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2001 Volume 18 Issue 10
2001, 18(10): 768-771
Abstract:
The nanocrystalline nickel-molybdenum-cobalt alloy deposits were obtained by electrodeposition method. The structures of the deposits were analyzed by XRD and XPS; considerable lattice deformation in alloy occured and only one diffraction peak was recorded on XRD spectrum. The XPS results of nanocrystalline Ni-Mo-Co deposit indicated that the nickel and molybdenum and cobalt coexist in metal state of the deposits, with binding energy being increased in some extent. The nanocrystalline Ni-Mo-Co alloy deposit electrode offered better electrocatalytic hydrogen evolution than nanocrystalline Ni Mo alloy electrode. The electrochemical impedance spectra of the nanocrystalline Ni-Mo-Co alloy electrode indicated that hydrogen evolution in 30%(m/m) KOH follows Volmer-Tafel mechanism at lower potential, but at higher potential it follows Volmer Heyrovsky mechanism.
The nanocrystalline nickel-molybdenum-cobalt alloy deposits were obtained by electrodeposition method. The structures of the deposits were analyzed by XRD and XPS; considerable lattice deformation in alloy occured and only one diffraction peak was recorded on XRD spectrum. The XPS results of nanocrystalline Ni-Mo-Co deposit indicated that the nickel and molybdenum and cobalt coexist in metal state of the deposits, with binding energy being increased in some extent. The nanocrystalline Ni-Mo-Co alloy deposit electrode offered better electrocatalytic hydrogen evolution than nanocrystalline Ni Mo alloy electrode. The electrochemical impedance spectra of the nanocrystalline Ni-Mo-Co alloy electrode indicated that hydrogen evolution in 30%(m/m) KOH follows Volmer-Tafel mechanism at lower potential, but at higher potential it follows Volmer Heyrovsky mechanism.
2001, 18(10): 772-776
Abstract:
Twenty one new derivatives of 1-substituted aryl-4-ethoxy carbonyl-5-amino-1,2,3-triazole(compound 1) were obtained by reactions of 1-aryl-4-ethoxycarbonyl-5-amino-1,2,3-triazoles with benzoyl chloride, chloroacetyl chloride, propionyl chloride, acetyl chloride etc., in good yields(61%~91%). The relationships between yields and properties of acyl halides were discussed. The structures of all heterocyclic compounds were characterized by elemental analyses, IR, 1H NMR and MS. Their antibacterial activities against Klebsiella, Escherichia coli, Pseudomonas aeruginosa, Staphlococcus aureus and Proteus vulgaris were screened.
Twenty one new derivatives of 1-substituted aryl-4-ethoxy carbonyl-5-amino-1,2,3-triazole(compound 1) were obtained by reactions of 1-aryl-4-ethoxycarbonyl-5-amino-1,2,3-triazoles with benzoyl chloride, chloroacetyl chloride, propionyl chloride, acetyl chloride etc., in good yields(61%~91%). The relationships between yields and properties of acyl halides were discussed. The structures of all heterocyclic compounds were characterized by elemental analyses, IR, 1H NMR and MS. Their antibacterial activities against Klebsiella, Escherichia coli, Pseudomonas aeruginosa, Staphlococcus aureus and Proteus vulgaris were screened.
2001, 18(10): 777-780
Abstract:
The photoelectrochemistry of α-Fe2O3 nanocrystalline thin films with different thickness in KCl solution was studied. It is found that the photocurrent response was decreased with the film thinkness. The decrease of photocurrent responses of thicker films is explained in terms of the electric resistance effect and recombination effect. For thinner α-Fe2O3 film (50 μm) no difference was found for the photocurrent response under frontwall (FW) and backwall (BW) illuminations, while for thicker α-Fe2O3 film (100 μm) the photocurrent response was larger under BW illumination than that under FW illumination.
