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2004 Volume 15 Issue 12
2004, 15(12): 1387-1388
Abstract:
Several iodohydrins are synthesized in fairly high yields by using polystyrene-supported phenyliodine(Ⅲ) bis (trifluoroacetate).
Several iodohydrins are synthesized in fairly high yields by using polystyrene-supported phenyliodine(Ⅲ) bis (trifluoroacetate).
2004, 15(12): 1389-1391
Abstract:
Using chiral hydrogenesterification reaction as the key step, the stereoselective synthesis of (+)-nuciferal 1, (+)-(E)-nuciferol 2 and (+)-α-curcumene 3 has been achieved.
Using chiral hydrogenesterification reaction as the key step, the stereoselective synthesis of (+)-nuciferal 1, (+)-(E)-nuciferol 2 and (+)-α-curcumene 3 has been achieved.
2004, 15(12): 1392-1394
Abstract:
A number of benzodioxane compounds were synthesized using the palladium-catalyzed etherification of aryl halides by employing triphenylphosphane ligands. This method was used askey step in the synthesis ofisoamericanol A and isoamericanin A.
A number of benzodioxane compounds were synthesized using the palladium-catalyzed etherification of aryl halides by employing triphenylphosphane ligands. This method was used askey step in the synthesis ofisoamericanol A and isoamericanin A.
2004, 15(12): 1395-1396
Abstract:
A stereoselective and economic synthesis of the carbapenem sidechain (2S, 4S)-4-ace-tylsulphanyl-2-[(S)1-phenylethyl-carbamoyl] pyrrolidine-l-carboxylic acid 4-nitrobenzyl ester was developed. Due to the effect of spatial hindrance, only the (2S,4S) diastereomer 3 was obtained by coupling 1 and the inexpensive racemic 2 catalyzed by EEDQ.
A stereoselective and economic synthesis of the carbapenem sidechain (2S, 4S)-4-ace-tylsulphanyl-2-[(S)1-phenylethyl-carbamoyl] pyrrolidine-l-carboxylic acid 4-nitrobenzyl ester was developed. Due to the effect of spatial hindrance, only the (2S,4S) diastereomer 3 was obtained by coupling 1 and the inexpensive racemic 2 catalyzed by EEDQ.
2004, 15(12): 1397-1399
Abstract:
A series of l-cyclopropyl-5-amino-6-fluoro-8-methoxyquinoline-3-carboxylic acids have been prepared and evaluated for antibacterial activity in vitro.
A series of l-cyclopropyl-5-amino-6-fluoro-8-methoxyquinoline-3-carboxylic acids have been prepared and evaluated for antibacterial activity in vitro.
2004, 15(12): 1400-1402
Abstract:
A novel approach to the synthesis of 6, 7-disubstituted-1H-quinoxalin-2-ones is described.The title compounds were regioselectively prepared by starting from substituted phenylamines and chloroacetyl chloride through the efficient sequence ofacylation, nitration, reduction, intramolecular alkylation, and oxidation.
A novel approach to the synthesis of 6, 7-disubstituted-1H-quinoxalin-2-ones is described.The title compounds were regioselectively prepared by starting from substituted phenylamines and chloroacetyl chloride through the efficient sequence ofacylation, nitration, reduction, intramolecular alkylation, and oxidation.
2004, 15(12): 1403-1406
Abstract:
In a quest for better chelating therapy drugs for the treatment of intoxication by Fe, Al, or actinides, two new series of mixed catechol-bisphosphonate through amide linkage were synthesized.Benzyl group was used as protecting group to avoid the breakage of amide by acid hydrolysis or imcomplete reaction in silylation-dealkylation using bromotrimethylsilane.
In a quest for better chelating therapy drugs for the treatment of intoxication by Fe, Al, or actinides, two new series of mixed catechol-bisphosphonate through amide linkage were synthesized.Benzyl group was used as protecting group to avoid the breakage of amide by acid hydrolysis or imcomplete reaction in silylation-dealkylation using bromotrimethylsilane.
