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2011 Volume 22 Issue 12
2011, 22(12): 1387-1390
doi: 10.1016/j.cclet.2011.09.005
Abstract:
A series of novel mono (2, 2, 2-trifluoroethyl) esters, mono L-amino acid ester prodrugs of acyclic nucleoside phosphonates was synthesized and their in vitro anti-HBVactivity was evaluated in HepG 2 2.2. 15 cells. Compound 1d exhibited more potent anti-HBV activity and lower cytotoxicity than those of adefovir dipivoxil and alamifovir (MCC-478) with EC50 and CC50 values of 0.01 μmol/L and >8000 μmol/L respectively.
A series of novel mono (2, 2, 2-trifluoroethyl) esters, mono L-amino acid ester prodrugs of acyclic nucleoside phosphonates was synthesized and their in vitro anti-HBVactivity was evaluated in HepG 2 2.2. 15 cells. Compound 1d exhibited more potent anti-HBV activity and lower cytotoxicity than those of adefovir dipivoxil and alamifovir (MCC-478) with EC50 and CC50 values of 0.01 μmol/L and >8000 μmol/L respectively.
2011, 22(12): 1391-1394
doi: 10.1016/j.cclet.2011.06.006
Abstract:
Sulfamic acid was proved to be a cost-effective and recyclable catalyst for Friedel-Crafts type reaction of indole with α, β-unsaturated carbonyl compound and benzyl alcohol. Various indoles, α, β-unsaturated carbonyl compounds and a benzyl alcohol were successfully used in this type of reaction, and the corresponding products were obtained in good to excellent yields.
Sulfamic acid was proved to be a cost-effective and recyclable catalyst for Friedel-Crafts type reaction of indole with α, β-unsaturated carbonyl compound and benzyl alcohol. Various indoles, α, β-unsaturated carbonyl compounds and a benzyl alcohol were successfully used in this type of reaction, and the corresponding products were obtained in good to excellent yields.
2011, 22(12): 1395-1398
doi: 10.1016/j.cclet.2011.07.006
Abstract:
A series of (Z)-2-chloro-l, 3-diarylpropen-l-ones were unexpectedly synthesized in moderate yields by treatment of easily available 2, 3-epoxy-l, 3-diarylpropan-1 -ones with Vilsmeier reagent, which was derived from bis (trichloromethyl) carbonate (BTC, triphosgene) and DMF. A possible mechanism was also proposed, where sequential ring-opening, halogenation and elimination reactions were involved.
A series of (Z)-2-chloro-l, 3-diarylpropen-l-ones were unexpectedly synthesized in moderate yields by treatment of easily available 2, 3-epoxy-l, 3-diarylpropan-1 -ones with Vilsmeier reagent, which was derived from bis (trichloromethyl) carbonate (BTC, triphosgene) and DMF. A possible mechanism was also proposed, where sequential ring-opening, halogenation and elimination reactions were involved.
2011, 22(12): 1399-1402
doi: 10.1016/j.cclet.2011.07.008
Abstract:
A convenient one-step synthesis of five-membered or six-membered imino-protected cyclic guanidine via an intramolecular ring-closure reaction of alkyl diamine (2a-2g) with 1, 3-diamino-protected methylisothiourea (la and 1b) was established and investigated. Amino guanidine such as 3-(2-aminoethyl)-l, 2-dibenzyloxycarbonylguanidine (4a) has been proved to be the intermediate of the reaction via utilizing mono-protected diamine as starting material. The intramolecular ring closure of 4a results in 2-benzyloxycarbonyliminoimidazolidine (3a). This new one-step synthesis has advantages of simple condition, easy workup procedure and reasonable yield.
A convenient one-step synthesis of five-membered or six-membered imino-protected cyclic guanidine via an intramolecular ring-closure reaction of alkyl diamine (2a-2g) with 1, 3-diamino-protected methylisothiourea (la and 1b) was established and investigated. Amino guanidine such as 3-(2-aminoethyl)-l, 2-dibenzyloxycarbonylguanidine (4a) has been proved to be the intermediate of the reaction via utilizing mono-protected diamine as starting material. The intramolecular ring closure of 4a results in 2-benzyloxycarbonyliminoimidazolidine (3a). This new one-step synthesis has advantages of simple condition, easy workup procedure and reasonable yield.
