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2008 Volume 25 Issue 3
2008, 25(3): 257-265
Abstract:
Unlike neutral C60,which is an electron-deficient molecule and reactive towards nucleophiles,C60 anions are electron-rich species and reactive towards electrophiles.Owing to the different electronic structures between the C60 anion and neutral C60,it is likely that C60 anions may undergo a different reaction mechanism compared with neutral C60 during the reactions,which may lead to the formation of novel fullerene derivatives.Herein,the progress of the chemistry of C60 anions is reviewed in order to get a better understanding of fullerene anions and fullerene chemistry.As the review indicates,it is necessary to further investigate the chemistry of fullerene anions since many aspects of it are not well understood at the current stage.
Unlike neutral C60,which is an electron-deficient molecule and reactive towards nucleophiles,C60 anions are electron-rich species and reactive towards electrophiles.Owing to the different electronic structures between the C60 anion and neutral C60,it is likely that C60 anions may undergo a different reaction mechanism compared with neutral C60 during the reactions,which may lead to the formation of novel fullerene derivatives.Herein,the progress of the chemistry of C60 anions is reviewed in order to get a better understanding of fullerene anions and fullerene chemistry.As the review indicates,it is necessary to further investigate the chemistry of fullerene anions since many aspects of it are not well understood at the current stage.
2008, 25(3): 266-269
Abstract:
The spectral properties of rare earth polyoxometalate(POM)-Crystal Violet(CV) systems were studied by absorption spectra and synchronous fluorescence in B-R buffer at pH=4.1.The addition of POM decreased the absorbance of CV at 590 nm with the appearance of a new band at 655 nm,which indicated the formation of POM-CV complex.Synchronous fluorescence showed that the addition of POM could enhance the fluorescence intensity of CV,which was explained in terms of the hindrance of the formation of the non-fluorescent twisted intramolecular charge transfer(TICT) states of CV by the assembled POM-CV system,and the surfactant CTAB could enhance the luminescence by coordinated assembly.
The spectral properties of rare earth polyoxometalate(POM)-Crystal Violet(CV) systems were studied by absorption spectra and synchronous fluorescence in B-R buffer at pH=4.1.The addition of POM decreased the absorbance of CV at 590 nm with the appearance of a new band at 655 nm,which indicated the formation of POM-CV complex.Synchronous fluorescence showed that the addition of POM could enhance the fluorescence intensity of CV,which was explained in terms of the hindrance of the formation of the non-fluorescent twisted intramolecular charge transfer(TICT) states of CV by the assembled POM-CV system,and the surfactant CTAB could enhance the luminescence by coordinated assembly.
2008, 25(3): 270-275
Abstract:
Octa(phenyl)silsesquioxane(POSS),a cubic cage-like nano particle was modified to introduce negative charges to the particle via sulfonation,and the structure of the sulfonation product,SOPS,was confirmed by FTIR and NMR.Ultra-thin hybrid films were fabricated via layer-by-layer self-assembly of the SOPS and poly(allylamine)(PAH).The assembly process was studied by quartz crystal microgravimetry(QCM),UV-Vis spectroscopy,contact angle(CA) measurement,and X-ray photoelectron spectroscopy(XPS).The deposited oligo-charged SOPS was found to desorb when in contact with PAH solution.However,when the assembly was carried out at higher pH,the desorption of SOPS was effective suppressed,and SOPS/PAH multilayers were obtained.This provides a facile and effective approach to fabrication of hybrid thin films containing inorganic nano particles.
Octa(phenyl)silsesquioxane(POSS),a cubic cage-like nano particle was modified to introduce negative charges to the particle via sulfonation,and the structure of the sulfonation product,SOPS,was confirmed by FTIR and NMR.Ultra-thin hybrid films were fabricated via layer-by-layer self-assembly of the SOPS and poly(allylamine)(PAH).The assembly process was studied by quartz crystal microgravimetry(QCM),UV-Vis spectroscopy,contact angle(CA) measurement,and X-ray photoelectron spectroscopy(XPS).The deposited oligo-charged SOPS was found to desorb when in contact with PAH solution.However,when the assembly was carried out at higher pH,the desorption of SOPS was effective suppressed,and SOPS/PAH multilayers were obtained.This provides a facile and effective approach to fabrication of hybrid thin films containing inorganic nano particles.
2008, 25(3): 276-280
Abstract:
PANI films were in-situ prepared on the surface of glass substrates dipped into the solution of dispersion polymerization of aniline,using inorganic nano-particulate-nanometer SiO2 as steric stabilizer instead of water soluble polymer.The film morphology,chemical structure and composition of PANI film were characterized by SEM,AFM,UV-Vis,FTIR and XRD.The results indicate that homogeneous,satin and transparent PANI films could be prepared.The most thickness of the films could reach to 200 nm,and their conductivity ranged between 3.0×10-3~1.8×10-2 S/cm.Preliminary result indicates that there were two direct actuating forces aroused by aniline's adsorption on glass surface:one was the soakage of glass surface;the other is the adsorption of aniline cation free radicals on glass surface.The growth of PANI films underwent three stages:adsorption nucleation,growth and growth saturation.
PANI films were in-situ prepared on the surface of glass substrates dipped into the solution of dispersion polymerization of aniline,using inorganic nano-particulate-nanometer SiO2 as steric stabilizer instead of water soluble polymer.The film morphology,chemical structure and composition of PANI film were characterized by SEM,AFM,UV-Vis,FTIR and XRD.The results indicate that homogeneous,satin and transparent PANI films could be prepared.The most thickness of the films could reach to 200 nm,and their conductivity ranged between 3.0×10-3~1.8×10-2 S/cm.Preliminary result indicates that there were two direct actuating forces aroused by aniline's adsorption on glass surface:one was the soakage of glass surface;the other is the adsorption of aniline cation free radicals on glass surface.The growth of PANI films underwent three stages:adsorption nucleation,growth and growth saturation.
