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2013 Volume 30 Issue 4
2013, 30(4): 367-372
doi: 10.3724/SP.J.1095.2013.20462
Abstract:
Similar to other carbon nano-materials,such as fullerenes,carbon nanotubes and graphene,carbon dots(C-dots) have inspired intensive research attention according to their superior solubility in water,chemical inertness,low toxicity,easy functionalization and resistance to photobleaching.C-dots can be produced inexpensively through lots of one-tep approaches on a large scale such as simple chemical oxidation reactions,ultrasonic treatment,microwave method and laser ablation strategy,etc. In this review,we mainly introduced different synthesis approaches of C-dots,size-and wavelength-dependent luminescence emission property,etc.Furthermore,applications of C-dots in photocatalysis,energy conversion/storage,bioimaging,optoelectronics,optical limiting,sensors,etc.were also discussed.
Similar to other carbon nano-materials,such as fullerenes,carbon nanotubes and graphene,carbon dots(C-dots) have inspired intensive research attention according to their superior solubility in water,chemical inertness,low toxicity,easy functionalization and resistance to photobleaching.C-dots can be produced inexpensively through lots of one-tep approaches on a large scale such as simple chemical oxidation reactions,ultrasonic treatment,microwave method and laser ablation strategy,etc. In this review,we mainly introduced different synthesis approaches of C-dots,size-and wavelength-dependent luminescence emission property,etc.Furthermore,applications of C-dots in photocatalysis,energy conversion/storage,bioimaging,optoelectronics,optical limiting,sensors,etc.were also discussed.
2013, 30(4): 373-377
doi: 10.3724/SP.J.1095.2013.20371
Abstract:
4-Methylamino-3-nitrobenzoic acid(3) was prepared from 3-nitro-4-chlorobenzoic acid by methylamination.3-[(Pyridin-2-yl)amino]propinoic acid ethyl ester(5) was prepared from 2-aminopyridine and ethyl acrylate by Michael addition.Dabigatran etexilate was synthesized from compounds 3 and 5 via condensation,catalytic hydrogenation,acylation with N-(4-cyanophenyl)glycine(9),cyclization,Pinner reaction,followed by reaction with n-hexyl chlorofomate.The overall yield is about 40% and the structure of the product was determined by IR,1H NMR and MS.
4-Methylamino-3-nitrobenzoic acid(3) was prepared from 3-nitro-4-chlorobenzoic acid by methylamination.3-[(Pyridin-2-yl)amino]propinoic acid ethyl ester(5) was prepared from 2-aminopyridine and ethyl acrylate by Michael addition.Dabigatran etexilate was synthesized from compounds 3 and 5 via condensation,catalytic hydrogenation,acylation with N-(4-cyanophenyl)glycine(9),cyclization,Pinner reaction,followed by reaction with n-hexyl chlorofomate.The overall yield is about 40% and the structure of the product was determined by IR,1H NMR and MS.
2013, 30(4): 378-382
doi: 10.3724/SP.J.1095.2013.20250
Abstract:
Two oxa macrocyclic compounds were synthesized via double[2+2] photocycloaddition reaction between 6,6'-dimethyl-4,4'-(trimethylenedioxy)-di-2-pyrone and ethylene glycol dimethacrylates(n=1~3) by photosensitizing effect of benzophenone in acetonitrile solution with yields of 14% and 7%,20% and 11%,31% and 14%,respectively.The structures of products were identified by FTIR,1H NMR,MS and elemental analysis.The synthetic method has several advantages such as mild reaction conditions,simple operation and environmental friendliness.
Two oxa macrocyclic compounds were synthesized via double[2+2] photocycloaddition reaction between 6,6'-dimethyl-4,4'-(trimethylenedioxy)-di-2-pyrone and ethylene glycol dimethacrylates(n=1~3) by photosensitizing effect of benzophenone in acetonitrile solution with yields of 14% and 7%,20% and 11%,31% and 14%,respectively.The structures of products were identified by FTIR,1H NMR,MS and elemental analysis.The synthetic method has several advantages such as mild reaction conditions,simple operation and environmental friendliness.
2013, 30(4): 383-388
doi: 10.3724/SP.J.1095.2013.20259
Abstract:
The synthesis of six oxime ether thiadiazolylthioether compounds(4a-4f) involved a β-chloropropiophenone substitution on 2-mercapto-5-substituded-1,3,4-thiadiazole,oximation with hydroxylamine and etherification with 5-chloromethyl-2-phenyl-1,3,4-oxadiazole.Their structures were characterized by 1H NMR,IR,MS and elemental analysis.The in vitro antitumor activities of the six compounds to B16,HL60 and SMMC-7721 cancer cell strains were evaluated by MTT assay.The preliminary results showed that some of them showed potential antiproliferation activity.
