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2007 Volume 18 Issue 4
2007, 18(4): 373-376
doi: 10.1016/j.cclet.2007.02.012
Abstract:
Two tigogenyl glycosides containing N-acetylglucosamine were synthesized. Their structures were confirmed by 1H and 13C NMR spectra. The shielding effect caused by benzoyl groups was elucidated by 1H NMR, COSY, HSQC, HMBC spectroscopy.
Two tigogenyl glycosides containing N-acetylglucosamine were synthesized. Their structures were confirmed by 1H and 13C NMR spectra. The shielding effect caused by benzoyl groups was elucidated by 1H NMR, COSY, HSQC, HMBC spectroscopy.
2007, 18(4): 377-379
doi: 10.1016/j.cclet.2007.01.045
Abstract:
Reaction of polystyrene-supported lithium selenide with 3-acetoxy-2-methylene-aikanoates afforded the corresponding allyl selenide resins and subsequent cleavage from the polymer by treating with methyl iodide to furnish (Z)-allyl iodides in good yields and high purities. The polymeric selenium reagent can be regenerated and reused. So it is a environmentally benign reagent.
Reaction of polystyrene-supported lithium selenide with 3-acetoxy-2-methylene-aikanoates afforded the corresponding allyl selenide resins and subsequent cleavage from the polymer by treating with methyl iodide to furnish (Z)-allyl iodides in good yields and high purities. The polymeric selenium reagent can be regenerated and reused. So it is a environmentally benign reagent.
2007, 18(4): 380-382
doi: 10.1016/j.cclet.2007.01.018
Abstract:
A series of 2-aryl-5-alkyl-7-methoxylbenzo[b]furan derivatives have been synthesized by utilizing the coupling of methyl 3-methoxy-4-hydroxy-5-bromocinnamate with cuprous phenylacetylide as the key step. The structures of the new compounds were confirmed by 1H NMR, IR and MS. The structure of compound 14 was further confirmed by single crystal X-ray. Compound 17 showed cytotoxic activity against human lung carcinoma A549.
A series of 2-aryl-5-alkyl-7-methoxylbenzo[b]furan derivatives have been synthesized by utilizing the coupling of methyl 3-methoxy-4-hydroxy-5-bromocinnamate with cuprous phenylacetylide as the key step. The structures of the new compounds were confirmed by 1H NMR, IR and MS. The structure of compound 14 was further confirmed by single crystal X-ray. Compound 17 showed cytotoxic activity against human lung carcinoma A549.
2007, 18(4): 383-386
doi: 10.1016/j.cclet.2007.01.024
Abstract:
An efficient route to synthesize the heteroaryl-substituted 1,8-naphthyridine derivatives was described. Eight 2-heteroaryl-and 2,7-diheteroaryl-l,8-naphthyridine derivatives were obtained through palladium-catalyzed C-N-coupling reactions of chloronaphthyridines with imidazole, benzimidazole, morpholine, 3,5-dimethylpyrazole, and phthalimide in moderate to good yields.
An efficient route to synthesize the heteroaryl-substituted 1,8-naphthyridine derivatives was described. Eight 2-heteroaryl-and 2,7-diheteroaryl-l,8-naphthyridine derivatives were obtained through palladium-catalyzed C-N-coupling reactions of chloronaphthyridines with imidazole, benzimidazole, morpholine, 3,5-dimethylpyrazole, and phthalimide in moderate to good yields.
2007, 18(4): 387-389
doi: 10.1016/j.cclet.2007.01.046
Abstract:
Various functionalized asymmetrical biaryls can be synthesized in high to excellent yields via coupling reaction of aryl iodides or bromides with NaBPh4 catalyzed by MCM-41-supported sulfur palladium(O) complex. This palladium complex can be easily recovered and reused many times without loss of activity.
Various functionalized asymmetrical biaryls can be synthesized in high to excellent yields via coupling reaction of aryl iodides or bromides with NaBPh4 catalyzed by MCM-41-supported sulfur palladium(O) complex. This palladium complex can be easily recovered and reused many times without loss of activity.