The photoelectrochemistry of α-Fe2O3 nanocrystalline thin films with different thickness in KCl solution was studied. It is found that the photocurrent response was decreased with the film thinkness. The decrease of photocurrent responses of thicker films is explained in terms of the electric resistance effect and recombination effect. For thinner α-Fe2O3 film (50 μm) no difference was found for the photocurrent response under frontwall (FW) and backwall (BW) illuminations, while for thicker α-Fe2O3 film (100 μm) the photocurrent response was larger under BW illumination than that under FW illumination.
2001, 18(10): 781-784
Abstract:
Terephthalate-pillared hydrotalcites, Mg4Al2(OH)12[C6H4(COO)2], were successfully synthesized through Mg4Al2(OH)12CO3·4H2O precursor in an organic solvent by ion exchange. The samples thereby obtained were characterized by XRD, FT-IR and DTA. The results show that the initial interlayer carbonates of the hydrotalcite can be completely replaced by terephthalic anions under special controlled conditions. The pillared hydrotalcites have good layered structure and the interlayer distance varies slightly (1.38~1.45 nm) with the exchange temperature (70~150℃). The interlayer terephthalic anions decompose at about 553℃.
Terephthalate-pillared hydrotalcites, Mg4Al2(OH)12[C6H4(COO)2], were successfully synthesized through Mg4Al2(OH)12CO3·4H2O precursor in an organic solvent by ion exchange. The samples thereby obtained were characterized by XRD, FT-IR and DTA. The results show that the initial interlayer carbonates of the hydrotalcite can be completely replaced by terephthalic anions under special controlled conditions. The pillared hydrotalcites have good layered structure and the interlayer distance varies slightly (1.38~1.45 nm) with the exchange temperature (70~150℃). The interlayer terephthalic anions decompose at about 553℃.
2001, 18(10): 785-789
Abstract:
In order to study the relationship between the fungicidal activity and the substituents on B cycle of flavanone derivatives, a series of flavanone derivatives containing various subtituents on B cycle were designed and synthesized starting from 2-hydroxylacetophenone. The structures of all compounds synthesized were confirmed by spectroscopic methods and microanalyses. Preliminary bioassays indicated that some compounds e.g. 3b, 3e, 3h and 3j showed excellent fungicidal activities against Rhizoctonia solani, Fusarium oxysporum, Physalospora piricola, Fusarium gramineum and Cercospora beticola at the dosage of 50 μg/L. Preliminary structure-activity relationship analysis indicated that the hydrophobicity and electronic effect of the substituents on B cycle have important effect on the fungicidal activity.
In order to study the relationship between the fungicidal activity and the substituents on B cycle of flavanone derivatives, a series of flavanone derivatives containing various subtituents on B cycle were designed and synthesized starting from 2-hydroxylacetophenone. The structures of all compounds synthesized were confirmed by spectroscopic methods and microanalyses. Preliminary bioassays indicated that some compounds e.g. 3b, 3e, 3h and 3j showed excellent fungicidal activities against Rhizoctonia solani, Fusarium oxysporum, Physalospora piricola, Fusarium gramineum and Cercospora beticola at the dosage of 50 μg/L. Preliminary structure-activity relationship analysis indicated that the hydrophobicity and electronic effect of the substituents on B cycle have important effect on the fungicidal activity.
2001, 18(10): 790-793
Abstract:
The nanocrystal Ni-W-P/p-Si electrodes with high catalytic activity for hydrogen evolution were prepared by electrodeposition of Ni-W-P alloy on p-Si. The effects of electroplating conditions on the catalytic activity of electrodes have been investigated, and the surface morphology and structure of the electrodes were investigated by SEM and X-ray diffraction. The result showed that the structure of Ni-W-P alloy deposit changes from crystal to amorphous state with the increase of pH and temperature of electroplating solution. The nanocrystal Ni-W-P alloy was obtained at electroplating conditions of 50℃, pH=6 and current density 15 A/dm2. The catalytic activity of the electrode for hydrogen evolution under illumination was studied.