2011, 22(12): 1403-1406
doi: 10.1016/j.cclet.2011.06.007
Abstract:
Disulfides have been synthesized by oxidation of thiols using air as oxidant catalyzed by Co-Salophen with high yields, mild and neutral conditions, and easy procedures of the catalyst. The products were confirmed by 1H NMR and IR.
Disulfides have been synthesized by oxidation of thiols using air as oxidant catalyzed by Co-Salophen with high yields, mild and neutral conditions, and easy procedures of the catalyst. The products were confirmed by 1H NMR and IR.
2011, 22(12): 1407-1410
doi: 10.1016/j.cclet.2011.07.009
Abstract:
Microwave assisted efficient Hantzsch reaction via four-component coupling reactions of tetrazolo[l, 5-a]quinoline-4-carbal-dehyde, dimedone/cyclohexane-l, 3-dione, ethyl/methyl acetoacetate and ammonium acetate was described as the preparation of tetrazolo[l, 5-a]quinoline based 1, 4-dihydropyridines, acridine-l, 8-diones and polyhydroquinolines. The process presented here is simple, rapid, environmentally welcoming and high yielding. All the derivatives were subjected to an in vitro antimicrobial screening against a representative panel of bacteria and fungi and results worth further investigations.
Microwave assisted efficient Hantzsch reaction via four-component coupling reactions of tetrazolo[l, 5-a]quinoline-4-carbal-dehyde, dimedone/cyclohexane-l, 3-dione, ethyl/methyl acetoacetate and ammonium acetate was described as the preparation of tetrazolo[l, 5-a]quinoline based 1, 4-dihydropyridines, acridine-l, 8-diones and polyhydroquinolines. The process presented here is simple, rapid, environmentally welcoming and high yielding. All the derivatives were subjected to an in vitro antimicrobial screening against a representative panel of bacteria and fungi and results worth further investigations.
2011, 22(12): 1411-1414
doi: 10.1016/j.cclet.2011.06.005
Abstract:
A novel pyrrolo-benzoxaborole, 6-(pyrrol-l-yl)-l, 3-dihydro-l-hydroxy-2, 1-benzoxaborole, was synthesized with 27% overall yield over six steps from 2-bromo-1-methyl-4-nitrobenzene as starting material. Its derivatization was achieved via Friedel-Crafts reaction catalyzed by anhydrous stannic chloride with various acyl chlorides giving 3-acyl-1-phenylpyrroles as the main products.
A novel pyrrolo-benzoxaborole, 6-(pyrrol-l-yl)-l, 3-dihydro-l-hydroxy-2, 1-benzoxaborole, was synthesized with 27% overall yield over six steps from 2-bromo-1-methyl-4-nitrobenzene as starting material. Its derivatization was achieved via Friedel-Crafts reaction catalyzed by anhydrous stannic chloride with various acyl chlorides giving 3-acyl-1-phenylpyrroles as the main products.
2011, 22(12): 1415-1418
doi: 10.1016/j.cclet.2011.09.004
Abstract:
An environmentally benign un-catalyzed one-pot synthesis of 4, 4'-(arylmethylene)bis (1H-pyrazol-5-ols) has been reported via tandem Knoevenagel-Michael reaction of aldehydes with two equivalents of 3-methyl-1-phenyl-1H-pyrazol-5 (4H)-one in aqueous medium.
An environmentally benign un-catalyzed one-pot synthesis of 4, 4'-(arylmethylene)bis (1H-pyrazol-5-ols) has been reported via tandem Knoevenagel-Michael reaction of aldehydes with two equivalents of 3-methyl-1-phenyl-1H-pyrazol-5 (4H)-one in aqueous medium.
2011, 22(12): 1419-1422
doi: 10.1016/j.cclet.2011.06.003
Abstract:
Copper oxide nanoparticles showed excellent catalytic activity through three-component condensation reaction of aldehydes, malononitrile, and 4-hydroxycoumarin for the synthesis of 3, 4-dihyropyrano[c]chromenes in water medium in excellent yields and very short reaction times.