2007, 18(4): 390-392
doi: 10.1016/j.cclet.2007.02.015
Abstract:
Under regular heating and microwave irradiation, 3-alkyl substituted imidazo[1,5-a] pyridines were synthesized from 2,2'-pyridil, di-2-pyridyl ketone and aliphatic aldehydes in the presence of ammonium acetate and acetic acid. Compared to the traditional heating condition, the reaction time under microwave irradiation was shorter and 3-alkyl imidazo[1,5-a]pyridines were given in higher yield.
Under regular heating and microwave irradiation, 3-alkyl substituted imidazo[1,5-a] pyridines were synthesized from 2,2'-pyridil, di-2-pyridyl ketone and aliphatic aldehydes in the presence of ammonium acetate and acetic acid. Compared to the traditional heating condition, the reaction time under microwave irradiation was shorter and 3-alkyl imidazo[1,5-a]pyridines were given in higher yield.
2007, 18(4): 393-396
doi: 10.1016/j.cclet.2007.01.048
Abstract:
An efficient way to coupling amine with the derivatives of steric N-Boc-pyrrolidine-2-carboxylic acid was reported in this paper.We have found that the synthesis of derivatives is problematic with the commonly used DCC/HOBT method. As a substitute, the mixed anhydride method was adopted. A series of 6-(3-nitroguanidino)hexanamidopyrrolidine derivatives were prepared with this method.
An efficient way to coupling amine with the derivatives of steric N-Boc-pyrrolidine-2-carboxylic acid was reported in this paper.We have found that the synthesis of derivatives is problematic with the commonly used DCC/HOBT method. As a substitute, the mixed anhydride method was adopted. A series of 6-(3-nitroguanidino)hexanamidopyrrolidine derivatives were prepared with this method.
2007, 18(4): 397-399
doi: 10.1016/j.cclet.2007.02.006
Abstract:
A [P. Rajakumar, A.M.A. Rasheed, Tetrahedron 61(22) (2005) 5351] para-cyclophane derivative was synthesized via intramolecular esterification of a dipeptide surrogate containing asparagine to form tetrahydropyrimidinone ring. The structures of the product and intermediates were characterized by 1H NMR, 13C NMR and mass spectrum.
A [P. Rajakumar, A.M.A. Rasheed, Tetrahedron 61(22) (2005) 5351] para-cyclophane derivative was synthesized via intramolecular esterification of a dipeptide surrogate containing asparagine to form tetrahydropyrimidinone ring. The structures of the product and intermediates were characterized by 1H NMR, 13C NMR and mass spectrum.
2007, 18(4): 400-402
doi: 10.1016/j.cclet.2007.02.008
Abstract:
The synthesis of a series of 3,6-dichloropyridazine derivatives was described. In vitro experiment, all compounds exhibited an anti-rhinovirus activity, and one of the compounds 6g showed the comparable activity as our lead compound pirodavir.
The synthesis of a series of 3,6-dichloropyridazine derivatives was described. In vitro experiment, all compounds exhibited an anti-rhinovirus activity, and one of the compounds 6g showed the comparable activity as our lead compound pirodavir.
2007, 18(4): 403-406
doi: 10.1016/j.cclet.2007.02.007
Abstract:
A novel series of pyrimidinylthiaalkoxycalix[4]arenes with the reaction between 4,6-dimethylpyrimidine-2-thiol and the different dibromides calix[4]aryl groups have been synthesized and structurally characterized by IR, 1H NMR and MS. From their analysis data, it was found that compounds 8, 9, 11 adopted a cone conformation, while compound 10 existed as a mixture of conformations.
A novel series of pyrimidinylthiaalkoxycalix[4]arenes with the reaction between 4,6-dimethylpyrimidine-2-thiol and the different dibromides calix[4]aryl groups have been synthesized and structurally characterized by IR, 1H NMR and MS. From their analysis data, it was found that compounds 8, 9, 11 adopted a cone conformation, while compound 10 existed as a mixture of conformations.
2007, 18(4): 407-408
doi: 10.1016/j.cclet.2007.01.049
Abstract:
A convenient and effective method for the synthesis of 6-demethoxycapillarisin was described. The highlight was involved in a simple access to the key intermediate 2-ethylthio-5,7-dimethoxy-4H-chromen-4-one from the inexpensive 2,4,6-trihydroxyace-tophenone, using AlCl3 as the demethylation reagent.
