2011 Volume 22 Issue 4

Radical reduction of Passerini 3CR adducts by SmI2/HMPA
Hui Yu , Tao Gai , Wen Liang Sun , Mei Su Zhang
2011, 22(4): 379-381  doi: 10.1016/j.cclet.2010.11.013
[Abstract](184) [FullText HTML] [PDF 212KB](0)
Abstract:
The Passerini 3-CR adducts of substituted cinnamaldehydes, isocyanides and acetic acid were treated with SmI2/HMPA in dry tetrahydrofuran (THF) at room temperature, and β, γ-unsaturated amides were obtained in moderate yields. The reaction was supposed involving a radical reduction procedure.
High selectively oxidative bromination of toluene derivatives by the H2O2-HBr system
Jie Ju , Yu Jin Li , Jian Rong Gao , Jian Hong Jia , Liang Han , Wei Jian Sheng , Yi Xia Jia
2011, 22(4): 382-384  doi: 10.1016/j.cclet.2010.11.005
[Abstract](178) [FullText HTML] [PDF 255KB](0)
Abstract:
An aqueous solution of hydrogen peroxide and hydrogen bromide illuminated by a 60 W incandescent light bulb serves as a source of bromine radicals. Various substituted toluenes (NO2,Cl, Br, H, CH3) were high selectively brominated at the benzyl position for monobromination in CH2C12 at ice water with catalyst free. This simple but effective bromination of toluene derivatives with an aqueous H2O2-HBr system is characterized with the use of inexpensive reagents and a lower impact on the environment, which make it a good alternative to the existing bromination methods.
A novel photo-initiated approach for preparing aluminum diethylphosphinate under atmospheric pressure
Li Yang , Xin Yu Han , Xue Jiao Tang , Chang Xiu Han , Yi Xiao Zhou , Bao Gui Zhang
2011, 22(4): 385-388  doi: 10.1016/j.cclet.2010.10.039
[Abstract](190) [FullText HTML] [PDF 283KB](0)
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A novel preparation of aluminum diethylphosphinate (AlPi) was carried out with free-radical addition reaction by means of UV-irradiation under atmospheric pressure. A solution of sodium hypophosphite was treated with ethylene and irradiated with ultraviolet light in the presence of an amount of photoinitiator effective to initiate the free-radical reaction between the hypophosphite anion and the double bond of the ethylene molecule. The ethylene was micro-bubbled into the reaction mixture with the addition of the photoinitiator, and the gas-liquid contact surface and the photoinitiator concentration in the gas-liquid interface were increased largely. The yield of the final product could be improved to about 96%. The contents of P, Al in samples were detected by ICP, and the molecular structure of the samples was confirmed by 31P NMR, 1H NMR and FTIR spectroscopic analysis. Thermal stability of the final products was investigated in detail by TG-DTA.
Citric acid:An efficient and green catalyst for rapid one pot synthesis of quinoxaline derivatives at room temperature
Radhakrishnan Mahesh , Arghya Kusum Dhar , Tara Sasank T. V. N. V. , Sappanimuthu Thirunavukkarasu , Thangaraj Devadoss
2011, 22(4): 389-392  doi: 10.1016/j.cclet.2010.11.002
[Abstract](192) [FullText HTML] [PDF 309KB](0)
Abstract:
The condensation of o-phenylenediamines with 1,2-dicarbonyl compounds in the presence of citric acid afforded the corresponding quinoxaline derivatives in higher yields at room temperature in ethanol, and most of the reactions were completed in less than 1 min.
Research on hydration of phenylacetylene assisted with additives in near-critical water
Shuang Li , Yong Juan Chang , Yu Wang , Li Yi Dai
2011, 22(4): 393-396  doi: 10.1016/j.cclet.2010.11.003
[Abstract](189) [FullText HTML] [PDF 292KB](0)
Abstract:
The hydration of phenylacetylene in near-critical water, assisted with additives (NaHSO4, ZnCl2, FeCl3), has been successfully conducted with temperature and residence time ranges of 220-300℃ and 60-180 min, respectively. The results showed the catalytic ability is FeCl3 > ZnCl2 > NaHSO4. The maximum yield of product acetophenone was 96.68% at 260℃, 120 min. Based on the results found, a possible mechanism of hydration of phenylacetylene in near-critical water was proposed.
