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1996 Volume 7 Issue 11
Chemisorbed dimethylammonium chlorochromate as selective oxidants for primary and second aryAlcohols
1996, 7(11): 973-974
Abstract:
Two new reagents.dimethylammonium chlorochromate adsorbed on alumina and silica gel are described as convenient reagents for efficient oxidation of a variety of primary and secondary alcohols.Tliese two reagents are very stable and can be safely used for the oxidation of alcohols containing double bond.
Two new reagents.dimethylammonium chlorochromate adsorbed on alumina and silica gel are described as convenient reagents for efficient oxidation of a variety of primary and secondary alcohols.Tliese two reagents are very stable and can be safely used for the oxidation of alcohols containing double bond.
1996, 7(11): 975-978
Abstract:
Acetalization of steroid ketones and cleavage of the acetals have been carried out in excellent yield under catalysis of montmorillonite K 10.
Acetalization of steroid ketones and cleavage of the acetals have been carried out in excellent yield under catalysis of montmorillonite K 10.
1996, 7(11): 979-980
Abstract:
Zinc(Ⅱ)complexes of new macrocyclic tetraamines(cyclam derivatives)having a strategically appended phenolate group,have been examined as catalyst for the hydrolysis of 4-nitrophenyl acetate(NA).It was proven that coordinated phenolate can serve as a good nucleophile that efficiently catalyze 4-nitrophenyl acetate(NA)hydrolysis.
Zinc(Ⅱ)complexes of new macrocyclic tetraamines(cyclam derivatives)having a strategically appended phenolate group,have been examined as catalyst for the hydrolysis of 4-nitrophenyl acetate(NA).It was proven that coordinated phenolate can serve as a good nucleophile that efficiently catalyze 4-nitrophenyl acetate(NA)hydrolysis.
1996, 7(11): 981-983
Abstract:
Various aromatic nitro compounds could be selectively and rapidly reduced to the corresponding amines in excellent yields by potassium borohydride-bismuth chloride/ethanol-water,a new and facile reductive system.
Various aromatic nitro compounds could be selectively and rapidly reduced to the corresponding amines in excellent yields by potassium borohydride-bismuth chloride/ethanol-water,a new and facile reductive system.
1996, 7(11): 984-986
Abstract:
A series of substituted 3'-N-benzoyl taxol analogs [7a~i] were synthesized by Schotten-Baumann acylation of the key intermediate,13-O-[(2'R,3'S)-3'-phenylisoserinoyl] baccatin Ⅲ[6].Evaluation of the newly prepared derivatives for cytotoxicity against KB cell line revealed that electron-donating groups at the para position(such as-CH3,-OCH3,etc.)have positive effect on activity,while electron-attracting groups(such as-NO2,-Br,etc.)have negative effect.Sterically hindered substituents at the ortho position could dramatically reduce the activity.But none of the analogs had higher cytotoxicity than taxol.
A series of substituted 3'-N-benzoyl taxol analogs [7a~i] were synthesized by Schotten-Baumann acylation of the key intermediate,13-O-[(2'R,3'S)-3'-phenylisoserinoyl] baccatin Ⅲ[6].Evaluation of the newly prepared derivatives for cytotoxicity against KB cell line revealed that electron-donating groups at the para position(such as-CH3,-OCH3,etc.)have positive effect on activity,while electron-attracting groups(such as-NO2,-Br,etc.)have negative effect.Sterically hindered substituents at the ortho position could dramatically reduce the activity.But none of the analogs had higher cytotoxicity than taxol.
1996, 7(11): 987-988
Abstract:
A series of analogues of etoposide(VP-16),the C-4 alkylamino-substituted 4'-demethyl-epipodophyllotoxins,have been synthesized and studied for their activity to inhibit L1210 and KB cells in vitro.Most new compounds are as active or more active than VP-16 in their inhibition of both L1210 and KB cells.
A series of analogues of etoposide(VP-16),the C-4 alkylamino-substituted 4'-demethyl-epipodophyllotoxins,have been synthesized and studied for their activity to inhibit L1210 and KB cells in vitro.Most new compounds are as active or more active than VP-16 in their inhibition of both L1210 and KB cells.
1996, 7(11): 989-990
Abstract:
A series of 2-methylenesuccinimides modified by germatranes were synthesized by two methods.The structures of products were confirmed by 1HNMR.IR,elemental analysis,and X-ray diffraction.