Copper oxide nanoparticles showed excellent catalytic activity through three-component condensation reaction of aldehydes, malononitrile, and 4-hydroxycoumarin for the synthesis of 3, 4-dihyropyrano[c]chromenes in water medium in excellent yields and very short reaction times.
2011, 22(12): 1423-1426
doi: 10.1016/j.cclet.2011.06.002
Abstract:
A wide range of mono-and disubstituted 2, 3-dihydroquinazolin-4 (1H)-ones were obtained in high yields by condensation of isatoic anhydride, aldehydes with ammonium salts or primary amines in the presence of strontium chloride in aqueous ethanol under reflux.
A wide range of mono-and disubstituted 2, 3-dihydroquinazolin-4 (1H)-ones were obtained in high yields by condensation of isatoic anhydride, aldehydes with ammonium salts or primary amines in the presence of strontium chloride in aqueous ethanol under reflux.
2011, 22(12): 1427-1430
doi: 10.1016/j.cclet.2011.06.001
Abstract:
Potassium ferrate impregnated on montmorillonite is a mild, cheap, and non-toxic reagent for the iodination of phenols, including naphthol, aromatic amines, and heterocyclic substrates in fair to excellent yields by a simple isolation procedure.
Potassium ferrate impregnated on montmorillonite is a mild, cheap, and non-toxic reagent for the iodination of phenols, including naphthol, aromatic amines, and heterocyclic substrates in fair to excellent yields by a simple isolation procedure.
2011, 22(12): 1431-1434
doi: 10.1016/j.cclet.2011.07.012
Abstract:
A mixture of guanidinium nitrate and silica sulfuric acid acts as mild and heterogeneous media for the efficient mono nitration of phenolic compounds in dichloromethane at room temperature.
A mixture of guanidinium nitrate and silica sulfuric acid acts as mild and heterogeneous media for the efficient mono nitration of phenolic compounds in dichloromethane at room temperature.
2011, 22(12): 1435-1438
doi: 10.1016/j.cclet.2011.07.019
Abstract:
A new protocol for the dehydrogenation of dihydropyridazin-3 (2H)-one has been carried out by catalytic amount of iodine in dimethyl sulphoxide in good yield with easy workup.
A new protocol for the dehydrogenation of dihydropyridazin-3 (2H)-one has been carried out by catalytic amount of iodine in dimethyl sulphoxide in good yield with easy workup.
2011, 22(12): 1439-1442
doi: 10.1016/j.cclet.2011.09.007
Abstract:
Chemically modified cellular co-factors that provide function, such as immobilization or incorporation of fluorescent dyes, are valuable probes of biological activity. A convenient route to obtain S-adenosyl methionine (AdoMet) analogues modified at N-6 adenosine to feature a linker terminating in azide functionality is described herein. Subsequent decoration of such AdoMet analogues with guanidinium terminated linkers leads to novel potential bisubstrate inhibitors for protein arginine methyltransferases, PRMTs.
Chemically modified cellular co-factors that provide function, such as immobilization or incorporation of fluorescent dyes, are valuable probes of biological activity. A convenient route to obtain S-adenosyl methionine (AdoMet) analogues modified at N-6 adenosine to feature a linker terminating in azide functionality is described herein. Subsequent decoration of such AdoMet analogues with guanidinium terminated linkers leads to novel potential bisubstrate inhibitors for protein arginine methyltransferases, PRMTs.
2011, 22(12): 1443-1446
doi: 10.1016/j.cclet.2011.07.020
Abstract:
The solution-phase synthesis of a muramyl dipeptide (MDP) analogue of Nα-[4-chlorocinnamoyl-L-alanyl-D-isoglutaminyl]-L-lysine (MDA, 2) is reported that possesses the features of easy feasibility, safety and low cost in large scale of synthesis.
The solution-phase synthesis of a muramyl dipeptide (MDP) analogue of Nα-[4-chlorocinnamoyl-L-alanyl-D-isoglutaminyl]-L-lysine (MDA, 2) is reported that possesses the features of easy feasibility, safety and low cost in large scale of synthesis.
