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2006 Volume 17 Issue 4
2006, 17(4): 427-430
Abstract:
4-(2-Ferrocenylethenyl)-phenyl-POSS Fc-CH=CH-C6H6-(C5H9)7Si8O12 (FEPS, Fc:ferrocene), containing metal and C=C double bond, was firstly synthesized as a mixture of E/Z isomers by the Wittig reaction. The chemical structure of FEPS was characterized by FTIR, 1H-, 13C and 29Si-NMR.
4-(2-Ferrocenylethenyl)-phenyl-POSS Fc-CH=CH-C6H6-(C5H9)7Si8O12 (FEPS, Fc:ferrocene), containing metal and C=C double bond, was firstly synthesized as a mixture of E/Z isomers by the Wittig reaction. The chemical structure of FEPS was characterized by FTIR, 1H-, 13C and 29Si-NMR.
2006, 17(4): 431-433
Abstract:
A convenient synthesis of cis-(±) isomer 1 and trans-(±) isomer 2 of lamivudine starting from benzoyloxyacetaldehyde and 1, 4-dithiane-2, 5-diol is described. The key steps include chlorination of oxathiolane lactol 5 by SOCl2/DMF, followed by coupling with silylated N4-acetylcytosine and deprotection. The overall yield was 42.6% and 20.1%, respectively.
A convenient synthesis of cis-(±) isomer 1 and trans-(±) isomer 2 of lamivudine starting from benzoyloxyacetaldehyde and 1, 4-dithiane-2, 5-diol is described. The key steps include chlorination of oxathiolane lactol 5 by SOCl2/DMF, followed by coupling with silylated N4-acetylcytosine and deprotection. The overall yield was 42.6% and 20.1%, respectively.
2006, 17(4): 434-436
Abstract:
A pair of derivatives of tetrameric N-methylpyrrole polyamide were synthesized in order to develop a new method for the study of interaction of the polyamide derivatives with DNA. Indole acetic acid and nicotinic acid were introduced to the polyamide in the synthesized compound, which showed an expected red shift in the UV spectrum. These compounds may function as a potential tool in the detection of the polyamide binding to DNA.
A pair of derivatives of tetrameric N-methylpyrrole polyamide were synthesized in order to develop a new method for the study of interaction of the polyamide derivatives with DNA. Indole acetic acid and nicotinic acid were introduced to the polyamide in the synthesized compound, which showed an expected red shift in the UV spectrum. These compounds may function as a potential tool in the detection of the polyamide binding to DNA.
2006, 17(4): 437-440
Abstract:
A novel method for the preparation of oligothiophene molecular wires is described via a bi-directional solid-phase synthesis. Using an alternating sequence of bromination and Stille coupling reactions, oligomers were obtained up to the heptamer in excellent yield and purity.
A novel method for the preparation of oligothiophene molecular wires is described via a bi-directional solid-phase synthesis. Using an alternating sequence of bromination and Stille coupling reactions, oligomers were obtained up to the heptamer in excellent yield and purity.
2006, 17(4): 441-443
Abstract:
Sulphur-containing aromatic amines were prepared efficiently in good to excellent yields by reduction of the corresponding sulphur-containing aromatic nitro compounds with hydrazine hydrate in the presence of iron(Ⅲ) oxide-MgO catalyst. The catalyst exhibited high activity and stability for the reduction of sulphur-containing aromatic nitro compounds. The yields of sulphur-containing aromatic amines were up to 91-99% at 355 K after reduction for 1-4 h over this catalyst.
Sulphur-containing aromatic amines were prepared efficiently in good to excellent yields by reduction of the corresponding sulphur-containing aromatic nitro compounds with hydrazine hydrate in the presence of iron(Ⅲ) oxide-MgO catalyst. The catalyst exhibited high activity and stability for the reduction of sulphur-containing aromatic nitro compounds. The yields of sulphur-containing aromatic amines were up to 91-99% at 355 K after reduction for 1-4 h over this catalyst.
2006, 17(4): 444-446
Abstract:
10, 11-Dihydro-10-hydroxycyproheptadine was synthesized in a new and facile synthetic route and resolved by L-(-)-2-(1, 3)-dioxo-1, 3-dihydroisoindol-2-yl)-propionic acid and D-(+)-tartaric acid, respectively. The free base of the two enantiomers has the same absolute specific rotation value.