2004, 15(12): 1407-1410
Abstract:
As photosensitizer for solar cell, a new ruthenium (Ⅱ) complex with four ester groups had been synthesized, in which a phenol substituted by {[(2-hydroxy-5-tert-butylbenzyl)(pyridyl2-methyl)amino]methyl} is covalently linked to ruthenium (Ⅱ) tris-bipyridine. The structures of the new compounds were confirmed by NMR and ESI-MS spectra. The electrochemical and photochemical properties were also studied.
As photosensitizer for solar cell, a new ruthenium (Ⅱ) complex with four ester groups had been synthesized, in which a phenol substituted by {[(2-hydroxy-5-tert-butylbenzyl)(pyridyl2-methyl)amino]methyl} is covalently linked to ruthenium (Ⅱ) tris-bipyridine. The structures of the new compounds were confirmed by NMR and ESI-MS spectra. The electrochemical and photochemical properties were also studied.
2004, 15(12): 1411-1414
Abstract:
The synthesis and characterization of two chiral fullerene complexes (+)430CD-[Mo(η2-C60)(CO)3(LRR)] 1 and (-)430CD-[Mo(η2-C60)(CO)3(LSS)] 2 were described. The CD spectra of 1 and 2 in the visible range show weak Cotton effects, which are approximately of mirror image, indicating that the appended pineno-groups with opposite chirality in bipyridines can perturb the fullerene chromophores through the molybdenum centers and lead to induced CD effects.
The synthesis and characterization of two chiral fullerene complexes (+)430CD-[Mo(η2-C60)(CO)3(LRR)] 1 and (-)430CD-[Mo(η2-C60)(CO)3(LSS)] 2 were described. The CD spectra of 1 and 2 in the visible range show weak Cotton effects, which are approximately of mirror image, indicating that the appended pineno-groups with opposite chirality in bipyridines can perturb the fullerene chromophores through the molybdenum centers and lead to induced CD effects.
2004, 15(12): 1415-1418
Abstract:
SbCl5-TEBA (PhCH2NEt3Cl) complex catalyzes the Friedel-Crafts acylation reactions efficiently.
SbCl5-TEBA (PhCH2NEt3Cl) complex catalyzes the Friedel-Crafts acylation reactions efficiently.
2004, 15(12): 1419-1422
Abstract:
The bicoordination chiral inducement catalysis of (R)-4-thiazolidinecarboxylic acid in the enantioselective borane reduction of prochiral ketones has been studied. The fact that the absolute configuration of the main product can be changed by simply using different operation methods was firstly verified. And the reason of bicoordination chiral inducement was discussed.
The bicoordination chiral inducement catalysis of (R)-4-thiazolidinecarboxylic acid in the enantioselective borane reduction of prochiral ketones has been studied. The fact that the absolute configuration of the main product can be changed by simply using different operation methods was firstly verified. And the reason of bicoordination chiral inducement was discussed.
2004, 15(12): 1423-1426
Abstract:
The synthesis and characterization of two new star-like liquid crystals are reported.They are made of a silicon core and four alkoxyazobenzene monomers in the periphery. Their phase behaviors and the structures are determined by infrared absorption spectroscopy (IR),nuclear magnetic resonance spectroscopy (NMR), elemental analysis (EA), polarizing optical microscope (POM) and differential scanning calorimetry (DSC).
The synthesis and characterization of two new star-like liquid crystals are reported.They are made of a silicon core and four alkoxyazobenzene monomers in the periphery. Their phase behaviors and the structures are determined by infrared absorption spectroscopy (IR),nuclear magnetic resonance spectroscopy (NMR), elemental analysis (EA), polarizing optical microscope (POM) and differential scanning calorimetry (DSC).
2004, 15(12): 1427-1429
Abstract:
A mono-funtionalised tetraphenylporphyrin (TPP) bearing valine moiety at the phenyl ring was synthesized for photocytotoxicity examination in four steps, starting from regiospecific mono-nitration of TPP at the phenyl ring. The in vitro photocytotoxicitic effect against SPC-A1 adenocarcinona cell line was tested.
A mono-funtionalised tetraphenylporphyrin (TPP) bearing valine moiety at the phenyl ring was synthesized for photocytotoxicity examination in four steps, starting from regiospecific mono-nitration of TPP at the phenyl ring. The in vitro photocytotoxicitic effect against SPC-A1 adenocarcinona cell line was tested.