2011, 22(12): 1447-1450
doi: 10.1016/j.cclet.2011.07.021
Abstract:
Novel isosorbide derivative containing perfluorocarbon group, bi (perfluorooctanesulfonyl)isosorbide ester as chiral dopant in liquid crystal, was synthesized. Chemical structure was characterized by elemental analysis, FT-IR, 1H NMR and19F NMR. The optical texture of the mixture was observed by polarized optical microscopy (POM). Novel chiral dopant containing perfluorocarbon group had excellent optical activity. Its specific rotation and molar rotation were noticeable higher than those of bi (4-chloromethylbenzenecarbonic)isosorbide ester. The fluorocarbon group improved the molar rotation of chiral compound and did not affect optical rotation direction. The texture of the mixture added isosorbide derivative with fluorocarbon group showed the oily streak texture.
Novel isosorbide derivative containing perfluorocarbon group, bi (perfluorooctanesulfonyl)isosorbide ester as chiral dopant in liquid crystal, was synthesized. Chemical structure was characterized by elemental analysis, FT-IR, 1H NMR and
2011, 22(12): 1451-1453
doi: 10.1016/j.cclet.2011.09.001
Abstract:
A new diterpene and a new sesquiterpene were isolated from Pteris dispar and identified on the basis of spectral data including 2D NMR. Compounds 1 and 2 showed potent cytotoxic activity against KB cell.
A new diterpene and a new sesquiterpene were isolated from Pteris dispar and identified on the basis of spectral data including 2D NMR. Compounds 1 and 2 showed potent cytotoxic activity against KB cell.
2011, 22(12): 1454-1456
doi: 10.1016/j.cclet.2011.07.018
Abstract:
A novel 8, 4'-oxyneolignan diglycoside, named ligusinenoside d (1), was isolated from the rhizomes of Ligusticum sinensis, together with five known analogues 2-6. The absolute configurations of 1 and 2 were elucidated by means of enzymatic hydrolysis and spectroscopic data.
A novel 8, 4'-oxyneolignan diglycoside, named ligusinenoside d (1), was isolated from the rhizomes of Ligusticum sinensis, together with five known analogues 2-6. The absolute configurations of 1 and 2 were elucidated by means of enzymatic hydrolysis and spectroscopic data.
2011, 22(12): 1457-1460
doi: 10.1016/j.cclet.2011.09.002
Abstract:
A new skeleton bisabolane-type sesquiterpene curcuminoid, bisabocurcumin (1), along with 5 known compounds, curcumin (2), demethoxycurcumin (3), bidemethoxycurcumin (4), (1E, 4E)-l, 5-bis (4-hydroxy-3-methoxyphenyl)-penta-1, 4-dien-3-one (5), and (1E, 4E)-1-(4-hydroxy-3-methoxyphenyl)-5-(4-hydroxy phenyl-)-penta-1, 4-dien-3-one (6) were isolated from the rhizomes of Curcuma longa L. Their structures were determined on the basis of spectroscopic analysis. Bisabocurcumin (1) is firstly obtained from nature with a new skeleton combined by a bisabolane-type sesquiterpene and a 1, 7-diphenylheptanoid through a C-C bond.
A new skeleton bisabolane-type sesquiterpene curcuminoid, bisabocurcumin (1), along with 5 known compounds, curcumin (2), demethoxycurcumin (3), bidemethoxycurcumin (4), (1E, 4E)-l, 5-bis (4-hydroxy-3-methoxyphenyl)-penta-1, 4-dien-3-one (5), and (1E, 4E)-1-(4-hydroxy-3-methoxyphenyl)-5-(4-hydroxy phenyl-)-penta-1, 4-dien-3-one (6) were isolated from the rhizomes of Curcuma longa L. Their structures were determined on the basis of spectroscopic analysis. Bisabocurcumin (1) is firstly obtained from nature with a new skeleton combined by a bisabolane-type sesquiterpene and a 1, 7-diphenylheptanoid through a C-C bond.
2011, 22(12): 1461-1464
doi: 10.1016/j.cclet.2011.09.003
Abstract:
Two new sapogenins, named (20S, 24R)-3β, 20, 21β, 25-tetrahydroxy-21, 24-cyclodammarane (1) and 3β-hydroxyetio-17β-dammaranic acid (2), were isolated from the alkaline hydrolysate of Gynostemma pentaphyllum saponins. Their structures were elucidated by spectroscopic methods.