The synthesis of six oxime ether thiadiazolylthioether compounds(4a-4f) involved a β-chloropropiophenone substitution on 2-mercapto-5-substituded-1,3,4-thiadiazole,oximation with hydroxylamine and etherification with 5-chloromethyl-2-phenyl-1,3,4-oxadiazole.Their structures were characterized by 1H NMR,IR,MS and elemental analysis.The in vitro antitumor activities of the six compounds to B16,HL60 and SMMC-7721 cancer cell strains were evaluated by MTT assay.The preliminary results showed that some of them showed potential antiproliferation activity.
2013, 30(4): 389-393
doi: 10.3724/SP.J.1095.2013.20372
Abstract:
Using home-made tris(acetylacetonato)ruthenium(Ⅲ),Ru(acac)3,as catalyst,the hydrogenation of nitrobenzene to aniline via a hydrogen transfer process using sodium formate as hydrogen donor was investigated.The effects of reaction conditions such as temperature,time,dosage of catalyst and categories of hydrogen donor were investigated.The optimized reaction conditions are:the reaction temperature is 80℃,the reaction time is 4 h and the molar ratio of sodium formate to nitrobenzene is 2:1.Under optimized conditions,the conversion of nitrobenzene is nearly 100% with 96.65% yield of aniline.This result shows that Ru(acac)3 exhibits good catalytic activities in the hydrogenation of nitrobenzene.
Using home-made tris(acetylacetonato)ruthenium(Ⅲ),Ru(acac)3,as catalyst,the hydrogenation of nitrobenzene to aniline via a hydrogen transfer process using sodium formate as hydrogen donor was investigated.The effects of reaction conditions such as temperature,time,dosage of catalyst and categories of hydrogen donor were investigated.The optimized reaction conditions are:the reaction temperature is 80℃,the reaction time is 4 h and the molar ratio of sodium formate to nitrobenzene is 2:1.Under optimized conditions,the conversion of nitrobenzene is nearly 100% with 96.65% yield of aniline.This result shows that Ru(acac)3 exhibits good catalytic activities in the hydrogenation of nitrobenzene.
2013, 30(4): 394-397
doi: 10.3724/SP.J.1095.2013.20309
Abstract:
An ionic liquid methyltri-n-octylammonium peroxotungstate[(CH3)N(n-C8H17)3]2W2O11 was synthesized via an one-step process using methyl trioctyl ammonium chloride[(CH3)N(n-C8H17)3]Cl and sodium tungstate as precursors.The oxidation of benzyl alcohol to benzoic acid by H2O2 was studied using the obtained ionic liquid as catalyst under solvent-free condition.The optimized reaction conditions are:the amount of benzyl alcohol substrate is 5.0 mmol,the molar fraction of ionic liquid catalyst to the substrate is 0.4%,the amount of hydrogen peroxide is 20.0 mmol and the reaction temperature is 70℃.Under these optimized conditions,the conversion of benzyl alcohol can reach 99% while the selectivity is over 98%.The advantages of this reaction include solvent free,mild reaction conditions,high yield and selectivity of target product.
An ionic liquid methyltri-n-octylammonium peroxotungstate[(CH3)N(n-C8H17)3]2W2O11 was synthesized via an one-step process using methyl trioctyl ammonium chloride[(CH3)N(n-C8H17)3]Cl and sodium tungstate as precursors.The oxidation of benzyl alcohol to benzoic acid by H2O2 was studied using the obtained ionic liquid as catalyst under solvent-free condition.The optimized reaction conditions are:the amount of benzyl alcohol substrate is 5.0 mmol,the molar fraction of ionic liquid catalyst to the substrate is 0.4%,the amount of hydrogen peroxide is 20.0 mmol and the reaction temperature is 70℃.Under these optimized conditions,the conversion of benzyl alcohol can reach 99% while the selectivity is over 98%.The advantages of this reaction include solvent free,mild reaction conditions,high yield and selectivity of target product.
2013, 30(4): 398-402
doi: 10.3724/SP.J.1095.2013.20243
Abstract:
Zwitterionic copolymers(P(AM DMAPS)) were successfully synthesized in aqueous solution via the atom-transfer radical polymerization(ATRP) between acrylamide(AM) and a homemade zwitterionic monomer of 3-dimethyl(methacryloyloxyethyl) ammonium propane sulfonate(DMAPS) under microwave irradiation(MI) using 2-chloropropionamide as initiator and CuCl/2,2'-bipyridine as catalyst.The effects of microwave power,reaction time and the amount of initiator,catalyst and ligand on the polymerization were studied and compared with those of conventional heating method.Our results showed that the apparent rate constant(Kpapp) of copolymerization under microwave radiation with radiation power of 240 W for 1250 s was 4.5 times that of traditional thermal polymerization.The conversion was 40.15% and Mn was 46410. The optimized conditions for copolymerization are as follows:the total monomer concentration is 4.0 mol/L in which the molar fraction of functional monomer DMAPS is 1%,the initiator concentration is 0.015 mol/L,and the catalyst concentration is 0.01 mol/L.