10, 11-Dihydro-10-hydroxycyproheptadine was synthesized in a new and facile synthetic route and resolved by L-(-)-2-(1, 3)-dioxo-1, 3-dihydroisoindol-2-yl)-propionic acid and D-(+)-tartaric acid, respectively. The free base of the two enantiomers has the same absolute specific rotation value.
2006, 17(4): 447-448
Abstract:
N, N'-Bis(3-hydroxyphenyl)-1, 8, 4, 5-naphthalenetetracarboxylic bisimide was prepared from the reaction of 1, 8, 4, 5-naphthalenetetrcarboxylic acid dianhydride and 2-aminophenol in N, N-dimethylformamide. Polymerization of this bisimide with 4, 4'-difluorodiphenylsulfone and disodium 3, 3'-disulfonate4, 4'-difluorodiphenylsulfone gave ion-exchange sulfonated poly(ether sulfone). The structure of the title compound was characterized with 1H-NMR and its polymer was characterized with FT-IR.
N, N'-Bis(3-hydroxyphenyl)-1, 8, 4, 5-naphthalenetetracarboxylic bisimide was prepared from the reaction of 1, 8, 4, 5-naphthalenetetrcarboxylic acid dianhydride and 2-aminophenol in N, N-dimethylformamide. Polymerization of this bisimide with 4, 4'-difluorodiphenylsulfone and disodium 3, 3'-disulfonate4, 4'-difluorodiphenylsulfone gave ion-exchange sulfonated poly(ether sulfone). The structure of the title compound was characterized with 1H-NMR and its polymer was characterized with FT-IR.
2006, 17(4): 449-452
Abstract:
The synthesis of (±)-5, 6, 7-trioxygenated dihydroflavonols was carried out. All synthetic compounds were passed through superoxide radical scavenging activity in vitro.Compounds 1e and 1g exhibited significant bioactivity with the inhibitory rates of 68.1% and 80.9% at 40μg/mL, respectively.
The synthesis of (±)-5, 6, 7-trioxygenated dihydroflavonols was carried out. All synthetic compounds were passed through superoxide radical scavenging activity in vitro.Compounds 1e and 1g exhibited significant bioactivity with the inhibitory rates of 68.1% and 80.9% at 40μg/mL, respectively.
2006, 17(4): 453-456
Abstract:
Differently substituted benzimidazoles have been synthesized in very good yields in solvent-free clnditions from o-phenlenediame and aldehydes im the pressemce of BF3·OEt2 as acatalyst. The method is applicable to aromatic, unsaturated and aliphatic aldehydes and to substituted o-phenylenediamines without significant differences.
Differently substituted benzimidazoles have been synthesized in very good yields in solvent-free clnditions from o-phenlenediame and aldehydes im the pressemce of BF3·OEt2 as acatalyst. The method is applicable to aromatic, unsaturated and aliphatic aldehydes and to substituted o-phenylenediamines without significant differences.
2006, 17(4): 457-460
Abstract:
Intramolecular cyclization of β-methyl substituted epoxide under aprotics (e.g. LDA in benzene) and protic conditions (e.g. LiOH in MeOH/H2O)both gave a mixture of β-, γ-, δ- and ε-lactam but in different ratio.
Intramolecular cyclization of β-methyl substituted epoxide under aprotics (e.g. LDA in benzene) and protic conditions (e.g. LiOH in MeOH/H2O)both gave a mixture of β-, γ-, δ- and ε-lactam but in different ratio.
2006, 17(4): 461-464
Abstract:
Flurbiprofen 1, an excellent nonsteroidal an tiinflammatory drug, was synthesized in 5steps in 69% overall yield. The key step of constructing the biaryl fragment was successfully achieved via Pd/C-catalyzed Suzuki coupling reaction in water using sodium tetraphenylborate as phenylation reagent.
Flurbiprofen 1, an excellent nonsteroidal an tiinflammatory drug, was synthesized in 5steps in 69% overall yield. The key step of constructing the biaryl fragment was successfully achieved via Pd/C-catalyzed Suzuki coupling reaction in water using sodium tetraphenylborate as phenylation reagent.
2006, 17(4): 465-468
Abstract:
Eight novel silybin analogues (7a-h) were synthesized and their antioxidant properties including the capability of scavenging superoxide anion free radicals and the inhibitory effect on DPPH free radicals were determined. Several synthetic compounds showed comparable antioxidative effect to that of quercetin.