2004, 15(12): 1430-1432
Abstract:
An efficient and selective method for the deprotection of primary alcoholic tert-butyl-dimethylsiyl(TBS) ethers using SnCL2·2H2O as catalyst is described. The reaction conditions allow primary alcoholic TBS ethers to be desilylated chemoselectively in the presence of phenolic TBS ethers, secondary and tertiary alcolholic TBS ethers, and the extensively used TBDPS-,acetyl-, benzyloxycarbonyl-, p-toluenesulfonyl-and benzyl protective groups.
An efficient and selective method for the deprotection of primary alcoholic tert-butyl-dimethylsiyl(TBS) ethers using SnCL2·2H2O as catalyst is described. The reaction conditions allow primary alcoholic TBS ethers to be desilylated chemoselectively in the presence of phenolic TBS ethers, secondary and tertiary alcolholic TBS ethers, and the extensively used TBDPS-,acetyl-, benzyloxycarbonyl-, p-toluenesulfonyl-and benzyl protective groups.
2004, 15(12): 1433-1436
Abstract:
Starting from shikimic acid, the total synthesis of zeylenone was studied. The product was proved to be the (+)antipode of zeylenone through analysis and comparison of their respective spectra (including NMR, MS, IR and CD) and optical data. The absolute configuration of the natural product was thus determined to be (1 S,2S,3R).
Starting from shikimic acid, the total synthesis of zeylenone was studied. The product was proved to be the (+)antipode of zeylenone through analysis and comparison of their respective spectra (including NMR, MS, IR and CD) and optical data. The absolute configuration of the natural product was thus determined to be (1 S,2S,3R).
2004, 15(12): 1437-1440
Abstract:
A simple, mild, efficient Mn(salen)-catalyzed oxidation system of secondary alcohols, in which the ionic liquid[bmim]PF6 acts as a powerfiil additive, has been described. The reaction proceeded with higher efficiency. The catalyst was more easier to recycle in ionic liquid[bmim]PF6 with a well-proportioned CH2Cl2 than in the single CH2Cl2 or ionic liquid.
A simple, mild, efficient Mn(salen)-catalyzed oxidation system of secondary alcohols, in which the ionic liquid[bmim]PF6 acts as a powerfiil additive, has been described. The reaction proceeded with higher efficiency. The catalyst was more easier to recycle in ionic liquid[bmim]PF6 with a well-proportioned CH2Cl2 than in the single CH2Cl2 or ionic liquid.
2004, 15(12): 1441-1444
Abstract:
From the alcoholic extract of the whole plant of Ligularia virgaurea spp. oligocephala,three novel eremophilane sesquiterpene lactones, 6α, 10α-dihydroxy-l-oxoeremophila-7(11),8(9)-dien-8, 12-olide, 6β, 10α-dihydroxy-1-oxoeremophila-7(11), 8(9)-dien-8, 12-olide and 10α-hydroxy-l-oxoeremophila-7(11), 8(9)-dien-8, 12-olide were isolated. Their structures were elucidated by various spectroscopic methods including intensive 2D NMR techniques (COSY,HMQC, HMBC and 1H-1H NOESY) and HR-MS.
From the alcoholic extract of the whole plant of Ligularia virgaurea spp. oligocephala,three novel eremophilane sesquiterpene lactones, 6α, 10α-dihydroxy-l-oxoeremophila-7(11),8(9)-dien-8, 12-olide, 6β, 10α-dihydroxy-1-oxoeremophila-7(11), 8(9)-dien-8, 12-olide and 10α-hydroxy-l-oxoeremophila-7(11), 8(9)-dien-8, 12-olide were isolated. Their structures were elucidated by various spectroscopic methods including intensive 2D NMR techniques (COSY,HMQC, HMBC and 1H-1H NOESY) and HR-MS.
2004, 15(12): 1445-1447
Abstract:
Two new steroidal glycosides were isolated from the Chinese medicinal plant Caryopteris terniflora. The spectroscopic and chemical evidences revealed that their structures to be 6'-(β-sitosteroyl-3-O-β-glucopyranosidyl) hexacosanate 1 and 6'-(stigmasteroyl-3-O-β-glucopyranosidyl) linolenate 2, respectively.