Zwitterionic copolymers(P(AM DMAPS)) were successfully synthesized in aqueous solution via the atom-transfer radical polymerization(ATRP) between acrylamide(AM) and a homemade zwitterionic monomer of 3-dimethyl(methacryloyloxyethyl) ammonium propane sulfonate(DMAPS) under microwave irradiation(MI) using 2-chloropropionamide as initiator and CuCl/2,2'-bipyridine as catalyst.The effects of microwave power,reaction time and the amount of initiator,catalyst and ligand on the polymerization were studied and compared with those of conventional heating method.Our results showed that the apparent rate constant(Kpapp) of copolymerization under microwave radiation with radiation power of 240 W for 1250 s was 4.5 times that of traditional thermal polymerization.The conversion was 40.15% and Mn was 46410. The optimized conditions for copolymerization are as follows:the total monomer concentration is 4.0 mol/L in which the molar fraction of functional monomer DMAPS is 1%,the initiator concentration is 0.015 mol/L,and the catalyst concentration is 0.01 mol/L.
2013, 30(4): 403-407
doi: 10.3724/SP.J.1095.2013.20231
Abstract:
Poly(ionic liquid) hydrogel was synthesized by radical polymerization of N-vinly-N'-ethylimidazolebromize and divinylbenzene, and then the hydrogel loading gold nanoparticles(GNPs) was obtained by one step in situ reduction. The dispersion of the gold nanoparticles in the poly(ionic liquid) hydrogel was studied,and the anion responsive aggregation was investigated by UV-Vis spectrum and TEM. It was found that the GNPs was well dispersed in the net of poly(ionic liquid) hydrogel with a spherical form(2-5 nm) and surface plasmon resonance(SPR) absorption peak at 527 nm due to the steric hindrance and electrostatic interactions. The hydrophobic hydrogel was formed due to the effect of PF6-,causing the contraction of the gel and the aggregation of the GNPs inside the gel. Consequently,the SPR absorption peak was shifted to 532 nm. The results indicate that this hydrogel has an anion responsiveness.
Poly(ionic liquid) hydrogel was synthesized by radical polymerization of N-vinly-N'-ethylimidazolebromize and divinylbenzene, and then the hydrogel loading gold nanoparticles(GNPs) was obtained by one step in situ reduction. The dispersion of the gold nanoparticles in the poly(ionic liquid) hydrogel was studied,and the anion responsive aggregation was investigated by UV-Vis spectrum and TEM. It was found that the GNPs was well dispersed in the net of poly(ionic liquid) hydrogel with a spherical form(2-5 nm) and surface plasmon resonance(SPR) absorption peak at 527 nm due to the steric hindrance and electrostatic interactions. The hydrophobic hydrogel was formed due to the effect of PF6-,causing the contraction of the gel and the aggregation of the GNPs inside the gel. Consequently,the SPR absorption peak was shifted to 532 nm. The results indicate that this hydrogel has an anion responsiveness.
2013, 30(4): 408-412
doi: 10.3724/SP.J.1095.2013.20274
Abstract:
The polymerisable glucose derivates,6-O-vinyladipoyl-D-glucose was sythesized by chemoenzymatic transesterification,the novel thermosensitive glycopolymers,poly (N-isopropylacryamide-co-6-O-vinyladipoyl-D-glucose)(NIPAAm-co-OVAG) were fabricated free radical copolymerization from N-isopropylacryamide(NIPAAm) and 6-O-vinyladipoyl-D-glucose(OVAG). The structures and properties of the copolymers were confirmed by 1H NMR,UV-Vis absorbance and GPC. Moreover,the hydrodynamic diameter and gyration radius of the poly(OVAG-co-NIPAAm) in aqueous solution were studied by laser light scattering. Finally,we found that the poly(OVAG-co-NIPAAm) chains exist in aqueous as nearly spherical nanoparticles with diameter around 60 nm and the lower critical solution temperature(LCST) increased from 32℃ of PNIPAAm homopolymer to 39℃.
The polymerisable glucose derivates,6-O-vinyladipoyl-D-glucose was sythesized by chemoenzymatic transesterification,the novel thermosensitive glycopolymers,poly (N-isopropylacryamide-co-6-O-vinyladipoyl-D-glucose)(NIPAAm-co-OVAG) were fabricated free radical copolymerization from N-isopropylacryamide(NIPAAm) and 6-O-vinyladipoyl-D-glucose(OVAG). The structures and properties of the copolymers were confirmed by 1H NMR,UV-Vis absorbance and GPC. Moreover,the hydrodynamic diameter and gyration radius of the poly(OVAG-co-NIPAAm) in aqueous solution were studied by laser light scattering. Finally,we found that the poly(OVAG-co-NIPAAm) chains exist in aqueous as nearly spherical nanoparticles with diameter around 60 nm and the lower critical solution temperature(LCST) increased from 32℃ of PNIPAAm homopolymer to 39℃.