A convenient and effective method for the synthesis of 6-demethoxycapillarisin was described. The highlight was involved in a simple access to the key intermediate 2-ethylthio-5,7-dimethoxy-4H-chromen-4-one from the inexpensive 2,4,6-trihydroxyace-tophenone, using AlCl3 as the demethylation reagent.
2007, 18(4): 409-411
doi: 10.1016/j.cclet.2007.01.031
Abstract:
Further phytochemical investigation of the unique C 18-norditerpenoid alkaloids from the roots of Aconitum delavayi Franch led to the isolation of two new norditerpenoid alkaloids, delavaconitine F 1 and delavaconitine G 2. Their structures were determined from spectroscopic evidence.
Further phytochemical investigation of the unique C 18-norditerpenoid alkaloids from the roots of Aconitum delavayi Franch led to the isolation of two new norditerpenoid alkaloids, delavaconitine F 1 and delavaconitine G 2. Their structures were determined from spectroscopic evidence.
2007, 18(4): 412-414
doi: 10.1016/j.cclet.2007.02.001
Abstract:
A new naphthoquinone-anthraquinone dimer named floribundiquinone E (1) and a new anthraquinone 2-acetylphyscion (2)were isolated from the roots of Berchemia floribunda Brongn. Their structures were elucidated on the basis of spectroscopic methods.
A new naphthoquinone-anthraquinone dimer named floribundiquinone E (1) and a new anthraquinone 2-acetylphyscion (2)were isolated from the roots of Berchemia floribunda Brongn. Their structures were elucidated on the basis of spectroscopic methods.
2007, 18(4): 415-417
doi: 10.1016/j.cclet.2007.01.047
Abstract:
A new C21-steroidal glycoside with two known compounds were isolated from the root of Cynanchum Stauntonii. Based on the spectral analysis, including MS, 1H NMR, 13C NMR, DEPT, 1H-1H COSY, 13C-1H COSY, HMQC and HMBC, their chemical structures were determinated as glaucogenin-C 3-O-α-L-cymaropyranosyl-(1→4)-β-D-digitoxopyranosyl-(1→4)-β-D-canaro-pyranoside (1), stigmasterol (2) and ursolic acid (3).
A new C21-steroidal glycoside with two known compounds were isolated from the root of Cynanchum Stauntonii. Based on the spectral analysis, including MS, 1H NMR, 13C NMR, DEPT, 1H-1H COSY, 13C-1H COSY, HMQC and HMBC, their chemical structures were determinated as glaucogenin-C 3-O-α-L-cymaropyranosyl-(1→4)-β-D-digitoxopyranosyl-(1→4)-β-D-canaro-pyranoside (1), stigmasterol (2) and ursolic acid (3).
2007, 18(4): 418-420
doi: 10.1016/j.cclet.2007.02.005
Abstract:
A new triterpenoid has been isolated from the leaves and stems of Fritillaria hupehensis Hsiao et K.C. Hsia. Its structure was established as (23Z)-9,19-cycloart-23-ene-3o,25-diol 1 through chemical and spectroscopic studies including 2D NMR. Another known triterpenoid 9,19-cycloart-25-ene-3β,24ξ-diol 2 was also isolated.
A new triterpenoid has been isolated from the leaves and stems of Fritillaria hupehensis Hsiao et K.C. Hsia. Its structure was established as (23Z)-9,19-cycloart-23-ene-3o,25-diol 1 through chemical and spectroscopic studies including 2D NMR. Another known triterpenoid 9,19-cycloart-25-ene-3β,24ξ-diol 2 was also isolated.
2007, 18(4): 421-423
doi: 10.1016/j.cclet.2007.02.011
Abstract:
Based on the active site of Aspergillus fumigatus lanosterol 14α-demethylase (AF-CYP51), novel triazole compounds were designed. Their chemical synthesis and the antifungal activities were reported. The results showed that all the target compounds exhibited excellent activities with broad spectrum;in which compounds 4, 12 and 15 showed comparable activities against A.fumigatus to the control drug itraconazole.
Based on the active site of Aspergillus fumigatus lanosterol 14α-demethylase (AF-CYP51), novel triazole compounds were designed. Their chemical synthesis and the antifungal activities were reported. The results showed that all the target compounds exhibited excellent activities with broad spectrum;in which compounds 4, 12 and 15 showed comparable activities against A.fumigatus to the control drug itraconazole.