Two new sapogenins, named (20S, 24R)-3β, 20, 21β, 25-tetrahydroxy-21, 24-cyclodammarane (1) and 3β-hydroxyetio-17β-dammaranic acid (2), were isolated from the alkaline hydrolysate of Gynostemma pentaphyllum saponins. Their structures were elucidated by spectroscopic methods.
2011, 22(12): 1465-1468
doi: 10.1016/j.cclet.2011.06.011
Abstract:
The separation optimization of nine organic and inorganic anions in tobacco leaves using gradient ion chromatography by response surface methodology was investigated. In order to achieve this goal the usefulness of the chromatographic response function (CRF) for the evaluation of the two different chromatographic performance goals (resolution and analysis time) was tested. The experiments were performed according to a Box-Behnken design response surface experimental design.
The separation optimization of nine organic and inorganic anions in tobacco leaves using gradient ion chromatography by response surface methodology was investigated. In order to achieve this goal the usefulness of the chromatographic response function (CRF) for the evaluation of the two different chromatographic performance goals (resolution and analysis time) was tested. The experiments were performed according to a Box-Behnken design response surface experimental design.
2011, 22(12): 1469-1472
doi: 10.1016/j.cclet.2011.06.010
Abstract:
The present work has focused on the modification of multiwalled carbon nanotube with a ligand, l-(2-pyridylazo)-2-naphthol, and its potential application for the development of a new, simple and selective modified glassy carbon electrode for stripping voltammetric determination of Cd (Ⅱ). The analytical curve for Cd (Ⅱ) ions covered the linear range varying from 0.8 up to 220.4 μg L-1. The limit of detection was found to be 0.1 μg L-1, while the relative standard deviation (RSD) at 50.0 μg L-1 was 1.8% (n=5). This modified electrode was successfully applied for determination of Cd (Ⅱ) in some water samples.
The present work has focused on the modification of multiwalled carbon nanotube with a ligand, l-(2-pyridylazo)-2-naphthol, and its potential application for the development of a new, simple and selective modified glassy carbon electrode for stripping voltammetric determination of Cd (Ⅱ). The analytical curve for Cd (Ⅱ) ions covered the linear range varying from 0.8 up to 220.4 μg L-1. The limit of detection was found to be 0.1 μg L-1, while the relative standard deviation (RSD) at 50.0 μg L-1 was 1.8% (n=5). This modified electrode was successfully applied for determination of Cd (Ⅱ) in some water samples.
2011, 22(12): 1473-1476
doi: 10.1016/j.cclet.2011.07.010
Abstract:
Near-infrared spectroscopy (NIR), which is generally used for online monitoring of the food analysis and production process, was applied to determine the internal quality of toothpaste samples. It is acknowledged that the spectra can be significantly influenced by non-linearities introduced by light scatter, therefore, four data preprocessing methods, including off-set correction, 1st-derivative, standard normal variate (SNV) and multiplicative scatter correction (MSC), were employed before the date analysis. The multivariate calibration model of partial least squares (PLS) was established and then was used to predict the pH values of the toothpaste samples of different brand. The results showed that the spectral date processed by MSC was the best one for predicting the pH value of the toothpaste samples.
Near-infrared spectroscopy (NIR), which is generally used for online monitoring of the food analysis and production process, was applied to determine the internal quality of toothpaste samples. It is acknowledged that the spectra can be significantly influenced by non-linearities introduced by light scatter, therefore, four data preprocessing methods, including off-set correction, 1st-derivative, standard normal variate (SNV) and multiplicative scatter correction (MSC), were employed before the date analysis. The multivariate calibration model of partial least squares (PLS) was established and then was used to predict the pH values of the toothpaste samples of different brand. The results showed that the spectral date processed by MSC was the best one for predicting the pH value of the toothpaste samples.