2008, 25(3): 281-285
Abstract:
Polylactide fibers containing different amounts of glycerol triacetate(GTA) were prepared by electrospinning.The fibers were characterized by environmental scanning electron microscopy,differential scanning calorimetry,water contact angle and mechanical properties.With increasing GTA content,the fibers became to adhere to each other and a network was formed,and as a result,the elongation at break,recovery ratio and tensile strength of the fibers could reach 200%,85% and 4.24 MPa,respectively.At a GTA content of over 50%,the fiber mats were capable of sucking water quickly.
Polylactide fibers containing different amounts of glycerol triacetate(GTA) were prepared by electrospinning.The fibers were characterized by environmental scanning electron microscopy,differential scanning calorimetry,water contact angle and mechanical properties.With increasing GTA content,the fibers became to adhere to each other and a network was formed,and as a result,the elongation at break,recovery ratio and tensile strength of the fibers could reach 200%,85% and 4.24 MPa,respectively.At a GTA content of over 50%,the fiber mats were capable of sucking water quickly.
2008, 25(3): 286-289
Abstract:
The reaction of six dialkyldiferrocenylmethanols(1a~1f) with BF3 in CH2Cl2 gave stable dialkyldiferrocenylmethyl caboniums(2a~2f),which futher reacted with diethanolamine without separation from the reaction solution,and afforded six novel correspongding compounds of dialkyldiferrocenylmethoxyethylamines Fc(R2Fc')CHOCH2CH2NH2(3a~3f),in the yields of 81%~87%.The structures of the title compounds were characterized by elemental analysis,IR,and 1H NMR.
The reaction of six dialkyldiferrocenylmethanols(1a~1f) with BF3 in CH2Cl2 gave stable dialkyldiferrocenylmethyl caboniums(2a~2f),which futher reacted with diethanolamine without separation from the reaction solution,and afforded six novel correspongding compounds of dialkyldiferrocenylmethoxyethylamines Fc(R2Fc')CHOCH2CH2NH2(3a~3f),in the yields of 81%~87%.The structures of the title compounds were characterized by elemental analysis,IR,and 1H NMR.
2008, 25(3): 290-294
Abstract:
CNTs with 5 nm wall thickness and 140~220 nm tube diameter as well as CNTs with 50 nm wall thickness and 80~200 nm tube diameter were prepared,and the effects of the pretreatment of the two kinds of CNTs with concentrated HNO3 on the structure and surface groups of the CNTs were studied.It was found that after the pretreatment,the amount of the charge and discharge of the double electrode layer for the CNTs with the thick wall(Qd) and the amount of the electricity for the oxidation of the oxygen-containing groups on the CNTs surface(Qo) increased by 1.34 and 0.098 mC,respectively,while for the CNTs with the thin wall,they increased by 5.69 and 0.175 mC,respectively.The result indicates that the CNTs with the thin wall are easier to break apart and the carbon atoms on the wall surface easier to oxidize when the CNTs are treated with concentrated HNO3.When the Pt particles obtained with the general liquid phase reduction method were deposited on the CNTs surfaces pretreated,the Pt particles were easier to uniformly adsorb on the surface of the CNTs with the thin wall,due to the fact that the specific surface area of the CNTs with the thin wall after the pretreatment was larger and the content of the oxygen-containing groups was higher.Therefore,the electrocatalytic activity of the Pt catalyst supported on the CNTs with the thin wall after the pretreatment was very high for methanol oxidation.
CNTs with 5 nm wall thickness and 140~220 nm tube diameter as well as CNTs with 50 nm wall thickness and 80~200 nm tube diameter were prepared,and the effects of the pretreatment of the two kinds of CNTs with concentrated HNO3 on the structure and surface groups of the CNTs were studied.It was found that after the pretreatment,the amount of the charge and discharge of the double electrode layer for the CNTs with the thick wall(Qd) and the amount of the electricity for the oxidation of the oxygen-containing groups on the CNTs surface(Qo) increased by 1.34 and 0.098 mC,respectively,while for the CNTs with the thin wall,they increased by 5.69 and 0.175 mC,respectively.The result indicates that the CNTs with the thin wall are easier to break apart and the carbon atoms on the wall surface easier to oxidize when the CNTs are treated with concentrated HNO3.When the Pt particles obtained with the general liquid phase reduction method were deposited on the CNTs surfaces pretreated,the Pt particles were easier to uniformly adsorb on the surface of the CNTs with the thin wall,due to the fact that the specific surface area of the CNTs with the thin wall after the pretreatment was larger and the content of the oxygen-containing groups was higher.Therefore,the electrocatalytic activity of the Pt catalyst supported on the CNTs with the thin wall after the pretreatment was very high for methanol oxidation.
2008, 25(3): 295-299
Abstract:
Poly(aryl ether sulfone ether ketone ketone) with side carboxyl(PESEKK-A) attached to the main chain was synthesized by Friedel-Crafts polycondensation of 4,4'-diphenyoxyl diphenyl sulfone(DPODPS) with trimellitic anhydride chloride(TMAC).The structure was determined by 1H NMR and FT-IR.PESEKK-A could only be dissovled in several solvents,such as,concentrated sulfuric acid(98%),dichloroacetic acid,and trifluoroacetic acid,showing high solvent-resistant and corrosion-resistant properties.Adsorptions of Cu2+,Ag+,Cd2+ onto PESEKK-Na were studied.Sodium salt of the resin(PESEKK-Na) exhibited better adsorption ability than PESEKK-A.The optimum pH for the adsorption of Cu2+,Ag+,Cd2+ onto PESEKK-Na were 4.7,4.5 and 5.7,respectively.The adsorption capacities for Cu2+,Ag+,Cd2+ were 1.03 mmol/g,0.815 3 mmol/g,and 0.558 6 mmol/g,respectively.The amount of Cu2+ adsorbed in 2 h was 80.4% that adsorbed in 48 h.90% of the adsorbed Cu2+ desorbed within 1 h in 1 mol/L HCl.From 12℃ to 45℃,the amount of adsorption increased with temperature,and reached 1.049 mmol/g at 45℃.The resin can be reused without loss of its adsorption ability.These results show that PESEKK-Na has potential in the fields of separating valuable metals and environmental protection.