The nanocrystal Ni-W-P/p-Si electrodes with high catalytic activity for hydrogen evolution were prepared by electrodeposition of Ni-W-P alloy on p-Si. The effects of electroplating conditions on the catalytic activity of electrodes have been investigated, and the surface morphology and structure of the electrodes were investigated by SEM and X-ray diffraction. The result showed that the structure of Ni-W-P alloy deposit changes from crystal to amorphous state with the increase of pH and temperature of electroplating solution. The nanocrystal Ni-W-P alloy was obtained at electroplating conditions of 50℃, pH=6 and current density 15 A/dm2. The catalytic activity of the electrode for hydrogen evolution under illumination was studied.
2001, 18(10): 794-797
Abstract:
Based on the solubility data of ternary systems, the single salt parameters and the solu bility product of Li2CO3(a), Li2B4O7(b) and Na2CO3(c), and the corresponding mixing parameters have been fitted by the multiple linear regression method. Their values are:Ua(0)=-1.235 5,Ua(1)=-2.654 6, CaO=-0.004 660 7, Ub(0)=-3.030 6, Ub(1)=-3.023 8, CbO=-0.290 89, Uc(0)=-0.293 04,Ua(1)=2.155 6, CcO=-0.004 256 0, θLi,Na=1.041 8, θB,C=-2.630 5, JLi,Na,C=-0.063 910,JLi,Na,B=0.493 56,JLi,B,C=-0.478 42, JNa,B,C=0.306 16, ln K (Li2CO3)=-8.962 9, ln K (Na2CO3·10H2O)=3.064 6, ln K (Li2B4O7·3H2O)=-7.356 6, ln K (Na2B4O7·10H2O)=-7.477 8. The predicted solubility values of the quaternary system Li+,Na+//CO32-, B4O72--H2O at 298 K are in good agreement with experimental results obtained from a isothermal method at 298 K.
Based on the solubility data of ternary systems, the single salt parameters and the solu bility product of Li2CO3(a), Li2B4O7(b) and Na2CO3(c), and the corresponding mixing parameters have been fitted by the multiple linear regression method. Their values are:Ua(0)=-1.235 5,Ua(1)=-2.654 6, CaO=-0.004 660 7, Ub(0)=-3.030 6, Ub(1)=-3.023 8, CbO=-0.290 89, Uc(0)=-0.293 04,Ua(1)=2.155 6, CcO=-0.004 256 0, θLi,Na=1.041 8, θB,C=-2.630 5, JLi,Na,C=-0.063 910,JLi,Na,B=0.493 56,JLi,B,C=-0.478 42, JNa,B,C=0.306 16, ln K (Li2CO3)=-8.962 9, ln K (Na2CO3·10H2O)=3.064 6, ln K (Li2B4O7·3H2O)=-7.356 6, ln K (Na2B4O7·10H2O)=-7.477 8. The predicted solubility values of the quaternary system Li+,Na+//CO32-, B4O72--H2O at 298 K are in good agreement with experimental results obtained from a isothermal method at 298 K.
2001, 18(10): 798-801
Abstract:
A series of system consisted of common solvents capable of dissolution of Nafion NR50 have been investigated:40%~70% water+60%~30% ethanol, 40%~70% water+60%~30% n-propanol, 10%~70% water+90%~30% i-propanol, 30%~70% water+60%~20% n-propanol+10% methanol and 10%~70% water+80%~20% i-propanol+10% methanol. Favorable dissolution temperature and time appeared to be ranged in 230℃ to 250℃ and 4 hours, respectively. During the dissolution processes alcohols could be isomerized, etherified or dehydrated catalyzed by Nafion NR50. Addition of methanol could promote the swelling of NR50, accelerating the dissolution process.