2013, 30(4): 413-419
doi: 10.3724/SP.J.1095.2013.20272
Abstract:
We report a facile melt radical grafting reaction method to fabricate covalent grafted polypropylene(PP)/carbon nanotubes(CNTs) nanocomposites using 2,5-dimethyl-2,5 (tert-butylperoxy) hexane peroxide(DHBP) to induce the radical and using tetramethylthiuram(TMTD) to control radical grafting reaction.The covalent grafting reaction was characterized by Raman spectroscopy and TEM.The crystallization,thermal and mechanical properties of the composites were studied.Compared with noncovalent grafted PP/CNTs composites and PP,the covalent grafted nanocomposites showed increased crystallization temperatures(2.6 and 12.0℃,respectively) and thermal decomposition temperatures(6.4 and 34.8℃,respectively),an increased tensile strength and tensile modulus to a little extent,and increased notched impact strength by 56.7% and 58.1%,respectively.
We report a facile melt radical grafting reaction method to fabricate covalent grafted polypropylene(PP)/carbon nanotubes(CNTs) nanocomposites using 2,5-dimethyl-2,5 (tert-butylperoxy) hexane peroxide(DHBP) to induce the radical and using tetramethylthiuram(TMTD) to control radical grafting reaction.The covalent grafting reaction was characterized by Raman spectroscopy and TEM.The crystallization,thermal and mechanical properties of the composites were studied.Compared with noncovalent grafted PP/CNTs composites and PP,the covalent grafted nanocomposites showed increased crystallization temperatures(2.6 and 12.0℃,respectively) and thermal decomposition temperatures(6.4 and 34.8℃,respectively),an increased tensile strength and tensile modulus to a little extent,and increased notched impact strength by 56.7% and 58.1%,respectively.
2013, 30(4): 420-426
doi: 10.3724/SP.J.1095.2013.20278
Abstract:
A facile soft-template method was developed for the synthesis of spherical micro-mesoporous hierarchical carbon material(SHC) by first reacting phenol with formaldehyde under basic conditions,and then self-assembling with Pluronic F127 as the template.The surface morphology and the performance of the material were examined with the surface area and porosity measurements,scanning electron spectroscopy(SEM),transmission electron microscope(TEM) and thermal analysis.The results showed that the morphologies of the samples were regulated by the soft-template,pH and activation temperature.The optimum conditions were determined as the following:the mass fraction for the surfactant is 20%,pH value is 0.5 and the activation temperature is 700℃.The prepared porous carbon under the above conditions exhibits spherical structure with a uniformly diameter of 100~200 nm and is well dispersed.Vermicular and bimodal pores of 2.9 nm and 1.3 nm were observed.The maximum surface area and the pore volume reach 503.20 m2/g and 0.42 cm3/g,respectively.The results reveal that the surface area and the pore total volume of samples increase with the increasing of activation temperature.However,the pore size of the samples shows a reverse trendency.
A facile soft-template method was developed for the synthesis of spherical micro-mesoporous hierarchical carbon material(SHC) by first reacting phenol with formaldehyde under basic conditions,and then self-assembling with Pluronic F127 as the template.The surface morphology and the performance of the material were examined with the surface area and porosity measurements,scanning electron spectroscopy(SEM),transmission electron microscope(TEM) and thermal analysis.The results showed that the morphologies of the samples were regulated by the soft-template,pH and activation temperature.The optimum conditions were determined as the following:the mass fraction for the surfactant is 20%,pH value is 0.5 and the activation temperature is 700℃.The prepared porous carbon under the above conditions exhibits spherical structure with a uniformly diameter of 100~200 nm and is well dispersed.Vermicular and bimodal pores of 2.9 nm and 1.3 nm were observed.The maximum surface area and the pore volume reach 503.20 m2/g and 0.42 cm3/g,respectively.The results reveal that the surface area and the pore total volume of samples increase with the increasing of activation temperature.However,the pore size of the samples shows a reverse trendency.
2013, 30(4): 427-430
doi: 10.3724/SP.J.1095.2013.20265
Abstract:
N,N-disubstituted sulfonamide between sulfonyl chlorides and tertiary amines was discovered.Four aromatic sulfonamides were synthesized in dichloromethane or acetone by using 4,6-dialkoxy-benzene-1,3-disulfonyl dichlorides and 2,4,6-tris(dimethylaminomethyl)phenol as the starting materials.The purified products were characterized by IR,1H NMR,elemental analysis and MS.Aromatic sulfonamides were then applied as the extraction reagents for Ca2+,Pb2+ and some transition metal cations.The primary results showed that the aromatic sulfonamides have better extraction capability for Ca2+.