Poly(aryl ether sulfone ether ketone ketone) with side carboxyl(PESEKK-A) attached to the main chain was synthesized by Friedel-Crafts polycondensation of 4,4'-diphenyoxyl diphenyl sulfone(DPODPS) with trimellitic anhydride chloride(TMAC).The structure was determined by 1H NMR and FT-IR.PESEKK-A could only be dissovled in several solvents,such as,concentrated sulfuric acid(98%),dichloroacetic acid,and trifluoroacetic acid,showing high solvent-resistant and corrosion-resistant properties.Adsorptions of Cu2+,Ag+,Cd2+ onto PESEKK-Na were studied.Sodium salt of the resin(PESEKK-Na) exhibited better adsorption ability than PESEKK-A.The optimum pH for the adsorption of Cu2+,Ag+,Cd2+ onto PESEKK-Na were 4.7,4.5 and 5.7,respectively.The adsorption capacities for Cu2+,Ag+,Cd2+ were 1.03 mmol/g,0.815 3 mmol/g,and 0.558 6 mmol/g,respectively.The amount of Cu2+ adsorbed in 2 h was 80.4% that adsorbed in 48 h.90% of the adsorbed Cu2+ desorbed within 1 h in 1 mol/L HCl.From 12℃ to 45℃,the amount of adsorption increased with temperature,and reached 1.049 mmol/g at 45℃.The resin can be reused without loss of its adsorption ability.These results show that PESEKK-Na has potential in the fields of separating valuable metals and environmental protection.
2008, 25(3): 300-304
Abstract:
One linear polysilane,poly(methylphenyl)silane,and two branched polysilanes poly(phenyl-dimethyl)silane and poly(phenyl-methylphenyl)silane,were synthesized via Wurtz reductive coupling reaction.Their Ultraviolet absorption(UV) and Photoluminescence(PL) spectra were obtained to characterize their optical properties,and thermogravity analysis(TGA) was used to characterize their thermal stability.The absorption bands of the branched polysilanes tailed to visible region and the corresponding emission peaks showed obvious red shift compared with that of the linear one,indicating that the branched polysilanes had lower energy band gap than the linear one.In addition,the branched polysilanes exhibited better thermal stability.Under the irradiation of ultraviolet light of 245 nm,the absorption intensity of the linear polysilane gradually fell with irradiation time,while that of the branched polysilanes remained almost unchanged,indicating that the branched polysilanes had better ultraviolet stability than the linear one.
One linear polysilane,poly(methylphenyl)silane,and two branched polysilanes poly(phenyl-dimethyl)silane and poly(phenyl-methylphenyl)silane,were synthesized via Wurtz reductive coupling reaction.Their Ultraviolet absorption(UV) and Photoluminescence(PL) spectra were obtained to characterize their optical properties,and thermogravity analysis(TGA) was used to characterize their thermal stability.The absorption bands of the branched polysilanes tailed to visible region and the corresponding emission peaks showed obvious red shift compared with that of the linear one,indicating that the branched polysilanes had lower energy band gap than the linear one.In addition,the branched polysilanes exhibited better thermal stability.Under the irradiation of ultraviolet light of 245 nm,the absorption intensity of the linear polysilane gradually fell with irradiation time,while that of the branched polysilanes remained almost unchanged,indicating that the branched polysilanes had better ultraviolet stability than the linear one.
2008, 25(3): 305-308
Abstract:
The volatile oil from Pistacia weinmannifolia's leaves was obtained by steam distillation and its chemical constituents were analyzed by GC-MS.Its biological activity was screened with microbiological method and Alamar Blue method.Analysis of the constituents of the volatile oil shows that 29 compounds were identified,accounting for 99.54% of its total content.The tested Escherichia coli,Staphylococcus aureus and Rhodotorula glutinis showed great sensitivity to the volatile oil,and the volatile oil could also obviously inhibit the growth of cultured tumor cells(NCI-H460).The inhibitory effects on the cell viability are dose-dependent with a inhibition rate of 92.56% at a volatile oil concentration of 0.1 g/L.
The volatile oil from Pistacia weinmannifolia's leaves was obtained by steam distillation and its chemical constituents were analyzed by GC-MS.Its biological activity was screened with microbiological method and Alamar Blue method.Analysis of the constituents of the volatile oil shows that 29 compounds were identified,accounting for 99.54% of its total content.The tested Escherichia coli,Staphylococcus aureus and Rhodotorula glutinis showed great sensitivity to the volatile oil,and the volatile oil could also obviously inhibit the growth of cultured tumor cells(NCI-H460).The inhibitory effects on the cell viability are dose-dependent with a inhibition rate of 92.56% at a volatile oil concentration of 0.1 g/L.
2008, 25(3): 309-312
Abstract:
In this article,the electrodeposition of lithium ions on magnesium electrode in molten salt of KCl-LiCl(58:42,molar ratio) was studied.The deposition of lithium ions on molybdenum and magnesium electrodes was investigated by cyclic voltammograms coupled with electrochemical station at a san rate of 20 mV/s and 450℃,and the results showed that the deposition potential was -2.4 V and -2.28 V respectively,which indicated the magnesium electrode had the induction effect on the electrodeposition of lithium compared with molybdenum electrode.The current efficiency was calculated,and the values were all larger than 92%.The morphology of the magnesium electrode and the magnesium electrode with lithium deposited were studied by scanning electronic microscopy.The results showed that on the magnesium electrode a compact and homogeneous alloy layer was form by lithium electrodeposition.The main impure element was oxygen,as observed by EDX,which probobly was introduced after the alloy was prepared.