Tributylphosphine-catalyzed reaction of ethanethiol with alkynyl ketones
Shen Zhao , Qing Fa Zhou , Jia Zhi Liu , Wei Fang Tang , Tao Lu
2011, 22(4): 397-400  doi: 10.1016/j.cclet.2010.11.007
[Abstract](185) [FullText HTML] [PDF 216KB](0)
Abstract:
A stereoselective and effective method for the synthesis of vinyl thioethers has been developed. This method is based on the Michael addition of ethanethiol to various alkynyl ketones using 10 mol% of tributylphosphine as catalyst. Most of alkynyl ketones react with ethanethiol in this system to yield mainly Z-isomer of vinyl thioether adducts, only in one case mainly E-isomer of vinyl thioether adducts was observed.
Mixed metal oxide catalysts for the selective oxidation of ethylbenzene to acetophenone
Warangkana Kanjina , Wimonrat Trakarnpruk
2011, 22(4): 401-404  doi: 10.1016/j.cclet.2010.10.035
[Abstract](183) [FullText HTML] [PDF 203KB](0)
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MgAl and MgMAl oxides (M=Co, Ni and Cu) with a Mg:M:Al molar ratio=4:1:1 were synthesized from the calcination of their corresponding layered double hydroxide (LDHs) precursors. Their catalytic activities were examined for the oxidation of ethylbenzene using tert-butylhydroperoxide (TBHP) as an oxidant. The oxidized product was mainly acetophenone. The catalytic activities were in the order of MgCuAl> MgNiAl~NiAl~MgCoAl~CoAl > CuAl > MgAl oxides. Reusability studies show that the catalysts are stable under the reaction conditions.
Synthesis of new hyodeoxycholic acid thiosemicarbazone derivatives under solvent-free conditions using microwave
Zhi Chuan Shi , Zhi Gang Zhao , Xing Li Liu , Yu Chen
2011, 22(4): 405-408  doi: 10.1016/j.cclet.2010.10.020
[Abstract](182) [FullText HTML] [PDF 229KB](0)
Abstract:
An efficient and simple method for synthesis of new hyodeoxycholic acid thiosemicarbazone derivatives under solvent-free conditions using microwave has been developed. Its main advantages are short reaction times, good conversions and the environmentally friendly nature of the process. The preliminary results indicate that some of these compounds possess inhibitory effects against E. coli.
Diclofenac derivatives with insulin-sensitizing activity
Jian Ta Wang , Ying Wang , Ji Quan Zhang , Xing Cui , Yi Zhang , Gao Feng Zhu , Lei Tang
2011, 22(4): 409-412  doi: 10.1016/j.cclet.2010.11.008
[Abstract](177) [FullText HTML] [PDF 343KB](0)
Abstract:
A series of diclofenac derivatives were synthesized. The insulin-sensitizing activity of 28 new compounds was evaluated in 3T3-L1 cells. The compounds 10a and 10f exhibited similar insulin-sensitizing activity with positive drag rosiglitazone.
Synthesis and bioactivity of novel nitric oxide-releasing ursolic acid derivatives
Li Chen , Wen Qiu , Jia Tang , Zhi Feng Wang , Shu Ying He
2011, 22(4): 413-416  doi: 10.1016/j.cclet.2010.10.036
[Abstract](182) [FullText HTML] [PDF 279KB](0)
Abstract:
A series of furoxan-based novel nitric oxide-donating ursolic acid (UA) derivatives (7a-f) were synthesized, and their cytotoxic activities against HepG2 cells in vitro were evaluated by MTT method. It was found that 7a-d and 7f showed more potent cytotoxic activities than control 5-fluorouracil and UA.