N,N-disubstituted sulfonamide between sulfonyl chlorides and tertiary amines was discovered.Four aromatic sulfonamides were synthesized in dichloromethane or acetone by using 4,6-dialkoxy-benzene-1,3-disulfonyl dichlorides and 2,4,6-tris(dimethylaminomethyl)phenol as the starting materials.The purified products were characterized by IR,1H NMR,elemental analysis and MS.Aromatic sulfonamides were then applied as the extraction reagents for Ca2+,Pb2+ and some transition metal cations.The primary results showed that the aromatic sulfonamides have better extraction capability for Ca2+.
2013, 30(4): 431-435
doi: 10.3724/SP.J.1095.2013.20260
Abstract:
The self-assembly of surface active ionic liquid 1-(2-hydroxyethyl)-3-dodecylimidazolium chloride([C2OHC12im]Cl) in aqueous solutions with various inorganic salts(NaX,X=Cl-,Br- and I-,Na2SO4) has been investigated by surface tension method and fluorescence probe method,respectively. The critical micelle concentration(CMC) and average aggregation number(Nm) of[C2OHC12im]Cl changed remarkably in aqueous medium with the presence of counter ions. It is believed that the[C2OHC12im]+ monomers or micelles are combined with the counter ions to neutralize their surface charges. The order of the counter ions in altering the self-assembly parameters of[C2OHC12im]Cl in aqueous medium follows Cl---42-. However, the effects of the category of counter ions on the critical aggregation number(Nm,c) and the micropolarity of micelle ([I1/I3]m) were marginal. Along with the increase of the concentration of Br-,the CMC decreases logarithmically and the Nm increases by an empirical power law.
The self-assembly of surface active ionic liquid 1-(2-hydroxyethyl)-3-dodecylimidazolium chloride([C2OHC12im]Cl) in aqueous solutions with various inorganic salts(NaX,X=Cl-,Br- and I-,Na2SO4) has been investigated by surface tension method and fluorescence probe method,respectively. The critical micelle concentration(CMC) and average aggregation number(Nm) of[C2OHC12im]Cl changed remarkably in aqueous medium with the presence of counter ions. It is believed that the[C2OHC12im]+ monomers or micelles are combined with the counter ions to neutralize their surface charges. The order of the counter ions in altering the self-assembly parameters of[C2OHC12im]Cl in aqueous medium follows Cl-
2013, 30(4): 436-443
doi: 10.3724/SP.J.1095.2013.20270
Abstract:
Poly benzimidazole and laccase were co-deposited on the surface of glassy carbon electrode by cyclic voltammetry method.Apparent catalytic reduction current was observed when the as-prepared laccase based electrode was immersed in oxygen-saturated phosphate buffer solution,indicating the viability of direct electron transfer between electrode and immobilized enzyme without external mediator existence.The result showed the onset potential of oxygen reduction reaction(ORR) was 645 mV,in the vicinity of the formal potential corresponding to T1 copper site in laccase(580 mV),while the limited diffusion catalytic current density could be up to 318.5 × 10-6 A/cm2. The slow diffusion in the dense-packed conductive polymer thin film layer on the surface of electrode(the diffusion coefficient is only 1.25% of measured value in solution) resulted in a slight enhancement in limited diffusion catalytic current density:~1 × 10-3 A/cm2 at the relatively high rotating speed. The average turn-over frequency of catalytic oxygen reduction induced by entrapped laccase was evaluated to be 21.7/s according to the stationary limit catalytic current density. This laccase based electrode displayed favorable reproducibility and long-term usability(catalytic activity could retain ca.80% of its initial value after a storage for 10 days). This biocathode had superior activity at physiological temperature of human being and under weak acidic conditions,and demonstrated excellent sensor function for oxygen molecules:low detection limit(0.5 μmol/L),high sensitivity(71.1 μA·L/mmol) and favorable affinity(KM=89.9 μmol/L).
Poly benzimidazole and laccase were co-deposited on the surface of glassy carbon electrode by cyclic voltammetry method.Apparent catalytic reduction current was observed when the as-prepared laccase based electrode was immersed in oxygen-saturated phosphate buffer solution,indicating the viability of direct electron transfer between electrode and immobilized enzyme without external mediator existence.The result showed the onset potential of oxygen reduction reaction(ORR) was 645 mV,in the vicinity of the formal potential corresponding to T1 copper site in laccase(580 mV),while the limited diffusion catalytic current density could be up to 318.5 × 10-6 A/cm2. The slow diffusion in the dense-packed conductive polymer thin film layer on the surface of electrode(the diffusion coefficient is only 1.25% of measured value in solution) resulted in a slight enhancement in limited diffusion catalytic current density:~1 × 10-3 A/cm2 at the relatively high rotating speed. The average turn-over frequency of catalytic oxygen reduction induced by entrapped laccase was evaluated to be 21.7/s according to the stationary limit catalytic current density. This laccase based electrode displayed favorable reproducibility and long-term usability(catalytic activity could retain ca.80% of its initial value after a storage for 10 days). This biocathode had superior activity at physiological temperature of human being and under weak acidic conditions,and demonstrated excellent sensor function for oxygen molecules:low detection limit(0.5 μmol/L),high sensitivity(71.1 μA·L/mmol) and favorable affinity(KM=89.9 μmol/L).