2011, 22(12): 1477-1480
doi: 10.1016/j.cclet.2011.07.013
Abstract:
A rapid and sensitive method to identify and analyze mixed pesticides of tricyclazole, paraquat and flusilazole by surface-enhanced Raman scattering has been reported. Aqueous samples can be detected by SERS in low concentrations of 0.01 mg/L, 0.1 mg/L and 2.85 mg/L for individual tricyclazole, paraquat and flusilazole respectively. When mixing the three pesticides in the low concentrations, their characteristic peaks can still be identified from the SERS spectrum of the mixture.
A rapid and sensitive method to identify and analyze mixed pesticides of tricyclazole, paraquat and flusilazole by surface-enhanced Raman scattering has been reported. Aqueous samples can be detected by SERS in low concentrations of 0.01 mg/L, 0.1 mg/L and 2.85 mg/L for individual tricyclazole, paraquat and flusilazole respectively. When mixing the three pesticides in the low concentrations, their characteristic peaks can still be identified from the SERS spectrum of the mixture.
2011, 22(12): 1481-1484
doi: 10.1016/j.cclet.2011.07.017
Abstract:
We report a new method for detection and oxidation of adsorbed carbon monoxide (CO (ads)) generated from serine on a polycrystalline platinum ultramicroelectrode (UME) by bromine (Br2) using in situ surface interrogation (SI) mode of scanning electrochemical microscopy (SECM). In the SI mode, tip and substrate are both Pt UMEs, and CO (ads) on Pt substrate, generated from serine, can be oxidized by the tip-generated Br2 giving a positive response. Dosing CO (ads) from serine instead of purging CO gas expands the newly introduced reaction of Br2 with CO (ads) and further enhances the hope to get rid of CO (ads) on Pt for fuel cells.
We report a new method for detection and oxidation of adsorbed carbon monoxide (CO (ads)) generated from serine on a polycrystalline platinum ultramicroelectrode (UME) by bromine (Br2) using in situ surface interrogation (SI) mode of scanning electrochemical microscopy (SECM). In the SI mode, tip and substrate are both Pt UMEs, and CO (ads) on Pt substrate, generated from serine, can be oxidized by the tip-generated Br2 giving a positive response. Dosing CO (ads) from serine instead of purging CO gas expands the newly introduced reaction of Br2 with CO (ads) and further enhances the hope to get rid of CO (ads) on Pt for fuel cells.
2011, 22(12): 1485-1488
doi: 10.1016/j.cclet.2011.09.008
Abstract:
A new method was developed for simultaneous determination of levels of AMP, ADP and ATP in blood by anion-exchange chromatography. The three adenosine phosphates were separated by Dionex IonPac AG18 (50 mm×4 mm) guard column and IonPac AS18 (250 mm×4 mm) analytical column using a gradient method and detected with a suppressed conductivity detector. The detection limits (S/N=3) of AMP, ADP and ATP were 38, 47, 108 ng/L, respectively. The relative standard deviations of retention time, peak area and peak height were all less than 1.87% and a good linear relationship was obtained. This method was applied to analyze human blood samples.
A new method was developed for simultaneous determination of levels of AMP, ADP and ATP in blood by anion-exchange chromatography. The three adenosine phosphates were separated by Dionex IonPac AG18 (50 mm×4 mm) guard column and IonPac AS18 (250 mm×4 mm) analytical column using a gradient method and detected with a suppressed conductivity detector. The detection limits (S/N=3) of AMP, ADP and ATP were 38, 47, 108 ng/L, respectively. The relative standard deviations of retention time, peak area and peak height were all less than 1.87% and a good linear relationship was obtained. This method was applied to analyze human blood samples.
2011, 22(12): 1489-1491
doi: 10.1016/j.cclet.2011.07.005
Abstract:
A water-soluble polymeric UV-absorber with polyvinylamine as backbone and benzotriazole type UV absorber as anti-UV functional group was synthesized by grafting brominated (2'-acetoxy-5'-methylphenyl)-2H-benzotriazole onto polyvinylamine. The intermediates and synthesized polymeric UV absorber were characterized by 1H NMR, MS, IR and UV spectroscopy. The finishing properties of the polymeric UV absorber on cotton were investigated to show good UV protection property and wash fastness.