In this article,the electrodeposition of lithium ions on magnesium electrode in molten salt of KCl-LiCl(58:42,molar ratio) was studied.The deposition of lithium ions on molybdenum and magnesium electrodes was investigated by cyclic voltammograms coupled with electrochemical station at a san rate of 20 mV/s and 450℃,and the results showed that the deposition potential was -2.4 V and -2.28 V respectively,which indicated the magnesium electrode had the induction effect on the electrodeposition of lithium compared with molybdenum electrode.The current efficiency was calculated,and the values were all larger than 92%.The morphology of the magnesium electrode and the magnesium electrode with lithium deposited were studied by scanning electronic microscopy.The results showed that on the magnesium electrode a compact and homogeneous alloy layer was form by lithium electrodeposition.The main impure element was oxygen,as observed by EDX,which probobly was introduced after the alloy was prepared.
2008, 25(3): 313-316
Abstract:
(Trans-4-(trans-4-n-pentylcyclohexyl)cyclohexyl)acetylene was synthesized with 1-(trans-4-(trans-4-n-pentylcyclohexyl)cyclohexyl)ethylene as starting material via bromine addition,then two molecules of hydrogen bromide were eliminated.The overall yield was 76.7% with a chromatogram purity of 96%.This method is facile to practise and contains a few steps.The impact of elimination conditions on yield was studied.The reaction was finished within 2 h at 80℃,and a cumulative diene by-product turned to be main product when the reaction time was prolonged to 6 h with a yield of 51.5%.The structures of products were identified by IR,MS and NMR.The mechanism of the rearrangement was proposed,i.e.,the hydrogen migrated under the action of alkaline,which resulted in a thermodynamically stable cumulative diene by-product.A new path was provided to obtain cyclohexyl-substituted acetylene or cumulative diene selectively by controlling the reaction conditions.
(Trans-4-(trans-4-n-pentylcyclohexyl)cyclohexyl)acetylene was synthesized with 1-(trans-4-(trans-4-n-pentylcyclohexyl)cyclohexyl)ethylene as starting material via bromine addition,then two molecules of hydrogen bromide were eliminated.The overall yield was 76.7% with a chromatogram purity of 96%.This method is facile to practise and contains a few steps.The impact of elimination conditions on yield was studied.The reaction was finished within 2 h at 80℃,and a cumulative diene by-product turned to be main product when the reaction time was prolonged to 6 h with a yield of 51.5%.The structures of products were identified by IR,MS and NMR.The mechanism of the rearrangement was proposed,i.e.,the hydrogen migrated under the action of alkaline,which resulted in a thermodynamically stable cumulative diene by-product.A new path was provided to obtain cyclohexyl-substituted acetylene or cumulative diene selectively by controlling the reaction conditions.
2008, 25(3): 317-321
Abstract:
PVA-SA/CS bipolar membrane was prepared by the paste method.PVA/sodium alginate(SA) and PVA/chitosan(CS) were cross-linked by Fe3+ and glutaraldehyde(GA),respectively.The swelling level of PVA/SA/CS bipolar membranes was in a range of 25%~80%.The morphology was investigated by SEM and the functional groups were studied by IR.PVA-SA/CS bipolar membrane exhibts a dense surface without pores.The anion layer(GA-PVA/CS) contains-N=C functional groups,while the cation layer(Fe-PVA/SA) contains-COO-functional groups.PVA-SA/CS bipolar membranes were used as the separator in the electrolysis cell for the electro-generation of hydroxypivalic acid.The cell voltage was quite stable.The average current efficiency was 52.2%,and the highest current efficiency reached to 68.9% at a current density of 28×10-3 A/cm2.
PVA-SA/CS bipolar membrane was prepared by the paste method.PVA/sodium alginate(SA) and PVA/chitosan(CS) were cross-linked by Fe3+ and glutaraldehyde(GA),respectively.The swelling level of PVA/SA/CS bipolar membranes was in a range of 25%~80%.The morphology was investigated by SEM and the functional groups were studied by IR.PVA-SA/CS bipolar membrane exhibts a dense surface without pores.The anion layer(GA-PVA/CS) contains-N=C functional groups,while the cation layer(Fe-PVA/SA) contains-COO-functional groups.PVA-SA/CS bipolar membranes were used as the separator in the electrolysis cell for the electro-generation of hydroxypivalic acid.The cell voltage was quite stable.The average current efficiency was 52.2%,and the highest current efficiency reached to 68.9% at a current density of 28×10-3 A/cm2.
2008, 25(3): 322-325
Abstract:
A new method for the preparation of thermal-sensitive membranes was proposed in this paper.Poly(N-isopropylacrylamide)(PNIPAAm) was successfully grafted onto a PAN membrane having photo-sensitive groups by UV photografting method.The FTIR spectrum and SEM photographs confirmed the existence of PNIPAAm chains on the surface and in the pores of the grafted membrane.When monomer concentration reached 0.4 mol/L,a maxium grafting yield of 4.89% could be achieved.An increase on reaction time and temperature favored the increase of grafting yield,but the grafting yield was slowed down at higher reaction temperature(35℃) and longer reaction time (15 min).In addition,the wettability of grafted membrane was significantly improved with the increasing of grafting yield.
A new method for the preparation of thermal-sensitive membranes was proposed in this paper.Poly(N-isopropylacrylamide)(PNIPAAm) was successfully grafted onto a PAN membrane having photo-sensitive groups by UV photografting method.The FTIR spectrum and SEM photographs confirmed the existence of PNIPAAm chains on the surface and in the pores of the grafted membrane.When monomer concentration reached 0.4 mol/L,a maxium grafting yield of 4.89% could be achieved.An increase on reaction time and temperature favored the increase of grafting yield,but the grafting yield was slowed down at higher reaction temperature(35℃) and longer reaction time (15 min).In addition,the wettability of grafted membrane was significantly improved with the increasing of grafting yield.