2013, 30(4): 444-447
doi: 10.3724/SP.J.1095.2013.20414
Abstract:
The electrooxidative behaviors of sulfonated 4,4'-biphenyl diphenol were investated on the stainless steel electrode by electrochemical methods.The alternative current(AC) impedance responses of the electrolyte system between the electrodes before and after electrooxidation were also in situ monitored.The results show that the electrooxidation of sulfonated 4,4'-biphenyl diphenol is irreversible similar to those of other phenolic compounds,and the onset potential and peak potential are 0.95 V and 1.2 V,respectively.After electrooxidation,the corresponding AC impedance increases only by 0.27 Ω·cm2,possibly due to the formation of polymer film.This increase is slight,which is attributed to the double promoting effects of biphenol and sulfonated acid group.
The electrooxidative behaviors of sulfonated 4,4'-biphenyl diphenol were investated on the stainless steel electrode by electrochemical methods.The alternative current(AC) impedance responses of the electrolyte system between the electrodes before and after electrooxidation were also in situ monitored.The results show that the electrooxidation of sulfonated 4,4'-biphenyl diphenol is irreversible similar to those of other phenolic compounds,and the onset potential and peak potential are 0.95 V and 1.2 V,respectively.After electrooxidation,the corresponding AC impedance increases only by 0.27 Ω·cm2,possibly due to the formation of polymer film.This increase is slight,which is attributed to the double promoting effects of biphenol and sulfonated acid group.
2013, 30(4): 448-452
doi: 10.3724/SP.J.1095.2013.20249
Abstract:
In this paper,the Ir catalysts supported on Vulcan XC-72 carbon(XC)(Ir/XC) and on the mixture of WC and Vulcan XC-72C(Ir-WC/XC) were prepared.Based on the characterizations with energy dispersive spectroscopy and X-ray diffraction patterns,the electrocatalytic performances of the two Ir catalysts on different supports for ammonia oxidation were investigated using the electrochemical techniques.It showed that the current density of the ammonia oxidation peak at the Ir-WC/XC catalyst electrode is 31.26% larger than that at the Ir/XC catalyst electrode.Furthermore,the electrocatalytic stability of the Ir-WC/XC catalyst is obviously better than that at the Ir/XC catalyst.
In this paper,the Ir catalysts supported on Vulcan XC-72 carbon(XC)(Ir/XC) and on the mixture of WC and Vulcan XC-72C(Ir-WC/XC) were prepared.Based on the characterizations with energy dispersive spectroscopy and X-ray diffraction patterns,the electrocatalytic performances of the two Ir catalysts on different supports for ammonia oxidation were investigated using the electrochemical techniques.It showed that the current density of the ammonia oxidation peak at the Ir-WC/XC catalyst electrode is 31.26% larger than that at the Ir/XC catalyst electrode.Furthermore,the electrocatalytic stability of the Ir-WC/XC catalyst is obviously better than that at the Ir/XC catalyst.
2013, 30(4): 453-457
doi: 10.3724/SP.J.1095.2013.20216
Abstract:
The inhibitive action of a composite thiadiazole inhibitor(TSJ-T6) against the corrosion of silver in solutions of simulation jet fuel has been studied using the method of mass gain and metallographic microscopy.All experimental results showed that TSJ-T6 has an excellent corrosion inhibition performance and the most effective concentration of inhibitor is 10.0 μg/g,when the inhibition efficiency can reach 94.37%.The adsorption of TSJ-T6 on the surface of silver strip obeys the Langmuir adsorption isotherm,and the thermodynamic parameters were determined and discussed.The kinetic parameters were calculated by the obtained corrosion inhibition rates at different temperatures.
The inhibitive action of a composite thiadiazole inhibitor(TSJ-T6) against the corrosion of silver in solutions of simulation jet fuel has been studied using the method of mass gain and metallographic microscopy.All experimental results showed that TSJ-T6 has an excellent corrosion inhibition performance and the most effective concentration of inhibitor is 10.0 μg/g,when the inhibition efficiency can reach 94.37%.The adsorption of TSJ-T6 on the surface of silver strip obeys the Langmuir adsorption isotherm,and the thermodynamic parameters were determined and discussed.The kinetic parameters were calculated by the obtained corrosion inhibition rates at different temperatures.