A series of system consisted of common solvents capable of dissolution of Nafion NR50 have been investigated:40%~70% water+60%~30% ethanol, 40%~70% water+60%~30% n-propanol, 10%~70% water+90%~30% i-propanol, 30%~70% water+60%~20% n-propanol+10% methanol and 10%~70% water+80%~20% i-propanol+10% methanol. Favorable dissolution temperature and time appeared to be ranged in 230℃ to 250℃ and 4 hours, respectively. During the dissolution processes alcohols could be isomerized, etherified or dehydrated catalyzed by Nafion NR50. Addition of methanol could promote the swelling of NR50, accelerating the dissolution process.
2001, 18(10): 802-805
Abstract:
The C rate performance of LiCrxMn2-xO4 has been studied by the current pulse relaxation technique as a function of the lithium diffusion coefficients in LiCrxMn2-xO4. The results revealed that the increment of the doped chromium ion can accelerate the diffusion rate of lithium ion, reduce the Jahn-Tellar effects, and improve the rate capacity and cycle life at higher C rates for LiCrxMn2-xO4. LiCr0.1Mn1.9O4 showed the best electrochemical performance at 1C rate charge discharge cycles.
The C rate performance of LiCrxMn2-xO4 has been studied by the current pulse relaxation technique as a function of the lithium diffusion coefficients in LiCrxMn2-xO4. The results revealed that the increment of the doped chromium ion can accelerate the diffusion rate of lithium ion, reduce the Jahn-Tellar effects, and improve the rate capacity and cycle life at higher C rates for LiCrxMn2-xO4. LiCr0.1Mn1.9O4 showed the best electrochemical performance at 1C rate charge discharge cycles.
2001, 18(10): 806-809
Abstract:
Three new _-oxamido heterobinuclear complexes bridged by N,N'-bis(3-amino-2,2-dimethylpropyl)oxamido dianion (Me2oxpn) and end capped with N,N,N',N' tetramethylethylene diamine (tmen) and 2,9-dimethyl-1,10-phenanthroline (Me2-phen), respectively; namely,[Cu-(Me2oxpn)Fe(tmen)2]SO 4(a),[Cu(Me2oxpn)Zn(tmen)2]SO4(b) and[Cu(Me2oxpn)Zn(Me2-phen)2]SO4(c), have been synthesized and characterized by elemental analyses, magnetic moment and molar conductivity measurements, and spectrometry. These complexes appeared to have oxamido bridged structures consisting of planar copper(Ⅱ) and octahedral iron(Ⅱ) ions. The temperature dependence of magnetic susceptibilities of the complex (a) has been measured at 4~300 K, giving the exchange integral J=-12.96 cm-1. The results indicated the existence of antiferromagnetic superexchange interactions between the metal ions. The antibacterial activity of the complexes was also examined.
Three new _-oxamido heterobinuclear complexes bridged by N,N'-bis(3-amino-2,2-dimethylpropyl)oxamido dianion (Me2oxpn) and end capped with N,N,N',N' tetramethylethylene diamine (tmen) and 2,9-dimethyl-1,10-phenanthroline (Me2-phen), respectively; namely,[Cu-(Me2oxpn)Fe(tmen)2]SO 4(a),[Cu(Me2oxpn)Zn(tmen)2]SO4(b) and[Cu(Me2oxpn)Zn(Me2-phen)2]SO4(c), have been synthesized and characterized by elemental analyses, magnetic moment and molar conductivity measurements, and spectrometry. These complexes appeared to have oxamido bridged structures consisting of planar copper(Ⅱ) and octahedral iron(Ⅱ) ions. The temperature dependence of magnetic susceptibilities of the complex (a) has been measured at 4~300 K, giving the exchange integral J=-12.96 cm-1. The results indicated the existence of antiferromagnetic superexchange interactions between the metal ions. The antibacterial activity of the complexes was also examined.