2007, 18(4): 424-426
doi: 10.1016/j.cclet.2006.12.044
Abstract:
Characteristic of Fura-2-Ca2+ interaction was studied based on the fluorescence technique. The apparent dissociation constants (Kd) of the Fura-2-Ca2+ complex were determined at different temperature. The effect of cefotaxime (CEFA) on intracellular Ca2+ concentration ([Ca2+]i) was discussed by using a ratiometric fluorescence dye Fura-2 as a probe. The basal [Ca2+]i in resting human peripheral lymphocytes was 100±7 nmol/L but after treatment with cefotaxime, the changes of [Ca2+]i were observed in different conditions. In the concentration range of 1-30 μmol/L of cefotaxime [Ca2+]i increased, as a result of releasing intracellular Ca2+ stores. Higher concentration of cefotaxime (50-500 μmol/L) stimulated to decrease of [Ca2+]i.
Characteristic of Fura-2-Ca2+ interaction was studied based on the fluorescence technique. The apparent dissociation constants (Kd) of the Fura-2-Ca2+ complex were determined at different temperature. The effect of cefotaxime (CEFA) on intracellular Ca2+ concentration ([Ca2+]i) was discussed by using a ratiometric fluorescence dye Fura-2 as a probe. The basal [Ca2+]i in resting human peripheral lymphocytes was 100±7 nmol/L but after treatment with cefotaxime, the changes of [Ca2+]i were observed in different conditions. In the concentration range of 1-30 μmol/L of cefotaxime [Ca2+]i increased, as a result of releasing intracellular Ca2+ stores. Higher concentration of cefotaxime (50-500 μmol/L) stimulated to decrease of [Ca2+]i.
2007, 18(4): 427-430
doi: 10.1016/j.cclet.2007.02.019
Abstract:
Spectrophotometric method has been developed for the direct quantitative determination of captopril in pharmaceutical preparation and biological fluids (human plasma and urine) samples. The method was accomplished based on parallel factor analysis (PARAFAC) and partial least squares (PLS). The study was carried out in the pH range from 2.0 to 12.8 and with a concentration from 0.70 to 61.50 μg mL-1 of captopril. Multivariate calibration models such as PLS at various pH and PARAFAC were elaborated from ultraviolet spectra deconvolution and captopril determination. The best models for this system were obtained with PARAFAC and PLS at pH 2.0. The applications of the method for determination of real samples were evaluated by analysis of captopril in pharmaceutical preparations and biological fluids with satisfactory results. The accuracy of the method, evaluated through the RMSEP, was 0.5801 for captopril with best calibration curve by PARAFAC and 0.6168 for captopril with PLS at pH 2.0 model.
Spectrophotometric method has been developed for the direct quantitative determination of captopril in pharmaceutical preparation and biological fluids (human plasma and urine) samples. The method was accomplished based on parallel factor analysis (PARAFAC) and partial least squares (PLS). The study was carried out in the pH range from 2.0 to 12.8 and with a concentration from 0.70 to 61.50 μg mL-1 of captopril. Multivariate calibration models such as PLS at various pH and PARAFAC were elaborated from ultraviolet spectra deconvolution and captopril determination. The best models for this system were obtained with PARAFAC and PLS at pH 2.0. The applications of the method for determination of real samples were evaluated by analysis of captopril in pharmaceutical preparations and biological fluids with satisfactory results. The accuracy of the method, evaluated through the RMSEP, was 0.5801 for captopril with best calibration curve by PARAFAC and 0.6168 for captopril with PLS at pH 2.0 model.
2007, 18(4): 431-434
doi: 10.1016/j.cclet.2007.02.018
Abstract:
A flow injection irreversible biamperometric method for the determination of chlorogenic acid is described. The proposed method is based on the electrochemical oxidation of chlorogenic acid at pretreated platinum electrode and the reduction of permanganate at another electrode to form an irreversible biamperometric detection system. Under the external potential difference(△E) of 0 V, in the 0.05 mol/L sulfuric acid, chlorogenic acid can be determined over the range 0.8-120 mg/L with a sample measurement frequency of 80 samples/h. The detection limit is 0.18 mg/L. The proposed method exhibits the satisfactory reproducibility with a relative standard derivation (R.S.D.) of 2.21% for 19 successive determinations of 40 mg/L.
