobutylaluminium(TIBA). The result shows that the titanocene has a high activity on propylene/styrene block copolymerization. The concentration of Cp^*Ti(OBz)₃, the amount of TIBAand the residual propylene monomer after prepolymerization were investigated and found to have pronounced influence on the catalytic activity. The appropriate concentration of the titanocene complex 〔c(Ti)=0.6～0.8×10^-3 mol·L^-1〕 will prevent the active centers from being buried by propylene prepolymers so that the copolymerization of the two monomers was promoted. Since the Ti(Ⅵ) catalytic system is favorable to propylene prepolymerization while the Ti(Ⅲ) catalytic system is required for styrene polymerization, TIBAhad played an important role in changing the active centers from Ti(Ⅳ) to Ti(Ⅲ) so that the block copolymerization can take place. The investigation also indicated the existence of residual propylene after propylene prepolymerization will prevent styrene from block copolymerization. The PPb sPSblock copolymers were separated from the gross products with successive extraction with boiling 2-butanone, heptane, THF, and chloroform. Each fraction of materials were characterized by ¹³C NMR, DSCand elemental analysis.

Preparation and Separation Properties of Sodium Alginate Composite Membrane with Interface Crosslinking

WANG Xin-Ping, FENG Yun-Fang, SHEN Zhi-Quan

2000, 21(10):  1598-1602. 

Asbtract ( )   PDF (263KB) ( )  

Related Articles | Metrics

A novel organic dehydration membrane with interface crosslink structure consisting of aminated PANmicroporous membrane as sublayer, sodium alginate coating as top layer and intermolecular crosslinking as middle layer has been prepared and characterized by pervaporation experiment. The influence of hydrolysis time of PANmicroporous membrane, the kinds and concentration of diamine used for amination of the microporous support layer on selectivity and flux was studied and it was shown that the amination of the sublayer with 1,6-hexanediamine(HDM) gave higher pervaporation performance of the composite membrane than that with ethylenediamine(EDM). This novel composite membrane prepared from the support layer aminated by 20% HDMafter being hydrolyzed for 2 h has a high separation factor of 2241 and a good permeation rate of 305 g·m^-2 ·h^-1 for pervaporation of 90% ethanol aqueous solution at 70 ℃, higher separation factors and fluxes for n-PrOH/water, i-PrOH/water, acetone/water and dioxane/water systems. The results show that the separation factor and flux of this membrane increase with raising the operating temperature. At the same time, SEMmicrograps show that hydrolysis and amination of PANmicroporous membrane change its pore structure. From the results it can be concluded that pore structure of the sublayer do make influence of the separation properties of the novel composite membrane.

Studies on the Glass Transition Temperature of Vinyls/ N-Substituted Maleimides Copolymers

SHAN Guo-Rong, WENG Zhi-Xue, HUANG Zhi-Ming, PAN Zu-Ren

2000, 21(10):  1603-1606. 

Asbtract ( )   PDF (204KB) ( )  

Related Articles | Metrics

The glass transition temperature( T_g) of vinyls/ N-substituted maleimides copolymers was determined by differential scanning calorimeter(DSC). The effects of copolymer composition and sequence distribution, types of vinyls and N-substituted maleimide on T_g were investigated. An equation in term of copolymer composition and sequence distribution was presented to predict T_g of copolymer. The equation can be used to describe not only the random copolymer, but also the copolymer with the alternating tendency.

Synthesis of Branched Polyethylene by Ethylene Homopolymerization with Novel Mono-titanocene Catalysts

ZHU Fang-Ming, FANG Yu-Tang, CEHN Han-Bin, LIN Shang-An

2000, 21(10):  1607-1609. 

Asbtract ( )   PDF (179KB) ( )  

Related Articles | Metrics

Branched polyethylene was synthesized by ethylene homopolymerization in the presence of a novel metallocene complex of η⁵-pentamethylcyclopentadienyl tribenzyloxy titanium[Cp^*Ti(OBz)₃] activated by four types of modified methylaluminoxanes(mMAO) which contained different amounts of residual trimethylaluminum(TMA). The activity of catalyst and molecular weight, branched degree and branch length of the resultant polymers depend on the oxidation states of active species of titanium and polymerization temperature. The higher content(%) of residual TMAin mMAOcould strongly reduce complexes Ti(Ⅳ) to Ti(Ⅲ) and Ti(Ⅱ) and Ti(Ⅳ) active species was suggested to be more effective for ethylene polymerization. The products obtained were confirmed by ¹³C NMRand IRspectra charac-terization to be branched polyethylene with isolated long branch and methyl pendant. There is a remar-kable increase in proportion of methyl pendant with the increase of polymerization temperature.

Principle and Application of Composition Distribution Measurement for Vinyls/ N-Phenylmaleimide Copolymer

SHAN Guo-Rong, WENG Zhi-Xue, HUANG Zhi-Ming, DU Miao, PAN Zu-Ren

2000, 21(10):  1610-1612. 

Asbtract ( )   PDF (170KB) ( )  

Related Articles | Metrics

The principle and calculation equation of composition distribution measurement for vinyls/ N-phenylmaleimide(PMI) copolymer were presented using the information of differential refractometer (DR) and ultraviolet spectrophotometer(UV) detectors connected with the gel permeation chromatography(GPC). With the information of DRand UVdetectors, the effects of copolymerization methods and process on the composition distributions of styrene-PMI, methyl methacrylate-PMI and vinyl chloride-PMI copolymers systems were studied. It was found that the composition distribution of copolymer was even at low conversion, but changed with the increasing of conversion.

Synthesis of Heat-resistant Copolymers by Atom Transfer Radical Polymerization

JIANG Xu-Lin, YAN De-Yue, LIU Wan-Li

2000, 21(10):  1613-1615. 

Asbtract ( )   PDF (182KB) ( )  

Related Articles | Metrics

Atom transfer radical copolymerization(ATRP) of styrene(St) and N-cyclohexylmaleimide(NCMI) with the CuBr/bpy catalyst in anisole, initiated by 1-phenylethyl bromide(1-PEBr) or tetra-(bromomethyl)benzene(TBMB), afforded well defined copolymer with predetermined molecular weights and low polydispersities, M_w/M_n<1.5. Other monomer pairs such as methyl methacrylate(MMA)/NCMI, St/N-phenylmaleimide, MMA/ N-phenylmaleimide were studied, too. The influences of several factors, such as temperature, solvent and monomer's ratio on the copolymerization with the CuBr/bpy catalyst system were subsequently investigated. The apparent activation energy of St(MMA)and NCMI was deduced from the kinetics figure of different temperatures. Using TBMBas the initiator produced four-armed star copolymer. The heat resistance of the resultant copolymer has been improved by increasing the NCMI.