2001, 18(10): 810-812
Abstract:
2-Hydroxy 1,4-naphtholquinone(HNQ) was prepared in alcoholic solution of NaOH with high conversion and selectivity from both 1-naphthol and 2-naphthol in the presence of metalloporphyrin catalyst. An oxygen iron porphyrin was observed from UV-Vis spectra when hydrogen peroxide was present in the catalytic system. The formation constants of the iron porphyrin intermediate were measured from its varying spectrum. The reactions of the formation and dissocination of HNQ are both of first order based on the relationship between HNQ concentration and reation time.
2-Hydroxy 1,4-naphtholquinone(HNQ) was prepared in alcoholic solution of NaOH with high conversion and selectivity from both 1-naphthol and 2-naphthol in the presence of metalloporphyrin catalyst. An oxygen iron porphyrin was observed from UV-Vis spectra when hydrogen peroxide was present in the catalytic system. The formation constants of the iron porphyrin intermediate were measured from its varying spectrum. The reactions of the formation and dissocination of HNQ are both of first order based on the relationship between HNQ concentration and reation time.
2001, 18(10): 813-816
Abstract:
α-Fe2O3-MgO powder was prepared by a chemical coprecipitation method. The preparation conditions, phase constitution, conductance and gas sensing properties were investigated. The results show that pure phase Mg-Fe2O4-MgO could be obtained when Mg(NO3)2 and (NO3)3 were mixed in 1:2 molar ratio of Mg2+ to Fe3+ and calcined at 500℃ for 4 hours. The Mg-Fe2O4-MgO is an n-type semiconductor. The sensor based on Mg-Fe2O4-MgO calcined at 600℃ for 4 hours exhibited high sensitivity and good selectivity to C2H5OH.
α-Fe2O3-MgO powder was prepared by a chemical coprecipitation method. The preparation conditions, phase constitution, conductance and gas sensing properties were investigated. The results show that pure phase Mg-Fe2O4-MgO could be obtained when Mg(NO3)2 and (NO3)3 were mixed in 1:2 molar ratio of Mg2+ to Fe3+ and calcined at 500℃ for 4 hours. The Mg-Fe2O4-MgO is an n-type semiconductor. The sensor based on Mg-Fe2O4-MgO calcined at 600℃ for 4 hours exhibited high sensitivity and good selectivity to C2H5OH.
2001, 18(10): 817-820
Abstract:
Two novel complexes of Zn(Ⅱ) with N-salicylidene p-methylsulfonyl phenyleneserine and N-salicylidene glycyl glycine have been synthesized. The compositions and structures of the complexes were characterized by elemental analyses, molar conductance, infrared spectra, TG DTA, X-ray powder diffraction. The compositions of two complexes are ZnC17H17O7NS(A) and ZnC11H13-O5.5 N2(B). The complexes are nonelectrolyte having coordination water for A, but only crystal water for B. The coordination numbers of zinc ion in the complexes are four. The XRD indexes results indicated that the crystal structure of the complex A belongs to monoclinic system, with lattice parameters:a=1.623 3 nm, b=2.270 0 nm, c=1.669 3 nm, U=94.39°; and the complex B belongs to triclinic system, with lattice parameters:a=1.786 5 nm, b=1.684 1 nm, c=2.032 1 nm, T=96.96°, U=96.51°, V=98.73° respectively.
Two novel complexes of Zn(Ⅱ) with N-salicylidene p-methylsulfonyl phenyleneserine and N-salicylidene glycyl glycine have been synthesized. The compositions and structures of the complexes were characterized by elemental analyses, molar conductance, infrared spectra, TG DTA, X-ray powder diffraction. The compositions of two complexes are ZnC17H17O7NS(A) and ZnC11H13-O5.5 N2(B). The complexes are nonelectrolyte having coordination water for A, but only crystal water for B. The coordination numbers of zinc ion in the complexes are four. The XRD indexes results indicated that the crystal structure of the complex A belongs to monoclinic system, with lattice parameters:a=1.623 3 nm, b=2.270 0 nm, c=1.669 3 nm, U=94.39°; and the complex B belongs to triclinic system, with lattice parameters:a=1.786 5 nm, b=1.684 1 nm, c=2.032 1 nm, T=96.96°, U=96.51°, V=98.73° respectively.