A flow injection irreversible biamperometric method for the determination of chlorogenic acid is described. The proposed method is based on the electrochemical oxidation of chlorogenic acid at pretreated platinum electrode and the reduction of permanganate at another electrode to form an irreversible biamperometric detection system. Under the external potential difference(△E) of 0 V, in the 0.05 mol/L sulfuric acid, chlorogenic acid can be determined over the range 0.8-120 mg/L with a sample measurement frequency of 80 samples/h. The detection limit is 0.18 mg/L. The proposed method exhibits the satisfactory reproducibility with a relative standard derivation (R.S.D.) of 2.21% for 19 successive determinations of 40 mg/L.
2007, 18(4): 435-436
doi: 10.1016/j.cclet.2007.01.015
Abstract:
The reaction of 1,3-dipropyn-2-yloxycalix[4]arene with mercury(Ⅱ) acetate could give mercury-containing alkynyl calixarene polymer. The extraction behavior of 1,3-dipropyn-2-yl-oxycalix[4]arene towards mercury(Ⅱ) ion was examined. When the mole ratio of Hg2+/calixarene was 1:1, the extractive percent can reach to 99.1%, and the extraction capacity was up to 431 mg/g. It could also decrease the Hg2+ concentration from 5 to 0.85 mg/L, which was only 17% of the national standard of effluent and satisfied the national standard of drinking water. The extraction process included chemical reaction.
The reaction of 1,3-dipropyn-2-yloxycalix[4]arene with mercury(Ⅱ) acetate could give mercury-containing alkynyl calixarene polymer. The extraction behavior of 1,3-dipropyn-2-yl-oxycalix[4]arene towards mercury(Ⅱ) ion was examined. When the mole ratio of Hg2+/calixarene was 1:1, the extractive percent can reach to 99.1%, and the extraction capacity was up to 431 mg/g. It could also decrease the Hg2+ concentration from 5 to 0.85 mg/L, which was only 17% of the national standard of effluent and satisfied the national standard of drinking water. The extraction process included chemical reaction.
2007, 18(4): 437-440
doi: 10.1016/j.cclet.2007.01.030
Abstract:
For the purpose of developing organic photovoltaic devices with good performance characteristics, we have fabricated two devices using 4T-CHO, 5T-CHO and PTCDA. The ITO/4T-CHO/PTCDA/A1 device has a Voc of 2.45 V and photoelectric conversion efficiency of 2.76%. The ITO/5T-CHO/PTCDA/Al device has a Voc of 2.1 3V and photoelectric conversion efficiency of 2.90%. The two devices have higher Voc (2.45 and 2.13 V). It is possible that intermolecular hydrogen bonding between -CHO group of nT-CHO and carboxylic dianhydride of PTCDA contribute to enhance the efficiency by promoting interfacial electron transfer and eliminating the subconducting band trap sites.
For the purpose of developing organic photovoltaic devices with good performance characteristics, we have fabricated two devices using 4T-CHO, 5T-CHO and PTCDA. The ITO/4T-CHO/PTCDA/A1 device has a Voc of 2.45 V and photoelectric conversion efficiency of 2.76%. The ITO/5T-CHO/PTCDA/Al device has a Voc of 2.1 3V and photoelectric conversion efficiency of 2.90%. The two devices have higher Voc (2.45 and 2.13 V). It is possible that intermolecular hydrogen bonding between -CHO group of nT-CHO and carboxylic dianhydride of PTCDA contribute to enhance the efficiency by promoting interfacial electron transfer and eliminating the subconducting band trap sites.
2007, 18(4): 441-444
doi: 10.1016/j.cclet.2007.01.012
Abstract:
An ss-DNA gold chip was prepared based on self-assembly of the thiol-derivatized oligonucleotide, and used for the determination of single-stranded binding protein (SSB) by surface plasmon resonance microscopy (SPR). The experiment results showed that SSB binds ss-DNA with high specificity, and relative signal of SPR response is proportional to the concentration of SSB in the range of 0.1-100 ng/mL with a detection limit (S/N=3) of 0.07 ng/mL.