A water-soluble polymeric UV-absorber with polyvinylamine as backbone and benzotriazole type UV absorber as anti-UV functional group was synthesized by grafting brominated (2'-acetoxy-5'-methylphenyl)-2H-benzotriazole onto polyvinylamine. The intermediates and synthesized polymeric UV absorber were characterized by 1H NMR, MS, IR and UV spectroscopy. The finishing properties of the polymeric UV absorber on cotton were investigated to show good UV protection property and wash fastness.
2011, 22(12): 1492-1496
doi: 10.1016/j.cclet.2011.05.040
Abstract:
Partial oxidation of methane (POM) co-fed with CO2 to syngas in a novel catalytic BaCo0.6Fe0.2Ta0.2O3-δ oxygen permeable membrane reactor was successfully reported. Adding CO2 to the partial oxidation of methane reaction not only alters the ratio of CO/H2, but also increases the oxygen permeation flux and CH4 conversion. Around 96% CH4 conversion with more than 93% CO2 conversion and 100% CO selectivity is achieved, which shows an excellent reaction performance. A steady oxygen permeation flux of 15 mL/ (cm2 min) is obtained during the 100-h operation, which shows good stability as well.
Partial oxidation of methane (POM) co-fed with CO2 to syngas in a novel catalytic BaCo0.6Fe0.2Ta0.2O3-δ oxygen permeable membrane reactor was successfully reported. Adding CO2 to the partial oxidation of methane reaction not only alters the ratio of CO/H2, but also increases the oxygen permeation flux and CH4 conversion. Around 96% CH4 conversion with more than 93% CO2 conversion and 100% CO selectivity is achieved, which shows an excellent reaction performance. A steady oxygen permeation flux of 15 mL/ (cm2 min) is obtained during the 100-h operation, which shows good stability as well.
2011, 22(12): 1497-1500
doi: 10.1016/j.cclet.2011.07.007
Abstract:
Phase behavior of binary system of bromobenzene-chlorobenzene (C6H5Br-C6H5Cl) confined in SBA-15 and MCM-41 (pore diameter 8 nm, 3.8 nm, respectively) has been investigated by means of differential scanning calorimetry (DSC). Phase diagram of C6H5Br-C6H5Cl system confined in SBA-15 is a type of the complete miscible both in liquid and solid state, the same phase behavior as the bulk system. However, the phase diagram comprises only one boundary line, which is shifted down 22-36 K with respect to the bulk system. C6H5Br, C6H5Cl or the mixture within nanopores of MCM-41 is nonfreezing. The different phase behavior of the system confined in SBA-15 and MCM-41 is thought mainly due to the relative size of pore to molecule.
Phase behavior of binary system of bromobenzene-chlorobenzene (C6H5Br-C6H5Cl) confined in SBA-15 and MCM-41 (pore diameter 8 nm, 3.8 nm, respectively) has been investigated by means of differential scanning calorimetry (DSC). Phase diagram of C6H5Br-C6H5Cl system confined in SBA-15 is a type of the complete miscible both in liquid and solid state, the same phase behavior as the bulk system. However, the phase diagram comprises only one boundary line, which is shifted down 22-36 K with respect to the bulk system. C6H5Br, C6H5Cl or the mixture within nanopores of MCM-41 is nonfreezing. The different phase behavior of the system confined in SBA-15 and MCM-41 is thought mainly due to the relative size of pore to molecule.
2011, 22(12): 1501-1504
doi: 10.1016/j.cclet.2011.07.016
Abstract:
In this research, a lucunary Keggin structure,[PMO2W9039]7- was selected as an efficient homogenous catalyst for degradation of an azo dye (direct blue 71) and a simple method was developed for degradation of DB71. The method is based on the oxidation of azo dye in the presence of a lucunary Keggin form of polyoxometalates, K7[PMO2W9O39]·19H2O, as a homogenous catalyst at room temperature. The reaction is monitored spectrophotometrically by measuring the absorbance of dye at λ=585 nm. Some parameters including concentration of catalyst, concentration of H2O2, pH and reaction time were investigated and optimized. Results show that K7[PMO2W9O39]·19H20 is more efficient in the presence of hydrogen peroxide. Degradation of dye in the presence of the catalyst and H2O2 could lead to the disappearance approximately 65% of dye after 60 min. But degradation for the same experiment performed in the absence of catalyst or in the absence of H2O2 was 22% or 5% respectively. Approximately 87% azo dyes has been eliminated after 90 min in the presence of catalyst, H2O2 and optimize conditions (0.6 g/L of K7[PMO2-W9O39]·19H2O, 0.08 mol/L hydrogen peroxide and room temperature).