Two new steroidal glycosides were isolated from the Chinese medicinal plant Caryopteris terniflora. The spectroscopic and chemical evidences revealed that their structures to be 6'-(β-sitosteroyl-3-O-β-glucopyranosidyl) hexacosanate 1 and 6'-(stigmasteroyl-3-O-β-glucopyranosidyl) linolenate 2, respectively.
2004, 15(12): 1448-1450
Abstract:
A new anthraquinone glycoside, emodin-1-O-β-gentiobioside 1, together with three known compounds, chrysophanol-1-O-β-gentiobioside 2, physcion-8-O-β-gentiobioside 3, and chrysophanol-1-O-β-D-glucopyranosyl-(1→3)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside 4 was isolated from the seeds of Cassia obtusifolia. Its structure was elucidated on the basis of spectroscopic evidence.
A new anthraquinone glycoside, emodin-1-O-β-gentiobioside 1, together with three known compounds, chrysophanol-1-O-β-gentiobioside 2, physcion-8-O-β-gentiobioside 3, and chrysophanol-1-O-β-D-glucopyranosyl-(1→3)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside 4 was isolated from the seeds of Cassia obtusifolia. Its structure was elucidated on the basis of spectroscopic evidence.
2004, 15(12): 1451-1453
Abstract:
A new diterpenoid trisaccharide, smithoside A, was isolated from Aster smithianus. Its structure was identified as pimar-15(16)-β-en-3β, 8β, 11α-triol-3-O-β-D-glucopyranosyl (l→3)-[β-glucopyranosyl (1→2)]-β-D-glucopyranoside on the basis of the spectral and chemical methods.
A new diterpenoid trisaccharide, smithoside A, was isolated from Aster smithianus. Its structure was identified as pimar-15(16)-β-en-3β, 8β, 11α-triol-3-O-β-D-glucopyranosyl (l→3)-[β-glucopyranosyl (1→2)]-β-D-glucopyranoside on the basis of the spectral and chemical methods.
2004, 15(12): 1454-1456
Abstract:
A new sesquiterpene lactone, Ainsliaolide A, was isolated from Ainsliaea bonatii. The structure was determined on the basis of spectral data.
A new sesquiterpene lactone, Ainsliaolide A, was isolated from Ainsliaea bonatii. The structure was determined on the basis of spectral data.
2004, 15(12): 1457-1460
Abstract:
Cellulose-tris(3,5-dimethylphenylcarbamate)(CDMPC) were synthesized as high-performance liquid chromatography (HPLC) chiral stationary phase(CSP). The successful resolution of four chiral pesticides on the CSP was realized and the influence of the temperature on the separation was studied.
Cellulose-tris(3,5-dimethylphenylcarbamate)(CDMPC) were synthesized as high-performance liquid chromatography (HPLC) chiral stationary phase(CSP). The successful resolution of four chiral pesticides on the CSP was realized and the influence of the temperature on the separation was studied.
2004, 15(12): 1461-1464
Abstract:
Electron transfer (ET) from ascorbic acid (AA) in aqueous to ferrocene (Fc) in 1,2-dichloroethane (DCE) was probed by the scanning electrochemical microscopy (SECM). The rate constants were extracted from the dependence of the steady-state current at ultramicro-electrode (UME, tip) on the distance between the tip and the phase boundary by comparison to theoretical working cures.
Electron transfer (ET) from ascorbic acid (AA) in aqueous to ferrocene (Fc) in 1,2-dichloroethane (DCE) was probed by the scanning electrochemical microscopy (SECM). The rate constants were extracted from the dependence of the steady-state current at ultramicro-electrode (UME, tip) on the distance between the tip and the phase boundary by comparison to theoretical working cures.