A series of 2-methylenesuccinimides modified by germatranes were synthesized by two methods.The structures of products were confirmed by 1HNMR.IR,elemental analysis,and X-ray diffraction.
1996, 7(11): 991-992
Abstract:
Synthesis of the protected tetrasaccharide 11 is reported as the key intermediate of tetrasaccharide from laminin that is an important glycoprotein on the basement membrane.
Synthesis of the protected tetrasaccharide 11 is reported as the key intermediate of tetrasaccharide from laminin that is an important glycoprotein on the basement membrane.
1996, 7(11): 993-994
Abstract:
Four F-alkylated muramyl dipeptides were synthesized by an efficient coupling reagent,Benzotriazol-1-yloxy-bis(pyrrolidino)carbonium hexafluoro-phosphate(BBC)[1].
Four F-alkylated muramyl dipeptides were synthesized by an efficient coupling reagent,Benzotriazol-1-yloxy-bis(pyrrolidino)carbonium hexafluoro-phosphate(BBC)[1].
1996, 7(11): 995-996
Abstract:
Treatment of N-cyanomethylsecurinine bromide with NaH in tetrahydrofuran gave ring enlargement products with [3,2] rearrangement
Treatment of N-cyanomethylsecurinine bromide with NaH in tetrahydrofuran gave ring enlargement products with [3,2] rearrangement
1996, 7(11): 997-998
Abstract:
Diacholest-13(17)-ene ozonides(1a and lb)and 4,4-dimethyldiacholest-13(17)-ene ozonides(2a and 2b)underwent pyrolysis to afford the coressponding 17-oxo-13,14;13,17-disecodiacholestano-13,14-lactones(3a and 3b)and 4,4-dimethyl-17-oxo-13,14;13,17-disecodiacholestano-13,14-lactones(4a and 4b),respectively.The stereochemistry of the migrating groups was proven to be conserved by comparison with the Baeyer-Villiger oxidation of the corresponding 13,17-secodiacholesta-13,17-diones(5)and 4,4-dimethyl-13,17secodiacholesta-13,17-diones(6).
Diacholest-13(17)-ene ozonides(1a and lb)and 4,4-dimethyldiacholest-13(17)-ene ozonides(2a and 2b)underwent pyrolysis to afford the coressponding 17-oxo-13,14;13,17-disecodiacholestano-13,14-lactones(3a and 3b)and 4,4-dimethyl-17-oxo-13,14;13,17-disecodiacholestano-13,14-lactones(4a and 4b),respectively.The stereochemistry of the migrating groups was proven to be conserved by comparison with the Baeyer-Villiger oxidation of the corresponding 13,17-secodiacholesta-13,17-diones(5)and 4,4-dimethyl-13,17secodiacholesta-13,17-diones(6).
1996, 7(11): 999-1002
Abstract:
We have used quantum chemical method to study the transition states of undine phosphorolysis reaction under the neutral condition.Comparing the activation energies of different reaction modes,we conclude that uridine phosphorolysis takes place mainly according to a concerted mechanism.The computational results are consistent with some critical experimental facts.
We have used quantum chemical method to study the transition states of undine phosphorolysis reaction under the neutral condition.Comparing the activation energies of different reaction modes,we conclude that uridine phosphorolysis takes place mainly according to a concerted mechanism.The computational results are consistent with some critical experimental facts.
1996, 7(11): 1003-1004
Abstract:
A d,l mixture(R-R and S-S)can be resolved into the d and the I enantiomers.while the meso isomer(R-S,identical with S-R)cannot be physically separated.This fact has occasionally been "extrapolated" to differentiate d,I and meso isomers with a chiral shift reagent,where the meso isomer is presumed not to show any signal "doubling" during the(usually)downfield shift.This assumption has been shown to be incorrect by the behavior of a meso molecule which does give signal "doubling".
A d,l mixture(R-R and S-S)can be resolved into the d and the I enantiomers.while the meso isomer(R-S,identical with S-R)cannot be physically separated.This fact has occasionally been "extrapolated" to differentiate d,I and meso isomers with a chiral shift reagent,where the meso isomer is presumed not to show any signal "doubling" during the(usually)downfield shift.This assumption has been shown to be incorrect by the behavior of a meso molecule which does give signal "doubling".