Markovnikov addition of vinyl acetate with azoles catalyzed by potassium tert-butoxide
Mazaahir Kidwai , Neeraj Kumar Mishra , Anwar Jahan
2011, 22(4): 417-420  doi: 10.1016/j.cclet.2010.10.048
[Abstract](182) [FullText HTML] [PDF 518KB](0)
Abstract:
A simple and efficient methodology for Markovnikov addition of azoles with vinyl acetate catalyzed by potassium tert-butoxide is described. N-heterocyclic compounds are synthesized from simple and commercially available starting materials under mild conditions in high yields.
Efficient regeneration of aldehydes from their corresponding 1,3-oxathiolanes in the absence of solvent
Farhad Shirini , Seyyedeh Kobra Mirhashemi , Aysa Pourvali , Masoumeh Abedini
2011, 22(4): 421-423  doi: 10.1016/j.cclet.2010.10.034
[Abstract](178) [FullText HTML] [PDF 182KB](0)
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A mild and efficient method for the oxidative deprotection of 1,3-oxathiolanes with Fe(NO3)3·9H2O and Cu(NO3)2·3H2O in the absence of solvent is reported.
Synthesis and dyeing performance of a novel polycarboxylic acid azo dye
Hua Xu , Bing Tao Tang , Shu Fen Zhang
2011, 22(4): 424-426  doi: 10.1016/j.cclet.2010.11.010
[Abstract](185) [FullText HTML] [PDF 205KB](0)
Abstract:
A novel reactive polycarboxylic acid dye was synthesized by the reaction of polymaleic anhydride (PMA) with 3-methyl-l-(4-sulfonylphenyl)-4-(4-aminophenylazo)-2-pyrazoline-5-one. The structure of the novel dye was characterized by FTIR, UV-vis and 13C NMR spectra. The dyeing properties of dye on cotton were tested, and the novel dye possessed high fixation and good fastness.
Eco-friendly synthesis of 2-substituted-2,3-dihydro-4(1H)-quinazolinones in water
Min Wang , Ting Ting Zhang , Zhi Guo Song
2011, 22(4): 427-430  doi: 10.1016/j.cclet.2010.10.038
[Abstract](182) [FullText HTML] [PDF 215KB](0)
Abstract:
2-Substituted-2,3-dihydro-4(1H)-quinazolinones were synthesized in high yield by condensation of 2-anthranilamide with aromatic aldehydes or ketones in refluxing water without catalyst. This protocol has advantages of high yield, simple work-up and environmental friendly procedure.
An effective method for the preparation of chlorolactones
Min Zhu , Li Li , Jiang Ying Tong , Hui Zhang
2011, 22(4): 431-434  doi: 10.1016/j.cclet.2010.11.014
[Abstract](185) [FullText HTML] [PDF 384KB](0)
Abstract:
The effective chlorolactonization of alkenoic acids with (diacetoxyiodo)benzene and lithium chloride under mild conditions have been studied. Experiments show that various 4-pentenoic acids react with (diacetoxyiodo)benzene and lithium chloride fluently in CH3OH at room temperature, obtaining five-membered chlorolactones in good yields in short times. Other alkenoic acids, such as 3-butenoic acid and trans 3-hexenoic acid give some more complicated results, and 4-pentynoic acid provides a chloroenol lactone with Z configuration in 40% of yield.
Preyssler-type heteropoly acid:A new, mild and efficient catalyst for protection of carbonyl compounds
Mohammad Rahimizadeh , Tahmineh Bazazan , Ali Shiri , Mehdi Bakavoli , Hassan Hassani
2011, 22(4): 435-438  doi: 10.1016/j.cclet.2010.10.052
[Abstract](191) [FullText HTML] [PDF 652KB](0)
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Preyssler-type heteropoly acid is introduced as a new, mild and efficient catalyst for protection of a variety of carbonyl compounds with 1,3-propane dithiol.