An ss-DNA gold chip was prepared based on self-assembly of the thiol-derivatized oligonucleotide, and used for the determination of single-stranded binding protein (SSB) by surface plasmon resonance microscopy (SPR). The experiment results showed that SSB binds ss-DNA with high specificity, and relative signal of SPR response is proportional to the concentration of SSB in the range of 0.1-100 ng/mL with a detection limit (S/N=3) of 0.07 ng/mL.
2007, 18(4): 445-448
doi: 10.1016/j.cclet.2007.01.005
Abstract:
The pyrolysis of biomass is a promising way for production of bio-gasoline if the stability and quality problems of the bio-crudeoil can be solved by catalytic cracking and reforming. In this paper, an on-line infrared spectrum was used to study the characteristics of catalytic pyrolysis with the following preliminary results. The removal of C=O of organic acid is more difficult than that of aldehydes and ketones. HUSY/γ-Al2O3 and REY/γ-Al2O3 catalysts exhibited better deoxygenating activities while HZSM-5/γ-Al2O3 catalyst exhibited preferred selectivities for production of iso-alkanes and aromatics. Finally, possible mechanisms of biomass catalytic pyrolysis are discussed as well.
The pyrolysis of biomass is a promising way for production of bio-gasoline if the stability and quality problems of the bio-crudeoil can be solved by catalytic cracking and reforming. In this paper, an on-line infrared spectrum was used to study the characteristics of catalytic pyrolysis with the following preliminary results. The removal of C=O of organic acid is more difficult than that of aldehydes and ketones. HUSY/γ-Al2O3 and REY/γ-Al2O3 catalysts exhibited better deoxygenating activities while HZSM-5/γ-Al2O3 catalyst exhibited preferred selectivities for production of iso-alkanes and aromatics. Finally, possible mechanisms of biomass catalytic pyrolysis are discussed as well.
2007, 18(4): 449-451
doi: 10.1016/j.cclet.2007.02.014
Abstract:
A new method for the determination of antithrombotic activity of egg white protein hydrolysate (EWPH) was developed using a microplate reader. Reaction was carried out at 37℃ and pH 7.2 with fibrinogen concentration 0.1%. Microplate reading was conducted at 405 nm. Inhibition rate of EWPH on thrombin activity showed linearity (R2=0.9971), when the inhibition rate was in the range of 10-90%. The lower limit of detection (LLD, at 99.7% probability) and the biological limit of detection (BLD, at 99.7% probability) of the method were 10.643 and 40 mg/mL, respectively. The repeatability standard deviation (R.S.D.) was 1.08%. The standard deviation of the method was±0.027 AT-U.
A new method for the determination of antithrombotic activity of egg white protein hydrolysate (EWPH) was developed using a microplate reader. Reaction was carried out at 37℃ and pH 7.2 with fibrinogen concentration 0.1%. Microplate reading was conducted at 405 nm. Inhibition rate of EWPH on thrombin activity showed linearity (R2=0.9971), when the inhibition rate was in the range of 10-90%. The lower limit of detection (LLD, at 99.7% probability) and the biological limit of detection (BLD, at 99.7% probability) of the method were 10.643 and 40 mg/mL, respectively. The repeatability standard deviation (R.S.D.) was 1.08%. The standard deviation of the method was±0.027 AT-U.
2007, 18(4): 452-454
doi: 10.1016/j.cclet.2007.02.009
Abstract:
A rapid and sensitive method for the analysis of three catecholamines by capillary electrophoresis (CE) with direct chemiluminescence (CL) detection is described. The detection limits (S/N=3) were 1.3×10-8 g/mL for isoprenaline,1.0×10-8 g/mL for epinephrine and 2.8×10-8 g/mL for dopamine. The proposed method was successfully applied to the analysis of catecholamines in urine samples of cigarette smokers and nonsmokers. The results showed that there is a close relation between the release of dopamine in human body fluids and cigarette smoking/nonsmoking.