2008, 25(3): 326-329
Abstract:
Chemiluminescence(CL) reagent luminol and permanganate were electrostatically immobilized on anion exchange resin separately,and a continuous flow sensor for the determination of lead ions combined with controlled-reagent-release technology in a FIA-CL-system was constructed.Lead ions were sensed by their enhancing effect on the follow-up CL reaction of luminol-KMnO4,which were eluted from the anion exchange column.The calibration curve was linear in the range of 5.0×10-8~1.0×10-5 g/mL,and the detection limit was 3×10-8 g/mL for lead(3σ).A complete analysis could be performed wthin 1 min with a relative standard deviation of 3.2%(2.0×10-6 g/mL,n=9).The sensor showed remarkable stability and could be easily reused over 300 times during 200 h.The sensor has successfully been applied to the determination of lead in gasoline samples.
Chemiluminescence(CL) reagent luminol and permanganate were electrostatically immobilized on anion exchange resin separately,and a continuous flow sensor for the determination of lead ions combined with controlled-reagent-release technology in a FIA-CL-system was constructed.Lead ions were sensed by their enhancing effect on the follow-up CL reaction of luminol-KMnO4,which were eluted from the anion exchange column.The calibration curve was linear in the range of 5.0×10-8~1.0×10-5 g/mL,and the detection limit was 3×10-8 g/mL for lead(3σ).A complete analysis could be performed wthin 1 min with a relative standard deviation of 3.2%(2.0×10-6 g/mL,n=9).The sensor showed remarkable stability and could be easily reused over 300 times during 200 h.The sensor has successfully been applied to the determination of lead in gasoline samples.
2008, 25(3): 330-333
Abstract:
Three new porphyrin quaternary ammonium salts which had never been reported preriously were synthesized:5-[4-(P-nitro) benzyl ammonium pyridinium]-10,15,20-tris(4-N-pyridinium) porphyrin bromide;5-[4-(P-methoxy) benzyl ammonium pyridinium]-10,15,20-tris(4-N-pyridinium) porphyrin chloro;5-[4-(P-chloro)benzyl ammonium pyridinium]-10,15,20-tris(4-N-pyridinium) porphyrin chloro.Their structures were demonstrated by IR,UV,MS,1H NMR and elementary analysis.During the determination of trace copper in water with the method of spectrophotometry experiments,the apparent molar absorption coefficients of the complexes are more than 1×105 L/(mol·cm).With the double function of colour reagent and surfactant active agent,the new type porphyrins are good colour sensitive reagent.This method has been used in the determination of trace copper(Ⅱ) of enviormenal water sample,and satisfied feedback was obtained.
Three new porphyrin quaternary ammonium salts which had never been reported preriously were synthesized:5-[4-(P-nitro) benzyl ammonium pyridinium]-10,15,20-tris(4-N-pyridinium) porphyrin bromide;5-[4-(P-methoxy) benzyl ammonium pyridinium]-10,15,20-tris(4-N-pyridinium) porphyrin chloro;5-[4-(P-chloro)benzyl ammonium pyridinium]-10,15,20-tris(4-N-pyridinium) porphyrin chloro.Their structures were demonstrated by IR,UV,MS,1H NMR and elementary analysis.During the determination of trace copper in water with the method of spectrophotometry experiments,the apparent molar absorption coefficients of the complexes are more than 1×105 L/(mol·cm).With the double function of colour reagent and surfactant active agent,the new type porphyrins are good colour sensitive reagent.This method has been used in the determination of trace copper(Ⅱ) of enviormenal water sample,and satisfied feedback was obtained.
Synthesis of Chitosan-Gelatin Copolymer in the Presence of MTGase and Its Bacteriostasis Properities
2008, 25(3): 334-339
Abstract:
Chitosan-Gelatin copolymer was synthesized with MTGase as catalyst from chitosan and gelatin.IR and DTA data indicated that chitosan and gelatin were linked via schiff bonds to yield the copolymer,the branched structure of which was confimed by AFM.The isoelectric point of the copolymer was 8.43,the average molelular mass was 36~38 KDa,and the solubility was 8.7 g/L in water at pH=5.0.The yield increased with the ratio of gelatin to chitosan,and bacteriostasis of the copolymer to Staphylococcus aureus decreased.When the ratio was 0.6,pH value was 6.0,temperature was 50℃,and reaction time was 40 min,the yield of the copolymer was 64.5%.Bacteriostasis to Staphylococcus aureus for 1% copolymer resolution was 70% that of chitosan.
Chitosan-Gelatin copolymer was synthesized with MTGase as catalyst from chitosan and gelatin.IR and DTA data indicated that chitosan and gelatin were linked via schiff bonds to yield the copolymer,the branched structure of which was confimed by AFM.The isoelectric point of the copolymer was 8.43,the average molelular mass was 36~38 KDa,and the solubility was 8.7 g/L in water at pH=5.0.The yield increased with the ratio of gelatin to chitosan,and bacteriostasis of the copolymer to Staphylococcus aureus decreased.When the ratio was 0.6,pH value was 6.0,temperature was 50℃,and reaction time was 40 min,the yield of the copolymer was 64.5%.Bacteriostasis to Staphylococcus aureus for 1% copolymer resolution was 70% that of chitosan.