2013, 30(4): 458-463
doi: 10.3724/SP.J.1095.2013.20264
Abstract:
A new anode of Al/Pb-0.23%Ag was prepared from methanesulfonic acid bath by electrodeposition for zinc electrowinning. The results of corrosion test and electrochemical analysis show that the Al/Pb-0.23%Ag anode has a lower corrosion rate,higher corrosion potential and lower corrosion current density,higher electrocatalytic activity as compared to conventional Pb-0.25%Ag anode. The metallographic structure and scanning electron microscopy(SEM) observations show that the Al/Pb-0.23%Ag anode has tiny and dense crystals. X-ray diffraction(XRD) analysis shows that the Al/Pb-0.23%Ag anode has the phase of PbSO4,α-PbO2 and β-PbO2 after 48 h of anodic polarization.
A new anode of Al/Pb-0.23%Ag was prepared from methanesulfonic acid bath by electrodeposition for zinc electrowinning. The results of corrosion test and electrochemical analysis show that the Al/Pb-0.23%Ag anode has a lower corrosion rate,higher corrosion potential and lower corrosion current density,higher electrocatalytic activity as compared to conventional Pb-0.25%Ag anode. The metallographic structure and scanning electron microscopy(SEM) observations show that the Al/Pb-0.23%Ag anode has tiny and dense crystals. X-ray diffraction(XRD) analysis shows that the Al/Pb-0.23%Ag anode has the phase of PbSO4,α-PbO2 and β-PbO2 after 48 h of anodic polarization.
2013, 30(4): 464-468
doi: 10.3724/SP.J.1095.2013.20224
Abstract:
An optical chemical sensor was developed for the determination of CO2+ based on the reversible fluorescence quenching of 5-tert-butyl-2-methoxy thiacalix[4] arene(Tc4a-OCH3) immobilized on a plasticized polyvinyl chloride(PVC) membrane.The optimum membrane of the sensor is composed of 50 mg of PVC,100 mg of dioctyl sebacate(DOS) and 2.5 mg of 5-tert-butyl-2-methoxy thiacalix[4] arene. The maximum response of the membrane for CO2+ was obtained in nitric acid solution with pH of 5.6,and the proposed sensor responds linearly in a concentration range of 6.31 × 10-6~1.26 × 10-2 mol/L,with a detection limit of 3.11 × 10-7 mol/L. The sensing membrane has the advantages of high reproducibility,reversibility of the fluorescence signal and good selectivity. Common inorganic ions have no interferences.
An optical chemical sensor was developed for the determination of CO2+ based on the reversible fluorescence quenching of 5-tert-butyl-2-methoxy thiacalix[4] arene(Tc4a-OCH3) immobilized on a plasticized polyvinyl chloride(PVC) membrane.The optimum membrane of the sensor is composed of 50 mg of PVC,100 mg of dioctyl sebacate(DOS) and 2.5 mg of 5-tert-butyl-2-methoxy thiacalix[4] arene. The maximum response of the membrane for CO2+ was obtained in nitric acid solution with pH of 5.6,and the proposed sensor responds linearly in a concentration range of 6.31 × 10-6~1.26 × 10-2 mol/L,with a detection limit of 3.11 × 10-7 mol/L. The sensing membrane has the advantages of high reproducibility,reversibility of the fluorescence signal and good selectivity. Common inorganic ions have no interferences.
2013, 30(4): 469-473
doi: 10.3724/SP.J.1095.2013.20246
Abstract:
A new flow-injection chemiluminescence method for the determination of 5-sulfosalicylic acid was proposed.Various factors affected the chemiluminescence signal were investigated and the possible mechanism was also studied.Under the optimum conditions,the linear range for the determination of 5-sulfosalicylic acid was 5.0 × 10-8~2.0 × 10-5 mol/L with a detection limit(S/N=3) of 1.0 × 10-8 mol/L. The relative standard deviation was 2.7% for 5.0 × 10-6 mol/L 5-sulfosalicylic acid solution in nine repeated measurements. The method was successfully applied to the determination of 5-sulfosalicylic acid in the waste water of doxycycline.
A new flow-injection chemiluminescence method for the determination of 5-sulfosalicylic acid was proposed.Various factors affected the chemiluminescence signal were investigated and the possible mechanism was also studied.Under the optimum conditions,the linear range for the determination of 5-sulfosalicylic acid was 5.0 × 10-8~2.0 × 10-5 mol/L with a detection limit(S/N=3) of 1.0 × 10-8 mol/L. The relative standard deviation was 2.7% for 5.0 × 10-6 mol/L 5-sulfosalicylic acid solution in nine repeated measurements. The method was successfully applied to the determination of 5-sulfosalicylic acid in the waste water of doxycycline.