1996, 7(11): 1005-1008
Abstract:
Two new saponins named asterlingulatosides A and B were isolated from the whole plants of Aster lingulatus.Their structures were elucidated by spectral and chemical evidence as 3-O-β-D-glucopyranosyl-3β,16α-dihydroxyolean-12-en-28-oic acid-28-O-α-L-arabinopyranoside and 3-O-β-D-glucopyranosyl-3β,16α-dihydroxyolean-12-en-28-oic acid-28-O-α-L-rhamnopy-ranosyl-(1→2)-α-L-arabinopyranoside respectively.They showed inhibitory activity on DNA synthesis of human leukemia HL-60 cells.
Two new saponins named asterlingulatosides A and B were isolated from the whole plants of Aster lingulatus.Their structures were elucidated by spectral and chemical evidence as 3-O-β-D-glucopyranosyl-3β,16α-dihydroxyolean-12-en-28-oic acid-28-O-α-L-arabinopyranoside and 3-O-β-D-glucopyranosyl-3β,16α-dihydroxyolean-12-en-28-oic acid-28-O-α-L-rhamnopy-ranosyl-(1→2)-α-L-arabinopyranoside respectively.They showed inhibitory activity on DNA synthesis of human leukemia HL-60 cells.
1996, 7(11): 1009-1010
Abstract:
Two homogeneous new peptidoglycans were obtained from Lycium barbarum L.They were found to be effective ingredients capable of resisting lipid peroxidation.The components and linkages of the two homogeneous polysaccharides were studied by means of complete acid hydrolysis,periodate oxidation,Smith degradation,enzyme hydrolysis,IR,GC and amino acid analysis.Homogeneous polysaccharide LBPC2 was found to be a β(1→4)(1→6)peptidoglycan with MW of 1.2×104,composed of Xyl,Rha,Man in a molar ratio of 8.8:2.3:1;LBP4,was found to be a α(1→4)(1→6)peptidoglycan with MW of 1.0×104,composed of glucans.
Two homogeneous new peptidoglycans were obtained from Lycium barbarum L.They were found to be effective ingredients capable of resisting lipid peroxidation.The components and linkages of the two homogeneous polysaccharides were studied by means of complete acid hydrolysis,periodate oxidation,Smith degradation,enzyme hydrolysis,IR,GC and amino acid analysis.Homogeneous polysaccharide LBPC2 was found to be a β(1→4)(1→6)peptidoglycan with MW of 1.2×104,composed of Xyl,Rha,Man in a molar ratio of 8.8:2.3:1;LBP4,was found to be a α(1→4)(1→6)peptidoglycan with MW of 1.0×104,composed of glucans.
1996, 7(11): 1011-1012
Abstract:
Two new glycosides 1,5-dihydroxyxathanone-6-o-β-D-glucoside and flavanonol-taxifolin-3,7-o-α-L-dirbamnoside.were isolated from the aerial parts of Hypericum japonicum Thunb.ex Murray.The chemical structures were determined by spectroscopic methods and chemical evidences
Two new glycosides 1,5-dihydroxyxathanone-6-o-β-D-glucoside and flavanonol-taxifolin-3,7-o-α-L-dirbamnoside.were isolated from the aerial parts of Hypericum japonicum Thunb.ex Murray.The chemical structures were determined by spectroscopic methods and chemical evidences
1996, 7(11): 1013-1015
Abstract:
Sophoridine N-oxide(A)was isolated from the seeds of Inner Mongolian Sophora alopecuroides L.Its structure was characterized.Deoxygenation of A gave sophoridine whereas N-oxidation of sophoridine gave two N-oxides,The stereochemical features of the two isomers were given by analysis of its 1H-and 13C-NMR spectra.
Sophoridine N-oxide(A)was isolated from the seeds of Inner Mongolian Sophora alopecuroides L.Its structure was characterized.Deoxygenation of A gave sophoridine whereas N-oxidation of sophoridine gave two N-oxides,The stereochemical features of the two isomers were given by analysis of its 1H-and 13C-NMR spectra.
1996, 7(11): 1016-1018
Abstract:
A procedure for preparing carbon paste microeletrodes is described.This procedure is based on incorporation of carbon paste into the microholes at the tips of chemically etched microdisk electrodes.The electrodes combine the advantages of microdisk electrodes and carbon paste electrodes.Sigmoidal-shape voltammograms were observed and steady-state currents were quickly achieved on these electrodes.
A procedure for preparing carbon paste microeletrodes is described.This procedure is based on incorporation of carbon paste into the microholes at the tips of chemically etched microdisk electrodes.The electrodes combine the advantages of microdisk electrodes and carbon paste electrodes.Sigmoidal-shape voltammograms were observed and steady-state currents were quickly achieved on these electrodes.