Eight novel silybin analogues (7a-h) were synthesized and their antioxidant properties including the capability of scavenging superoxide anion free radicals and the inhibitory effect on DPPH free radicals were determined. Several synthetic compounds showed comparable antioxidative effect to that of quercetin.
2006, 17(4): 469-472
Abstract:
Eight N-substituted diketopiperazines (DKPs) were synthesized by solid-phase protocols. The introduction of iminodiacetic acid (Ida) and followed another α-amino acid residue as the precursor of DKP framework made the present synthesis to bc very facile and efficient.
Eight N-substituted diketopiperazines (DKPs) were synthesized by solid-phase protocols. The introduction of iminodiacetic acid (Ida) and followed another α-amino acid residue as the precursor of DKP framework made the present synthesis to bc very facile and efficient.
2006, 17(4): 473-476
Abstract:
The palladium chloride-catalyzed Suzuki coupling reaction of sodium tetraphenylborate with hypervalent iodonium salts was achieved under microwave irradiation in water without base in excellent yield. A convenient and rapidmethod for formation of carbon-carbon bonds was afforded.
The palladium chloride-catalyzed Suzuki coupling reaction of sodium tetraphenylborate with hypervalent iodonium salts was achieved under microwave irradiation in water without base in excellent yield. A convenient and rapidmethod for formation of carbon-carbon bonds was afforded.
2006, 17(4): 477-480
Abstract:
New minor cyclic peptides, named arenariphilin C 1 and arenariphilin D 2, were isolated from the whole plants of Arenaria oreophila (Caryophyllaceae). Their structures were determined as cyclo(Pro1-Pro2-Leu1-Leu2-Phe-Ser-Gly-Thr) and cyclo (Ser-Cys) on the basis of spectroscopic data, especially by two-dimension NMR (2D NMR) technologies.
New minor cyclic peptides, named arenariphilin C 1 and arenariphilin D 2, were isolated from the whole plants of Arenaria oreophila (Caryophyllaceae). Their structures were determined as cyclo(Pro1-Pro2-Leu1-Leu2-Phe-Ser-Gly-Thr) and cyclo (Ser-Cys) on the basis of spectroscopic data, especially by two-dimension NMR (2D NMR) technologies.
2006, 17(4): 481-484
Abstract:
A new abietane diterpene 12-hydroxy-7-oxo-5, 8, 11, 13-tetraene-18, 6-abietanolide, together with a new natural sterol stigmasta-7, 22-diene-3β, 5α, 6α-triol have been isolated from the fruiting body of the fungus Phellinus igniarius. Their structures were elucidated by spectroscopic methods including 2D NMR techniques.
A new abietane diterpene 12-hydroxy-7-oxo-5, 8, 11, 13-tetraene-18, 6-abietanolide, together with a new natural sterol stigmasta-7, 22-diene-3β, 5α, 6α-triol have been isolated from the fruiting body of the fungus Phellinus igniarius. Their structures were elucidated by spectroscopic methods including 2D NMR techniques.
2006, 17(4): 485-488
Abstract:
Two new dihydroflavonoids named villosin A and villosin B were obtained from the traditional Chinese medicinal herb Patrinia villosa Juss. Their structures were elucidated as (2S)-5, 2', 6'-trihydroxy-2", 2"-dimethylpyrano [5", 6":6, 7]flavanone 1 and (2S, 3"S)-5, 2', 6'-trihydroxy-3"-γ, γ-dimethylallyl-2", 2"-dimethyl-3", 4"-dihydropyrano [5", 6":6, 7] flavanone 2 by spectroscopic methods including UV, IR, HR-TOF-MS, 1D NMR and 2D NMR techniques.
Two new dihydroflavonoids named villosin A and villosin B were obtained from the traditional Chinese medicinal herb Patrinia villosa Juss. Their structures were elucidated as (2S)-5, 2', 6'-trihydroxy-2", 2"-dimethylpyrano [5", 6":6, 7]flavanone 1 and (2S, 3"S)-5, 2', 6'-trihydroxy-3"-γ, γ-dimethylallyl-2", 2"-dimethyl-3", 4"-dihydropyrano [5", 6":6, 7] flavanone 2 by spectroscopic methods including UV, IR, HR-TOF-MS, 1D NMR and 2D NMR techniques.