A rapid and sensitive method for the analysis of three catecholamines by capillary electrophoresis (CE) with direct chemiluminescence (CL) detection is described. The detection limits (S/N=3) were 1.3×10-8 g/mL for isoprenaline,1.0×10-8 g/mL for epinephrine and 2.8×10-8 g/mL for dopamine. The proposed method was successfully applied to the analysis of catecholamines in urine samples of cigarette smokers and nonsmokers. The results showed that there is a close relation between the release of dopamine in human body fluids and cigarette smoking/nonsmoking.
2007, 18(4): 455-457
doi: 10.1016/j.cclet.2007.01.039
Abstract:
Novel NaA/carbon nanocomposite thin films were successfully prepared on a porous α-Al2O3 substrate by incorporating nanosized NaA zeolite into novolak-type phenolic resin. The prepared films were characterized by XRD, SEM and single gas permeation tests. The NaA zeolite/carbon nanocomposite thin films exhibited that the ideal separation factor of CO2/CH4 was 28.4and the carbon dioxide flux was 3.39×10-7 mol/(Pa m2 s) at room temperature and under a pressure difference of 100 kPa, which was two orders of magnitude higher than that of pure carbon membrane prepared at the same procedures and conditions as those of composite films. From the SEM images, the films were continuous and highly intergrown. Compared with carbon membranes, the thickness of nanocomposite films was drastically decreased, which was helpful to reduce the diffusion resistance and increase the flux of gas permeance.
Novel NaA/carbon nanocomposite thin films were successfully prepared on a porous α-Al2O3 substrate by incorporating nanosized NaA zeolite into novolak-type phenolic resin. The prepared films were characterized by XRD, SEM and single gas permeation tests. The NaA zeolite/carbon nanocomposite thin films exhibited that the ideal separation factor of CO2/CH4 was 28.4and the carbon dioxide flux was 3.39×10-7 mol/(Pa m2 s) at room temperature and under a pressure difference of 100 kPa, which was two orders of magnitude higher than that of pure carbon membrane prepared at the same procedures and conditions as those of composite films. From the SEM images, the films were continuous and highly intergrown. Compared with carbon membranes, the thickness of nanocomposite films was drastically decreased, which was helpful to reduce the diffusion resistance and increase the flux of gas permeance.
2007, 18(4): 458-460
doi: 10.1016/j.cclet.2007.02.013
Abstract:
ZrCl4/Hantzsch 1,4-dihydropyridine is a mild and highly efficient reagent combination for the direct reductive amination.Weakly basic amines such as anilines substituted by electron-withdrawing group and heteroaromatic amines can be reductivelyalkylated with electron rich aldehydes and ketones under mild conditions to form the secondary amines in excellent yields.
ZrCl4/Hantzsch 1,4-dihydropyridine is a mild and highly efficient reagent combination for the direct reductive amination.Weakly basic amines such as anilines substituted by electron-withdrawing group and heteroaromatic amines can be reductivelyalkylated with electron rich aldehydes and ketones under mild conditions to form the secondary amines in excellent yields.
2007, 18(4): 461-464
doi: 10.1016/j.cclet.2007.02.010
Abstract:
Three novel chiral selectors 4a-c were synthesized from (S)-amino acids and (R)-1-phenyl-2-(4-methylphenyl)ethylamine. 4a-c were connected to 3-aminopropylsilanized silica gel to be used as the chiral stationary phase for HPLC. Five amino acid derivatives and two pyrethroid insecticides were fairly resolved on these three new chiral stationary phases under normal phase condition.
Three novel chiral selectors 4a-c were synthesized from (S)-amino acids and (R)-1-phenyl-2-(4-methylphenyl)ethylamine. 4a-c were connected to 3-aminopropylsilanized silica gel to be used as the chiral stationary phase for HPLC. Five amino acid derivatives and two pyrethroid insecticides were fairly resolved on these three new chiral stationary phases under normal phase condition.
2007, 18(4): 465-468
doi: 10.1016/j.cclet.2007.01.040
Abstract:
Nanofibers of poly(vinyl pyrrolidone) (PVP)/Eu3+ with diameters of 300-900 nm were prepared by using sol-gel processing and electrospinning technique. The products were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), and photoluminescence (PL). The results indicated that, Eu3+ was successfully embedded in the onedimensional hybrid nanofibers, and the PVP/Eu3+ hybrid nanofibers had favorable photoluminescence properties.