2001, 18(10): 821-824
Abstract:
For the purpose of optimizing the counter current extraction process some new equations have been derived for calculating the optimized extraction factors to search the minmum total volume of mixer settler extractor or scrubbing section at the same production capacity and product quality. With new equation the error rate of the expansion approximation equation of logarithm is small, the calculated optimized extraction factors are more precise. The new equations derived are able to calculate precisely the optimization extraction factors.
For the purpose of optimizing the counter current extraction process some new equations have been derived for calculating the optimized extraction factors to search the minmum total volume of mixer settler extractor or scrubbing section at the same production capacity and product quality. With new equation the error rate of the expansion approximation equation of logarithm is small, the calculated optimized extraction factors are more precise. The new equations derived are able to calculate precisely the optimization extraction factors.
2001, 18(10): 825-827
Abstract:
The uniform design and statistical analysis system(SAS) have been employed to study the reaction conditions of graft polymerization of acrylonitrile(AN) onto chitosan using K2S2O8-NaHSO3 as initiators. The optimum reaction conditions as follows:K(chitosan)=3.35%, K(HAc)=2%, n(AN)/n (chitosan)=7, n(chitosan)/n(K2S2O8)=6, n(NaHSO3)/n(K2S2O8)=0.538, reaction time 3.5 h, temperature 40℃, grafting efficiency being 92.24%. The results showed that the uniform design, as compared with the orthogonal factorization method, has the advantages of timesaving and easier analyse of the influence factors.
The uniform design and statistical analysis system(SAS) have been employed to study the reaction conditions of graft polymerization of acrylonitrile(AN) onto chitosan using K2S2O8-NaHSO3 as initiators. The optimum reaction conditions as follows:K(chitosan)=3.35%, K(HAc)=2%, n(AN)/n (chitosan)=7, n(chitosan)/n(K2S2O8)=6, n(NaHSO3)/n(K2S2O8)=0.538, reaction time 3.5 h, temperature 40℃, grafting efficiency being 92.24%. The results showed that the uniform design, as compared with the orthogonal factorization method, has the advantages of timesaving and easier analyse of the influence factors.
2001, 18(10): 828-830
Abstract:
(R) and (S) 4-Methyl-1-nonanol, the sex attractant of the yellow mealworn(Tenebrio molitor L.), were synthesized from bornane-10,2-sultam via asymmetric alkylation of N-acylbornane-10,2-sultam with alkyl iodide, reductive cleavage with LiAlH4, bromination with HBr and reaction of organocuprate reagent with ethylene oxide in the presence of BF3·Et2O. The enantiomeric excess of the total syntheses was over 97%e.e..
(R) and (S) 4-Methyl-1-nonanol, the sex attractant of the yellow mealworn(Tenebrio molitor L.), were synthesized from bornane-10,2-sultam via asymmetric alkylation of N-acylbornane-10,2-sultam with alkyl iodide, reductive cleavage with LiAlH4, bromination with HBr and reaction of organocuprate reagent with ethylene oxide in the presence of BF3·Et2O. The enantiomeric excess of the total syntheses was over 97%e.e..
2001, 18(10): 831-833
Abstract:
Two kinds of bactericidal and adsorptive cotton fibers(BACF-1,BACF-2) were made through epoxidation, amination and quaternarization. Which were associated with the test of their bactericidal activity and adsorption capacity tests showed that both functionatized cotton fibers have good adsorption capacity to Cu2+ and antibacterial action to staphylococcus aureus and bacilluscoli. They can be regenerated for repeated use after acidification with dilute hydrochloric acid and washing and sterilization with water and 95%alcohol successively.