2006, 17(4): 489-492
Abstract:
A novel electrochemical immunosensor with amplification effect based on the enzyme inhibition of silver deposition was proposed. In this method, the capture antibody was first immobilized onto a gold electrode via a self-assembled layer. After a sandwich immunoreaction, HRP labeled antibody was bound to the gold electrode. The HRP on the electrode inhibited silver deposition when the electrode was incubated in hydroquinone-H2O2 solution and silver ion solution.The linear sweep voltammetry was chosen to detect the deposited silver and the result showed that the peak current was linearly proportional to the content of IgG in the range of 50 to 2500 ng/mL with a detection limit of 35 ng/mL.
A novel electrochemical immunosensor with amplification effect based on the enzyme inhibition of silver deposition was proposed. In this method, the capture antibody was first immobilized onto a gold electrode via a self-assembled layer. After a sandwich immunoreaction, HRP labeled antibody was bound to the gold electrode. The HRP on the electrode inhibited silver deposition when the electrode was incubated in hydroquinone-H2O2 solution and silver ion solution.The linear sweep voltammetry was chosen to detect the deposited silver and the result showed that the peak current was linearly proportional to the content of IgG in the range of 50 to 2500 ng/mL with a detection limit of 35 ng/mL.
2006, 17(4): 493-495
Abstract:
A setup for recording surface tension curves at a mercury drop during potential scanning is designed based on photo-sensitive detection system. Surface tension spectrum at Hg drop can be recorded by voltammetric study. A Yb(Ⅲ)-NO2- catalytic reduction system was used for characterization. The simple, sensitive technique can be expected to provide fresh information on molecular interactions at electrode surfaces.
A setup for recording surface tension curves at a mercury drop during potential scanning is designed based on photo-sensitive detection system. Surface tension spectrum at Hg drop can be recorded by voltammetric study. A Yb(Ⅲ)-NO2- catalytic reduction system was used for characterization. The simple, sensitive technique can be expected to provide fresh information on molecular interactions at electrode surfaces.
2006, 17(4): 496-498
Abstract:
A novel amperometric sensor for the determination of nitric oxide was developed by coating polythionine/nafion on a glassy carbon electrode. This sensor exhibited a great enhancement to the oxidation of nitric oxide. The oxidation peak currents were linear to the concentration of nitric oxide over the wide range from 3.6×10-7 to 6.8×10-5 mol·L-1, and the detection limit was 7.2×10-8 mol·L-1. Experimental results showed that this nitric oxide sensor possessed excellent selectivity and longer stability. NO releasing from rat kidney was monitored by this sensor.
A novel amperometric sensor for the determination of nitric oxide was developed by coating polythionine/nafion on a glassy carbon electrode. This sensor exhibited a great enhancement to the oxidation of nitric oxide. The oxidation peak currents were linear to the concentration of nitric oxide over the wide range from 3.6×10-7 to 6.8×10-5 mol·L-1, and the detection limit was 7.2×10-8 mol·L-1. Experimental results showed that this nitric oxide sensor possessed excellent selectivity and longer stability. NO releasing from rat kidney was monitored by this sensor.
2006, 17(4): 499-501
Abstract:
Current methods for single nucleotide polymorphism (SNP) analysis are timeconsuming and complicated. We aimed at development of one-step real-time fluorescence mutant-allele-specific amplification (MASA) method for rapid SNP analysis. The method is a marriage of two technologies: MASA primers for target DNA and a double-stranded DNA-selective fluorescent dye, SYBR Green I. Genotypes are separated according to the different threshold cycles of the wild-type and mutant primers. K-ras oncogene was used as a target to validate the feasibility of the method. The experimental results showed that the different genotypes can be clearly discriminated by the assay. The real-time fluorescence MASA method will have an enormous potential for fast and reliable SNP analysis due to its simplicity and low cost.
Current methods for single nucleotide polymorphism (SNP) analysis are timeconsuming and complicated. We aimed at development of one-step real-time fluorescence mutant-allele-specific amplification (MASA) method for rapid SNP analysis. The method is a marriage of two technologies: MASA primers for target DNA and a double-stranded DNA-selective fluorescent dye, SYBR Green I. Genotypes are separated according to the different threshold cycles of the wild-type and mutant primers. K-ras oncogene was used as a target to validate the feasibility of the method. The experimental results showed that the different genotypes can be clearly discriminated by the assay. The real-time fluorescence MASA method will have an enormous potential for fast and reliable SNP analysis due to its simplicity and low cost.
2006, 17(4): 502-504
Abstract:
After the treatment of oxygen gas, the small molecules containing amine group could emit fluorescence. Oxidation was believed to play an important role in the formation of fluorescence centers. Compared to previous results, both small molecules and macromolecules might have the same fluorescence centers.