1996, 7(11): 1019-1022
Abstract:
A new type of all-solid-state Ag/AgCl reference electrode was constructed by using urea-formaldehyde resin as the frame material and KCl powder as the active component.The properties of the electrode were studied in detail.The electrode exhibited excellent characteristics and could be applied to the electrochemical measurements in syrupy,colloidal and higher temperature solutions as a reference electrode.
A new type of all-solid-state Ag/AgCl reference electrode was constructed by using urea-formaldehyde resin as the frame material and KCl powder as the active component.The properties of the electrode were studied in detail.The electrode exhibited excellent characteristics and could be applied to the electrochemical measurements in syrupy,colloidal and higher temperature solutions as a reference electrode.
1996, 7(11): 1023-1026
Abstract:
A novel chemiluminescence.Cl sensor combined with flow-injection analysis has been developed for determining free chlorine in tap water.The analytical reagent luminol was immobilized on an anion exchange resin column.While a volume of the sodium hydroxide passed the column,luminol was eluted from the resin in alkaline aqueous solution and then mixed with the sample stream to react and produce Cl.The Cl emission intensity was correlated with the standard C10- concentration in the range of 1×10-3 to 4×10-5 g ml-1,and the detection limit was 8×10-9g ml-1 C10-.Interfering metal ions present in water were effectively separated by a pre-column cation exchanger.A complete analysis,including sampling and washing,could be performed in 1 min with a relative standard deviation of less than 5%.The sensor was stable for over 200 times and has been applied successfully to the determination of C10- in tap water.
A novel chemiluminescence.Cl sensor combined with flow-injection analysis has been developed for determining free chlorine in tap water.The analytical reagent luminol was immobilized on an anion exchange resin column.While a volume of the sodium hydroxide passed the column,luminol was eluted from the resin in alkaline aqueous solution and then mixed with the sample stream to react and produce Cl.The Cl emission intensity was correlated with the standard C10- concentration in the range of 1×10-3 to 4×10-5 g ml-1,and the detection limit was 8×10-9g ml-1 C10-.Interfering metal ions present in water were effectively separated by a pre-column cation exchanger.A complete analysis,including sampling and washing,could be performed in 1 min with a relative standard deviation of less than 5%.The sensor was stable for over 200 times and has been applied successfully to the determination of C10- in tap water.
1996, 7(11): 1027-1028
Abstract:
A high-performance liquid chromatographic method using uv detection for the determination of 10 drugs of abuse is described.The method is simple and sensitive.The linear ranges are 20~100 ng/ml with relative standard deviations of 0.7~2.6%(n=7)and detection limits of 5~10ng/ml.
A high-performance liquid chromatographic method using uv detection for the determination of 10 drugs of abuse is described.The method is simple and sensitive.The linear ranges are 20~100 ng/ml with relative standard deviations of 0.7~2.6%(n=7)and detection limits of 5~10ng/ml.
1996, 7(11): 1029-1032
Abstract:
The protein assay with bromocresol green(BCG)method is commonly used because of its convenience,but it is not well understood on a molecular level.In this paper,the study on the reaction between BCG and bovine serum albumin(BSA)is reported.The binding numbers and the binding constants are given at different pH by using three methods with relevant comparison.It was proved that there were three sorts of binding sites of BSA to react with BCG and BCG transformed into its basic form in the presence of BSA.
The protein assay with bromocresol green(BCG)method is commonly used because of its convenience,but it is not well understood on a molecular level.In this paper,the study on the reaction between BCG and bovine serum albumin(BSA)is reported.The binding numbers and the binding constants are given at different pH by using three methods with relevant comparison.It was proved that there were three sorts of binding sites of BSA to react with BCG and BCG transformed into its basic form in the presence of BSA.
1996, 7(11): 1033-1034
Abstract:
The CE separation of monosialoganglioads(MSGLS)is generally difficult owing to their mixed micelle formation.The addition of high concentration of borax to the buffer containing α-Cyclodextrin allowed for improvement of selectivity of separation.Under the optimum conditions,several forms of MSGLS were successfully separated and the commercial standard GMl gave two peaks,suggesting that the standard may contain two different types of species.
The CE separation of monosialoganglioads(MSGLS)is generally difficult owing to their mixed micelle formation.The addition of high concentration of borax to the buffer containing α-Cyclodextrin allowed for improvement of selectivity of separation.Under the optimum conditions,several forms of MSGLS were successfully separated and the commercial standard GMl gave two peaks,suggesting that the standard may contain two different types of species.