2008, 25(3): 340-344
Abstract:
The thermal mass-loss of maleic anhydride was studied under non-isothermal conditions by thermogravimetry(TG) technique in N2 atmosphere,and the thermal analysis kinetic equation and kinetic parameters were obtained.Under the experimental conditions,the mass-loss temperature of maleic anhydride was in a range of 110~160℃.The mass-loss rate was found greater than 98%,and the solid mass-loss products were characterized with infrared and thermogravimetry methods.Maleic anhydride gas was found as the final gas product which suggested that the thermal mass-loss of maleic anhydride was a sublimation process.The iterative iso-conversional method was applied to estimate the apparent activation energy Ea when the mass-loss rate was in a range of 0.2~0.9.The apparent activation energy was(75.147±0.48) kJ/mol which agreed with that obtained by Coats-Redfern method.It is concluded that the mass loss of maleic anhydride can be described with a single mechanism function,excluding the possibility of overlapping of multiple-step decomposition reaction.The most probable mechanism function G(α) was determined by master plots method,and G(α)=1-(1-α)m(m=0.813 9±0.02).The pre-exponential factor A of rate equation was obtained on the basis of Ea and G(α),and the pre-exponential factor was ln(A/s-1)=23.57±0.018.
The thermal mass-loss of maleic anhydride was studied under non-isothermal conditions by thermogravimetry(TG) technique in N2 atmosphere,and the thermal analysis kinetic equation and kinetic parameters were obtained.Under the experimental conditions,the mass-loss temperature of maleic anhydride was in a range of 110~160℃.The mass-loss rate was found greater than 98%,and the solid mass-loss products were characterized with infrared and thermogravimetry methods.Maleic anhydride gas was found as the final gas product which suggested that the thermal mass-loss of maleic anhydride was a sublimation process.The iterative iso-conversional method was applied to estimate the apparent activation energy Ea when the mass-loss rate was in a range of 0.2~0.9.The apparent activation energy was(75.147±0.48) kJ/mol which agreed with that obtained by Coats-Redfern method.It is concluded that the mass loss of maleic anhydride can be described with a single mechanism function,excluding the possibility of overlapping of multiple-step decomposition reaction.The most probable mechanism function G(α) was determined by master plots method,and G(α)=1-(1-α)m(m=0.813 9±0.02).The pre-exponential factor A of rate equation was obtained on the basis of Ea and G(α),and the pre-exponential factor was ln(A/s-1)=23.57±0.018.
2008, 25(3): 345-349
Abstract:
A novel and simple procedure for the synthesis of aza-nucleoside by Mitsunobu reaction between N-(p-nitrobenzyloxycarbonyl)-trans-4-hydroxy-D-proline methyl ester obtained from trans-4-hydroxy-L-proline after six-step reaction and 2,6-dichloropurine is described.The azanucleoside is reduced,deprotected,nitrosated reduced and fluorided by new fluoridizer 2,2-difluoro-1,3-dimethylimidazolidine(DFI).Mitsunobu reaction could be carried out at ambient temperature.Intermediates and the target compound are characterized by IR,MS,H NMR.
A novel and simple procedure for the synthesis of aza-nucleoside by Mitsunobu reaction between N-(p-nitrobenzyloxycarbonyl)-trans-4-hydroxy-D-proline methyl ester obtained from trans-4-hydroxy-L-proline after six-step reaction and 2,6-dichloropurine is described.The azanucleoside is reduced,deprotected,nitrosated reduced and fluorided by new fluoridizer 2,2-difluoro-1,3-dimethylimidazolidine(DFI).Mitsunobu reaction could be carried out at ambient temperature.Intermediates and the target compound are characterized by IR,MS,H NMR.
2008, 25(3): 350-355
Abstract:
The adsorption of Cu2+,Ni2+,and Cd2+ from single,binary,and tertiary solutions onto triethylene-tetramine cross-linked chitosan(CCTS) was studied at pH of 1 to 6 and initial concentration of 1 to 15 mmol/L.It was found that the influence of pH on the amount of adsorption in the pH range of 3~6 was trivial,but the influence of initial concentration ratio on the amount of adsorption was significant in binary and tertiary solutions.In addition,there was no selective adsorption for Cu2+,Ni2+,and Cd2+ onto CCTS in binary and tertiary solutions.The maximum capacities(QCd2+、QCu2+、QNi2+) obtained from single solution(c0=3.0 mmol/L) were 2.57 mmol/g(pH=5),2.19 mmol/g(pH=6),1.90 mmol/g(pH=6) respectively.
The adsorption of Cu2+,Ni2+,and Cd2+ from single,binary,and tertiary solutions onto triethylene-tetramine cross-linked chitosan(CCTS) was studied at pH of 1 to 6 and initial concentration of 1 to 15 mmol/L.It was found that the influence of pH on the amount of adsorption in the pH range of 3~6 was trivial,but the influence of initial concentration ratio on the amount of adsorption was significant in binary and tertiary solutions.In addition,there was no selective adsorption for Cu2+,Ni2+,and Cd2+ onto CCTS in binary and tertiary solutions.The maximum capacities(QCd2+、QCu2+、QNi2+) obtained from single solution(c0=3.0 mmol/L) were 2.57 mmol/g(pH=5),2.19 mmol/g(pH=6),1.90 mmol/g(pH=6) respectively.
2008, 25(3): 356-360
Abstract:
Effects of 2-phosphonobutane-1,2,4-tricarboxylic acid(PBTCA) on the nucleation kinetics of BaSO4 were studied by means of solution conductivity measurement.According to the classic homogeneous nucleation theory,the surface free energy between BaSO4 and supersaturated solutions was estimated to be 61.1 mJ/m2 in the absence of PBTCA.It increases with increasing the concentration of PBTCA(to be 73.7 mJ/m2 in the presence of 12 mg/L PBTCA).The induction periods of BaSO4 of four supersaturated solutions can be prolonged in the presence of PBTCA,which increase from 61.6,39.9,6.5,3.1 s in the absence PBTCA to 18 000.4,7 204.2,800.8,60.3 s at a concentration of 12 mg/L of PBTCA.BaSO4 crystal growth can be expressed as a first order reaction.The growth rate is decreased with the increase of the concentration of PBTCA.Especially at the lower supersaturation index,the growth rate constant is decreased by a factor of two orders of magnitude.PBTCA is adsorbed at active sites on the BaSO4 crystal surface.The adsorption follows a Langmuir adsorption model.