After the treatment of oxygen gas, the small molecules containing amine group could emit fluorescence. Oxidation was believed to play an important role in the formation of fluorescence centers. Compared to previous results, both small molecules and macromolecules might have the same fluorescence centers.
2006, 17(4): 505-508
Abstract:
Using four β-cyclodextrin derivatives, 2, 6-di-O-benzyl-3-O-heptanonyl-β-CD, 2, 6-di-O-benzyl-3-O-octanonyl-β-CD, 2, 3-di-O-benzyl-6-O-heptanonyl-β-CD, and 2, 3-di-O-benzy1-6-O-octanonyl-β-CD, as chiral stationary phases of capillary gas chromatography (CGC), the enantiomers of Sharpless epoxides were well separated. The enantiomer excess values (e.e.%) of some chiral Sharpless epoxides were also determined successfully using these CDs.
Using four β-cyclodextrin derivatives, 2, 6-di-O-benzyl-3-O-heptanonyl-β-CD, 2, 6-di-O-benzyl-3-O-octanonyl-β-CD, 2, 3-di-O-benzyl-6-O-heptanonyl-β-CD, and 2, 3-di-O-benzy1-6-O-octanonyl-β-CD, as chiral stationary phases of capillary gas chromatography (CGC), the enantiomers of Sharpless epoxides were well separated. The enantiomer excess values (e.e.%) of some chiral Sharpless epoxides were also determined successfully using these CDs.
2006, 17(4): 509-512
Abstract:
The quartz crystal microbalance (QCM) was used to monitor the one-day incubation of human breast cancer cells (MCF-7) on the gold electrode. In combination with an optical microscope simulation experiment, the cell-population pictures at various stages, the QCM responses to the cells' adhesion, spreading and proliferation on the electrode surface were discussed. The △f0 and △R1responses were found mainly from mixed effects of viscodensity and surface stress, and in proportion to the cell coverage, rather than to the number of cells at the electrode. The significant fore-and-aft changes in cyclic voltammetry and electrochemical impedance spectroscopy of the ferri-ferrocyanide redox couple also proved that the cells were adhesion to the gold surface.
The quartz crystal microbalance (QCM) was used to monitor the one-day incubation of human breast cancer cells (MCF-7) on the gold electrode. In combination with an optical microscope simulation experiment, the cell-population pictures at various stages, the QCM responses to the cells' adhesion, spreading and proliferation on the electrode surface were discussed. The △f0 and △R1responses were found mainly from mixed effects of viscodensity and surface stress, and in proportion to the cell coverage, rather than to the number of cells at the electrode. The significant fore-and-aft changes in cyclic voltammetry and electrochemical impedance spectroscopy of the ferri-ferrocyanide redox couple also proved that the cells were adhesion to the gold surface.
2006, 17(4): 513-516
Abstract:
Ultrafast cyclic voltammetry was used to study the redox behavior of a gold electrode in acetonitrile. The direct electrochemical evidence of the dissociation and adsorption behavior of acetonitrile at gold electrodes was found. It could be stated that two consecutive redox paths are involved, each with a special adsorption state acting as the reaction intermediate. The mean value, obtained of the electron-transfer rate constant of the second path, was 1.3×105 s-1 with a standard deviation of 0.24×105 s-1.
Ultrafast cyclic voltammetry was used to study the redox behavior of a gold electrode in acetonitrile. The direct electrochemical evidence of the dissociation and adsorption behavior of acetonitrile at gold electrodes was found. It could be stated that two consecutive redox paths are involved, each with a special adsorption state acting as the reaction intermediate. The mean value, obtained of the electron-transfer rate constant of the second path, was 1.3×105 s-1 with a standard deviation of 0.24×105 s-1.
2006, 17(4): 517-520
Abstract:
The molar absorption coefficients of each of 14 kinds of amino acids were determined by the spectrophotometric method, and the mean molar absorption coefficients of 37 different mixtures of each with amino acid composition exactly equivalent to that of the peptide chain of the corresponding lipopeptide were determined based on calculation or experimental. The significance of the results is that the mean molar absorption coefficients strongly demonstrate the regular patterns, though different amino acids bear quite different molar absorption coefficients.