Competitive Adsorption between Bovine Serum Albumin and Collagen Observed by Atomic Force Microscope
2004, 15(12): 1465-1468
Abstract:
Atomic force microscopy (AFM) was used to study the competitive adsorption between bovine serum albumin (BSA) and type Ⅰ collagen on hydrophilic and hydrophobic silicon wafers.BSA showed a grain shape and the type Ⅰ collagen displayed fibril-like molecules with relatively homogeneous height and width, characterized with clear twisting (helical formation). These AFM images illustrated that quite a lot of type Ⅰ collagen appeared in the adsorption layer on hydrophilic surface in a competitive adsorption state, but the adsorption of BSA was more preponderant than that of type Ⅰ collagen on hydrophobic silicon wafer surface. The experiments showed that the influence of BSA on type Ⅰ collagen adsorption on hydrophilic surface was less than that on hydrophobic surface.
Atomic force microscopy (AFM) was used to study the competitive adsorption between bovine serum albumin (BSA) and type Ⅰ collagen on hydrophilic and hydrophobic silicon wafers.BSA showed a grain shape and the type Ⅰ collagen displayed fibril-like molecules with relatively homogeneous height and width, characterized with clear twisting (helical formation). These AFM images illustrated that quite a lot of type Ⅰ collagen appeared in the adsorption layer on hydrophilic surface in a competitive adsorption state, but the adsorption of BSA was more preponderant than that of type Ⅰ collagen on hydrophobic silicon wafer surface. The experiments showed that the influence of BSA on type Ⅰ collagen adsorption on hydrophilic surface was less than that on hydrophobic surface.
2004, 15(12): 1469-1472
Abstract:
Molecularly imprinted polymers using p-hydroxybenzoic acid as templates was synthesized by an in situ polymerization reaction and rendered capillary monolithic column was used in capillary electrochromatographic mode. Good molecular recognition was achieved for p-hydroxybenzoic acid and good resolution of isomers can be realized.
Molecularly imprinted polymers using p-hydroxybenzoic acid as templates was synthesized by an in situ polymerization reaction and rendered capillary monolithic column was used in capillary electrochromatographic mode. Good molecular recognition was achieved for p-hydroxybenzoic acid and good resolution of isomers can be realized.
2004, 15(12): 1473-1476
Abstract:
A novel fibroin modified electrode with ion recognition was reported. The membrane with isoelectric point of pH 4.5, was modified on graphite and carbon fiber electrodes. The pH-responsive ion recognition of the modified electrode was investigated by use of some neurocompounds. The fibroin carbon fiber electrode has been used for in-vivo determination.
A novel fibroin modified electrode with ion recognition was reported. The membrane with isoelectric point of pH 4.5, was modified on graphite and carbon fiber electrodes. The pH-responsive ion recognition of the modified electrode was investigated by use of some neurocompounds. The fibroin carbon fiber electrode has been used for in-vivo determination.
2004, 15(12): 1477-1479
Abstract:
Polymeric monolithic capillary colunm-poly(GMA-co-EDMA-co-AMPS) was prepared and used for resolution of aromatic compounds (benz alcohol, 2-phenylethanol, toluene, ethylbenzene).
Polymeric monolithic capillary colunm-poly(GMA-co-EDMA-co-AMPS) was prepared and used for resolution of aromatic compounds (benz alcohol, 2-phenylethanol, toluene, ethylbenzene).
2004, 15(12): 1480-1482
Abstract:
The spillover phenomenon is observed on the platinum (Pt) disk electrode modified bymulti-wall carbon nanotubes (MWNTs). The rate of the spillover of oxygen-containing species produced on Pt surface to and from MWNTs is fast. However for hydrogen-adatoms, the spillover is very weak. The selective spillover on the Pt/MWNTs electrode may provide a novel way to design catalysts.
The spillover phenomenon is observed on the platinum (Pt) disk electrode modified bymulti-wall carbon nanotubes (MWNTs). The rate of the spillover of oxygen-containing species produced on Pt surface to and from MWNTs is fast. However for hydrogen-adatoms, the spillover is very weak. The selective spillover on the Pt/MWNTs electrode may provide a novel way to design catalysts.