Synthesis and characterization of new azo containing Schiff base macrocycle
Saeed Malek-Ahmadi , Amir Abdolmaleki
2011, 22(4): 439-442  doi: 10.1016/j.cclet.2010.10.040
[Abstract](182) [FullText HTML] [PDF 357KB](0)
Abstract:
Fully conjugated Schiff base macrocycle has been prepared through a simple and mild condition, a one-pot cyclization procedure of four-component without using a template. The condensation reaction of related bis (hydroxybenzaldehyde) with phenylenediamines to prepare a conjugated[2+2] Schiff base macrocycle has been investigated and fluorescent[2+2] Schiff base macrocycles with N2O2 binding pockets has been prepared and characterized by elemental analysis,1H NMR, IR, fluorescent, UV-visible and MALDI mass spectroscopies.
An efficient route for synthesis of 2-alkylamino benzo [b] thieno [3,2-d]pyrimidin-4(3H)-one
Min Hui Cao , Sheng Zhen Xu , Chang Shui Chen
2011, 22(4): 443-446  doi: 10.1016/j.cclet.2010.11.015
[Abstract](179) [FullText HTML] [PDF 207KB](0)
Abstract:
The carbodiimide 2, obtained from the aza-Wittig reactions of iminophosphorane 1 with alkyl isocyanates, reacted with primary amino to give 2-alkylamino benzo[b]thieno[3,2-d]pyrimidin-4(3H)-ones 4 and 5. The formation mechanism of the title compounds has been investigated.
Silica-supported l,3-dichloro-5,5-dimethylhydantoin (DCH) as a useful reagent for microwave-assisted aromatization of 1,3,5-trisubstituted pyrazolines under solvent-free conditions
Davood Azarifar , Elahe Nadimi , Mohammd Mehdi Ghanbari
2011, 22(4): 447-450  doi: 10.1016/j.cclet.2010.10.023
[Abstract](184) [FullText HTML] [PDF 227KB](0)
Abstract:
1,3,5-Trisubstituted pyrazolines are rapidly and conveniently oxidized to their corresponding pyrazoles by l,3-dichloro-5,5-dimethylhydantoin (DCH) in solution and solvent-free conditions under microwave irradiation. The presence of silica gel as a supporting agent is shown to be effective in reducing the reaction times and increasing the yields.
Isolation and characterization of ingenol esters from Euphorbia cornigera
Imam Bakhsh Baloch , Musa Kaleem Baloch
2011, 22(4): 451-454  doi: 10.1016/j.cclet.2010.11.001
[Abstract](188) [FullText HTML] [PDF 278KB](0)
Abstract:
Methanolic extract of Euphorbia cornigera Boiss. on HPLC separation yielded three new compounds. Their structures and relative stereochemistry were established through 2D-NMR spectroscopic measurements.
Brainin A, a novel flavanol from Brainea insignis
Ming Hui Yang , Le Cai , Zhi Gang Tai , Xue Qiong Yang , Zhong Tao Ding
2011, 22(4): 455-457  doi: 10.1016/j.cclet.2010.11.009
[Abstract](175) [FullText HTML] [PDF 359KB](0)
Abstract:
A novel flavanol bearing phenylpropionic acid moiety at C-4 through a C-C bonding, named brainin A (1), was isolated from the rhizomes of Brainea insignis. Its structure was elucidated on the basis of spectral data including 2D NMR and HR-ESI-MS.
Detection of H2O2 at a composite film modified electrode with highly dispersed Ag nanoparticles in Nafion
Mei Xiu Kan , Xue Ji Wang , Hui Min Zhang
2011, 22(4): 458-460  doi: 10.1016/j.cclet.2010.12.009
[Abstract](183) [FullText HTML] [PDF 907KB](0)
Abstract:
Ag nanoparticles were prepared by using the ion-exchange of Nafion combined with electrochemical reduction on the electrode. Ag nanoparticles are highly dispersed in Nafion film with an average size of 4.0±0.2 nm. The amount of Ag nanoparticles can be readily controlled by the amount of Nafion coated on the electrode. Thus obtained Ag nanoparticles exhibit good catalytic activity for the reduction of H2O2 with a linear response to H2O2 in the concentration range of 0.04-8.0 mmol/L with a sensitivity of 0.34 μA/mmol/L and a detection limit of 1.0×10-8 mol/L.