The molar absorption coefficients of each of 14 kinds of amino acids were determined by the spectrophotometric method, and the mean molar absorption coefficients of 37 different mixtures of each with amino acid composition exactly equivalent to that of the peptide chain of the corresponding lipopeptide were determined based on calculation or experimental. The significance of the results is that the mean molar absorption coefficients strongly demonstrate the regular patterns, though different amino acids bear quite different molar absorption coefficients.
2006, 17(4): 521-524
Abstract:
A single molecule detection technique was developed by the combination of a single channel poly (dimethylsiloxane)/glass micro-fluidic chip and fluorescence correlation spectroscopy (FCS). This method was successfully used to determine the proportion of two model components in the mixture containing fluorescein and the rhodamine-green succinimidyl ester.
A single molecule detection technique was developed by the combination of a single channel poly (dimethylsiloxane)/glass micro-fluidic chip and fluorescence correlation spectroscopy (FCS). This method was successfully used to determine the proportion of two model components in the mixture containing fluorescein and the rhodamine-green succinimidyl ester.
2006, 17(4): 525-528
Abstract:
Novel layered silinaite has been synthesized using an aqueous mixture of water glass, LiOH and NaOH under hydrothermal crystallization. Subsequently transformation of silinaite into mesoporous materials (SDM) was achieved at mild condition using cetyltrimethylammonium bromide as structure-directing agents. The resulting samples were characterized by XRD, SEM, FTIR nitrogen adsorption-desorption isotherms and catalytic performance in bulky molecular involved reaction. The results revealed that synthesized mesoporous materials derived from the silinaite exhibited an ordered hexagonal crystal structure with average pore diameter 2.7 nm and BET surface area 817m2/g. The SDM-supported ZnCl2 catalyst, prepared by impregnationevaporation method, retained the mesoporous structure and showed high selectivity in alkylation of benzene with benzyl chloride.
Novel layered silinaite has been synthesized using an aqueous mixture of water glass, LiOH and NaOH under hydrothermal crystallization. Subsequently transformation of silinaite into mesoporous materials (SDM) was achieved at mild condition using cetyltrimethylammonium bromide as structure-directing agents. The resulting samples were characterized by XRD, SEM, FTIR nitrogen adsorption-desorption isotherms and catalytic performance in bulky molecular involved reaction. The results revealed that synthesized mesoporous materials derived from the silinaite exhibited an ordered hexagonal crystal structure with average pore diameter 2.7 nm and BET surface area 817m2/g. The SDM-supported ZnCl2 catalyst, prepared by impregnationevaporation method, retained the mesoporous structure and showed high selectivity in alkylation of benzene with benzyl chloride.
2006, 17(4): 529-532
Abstract:
A high active novel TiO2/AC composite photocatalyst was prepared and used for phenol degradation. It was much more active than P-25 and exhibiting good decantability, less deactivation after several runs and less sensitive to pH change. Diffuse reflectance spectra (DRS)revealed that the electronic change in TiO2 did not occur by the addition of AC. Results of SEM and XRD suggested that better TiO2 distribution can be achieved when optimal AC content was adopted. The performance of the prepared TiO2/5AC catalyst revealed great practical potential in wastewater treatment field.
A high active novel TiO2/AC composite photocatalyst was prepared and used for phenol degradation. It was much more active than P-25 and exhibiting good decantability, less deactivation after several runs and less sensitive to pH change. Diffuse reflectance spectra (DRS)revealed that the electronic change in TiO2 did not occur by the addition of AC. Results of SEM and XRD suggested that better TiO2 distribution can be achieved when optimal AC content was adopted. The performance of the prepared TiO2/5AC catalyst revealed great practical potential in wastewater treatment field.
2006, 17(4): 533-536
Abstract:
Allyl terminated polyether was used to improve the hydrophilicity of addition-cured room temperature vulcanization silicone rubber. With the increasing of the polyether, both the hydrophilicity and water absorbed of the vulcanizates were increased. The mechanical properties were also improved by adding the polyether. The result showed that 1.5wt% of the polyether provided the silicone rubber with proper hydrophilicity.
Allyl terminated polyether was used to improve the hydrophilicity of addition-cured room temperature vulcanization silicone rubber. With the increasing of the polyether, both the hydrophilicity and water absorbed of the vulcanizates were increased. The mechanical properties were also improved by adding the polyether. The result showed that 1.5wt% of the polyether provided the silicone rubber with proper hydrophilicity.