Effects of 2-phosphonobutane-1,2,4-tricarboxylic acid(PBTCA) on the nucleation kinetics of BaSO4 were studied by means of solution conductivity measurement.According to the classic homogeneous nucleation theory,the surface free energy between BaSO4 and supersaturated solutions was estimated to be 61.1 mJ/m2 in the absence of PBTCA.It increases with increasing the concentration of PBTCA(to be 73.7 mJ/m2 in the presence of 12 mg/L PBTCA).The induction periods of BaSO4 of four supersaturated solutions can be prolonged in the presence of PBTCA,which increase from 61.6,39.9,6.5,3.1 s in the absence PBTCA to 18 000.4,7 204.2,800.8,60.3 s at a concentration of 12 mg/L of PBTCA.BaSO4 crystal growth can be expressed as a first order reaction.The growth rate is decreased with the increase of the concentration of PBTCA.Especially at the lower supersaturation index,the growth rate constant is decreased by a factor of two orders of magnitude.PBTCA is adsorbed at active sites on the BaSO4 crystal surface.The adsorption follows a Langmuir adsorption model.
2008, 25(3): 361-365
Abstract:
The electrocatalytic activities and selectivities of Pt and Ir catalysts for the NH3 oxidation in neutral NaClO4 solution were compared.It was found that the electrooxidation of NH3 and NH4OH at the Pt and Ir catalysts are similar.Thus,NH4OH can be used to study instead of NH3.Both peak currents of the anodic peaks of NH4OH at Pt and Ir catalyst electrodes are linearly proportional to the concentration of NH4OH.Thus,both the Pt and Ir can be used as the catalysts of the potential fixed electrochemical NH3 sensor.When the concentration of NH4OH is 0.013 mol/L,the anodic peaks of NH4OH at the Pt and Ir electrodes are located at 0.4 and 0.8 V,respectively,indicating that the potential of the anodic peak of NH4OH at the Pt catalyst is more negative than that at the Ir catalyst and it is the advantage of the Pt catalyst.However,the current density of the anodic peak of NH4OH at the Ir catalyst is 2.5 times larger than that at the Pt catalyst.Furthermore,CO does not disturb the measurement of NH4OH at the Ir catalyst,but obviously interferes the measurement of NH4OH at the Pt catalyst.Therefore,the preliminary results indicate that the Ir catalyst is a suitable catalyst for the potential fixed electrochemical NH3 sensor.
The electrocatalytic activities and selectivities of Pt and Ir catalysts for the NH3 oxidation in neutral NaClO4 solution were compared.It was found that the electrooxidation of NH3 and NH4OH at the Pt and Ir catalysts are similar.Thus,NH4OH can be used to study instead of NH3.Both peak currents of the anodic peaks of NH4OH at Pt and Ir catalyst electrodes are linearly proportional to the concentration of NH4OH.Thus,both the Pt and Ir can be used as the catalysts of the potential fixed electrochemical NH3 sensor.When the concentration of NH4OH is 0.013 mol/L,the anodic peaks of NH4OH at the Pt and Ir electrodes are located at 0.4 and 0.8 V,respectively,indicating that the potential of the anodic peak of NH4OH at the Pt catalyst is more negative than that at the Ir catalyst and it is the advantage of the Pt catalyst.However,the current density of the anodic peak of NH4OH at the Ir catalyst is 2.5 times larger than that at the Pt catalyst.Furthermore,CO does not disturb the measurement of NH4OH at the Ir catalyst,but obviously interferes the measurement of NH4OH at the Pt catalyst.Therefore,the preliminary results indicate that the Ir catalyst is a suitable catalyst for the potential fixed electrochemical NH3 sensor.
2008, 25(3): 366-368
Abstract:
Microwave-assisted synthesis of nine 4-arylideneamino-5-mercapto-3-substituted-4H-1,2,4-triazoles via the reaction of 4-amino-5-mercapto-3-substituent-1,2,4-triazoles with arylaldehydes under solvent-free conditions without catalyst was completed.The reactants were mixed in an equal molar ratio,and exposed to MW irradiation for 9~10 min,and the yields were 81%~92%.The mercapto group did not react with the imine group to give the products with two heterocycles.This method avoids the long reaction time of usual synthesis route using ethanol as solvent and acid as catalyst,and saved the troubles of using acetic acid as solvent and catalyst.The structures of the products were confirmed by 1H NMR and IR.
Microwave-assisted synthesis of nine 4-arylideneamino-5-mercapto-3-substituted-4H-1,2,4-triazoles via the reaction of 4-amino-5-mercapto-3-substituent-1,2,4-triazoles with arylaldehydes under solvent-free conditions without catalyst was completed.The reactants were mixed in an equal molar ratio,and exposed to MW irradiation for 9~10 min,and the yields were 81%~92%.The mercapto group did not react with the imine group to give the products with two heterocycles.This method avoids the long reaction time of usual synthesis route using ethanol as solvent and acid as catalyst,and saved the troubles of using acetic acid as solvent and catalyst.The structures of the products were confirmed by 1H NMR and IR.
2008, 25(3): 369-371
Abstract:
Three kinds of interpenetrating polymer networks(CO-TDI/St,CO-TDI/AN,CO-TDI/MMA) were synthesized by a stepwise reaction of castor oil(CO) with 2,4-Toluene diisocyanate(TDI),crosslinking agent phenylethylene(St),Acrylonitrile(AN),methyl methacrylate(MMA).Thermal stability of IPN and its decomposition products were studied by differential scaning calorimetry(DSC),thermogravimetric analysis(TG) and FTIR-TG.The results show the IPN degeneration is a fractional process during heating.The decomposition of the polyurethane network probably took place between 240~330℃.The decomposition of the polyolefine network probably took place between 330~390℃.The later period decomposition of the polymer took place approximately at 390~500℃.The decomposition products of the polyurethane network were mainly CO2,H2O,isocyanate,alcohol and so on.The decomposition products of polyolefin network mainly formed the alkene,paraffins.In the decomposition products of the later period of polymer did not includes CO2 and H2O.The system composition had influence on the IPN thermal stability.In three kinds of IPNs,CO-TDI/AN thermal stability is best,the decomposition enthalpy variable and speed of CO-TDI/St and CO-TDI/MMA are quite similar.