In this research, a lucunary Keggin structure,[PMO2W9039]7- was selected as an efficient homogenous catalyst for degradation of an azo dye (direct blue 71) and a simple method was developed for degradation of DB71. The method is based on the oxidation of azo dye in the presence of a lucunary Keggin form of polyoxometalates, K7[PMO2W9O39]·19H2O, as a homogenous catalyst at room temperature. The reaction is monitored spectrophotometrically by measuring the absorbance of dye at λ=585 nm. Some parameters including concentration of catalyst, concentration of H2O2, pH and reaction time were investigated and optimized. Results show that K7[PMO2W9O39]·19H20 is more efficient in the presence of hydrogen peroxide. Degradation of dye in the presence of the catalyst and H2O2 could lead to the disappearance approximately 65% of dye after 60 min. But degradation for the same experiment performed in the absence of catalyst or in the absence of H2O2 was 22% or 5% respectively. Approximately 87% azo dyes has been eliminated after 90 min in the presence of catalyst, H2O2 and optimize conditions (0.6 g/L of K7[PMO2-W9O39]·19H2O, 0.08 mol/L hydrogen peroxide and room temperature).
2011, 22(12): 1505-1508
doi: 10.1016/j.cclet.2011.06.004
Abstract:
A series of poly (2-acetoxyethyl methacrylate)/polystyrene (PAEMA/PS) latex interpenetrating polymer networks (LIPNs) were prepared by seeded soap-free emulsion polymerization of styrene on the crosslinked PAEMA seed particles using an oil-soluble initiator. These PAEMA/PS LIPNs showed a well-defined phase-separated structure with PS phase dispersing in continuous PAEMA phase. The domain size of PS phase was found to depend on the crosslinking degree of PAEMA seed particles and the amount of second-stage styrene monomer.
A series of poly (2-acetoxyethyl methacrylate)/polystyrene (PAEMA/PS) latex interpenetrating polymer networks (LIPNs) were prepared by seeded soap-free emulsion polymerization of styrene on the crosslinked PAEMA seed particles using an oil-soluble initiator. These PAEMA/PS LIPNs showed a well-defined phase-separated structure with PS phase dispersing in continuous PAEMA phase. The domain size of PS phase was found to depend on the crosslinking degree of PAEMA seed particles and the amount of second-stage styrene monomer.
2011, 22(12): 1509-1512
doi: 10.1016/j.cclet.2011.07.011
Abstract:
Ring-opening suspension polymerization of p-dioxanone (PDO) in supercritical carbon dioxide (scCO2) was investigated in the presence of poly (caprolactone)-perfluropolyether-poly (caprolactone) (PCL-PFPE-PCL). The molecular weight, yield and particle morphology of poly (p-dioxanone) (PPDO) were studied. The stabilizer was effective to stabilize the ring-opening polymerization (ROP) of PDO in scCO2, leading to the formation of resorbable microparticles in a "one pot" procedure. The mean size of PPDO microparticles obtained from suspension polymerizations was sensitive to the rate of agitation and the stabilizer concentration. The method to generate PPDO microparticles has overcome its unprocessable drawback with common organic solvents and provided new product form for biomedical applications.
Ring-opening suspension polymerization of p-dioxanone (PDO) in supercritical carbon dioxide (scCO2) was investigated in the presence of poly (caprolactone)-perfluropolyether-poly (caprolactone) (PCL-PFPE-PCL). The molecular weight, yield and particle morphology of poly (p-dioxanone) (PPDO) were studied. The stabilizer was effective to stabilize the ring-opening polymerization (ROP) of PDO in scCO2, leading to the formation of resorbable microparticles in a "one pot" procedure. The mean size of PPDO microparticles obtained from suspension polymerizations was sensitive to the rate of agitation and the stabilizer concentration. The method to generate PPDO microparticles has overcome its unprocessable drawback with common organic solvents and provided new product form for biomedical applications.