2006, 17(4): 537-540
Abstract:
Boron nitride (BN) has been synthesized using hydrothermal synthesis method. The experimental results showed that the pH value of the reaction solution has an important effect on the yield and phases of BN samples. As the pH value decreased, the content of cBN increased and the yield improved. The increase in cBN content is resulted from the conversion of oBN into cBN under hydrothermal condition, and the growth of cBN nanocrystals may due to the decrease in the reaction speed, thus the crystalline perfection of BN improved when the pH value decreased.
Boron nitride (BN) has been synthesized using hydrothermal synthesis method. The experimental results showed that the pH value of the reaction solution has an important effect on the yield and phases of BN samples. As the pH value decreased, the content of cBN increased and the yield improved. The increase in cBN content is resulted from the conversion of oBN into cBN under hydrothermal condition, and the growth of cBN nanocrystals may due to the decrease in the reaction speed, thus the crystalline perfection of BN improved when the pH value decreased.
2006, 17(4): 541-544
Abstract:
In order to improve 4-CP degradation efficiency, a novel gas-liquid hybrid discharge (HD) reactor was developed. Removal of 4-CP with spark-spark discharge (SSD) was higher than that with spark-corona discharge (SCD). Amount of H2O2 and O3 produced with SSD were larger than that with SCD. ·OH formation was increased by the combination of H2O2 and O3.The contribution of ·OH (38% formed by O3 conversion) oxidation on removal of 4-CP accounted for nearly 60%. The other effects of ultraviolet radiation, intense shock waves and pyrolysis, played partial roles in about 40% of removal rate.
In order to improve 4-CP degradation efficiency, a novel gas-liquid hybrid discharge (HD) reactor was developed. Removal of 4-CP with spark-spark discharge (SSD) was higher than that with spark-corona discharge (SCD). Amount of H2O2 and O3 produced with SSD were larger than that with SCD. ·OH formation was increased by the combination of H2O2 and O3.The contribution of ·OH (38% formed by O3 conversion) oxidation on removal of 4-CP accounted for nearly 60%. The other effects of ultraviolet radiation, intense shock waves and pyrolysis, played partial roles in about 40% of removal rate.
2006, 17(4): 545-548
Abstract:
The depolymerization of poly(bisphenol A carbonate)(PC) in subcritical and supercritical toluene was studied. The experimental parameters, which influence the depolymerization reaction such as temperature (570-633 K), pressure (4.0-7.0 MPa), reaction time (5-60 min), and toluene to PC weight ratio (3.0-11.0), were investigated, and the reaction products were determined by GC, GC/MS and FT-IR spectrometer. It was found that the main product of the depolymerization reaction was bisphenol A(BPA). BPA accounted for over 55.7% of the depolymerization products at reaction temperature 613 K, pressure 5.0-6.0 MPa, reaction time 15 min and toluene/PC weight ratio of around 7.0.
The depolymerization of poly(bisphenol A carbonate)(PC) in subcritical and supercritical toluene was studied. The experimental parameters, which influence the depolymerization reaction such as temperature (570-633 K), pressure (4.0-7.0 MPa), reaction time (5-60 min), and toluene to PC weight ratio (3.0-11.0), were investigated, and the reaction products were determined by GC, GC/MS and FT-IR spectrometer. It was found that the main product of the depolymerization reaction was bisphenol A(BPA). BPA accounted for over 55.7% of the depolymerization products at reaction temperature 613 K, pressure 5.0-6.0 MPa, reaction time 15 min and toluene/PC weight ratio of around 7.0.
2006, 17(4): 549-552
Abstract:
Surface molecularly imprinted polymers (SMIP) was prepared via the reversible addition-fragmentation chain transfer (RAFT) polymerization on the chloromethyl polystyrene resin (CPR) in the presence of the template D-phenylalanine. The structure of SMIP was characterized by FTIR and SEM. The adsorption behavior of D-phenylalanine of SMIP was preliminarily investigated.
Surface molecularly imprinted polymers (SMIP) was prepared via the reversible addition-fragmentation chain transfer (RAFT) polymerization on the chloromethyl polystyrene resin (CPR) in the presence of the template D-phenylalanine. The structure of SMIP was characterized by FTIR and SEM. The adsorption behavior of D-phenylalanine of SMIP was preliminarily investigated.