Trace analysis of anions in organic matrices by ion chromatography coupled with a novel reversed-phase column for on-line sample pretreatment
Ying Ying Zhong , Wen Fang Zhou , Xue Ling Zeng , Ming Li Ye , Yan Zhu
2011, 22(4): 461-464  doi: 10.1016/j.cclet.2010.11.011
[Abstract](181) [FullText HTML] [PDF 260KB](0)
Abstract:
An ion chromatography (IC) system coupled with on-line column-switching technique was used to determine anions of μg/g levels in organic chemicals of analytical reagent grade. A novel polystyrene-divinylbenzene-carbon nanotube (PS-DVB-CNT) stationary phase was utilized for matrix elimination. A calibration study was conducted by preparing and analyzing eight concentrations (between 10 and 5000 μg/L) of eight standards in deionized water. The linearity was between 0.9978 and 1. And the detection limits ranged from 1.54 μg/L to 10.02 μg/L. A spiking study was performed on two representative organic chemicals. The recoveries were between 84.3% and 119.6%.
Direct electrochemistry and electrocatalysis of myoglobin in dodecyltrimethylammonium bromide film modified carbon ceramic electrode
Yuan Zhen Zhou , Hui Wang , She Ying Dong , An Xiang Tian , Zhi Xian He , Bin Chen
2011, 22(4): 465-468  doi: 10.1016/j.cclet.2010.11.012
[Abstract](188) [FullText HTML] [PDF 357KB](0)
Abstract:
Direct electrochemistry and electrocatalysis of myoglobin (Mb) were studied with Mb immobilized on dodecyltrimethylammonium bromide (DTAB) film modified carbon ceramic (CC) electrode. Cyclic voltammetry showed a pair of well-defined and nearly reversible redox peaks of Mb (Fe/Fe) at about -0.3 V vs. SCE (pH=6.98). The currents of the redox peak were linear to scan rate, and rate constant (Ks) was estimated to be 3.03 s-1. The formal potential (E°') of Mb in the DTAB/CC electrodes shifted linearly with pH with a slope of -36.44 mV/pH, implying that the electron transfer between DTAB and CC electrodes is accompanied by proton transportation. The immobilized Mb exhibited excellent electrocatalytic response to the reduction of hydrogen peroxide (H2O2).
Extraction of cobalt(II) from aqueous solution by N,N'-carbonyl difatty amides
Emad A. Jaffar Al-Mulla , Khalid Waleed S. Al-Janabi
2011, 22(4): 469-472  doi: 10.1016/j.cclet.2010.10.037
[Abstract](192) [FullText HTML] [PDF 267KB](0)
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The development of economic and environmentally friendly extractants to recover cobalt metal is required due to the increasing demand for this metal. In this study, solvent extraction of Co(Ⅱ) from aqueous solution using a mixture of N,N'-carbonyl difatty amides (CDFAs) synthesised from palm oil as the extractant was carried out. The effects of various parameters such as acid, contact time, extractant concentration, metal ion concentration and stripping agent and the separation of Co(Ⅱ) from other metal ions such as Fe(Ⅱ), Ni(Ⅱ), Zn(Ⅲ) and Cd(Ⅱ) were investigated. It was found that the extraction of Co(Ⅱ) into the organic phase involved the formation of 1:1 complexes. Co(Ⅱ) was successfully separated from commonly associated metal ions such as Fe(Ⅱ), Ni(Ⅱ), Zn(Ⅲ) and Cd(Ⅱ). Co(Ⅱ) stripping from the loaded organic phase was studied in aqueous solution. These results are useful to recover Co(Ⅱ) from aqueous solution utilising (CDFAs) as an extractant.