2004, 15(12): 1483-1486
Abstract:
The deactivation of nickel hydroxide to the electrooxidation of hypophosphite on a nickel electrode was studied by means of in situ UV-Vis subtractive reflectance spectroscopy. The experimental results show that when the potential is lower than-1.0V (SCE), the surface on nickel electrode is free of nickel hydroxide, on which hypophosphite is active. When the potential moves positively to about-0.75V, two absorbency bands around 300 nm and 550 nm, which were ascribed to the formation of α-nickel hydroxide, were observed, nickel is oxidized to α-nickel hydroxide.Severe deactivation of the surface occurs when the nickel surface is covered with nickel hydroxide,which separates the hypophosphite ion from nickel substrate.
The deactivation of nickel hydroxide to the electrooxidation of hypophosphite on a nickel electrode was studied by means of in situ UV-Vis subtractive reflectance spectroscopy. The experimental results show that when the potential is lower than-1.0V (SCE), the surface on nickel electrode is free of nickel hydroxide, on which hypophosphite is active. When the potential moves positively to about-0.75V, two absorbency bands around 300 nm and 550 nm, which were ascribed to the formation of α-nickel hydroxide, were observed, nickel is oxidized to α-nickel hydroxide.Severe deactivation of the surface occurs when the nickel surface is covered with nickel hydroxide,which separates the hypophosphite ion from nickel substrate.
2004, 15(12): 1487-1490
Abstract:
Black lead, Ti-Ru and Ti-PbO2 were used as anode and stainless steel was used as cathode.The electrolytic process of producing hypophosphorous acid with four-compartment electrodialytic cell was studied. The comparison of some factors, such as anodic voltage, product concentration and current efficiency, of black lead, Ti-Ru, and Ti-PbO2 electrodes was conducted. As a result, the Ti-PbO2 electrode is the optimal anode material used, it can be in electrolytic process for producing hypophosphorous acid.
Black lead, Ti-Ru and Ti-PbO2 were used as anode and stainless steel was used as cathode.The electrolytic process of producing hypophosphorous acid with four-compartment electrodialytic cell was studied. The comparison of some factors, such as anodic voltage, product concentration and current efficiency, of black lead, Ti-Ru, and Ti-PbO2 electrodes was conducted. As a result, the Ti-PbO2 electrode is the optimal anode material used, it can be in electrolytic process for producing hypophosphorous acid.
2004, 15(12): 1491-1493
Abstract:
A new quaternary ammonium heteropolyoxotungstant (cat. C) is prepared and characterized. And the cat. C also is an reaction-controlled phase-transfer catalyst. The catalytic system of O2/EAHQ (2-ethylanthrahydroquinone)/cat.c is used for the epoxidation of propylene.Under the optimal conditions, the yield of propylene oxide based on EAHQ is 84.1%, the selectivity for propylene oxide based on propylene is 99.8% and the conversion ofpropylene based on EAHQ is 84.3%. The cat.c precipitates after the epoxidation reaction for easy separation.The cat. C is stable enough to be recycled three times without any loss in selectivity.
A new quaternary ammonium heteropolyoxotungstant (cat. C) is prepared and characterized. And the cat. C also is an reaction-controlled phase-transfer catalyst. The catalytic system of O2/EAHQ (2-ethylanthrahydroquinone)/cat.c is used for the epoxidation of propylene.Under the optimal conditions, the yield of propylene oxide based on EAHQ is 84.1%, the selectivity for propylene oxide based on propylene is 99.8% and the conversion ofpropylene based on EAHQ is 84.3%. The cat.c precipitates after the epoxidation reaction for easy separation.The cat. C is stable enough to be recycled three times without any loss in selectivity.
2004, 15(12): 1494-1496
Abstract:
The effect of transition metals (Cr, Mn, Fe, Co and Ni) on the hydrogenation of cinnamaldehyde over Pt/ZrO2 catalysts was studied in ethanol at 343K under 2.0MPa H2 pressure.PtCo/ZrO2 and PtFe/ZrO2 catalysts exhibit high selectivity and activity of hydrogenation for C=O(93.8% at 87.3% conversion and 83.6% at 88.6% conversion, respectively), and PtNi/ZrO2 exhibits high selectivity of hydrogenation for C=C (64.3% at 70.6% conversion). In the presence of trace H2O and NaOH, over the PtNi/ZrO2 (0.4wt%Ni) catalyst the selectivity to hydrocinnamaldehyde reaches 90.6% and the conversion of cirmamaldehyde is 90.5%.