1996, 7(11): 1035-1036
Abstract:
L-(+)-diethyl tartrate was bound to hydroxymethyl polystyrene bead as a chiral stationary phase in high-performance liquid chromatography(HPLC)for the resolution of pharmaceutically racemic compounds,such as D,L-amygdalic acid,D,L-brufen,and D,L-phenylephrine in an isocratic elution mode.
L-(+)-diethyl tartrate was bound to hydroxymethyl polystyrene bead as a chiral stationary phase in high-performance liquid chromatography(HPLC)for the resolution of pharmaceutically racemic compounds,such as D,L-amygdalic acid,D,L-brufen,and D,L-phenylephrine in an isocratic elution mode.
1996, 7(11): 1037-1038
Abstract:
The stability of the photoluminescence(PL)from porous silicon(PS)has evidently improved by HNO3 chemical oxidation.The PL intensity and peak wavelength of PS were changed with the increase of HNO3 concentration and oxidation time.Being different from other oxidized ways,the PS oxidized by HNO3 remains sensitive to adsorbates.PTIR spectroscopic data suggest that these phenomena are attributed to the presence of HSi(SiaO3-a)(a≤3)layer on PS surface.
The stability of the photoluminescence(PL)from porous silicon(PS)has evidently improved by HNO3 chemical oxidation.The PL intensity and peak wavelength of PS were changed with the increase of HNO3 concentration and oxidation time.Being different from other oxidized ways,the PS oxidized by HNO3 remains sensitive to adsorbates.PTIR spectroscopic data suggest that these phenomena are attributed to the presence of HSi(SiaO3-a)(a≤3)layer on PS surface.
1996, 7(11): 1039-1040
Abstract:
Four ferrocenyl long-chain alkyl β-diketonato zinc(Ⅱ)complexes with a general formula ZnL2(L=C5H5FeC5H4COCHCOCnH2n+1.n=6-9)were synthesized.These complexes were characterized by elementary analysis,IR.1HNMR MS、polarizing microscopy with a heating stage and DSC.It was found that the complexes have thermotropic liquid crystalline properties.The type of the heteronuclear liquid crystalline metal complexes have not been reported so far.
Four ferrocenyl long-chain alkyl β-diketonato zinc(Ⅱ)complexes with a general formula ZnL2(L=C5H5FeC5H4COCHCOCnH2n+1.n=6-9)were synthesized.These complexes were characterized by elementary analysis,IR.1HNMR MS、polarizing microscopy with a heating stage and DSC.It was found that the complexes have thermotropic liquid crystalline properties.The type of the heteronuclear liquid crystalline metal complexes have not been reported so far.
1996, 7(11): 1041-1042
Abstract:
Monolayers of porphyrin and phthalocyanine at the air-water interface were studied by means of film balance and Brewster angle microscopy(BAM).Results showed that the final point of compression isotherm and that of recompression isotherm were coincident or not coincident depending on the target pressures.Results were discussed in terms of the morphology of monolayers observed by BAM.
Monolayers of porphyrin and phthalocyanine at the air-water interface were studied by means of film balance and Brewster angle microscopy(BAM).Results showed that the final point of compression isotherm and that of recompression isotherm were coincident or not coincident depending on the target pressures.Results were discussed in terms of the morphology of monolayers observed by BAM.
1996, 7(11): 1043-1046
Abstract:
Ab initio study on the reaction of the ground state(a3F)and excited state(a1D)of La+ with methane has been performed.Reaction channel on the singlet and triplet potential energy surface(PES)has been examined and the reaction mechanism are discussed.Comparisons between singlet and triplet PESs show that the excited state(a1D)of La+ is more reactive than its ground state(a3F)due to the spin quantum number conservation with the more stable insertion intermediate for excited state(1D),which is in good agreement with the experiment.
Ab initio study on the reaction of the ground state(a3F)and excited state(a1D)of La+ with methane has been performed.Reaction channel on the singlet and triplet potential energy surface(PES)has been examined and the reaction mechanism are discussed.Comparisons between singlet and triplet PESs show that the excited state(a1D)of La+ is more reactive than its ground state(a3F)due to the spin quantum number conservation with the more stable insertion intermediate for excited state(1D),which is in good agreement with the experiment.