A novel method for the determination of trace copper in cereals by dispersive liquid-liquid microextraction based on solidification of floating organic drop coupled with flame atomic absorption spectrometry
Chun Xia Wu , Qiu Hua Wu , Chun Wang , Zhi Wang
2011, 22(4): 473-476  doi: 10.1016/j.cclet.2010.10.049
[Abstract](183) [FullText HTML] [PDF 192KB](0)
Abstract:
A novel, simple, rapid, efficient and environment-friendly method for the determination of trace copper in cereal samples was developed by using dispersive liquid-liquid microextraction based on solidification of floating organic drop (DLLME-SFO) followed by flame atomic absorption spectrometry. In the DLLME-SFO, copper was complexed with 8-hydroxy quinoline and extracted into a small volume of 1-dodecanol, which is of low density, low toxicity and proper melting point near room temperature. The experimental parameters affecting the extraction efficiency were investigated and optimized. Under the optimum conditions, the calibration graph exhibited linearity over the range of 0.5-500 ng/mL with the correlation coefficient (r) of 0.9996. The enrichment factor was 122 and the limit of detection was 0.1 ng/mL. The method was applied to the determination of copper in the complex matrix samples such as rice and millet with the recoveries for the spiked samples at 5.0 and 10.0 μg/g falling in the range of 92.0-98.0% and the relative standard deviation of 3.9-5.7%.
Molecularly imprinted polymers for highly sensitive detection of morphine using surface plasmon resonance spectroscopy
Hong Xia Hao , Hong Zhou , Jing Chang , Jun Zhu , Tian Xin Wei
2011, 22(4): 477-480  doi: 10.1016/j.cclet.2010.11.004
[Abstract](188) [FullText HTML] [PDF 655KB](0)
Abstract:
Molecular imprinting technology is applied in surface plasmon resonance spectroscopy for highly sensitive and selective detection of morphine (MO). As SPR-based sensor of MO, the preparation of molecular imprinted polymer is as follows:methacrylic acids (MAA), ethylene glycol dimethacrylate (EGDMA), azodiisobutyronitrile (AIBN) were used as functional monomer, cross-linker and initiator, respectively. The experiment results showed that morphine imprinted polymer had the performance of high sensitivity and specificity, i.e. the relative signal of SPR response was proportional to the concentration of morphine in acetonitrile in the range of 10-9 mol/L to 10-6mol/L (1 ppb-1 ppm) with LOD of 10-10mol/L, and MO was distinguished from its analogs, such as codeine.
A V-shaped spectroscopic cell for FTIR measurements
Xiang Qin Lin , Zhi Xiang Zhang , Wan Qun Hu
2011, 22(4): 481-484  doi: 10.1016/j.cclet.2010.10.043
[Abstract](178) [FullText HTML] [PDF 579KB](0)
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A V-shaped spacroscopic cell (V-cell) was constructed using two CaF2 optical plates for FTIR light transparent measurements in the range of 4000-1000 cm-1. The spectrum of ethanol was characterized with the standard spectra, excellent fitting was achieved with a bottom-width correction method. The principle of the V-cell was discussed, giving equations for the data interpretation. It shows that the V-cell is an auto-focus type spectroscopic cell, which can effectively avoid absorption saturation with amplifications for weak absorption bands. The V-cell design is simple and effective, easy to operate, suitable for applications in liquid samples with high absorption bands, willing to have broad application prospects.
Functionalization of nanodiamond with epoxy monomer
Huan Huan Zhang , Ya Ting Liu , Rong Wang , Xiao Yan Yu , Xiong Wei Qu , Qing Xin Zhang
2011, 22(4): 485-488  doi: 10.1016/j.cclet.2010.10.047
[Abstract](193) [FullText HTML] [PDF 345KB](0)
Abstract:
A novel nanodiamond-epoxy derivative (ND-EP) was synthesized by grafting epoxy monomers onto the surface of nanodiamond (ND), and characterized by FTIR and TGA. The ratio of grafted epoxy groups was determined to be 32.5 wt% by TGA. The developed methodology provides an efficient method for the functionalization of nanodiamond material, which enables a variety of advanced engineering and biomedical applications of ND.