Two kinds of bactericidal and adsorptive cotton fibers(BACF-1,BACF-2) were made through epoxidation, amination and quaternarization. Which were associated with the test of their bactericidal activity and adsorption capacity tests showed that both functionatized cotton fibers have good adsorption capacity to Cu2+ and antibacterial action to staphylococcus aureus and bacilluscoli. They can be regenerated for repeated use after acidification with dilute hydrochloric acid and washing and sterilization with water and 95%alcohol successively.
2001, 18(10): 834-836
Abstract:
The potentiostatic intermittent titration technique(PITT) method was used to determine lithium ion diffusion coefficients in graphitized carbon fiber anode material as function of potentials. The plot of lg D vs E shows that the value of lithium ion coefficients in graphitized carbon fiber anode material has three minima, the least value obtained is 1 9×10-13cm2/s.
The potentiostatic intermittent titration technique(PITT) method was used to determine lithium ion diffusion coefficients in graphitized carbon fiber anode material as function of potentials. The plot of lg D vs E shows that the value of lithium ion coefficients in graphitized carbon fiber anode material has three minima, the least value obtained is 1 9×10-13cm2/s.
2001, 18(10): 837-839
Abstract:
The tris(N,N-iminodiethanoldithiocarbamate) bismuth(Ⅲ) complex (Bi2(deadtc)6) has been synthesized and its structure has been investigated by single crystal X-ray diffractometry. The binuclear complex is centrosymmetric. The resulting coordination polyhedron appears a distorted octahedra with four strong (0.266 7~0.280 9 nm) and two weak (0.306 3~0.310 5 nm) Bi-S bonds. Experiments show that the antibacterial activity of the complex is superior to that of the ligand and that of Mancozeb.
The tris(N,N-iminodiethanoldithiocarbamate) bismuth(Ⅲ) complex (Bi2(deadtc)6) has been synthesized and its structure has been investigated by single crystal X-ray diffractometry. The binuclear complex is centrosymmetric. The resulting coordination polyhedron appears a distorted octahedra with four strong (0.266 7~0.280 9 nm) and two weak (0.306 3~0.310 5 nm) Bi-S bonds. Experiments show that the antibacterial activity of the complex is superior to that of the ligand and that of Mancozeb.
2001, 18(10): 840-842
Abstract:
A S2O82-/ZrO2-Al2O3 type solid superacid catalyst was prepared from ZrOCl2·8H2O, AlCl3·6H2O and (NH4)2S2O8 by coprecipitation, maceration and calcination processes. Their crystal structures and acidities were determined by XRD and Hammett method, respectively. The activity of the catalyst was studied as function of Al2O3 content, calcination temperature and time in the esterification of acetic acid with butanol, and a conversion of 96.5% was obtained. The catalyst gave also higher yields in syntheses of ketals and acetals:cyclohexanone ethylene ketal(86.2%), acetophenone ethylene ketal(78.5%), acetylacetic ester ketal(88.5%), benzaldehyde glycol acetal(76.3%). The chemical structures of the products were confirmed by IR spectra.
A S2O82-/ZrO2-Al2O3 type solid superacid catalyst was prepared from ZrOCl2·8H2O, AlCl3·6H2O and (NH4)2S2O8 by coprecipitation, maceration and calcination processes. Their crystal structures and acidities were determined by XRD and Hammett method, respectively. The activity of the catalyst was studied as function of Al2O3 content, calcination temperature and time in the esterification of acetic acid with butanol, and a conversion of 96.5% was obtained. The catalyst gave also higher yields in syntheses of ketals and acetals:cyclohexanone ethylene ketal(86.2%), acetophenone ethylene ketal(78.5%), acetylacetic ester ketal(88.5%), benzaldehyde glycol acetal(76.3%). The chemical structures of the products were confirmed by IR spectra.