1996, 7(11): 1047-1050
Abstract:
Deuterium isotope effects in the CO2-reforming of methane to syngas were first investigated over SiO2-supported rhodium catalysts.Normal deuterium isotope effect was more noticeable on the methane conversion reaction than on the CO formation reaction,while there was no such effect on the CO2 conversion reaction.It can be concluded that the dissociation of the C-H bond in methane is a key step and some CO is formed by the reverse water-gas shift reaction.
Deuterium isotope effects in the CO2-reforming of methane to syngas were first investigated over SiO2-supported rhodium catalysts.Normal deuterium isotope effect was more noticeable on the methane conversion reaction than on the CO formation reaction,while there was no such effect on the CO2 conversion reaction.It can be concluded that the dissociation of the C-H bond in methane is a key step and some CO is formed by the reverse water-gas shift reaction.
1996, 7(11): 1051-1053
Abstract:
I.r.bands at 1559.0,1441.0,1378.9,1360.3,1031.1,981.4 and 947.3 cm-1 due to various types of dissociative adsorption of H2 over ZrO2 with changing temperature were observed by in situ FT-IR spectroscopy.
I.r.bands at 1559.0,1441.0,1378.9,1360.3,1031.1,981.4 and 947.3 cm-1 due to various types of dissociative adsorption of H2 over ZrO2 with changing temperature were observed by in situ FT-IR spectroscopy.
1996, 7(11): 1054-1056
Abstract:
Several precursors of organic conductors based on metal-(dmit)2 anion complex with carbonium as counter cations were first synthesized.Some of them exhibit greatly increased conductivities upon iodine doping.
Several precursors of organic conductors based on metal-(dmit)2 anion complex with carbonium as counter cations were first synthesized.Some of them exhibit greatly increased conductivities upon iodine doping.
1996, 7(11): 1057-1058
Abstract:
A Fe-containing mesoporous silica has been synthesized at room temperature using alkylamine as templating surfactant;XRD,IR,ESR and 29Si MAS NMR spectra provided evidence of the presence of framework and non-framework iron(Ⅲ)in Fe-HMS material.
A Fe-containing mesoporous silica has been synthesized at room temperature using alkylamine as templating surfactant;XRD,IR,ESR and 29Si MAS NMR spectra provided evidence of the presence of framework and non-framework iron(Ⅲ)in Fe-HMS material.
1996, 7(11): 1059-1060
Abstract:
The present work reported the results of the characterization of the surface oxygen species on single crystal MgO(100)using surface sensitive analyzing methods ARXPS(angular resolved X-ray photoelectron spectroscopy)and SRPES(synchrotron radiation photoelectron spectroscopy).
The present work reported the results of the characterization of the surface oxygen species on single crystal MgO(100)using surface sensitive analyzing methods ARXPS(angular resolved X-ray photoelectron spectroscopy)and SRPES(synchrotron radiation photoelectron spectroscopy).
1996, 7(11): 1061-1064
Abstract:
The optimum conditions of supercritical fluid extraction(SFE)desorping the organic pollutants adsorbed and enriched by the adsorbent Porapak P and the effects of the conditions on the efficiencies of SFE desorping organic pollutants are studied emphatically.Different kinds of organic adsorbents and modifiers were tested.The recoveries of SFE are compared with Soxhlet extraction.The recoveries between 93.1% and 109.3% are obtained for 25 kinds of compounds at 35 MPa,100℃ and 9.0 ml SF-CO2,and their relative standard deviations(RSD)are in the range of 0.6-12.6 percent.
The optimum conditions of supercritical fluid extraction(SFE)desorping the organic pollutants adsorbed and enriched by the adsorbent Porapak P and the effects of the conditions on the efficiencies of SFE desorping organic pollutants are studied emphatically.Different kinds of organic adsorbents and modifiers were tested.The recoveries of SFE are compared with Soxhlet extraction.The recoveries between 93.1% and 109.3% are obtained for 25 kinds of compounds at 35 MPa,100℃ and 9.0 ml SF-CO2,and their relative standard deviations(RSD)are in the range of 0.6-12.6 percent.
1996, 7(11): 1065-1066
Abstract:
In this paper,the "periodic table" (PT)classification method(PTCM)using three parameters "Z1/ZT/Pn" for organic compounds has been presented.About 460 classes of compounds have been classified by PTCM.
In this paper,the "periodic table" (PT)classification method(PTCM)using three parameters "Z1/ZT/Pn" for organic compounds has been presented.About 460 classes of compounds have been classified by PTCM.