The effect of transition metals (Cr, Mn, Fe, Co and Ni) on the hydrogenation of cinnamaldehyde over Pt/ZrO2 catalysts was studied in ethanol at 343K under 2.0MPa H2 pressure.PtCo/ZrO2 and PtFe/ZrO2 catalysts exhibit high selectivity and activity of hydrogenation for C=O(93.8% at 87.3% conversion and 83.6% at 88.6% conversion, respectively), and PtNi/ZrO2 exhibits high selectivity of hydrogenation for C=C (64.3% at 70.6% conversion). In the presence of trace H2O and NaOH, over the PtNi/ZrO2 (0.4wt%Ni) catalyst the selectivity to hydrocinnamaldehyde reaches 90.6% and the conversion of cirmamaldehyde is 90.5%.
2004, 15(12): 1497-1480
Abstract:
One-step synthesis of n-butanol from bimolecular condensation of ethanol was firstly achieved over nickel supported gamma alumina catalyst. A mechanism of dehydration path for the growth of carbon chain by eliminating a hydroxy group from one ethanol molecule with a α-H of other ethanol molecule rather than aldol condensation was verified.
One-step synthesis of n-butanol from bimolecular condensation of ethanol was firstly achieved over nickel supported gamma alumina catalyst. A mechanism of dehydration path for the growth of carbon chain by eliminating a hydroxy group from one ethanol molecule with a α-H of other ethanol molecule rather than aldol condensation was verified.
2004, 15(12): 1501-1504
Abstract:
The present work studies the electrical conduction performance of carbon black (CB)filled poly(ethylene oxide) (PEO) composites. The addition of CB leads to reduced matrix crystallinity as the fillers which are partly situated inside the lamellae and hinder the growth of PEO crystallites. As a result, the electrical percolation behavior is related with the matrix morphology.
The present work studies the electrical conduction performance of carbon black (CB)filled poly(ethylene oxide) (PEO) composites. The addition of CB leads to reduced matrix crystallinity as the fillers which are partly situated inside the lamellae and hinder the growth of PEO crystallites. As a result, the electrical percolation behavior is related with the matrix morphology.
2004, 15(12): 1505-1508
Abstract:
New Ge/SiO2 glasses have been synthesized by heating the GeO2/SiO2 dry gels under H2 gas at 700℃. The resulting fluorescence spectra show that this kind of Ge/SiO2 glasses emit strong photoluminescence at 392 nm (3.12 eV), medium strong photoluminescence at 600 nm (2.05 eV)and weak photoluminescence at 770 nm (1.60 eV) respectively. Possible photolnminescence mechanisms are also discussed based on the results of X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS).
New Ge/SiO2 glasses have been synthesized by heating the GeO2/SiO2 dry gels under H2 gas at 700℃. The resulting fluorescence spectra show that this kind of Ge/SiO2 glasses emit strong photoluminescence at 392 nm (3.12 eV), medium strong photoluminescence at 600 nm (2.05 eV)and weak photoluminescence at 770 nm (1.60 eV) respectively. Possible photolnminescence mechanisms are also discussed based on the results of X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS).
2004, 15(12): 1509-1512
Abstract:
The sensitivity and selectivity to H2 of a new In2O3-based gas sensor were improved significantly by surface chemical modification. A dense layer of SiO2 near the surface of the porous In2O3 bead was formed by chemical vapor deposition (CVD) of diethoxydimethysilane (DEMS).The dense layer functioned as a molecular sieve, thereby the diffusion of gases with large molecular diameters, except for H2, was effectively controlled, resulting in a prominent selectivity and high sensitivity for H2. The working mechanism of the sensor was also presented.
The sensitivity and selectivity to H2 of a new In2O3-based gas sensor were improved significantly by surface chemical modification. A dense layer of SiO2 near the surface of the porous In2O3 bead was formed by chemical vapor deposition (CVD) of diethoxydimethysilane (DEMS).The dense layer functioned as a molecular sieve, thereby the diffusion of gases with large molecular diameters, except for H2, was effectively controlled, resulting in a prominent selectivity and high sensitivity for H2. The working mechanism of the sensor was also presented.