2006, 17(4): 553-556
Abstract:
Stable poly(styrene-co-sodium styrene suffonate) (P(St-NaSS) nanoparticles with broader size distribution were synthesized by thermal emulsion polymerization without any conventional initiators and emulsifiers. The obtained polymer nanoparticles have higher ξ potential, and the particle sizes have broad distribution. The stability of polymer particles originated from the addition of small amounts of ionic comonomer, NaSS, which can act as an emulsifier in somewhat. The monomer conversion could reach up to about 28 wt% in 48 h, and did not increase by further polymerization when higher polymerization temperature (120℃) was employed. This polymerization system may be give some further understand for mechanism of emulsion polymerization.
Stable poly(styrene-co-sodium styrene suffonate) (P(St-NaSS) nanoparticles with broader size distribution were synthesized by thermal emulsion polymerization without any conventional initiators and emulsifiers. The obtained polymer nanoparticles have higher ξ potential, and the particle sizes have broad distribution. The stability of polymer particles originated from the addition of small amounts of ionic comonomer, NaSS, which can act as an emulsifier in somewhat. The monomer conversion could reach up to about 28 wt% in 48 h, and did not increase by further polymerization when higher polymerization temperature (120℃) was employed. This polymerization system may be give some further understand for mechanism of emulsion polymerization.
2006, 17(4): 557-560
Abstract:
Chloro-propylene sulfite (ClPS) was employed as electrolyte additive of Li/S batteries for the first time. Linear potential sweep test showed that the ClPS keeps high electrochemical stability even under the voltage of 5.0V. Being used as electrolyte additive in Li/S batteries, ClPS displayed an excellent property for self-discharge prohibition. With ClPS additive the Li/S cells' initial discharge capacity was 856.2 mAh·g-1 and 830.8 mAh·g-1 at the current density of 15 mA·g-1and 30 mA·g-1, after 30 cycles the discharge capacities were contained at as high as 753.8 mAh·g-1 and 715.6 mAh·g-1. By means of infrared spectra, TG/DTA experiment and element content analysis the speculated reason of ClPS's novel function as additive was proposed.
Chloro-propylene sulfite (ClPS) was employed as electrolyte additive of Li/S batteries for the first time. Linear potential sweep test showed that the ClPS keeps high electrochemical stability even under the voltage of 5.0V. Being used as electrolyte additive in Li/S batteries, ClPS displayed an excellent property for self-discharge prohibition. With ClPS additive the Li/S cells' initial discharge capacity was 856.2 mAh·g-1 and 830.8 mAh·g-1 at the current density of 15 mA·g-1and 30 mA·g-1, after 30 cycles the discharge capacities were contained at as high as 753.8 mAh·g-1 and 715.6 mAh·g-1. By means of infrared spectra, TG/DTA experiment and element content analysis the speculated reason of ClPS's novel function as additive was proposed.
2006, 17(4): 561-564
Abstract:
C-H bond can undergo vicarious Michael addition reaction (VMA) with doubleactivated double bond in the absence of strong base and catalyst under mild conditions.Intramolecular H-bonding, electron-withdrawing inductive effect, and steric hindrance at α-position of nucleophile facilitates C-H addition over N-H addition. By using VMA, high branching multiplicity, novel branching pattern, controllable density and distribution of functional groups can be envisioned for novel dendrimer synthesis.
C-H bond can undergo vicarious Michael addition reaction (VMA) with doubleactivated double bond in the absence of strong base and catalyst under mild conditions.Intramolecular H-bonding, electron-withdrawing inductive effect, and steric hindrance at α-position of nucleophile facilitates C-H addition over N-H addition. By using VMA, high branching multiplicity, novel branching pattern, controllable density and distribution of functional groups can be envisioned for novel dendrimer synthesis.
2006, 17(4): 565-568
Abstract:
It is still a formidable challenge to study CH2O+CH3·→CHO+CH4 reaction in the gas phase by traditional dynamics, because of the large number of freedom degrees for the system.In this paper, direct dynamics, in which trajectories were run directly on the DFT potential energy surface, have been applied to the reaction, which gave a direct look in the reaction processes.Two sets of trajectories at different initial orientations of reactants and temperature have been simulated. And the detailed reaction mechanisms have been described.
It is still a formidable challenge to study CH2O+CH3·→CHO+CH4 reaction in the gas phase by traditional dynamics, because of the large number of freedom degrees for the system.In this paper, direct dynamics, in which trajectories were run directly on the DFT potential energy surface, have been applied to the reaction, which gave a direct look in the reaction processes.Two sets of trajectories at different initial orientations of reactants and temperature have been simulated. And the detailed reaction mechanisms have been described.