Three kinds of interpenetrating polymer networks(CO-TDI/St,CO-TDI/AN,CO-TDI/MMA) were synthesized by a stepwise reaction of castor oil(CO) with 2,4-Toluene diisocyanate(TDI),crosslinking agent phenylethylene(St),Acrylonitrile(AN),methyl methacrylate(MMA).Thermal stability of IPN and its decomposition products were studied by differential scaning calorimetry(DSC),thermogravimetric analysis(TG) and FTIR-TG.The results show the IPN degeneration is a fractional process during heating.The decomposition of the polyurethane network probably took place between 240~330℃.The decomposition of the polyolefine network probably took place between 330~390℃.The later period decomposition of the polymer took place approximately at 390~500℃.The decomposition products of the polyurethane network were mainly CO2,H2O,isocyanate,alcohol and so on.The decomposition products of polyolefin network mainly formed the alkene,paraffins.In the decomposition products of the later period of polymer did not includes CO2 and H2O.The system composition had influence on the IPN thermal stability.In three kinds of IPNs,CO-TDI/AN thermal stability is best,the decomposition enthalpy variable and speed of CO-TDI/St and CO-TDI/MMA are quite similar.
2008, 25(3): 372-374
Abstract:
Bismuth oxide hydroxide was prepared by rapid precipitation from a solution of bismuth(Ⅲ) chloride with sodium hydroxide,which was used as a catalyst for the reduction of nitro aromatic compounds with sodium borohydride.The catalytic performance of bismuth oxide hydroxide and the effect of the amount of sodium borohydride on the reduction were investigated.The results showed that bismuth oxide hydroxide had a high activity and selectivity for the reduction under mild reaction conditions.At a mole ratio of 1.04:1 of sodium borohydride to each of nitro aromatic compounds in methanol and 2 h and r.t.,the corresponding azoxy compounds were prepared in 80.4%~96.9% yields.Moreover,no obvious deactivation was observed after five times recycling of the catalyst,which can be regenerated at 120℃ and then recycled very easily.
Bismuth oxide hydroxide was prepared by rapid precipitation from a solution of bismuth(Ⅲ) chloride with sodium hydroxide,which was used as a catalyst for the reduction of nitro aromatic compounds with sodium borohydride.The catalytic performance of bismuth oxide hydroxide and the effect of the amount of sodium borohydride on the reduction were investigated.The results showed that bismuth oxide hydroxide had a high activity and selectivity for the reduction under mild reaction conditions.At a mole ratio of 1.04:1 of sodium borohydride to each of nitro aromatic compounds in methanol and 2 h and r.t.,the corresponding azoxy compounds were prepared in 80.4%~96.9% yields.Moreover,no obvious deactivation was observed after five times recycling of the catalyst,which can be regenerated at 120℃ and then recycled very easily.
2008, 25(3): 375-377
Abstract:
The peroxides is an important indicator of the edible oil.A method for the determination of peroxides in peanut oil by the near-infrared spectroscopy was presented.The PLS was used to establish a mathematical model in the spectral region of 9 214~4 559 cm-1 by using Fourier transform near-infrared spectroscopy.The main factorial number found by cross-validation was 9.The root mean square error of cross-validation(RMSECV) was 6.88×10-4 g/mL.In this model,the correlation coefficient was 0.991.The standard deviation was 1.10×10-4 g/mL.The inverse relative error determined by the mathematical model and the GB standard method is 1.77%.
The peroxides is an important indicator of the edible oil.A method for the determination of peroxides in peanut oil by the near-infrared spectroscopy was presented.The PLS was used to establish a mathematical model in the spectral region of 9 214~4 559 cm-1 by using Fourier transform near-infrared spectroscopy.The main factorial number found by cross-validation was 9.The root mean square error of cross-validation(RMSECV) was 6.88×10-4 g/mL.In this model,the correlation coefficient was 0.991.The standard deviation was 1.10×10-4 g/mL.The inverse relative error determined by the mathematical model and the GB standard method is 1.77%.
2008, 25(3): 378-380
Abstract:
In this article,CL-20 was synthesized via nitration and nitrolysis of 2,6,8,12-tetraacetyl-2,4,6,8,10,12-hexaazatetracyclo[5,5,0,03,1105,9] dodecane(TAIW) with N2O5/HNO3 as the nitrating agent.The product yield was 86.1% and the purity was 99%.The effects of reaction temperature,reaction time,and the molar ratio of the reagents on the yield were also investigated.The optimal reaction conditions were reaction temperature 40℃,reaction time 1 h,and a molar ratio of TAIW:N2O5:HNO3 of 1:4:36.The structure of the compound was characterized by elemental analysis,NMR and MS.
In this article,CL-20 was synthesized via nitration and nitrolysis of 2,6,8,12-tetraacetyl-2,4,6,8,10,12-hexaazatetracyclo[5,5,0,03,1105,9] dodecane(TAIW) with N2O5/HNO3 as the nitrating agent.The product yield was 86.1% and the purity was 99%.The effects of reaction temperature,reaction time,and the molar ratio of the reagents on the yield were also investigated.The optimal reaction conditions were reaction temperature 40℃,reaction time 1 h,and a molar ratio of TAIW:N2O5:HNO3 of 1:4:36.The structure of the compound was characterized by elemental analysis,NMR and MS.