2013, 30(4): 474-480
doi: 10.3724/SP.J.1095.2013.20267
Abstract:
In alkaline medium of pH=9.0,Hg2+ reacts with phenanthroline(phen) to form a colorless chelate[Hg(phen)3]2+,which further reacts with Congo red(CR) to form 1:1 ion-association complex.As a result,new peaks appear in the spectra of resonance Rayleigh scattering(RRS),second order scattering(SOS) and frequency doubling scattering(FDS),and their intensities are enhanced greatly.The maximum peaks of RRS,SOS and FDS are located at 378 nm,612 nm and 352 nm,respectively.The enhanced RRS,SOS and FDS intensities are directly proportional to the concentrations of Hg2+. These methods have very high sensitivities and good selectivities,and the detection limits are 2.32 μg/L for RRS,3.20 μg/L for SOS,1.56 μg/L for FDS,respectively. In addition,the influencing factors and the effects of coexisting substances of the reaction were examined by RRS under optimum conditions. The results show that this method has a good selectivity.Therefore,a new method has been developed to determine trace amounts of Hg2+.The reasons for RRS enhancement of the system and reaction mechanism have been investigated.
In alkaline medium of pH=9.0,Hg2+ reacts with phenanthroline(phen) to form a colorless chelate[Hg(phen)3]2+,which further reacts with Congo red(CR) to form 1:1 ion-association complex.As a result,new peaks appear in the spectra of resonance Rayleigh scattering(RRS),second order scattering(SOS) and frequency doubling scattering(FDS),and their intensities are enhanced greatly.The maximum peaks of RRS,SOS and FDS are located at 378 nm,612 nm and 352 nm,respectively.The enhanced RRS,SOS and FDS intensities are directly proportional to the concentrations of Hg2+. These methods have very high sensitivities and good selectivities,and the detection limits are 2.32 μg/L for RRS,3.20 μg/L for SOS,1.56 μg/L for FDS,respectively. In addition,the influencing factors and the effects of coexisting substances of the reaction were examined by RRS under optimum conditions. The results show that this method has a good selectivity.Therefore,a new method has been developed to determine trace amounts of Hg2+.The reasons for RRS enhancement of the system and reaction mechanism have been investigated.
2013, 30(4): 481-485
doi: 10.3724/SP.J.1095.2013.20273
Abstract:
A method was developed for the rapid determination of auramine O in yellow croaker by microchip capillary electrophoresis with contactless conductivity detection.Effects of the type and concentration of buffer,separation voltage and injection time on the separation and detection were investigated,and the optimal analysis conditions were obtained in the buffer solution of 5.0 mmol/L lactate(pH=3.29) at the separation voltage of 1.8 kV,where auramine O could be separated and determined within 1.0 min.The linear range of the concentration of auramine O is from 5.0 mg/L to 100.0 mg/L,and the limit of detection is 0.2 mg/kg(S/N=3).The method was used for the analysis of auramine O in the yellow croaker satisfactorily.
A method was developed for the rapid determination of auramine O in yellow croaker by microchip capillary electrophoresis with contactless conductivity detection.Effects of the type and concentration of buffer,separation voltage and injection time on the separation and detection were investigated,and the optimal analysis conditions were obtained in the buffer solution of 5.0 mmol/L lactate(pH=3.29) at the separation voltage of 1.8 kV,where auramine O could be separated and determined within 1.0 min.The linear range of the concentration of auramine O is from 5.0 mg/L to 100.0 mg/L,and the limit of detection is 0.2 mg/kg(S/N=3).The method was used for the analysis of auramine O in the yellow croaker satisfactorily.
2013, 30(4): 486-488
doi: 10.3724/SP.J.1095.2013.20223
Abstract:
The spectroscopic and electrochemical properties of a series of thiol-porphyrin self-assembled monolayers(SAMs) were studied.The results show that the absorption and fluorescent spectra of the SAMs changed dramatically in comparison with their corresponding precursors in the solution.With the number of thiol in porphyrin increases,the fluorescent peak of the SAMs tends to red shift.Among them,the impede ability to electron transfer in electrolyte are different.The highest block ability and coverage are observed for 5,10-bis(4-hydroxyphenyl)-15,20-bisphenyl porphyrin(cis-TPP(SH)2) SAMs.
The spectroscopic and electrochemical properties of a series of thiol-porphyrin self-assembled monolayers(SAMs) were studied.The results show that the absorption and fluorescent spectra of the SAMs changed dramatically in comparison with their corresponding precursors in the solution.With the number of thiol in porphyrin increases,the fluorescent peak of the SAMs tends to red shift.Among them,the impede ability to electron transfer in electrolyte are different.The highest block ability and coverage are observed for 5,10-bis(4-hydroxyphenyl)-15,20-bisphenyl porphyrin(cis-TPP(SH)2) SAMs.