2001, 18(10): 843-845
Abstract:
The extraction of lactic acid(HA) with primary amine N1923(RNH2) has been studied by means of a slope method and IR spectrophotometry at (298±1) K. The composition of the extracted complex was found to be RNH2HA. The equilibrium constant of extraction was determined as lg Kex=1.63. The results showed that lower temperature was favorable for the extraction.
The extraction of lactic acid(HA) with primary amine N1923(RNH2) has been studied by means of a slope method and IR spectrophotometry at (298±1) K. The composition of the extracted complex was found to be RNH2HA. The equilibrium constant of extraction was determined as lg Kex=1.63. The results showed that lower temperature was favorable for the extraction.
2001, 18(10): 846-848
Abstract:
Refined soybean oil and lard were interesterified in the presence of a basic anion exchange resin as heterogeneous catalyst. The structural composition of the interesterification products was determined by 1,3 specific lipase hydrolysis method followed by chromotographic analysis. The influences of the acidity of reactants, reaction time and reaction temperature on the interesterfication have been investigated. The experimental results showed that a mixture of 60% soybean oil and 40% lard(in mass ratio) with acid value of 0 116 was found to have remarkable interesterification at 50℃, for 150 min by using 10% basic anion exchange resin as a catalyst. The melting point of the final product was 37.6℃.
Refined soybean oil and lard were interesterified in the presence of a basic anion exchange resin as heterogeneous catalyst. The structural composition of the interesterification products was determined by 1,3 specific lipase hydrolysis method followed by chromotographic analysis. The influences of the acidity of reactants, reaction time and reaction temperature on the interesterfication have been investigated. The experimental results showed that a mixture of 60% soybean oil and 40% lard(in mass ratio) with acid value of 0 116 was found to have remarkable interesterification at 50℃, for 150 min by using 10% basic anion exchange resin as a catalyst. The melting point of the final product was 37.6℃.
2001, 18(10): 849-850
Abstract:
Copoly(ether imide)s were obtained from diamine containing phthalazone and p-phenylenediamine or m-phenylenediamine with BPA dianhydride by "one step" polycondensation. The copolymers were studied by IR、DSC、mechanical property and solubility measurements. The results show that the Tgs of the copolymers are 8~35℃ higher than that of Ultem and increase with increase in phthalazone in the polymer's backbone. The copolymers have good solubility and a little increased tensile strengths.
Copoly(ether imide)s were obtained from diamine containing phthalazone and p-phenylenediamine or m-phenylenediamine with BPA dianhydride by "one step" polycondensation. The copolymers were studied by IR、DSC、mechanical property and solubility measurements. The results show that the Tgs of the copolymers are 8~35℃ higher than that of Ultem and increase with increase in phthalazone in the polymer's backbone. The copolymers have good solubility and a little increased tensile strengths.
2001, 18(10): 851-852
Abstract:
The content of phenoxymethylpenicillin potassium in phenoxymethylpenicillin potassium tablet was determined indirectly with second order differential simple oscillographic voltammetry. The linear concentration range and the detection limit is 2.6×10-6~3.5×10-5mol/L and 1×10-6 mol/L, respectively. The regressive equation is h(V)=1.169-1.129×104c(mol/L), (r=-0.999 8). The RSD of the determination for 1.8×10-5 mol/L phenoxymethylpenicillin potassium is 3.2%, and the recovery is 102.2%(n=8). This method has the advantages of convenient, rapid and without special pretreatment of the sample.
The content of phenoxymethylpenicillin potassium in phenoxymethylpenicillin potassium tablet was determined indirectly with second order differential simple oscillographic voltammetry. The linear concentration range and the detection limit is 2.6×10-6~3.5×10-5mol/L and 1×10-6 mol/L, respectively. The regressive equation is h(V)=1.169-1.129×104c(mol/L), (r=-0.999 8). The RSD of the determination for 1.8×10-5 mol/L phenoxymethylpenicillin potassium is 3.2%, and the recovery is 102.2%(n=8). This method has the advantages of convenient, rapid and without special pretreatment of the sample.