Effects of cosolvent on formation and morphology of microspheres in precipitation polymerization of divinylbenzene in supercritical carbon dioxide
Chun Sheng Li , Jing Cui Liang , Xiao Li Zhu , Xiang Zheng Kong
2011, 22(4): 489-492  doi: 10.1016/j.cclet.2010.10.022
[Abstract](182) [FullText HTML] [PDF 1143KB](0)
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Precipitation polymerizations of divinylbenzene (DVB) in pure supercritical carbon dioxide, and parallel runs with presence of a cosolvent were carried out. The results showed that use of acetone as the cosolvent contributed greatly to the formation of the monodisperse microspheres. PDVB microspheres, with obviously higher uniformity than reported up to date, were achieved using 6-7 mL of acetone in a reactor of 50 mL with DVB concentration of 0.4 mol/L under 16 MPa, a much lower pressure than previously reported without use of cosolvent.
Preparation of a PTE simulacrum based on surface molecular imprinting
Yong Guo , Ying Yang , Tian Ying Guo
2011, 22(4): 493-496  doi: 10.1016/j.cclet.2010.10.050
[Abstract](190) [FullText HTML] [PDF 802KB](0)
Abstract:
Firstly, we synthesized N-methacryloyl-histidine monomer and N-methacryIoyl-histidine-Cu2+ complex (MAH-Cu2+). Then the molecular imprinting polymers (MIP) has been prepared by surface grafting on uniform polystyrene (PS) core using reversible addition-fragmentation transfer polymerization (RAFT) with MAH-Cu2+ as the functional monomer, methyl paraoxon as the template to simulate phosphotriesterase (PTE). Finally, we have investigated the catalytic hydrolytic activities of MIP and non-imprinting polymers (NIP) to the template methyl paraoxon and the template analogue ethyl paraoxon respectively by UV spectrophotometry. The results showed that the catalytic hydrolytic activity of MIP to the template methyl paraoxon was highest and the value of k is 8.67×10-5 mmol L-1 min-1 3.89-fold higher than MIP to the template analogue ethyl paraoxon, 2.79-fold higher than NIP to the template methyl paraoxon. The KM, rm of MIP are also determined, and Km=3.95×10-4 mol/L, rm=2.12 μmol/min. The MIP can be reused with only lose 7% of catalytic activity for four cycles.
Polyporous C@WC1-x composite and its electrocatalytic activity for p-nitrophenol reduction
Hua Jun Zheng , Ai Mei Yu , Chun An Ma
2011, 22(4): 497-500  doi: 10.1016/j.cclet.2010.10.051
[Abstract](199) [FullText HTML] [PDF 928KB](0)
Abstract:
The polyporous carbon supported tungsten carbide (polyporous C@WC1-x) composite was prepared using hexagonal silica MCM-41 as the hard template by raw material solution impregnation, mechanical milling and simultaneous reduction and carbonization by temperature programming in mixture gas (CH4/H2). The structure and morphology of polyporous C@WC1-x composite were studied via X-ray diffraction, transmission electron microscopy and so on. The electrocatalytic property was tested for the electroreduction of p-nitrophenol (PNP) in neutral media. Results revealed that the composite is consisted of polyporous carbon and nanocrystalline WC1-x, possessing good electrocatalytic activity in the reaction of PNP reduction.
Removal of methyl orange from aqueous solution by Azolla filicoloides:Synthesis of Fe3O4 nano-particles and its surface modification by the extracted pectin of Azolla
Roohan Rakhshaee , Masoud Giahi , Afshin Pourahmad
2011, 22(4): 501-504  doi: 10.1016/j.cclet.2010.10.041
[Abstract](186) [FullText HTML] [PDF 404KB](0)
Abstract:
The modified Fe3O4 nano-particles with the extracted pectin from the cell wall of Azolla filicoloides (FN-EP) can remove methyl orange as a water-soluble azo dye from waste water better than Azolla and the extracted pectin from Azolla (EPA), alone. It could be due to more crowding the main functional groups of uptake after binding pectin with nano-particles. Thermodynamic studies showed that adsorption equilibrium constant (KL) and maximum adsorption capacities (Qmax) were increased with decreasing temperature (exothermic). The maximum uptake capacity (Qmax) of dye by FN-EP in a batch reactor was 0.533, 0.498 and 0.446 mmol/g at 5, 25 and 50℃, respectively. The enthalpy change (△H) and entropy change (△S) were-15.31 kJ/mol and-0.02434 kJ/mol K, respectively.
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