Nanofibers of poly(vinyl pyrrolidone) (PVP)/Eu3+ with diameters of 300-900 nm were prepared by using sol-gel processing and electrospinning technique. The products were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), and photoluminescence (PL). The results indicated that, Eu3+ was successfully embedded in the onedimensional hybrid nanofibers, and the PVP/Eu3+ hybrid nanofibers had favorable photoluminescence properties.
2007, 18(4): 469-472
doi: 10.1016/j.cclet.2006.12.033
Abstract:
A novel multifunctional epoxy resin was synthesized by polyphenol and epichlorohydrin. The structure and molecular weight of the multifunctional epoxy were characterized by FTIR and ESI-MS. DSC and DMTA were used to investigate the thermal property of multifunctional epoxy cured by DDS. The thermal resistance of the synthesized multifunctional epoxy was much better than a standard diglycidyl ether of bisphenol-A epoxy.
A novel multifunctional epoxy resin was synthesized by polyphenol and epichlorohydrin. The structure and molecular weight of the multifunctional epoxy were characterized by FTIR and ESI-MS. DSC and DMTA were used to investigate the thermal property of multifunctional epoxy cured by DDS. The thermal resistance of the synthesized multifunctional epoxy was much better than a standard diglycidyl ether of bisphenol-A epoxy.
2007, 18(4): 473-475
doi: 10.1016/j.cclet.2007.02.004
Abstract:
Photodegradation of nonylphenol ethoxylates (NP10EO) was investigated in laboratory scale under UV irradiation. The intermediate photodegradation products were analyzed by LC-ESI-MS. Three kinds of intermediate products including aldehydic compounds, carboxylic compounds and cyclohexanyl compounds were identified. Five main degradation routes involving the oxidation of the alkyl chain and ethoxylate unit, shortening of the alkyl chain and ethoxylate unit, hydrogenation of the benzene ring were proposed.
Photodegradation of nonylphenol ethoxylates (NP10EO) was investigated in laboratory scale under UV irradiation. The intermediate photodegradation products were analyzed by LC-ESI-MS. Three kinds of intermediate products including aldehydic compounds, carboxylic compounds and cyclohexanyl compounds were identified. Five main degradation routes involving the oxidation of the alkyl chain and ethoxylate unit, shortening of the alkyl chain and ethoxylate unit, hydrogenation of the benzene ring were proposed.
2007, 18(4): 476-478
doi: 10.1016/j.cclet.2007.01.043
Abstract:
A promising catalyst, KNaY was prepared by an ion exchange method with aqueous potassium chloride solution. Compared with NaY, KNaY was an effective catalyst for the dehydration of methyl lactate to methyl acrylate. Under the optimized conditions,an improved yield of 37.9 mol% was achieved.
A promising catalyst, KNaY was prepared by an ion exchange method with aqueous potassium chloride solution. Compared with NaY, KNaY was an effective catalyst for the dehydration of methyl lactate to methyl acrylate. Under the optimized conditions,an improved yield of 37.9 mol% was achieved.
2007, 18(4): 479-482
doi: 10.1016/j.cclet.2007.01.044
Abstract:
The Pd-promoted Ga/HZSM-5 catalyst was prepared by impregnation method and its catalytic activity for non-oxidative aromatization of C1 to C3 hydrocarbons was assessed using a microreactor-GC system operated with temperature at 823 K and space velocity at 410 h-1. The catalyst is more catalytically active for methane conversion than Ga/HZSM-5. The mass spectroscopy analyses confirmed that 13CH4 was converted to aromatic products.
The Pd-promoted Ga/HZSM-5 catalyst was prepared by impregnation method and its catalytic activity for non-oxidative aromatization of C1 to C3 hydrocarbons was assessed using a microreactor-GC system operated with temperature at 823 K and space velocity at 410 h-1. The catalyst is more catalytically active for methane conversion than Ga/HZSM-5. The mass spectroscopy analyses confirmed that 13CH4 was converted to aromatic products.
2007, 18(4): 483-486
doi: 10.1016/j.cclet.2007.02.002
Abstract:
ZnS nanoparticles were prepared with normal ZnO and Na2S by solid-liquid chemical reaction under ultrasonic condition and characterized by XRD, TEM, SEM, IR and TG-DTG. The results showed that these particles were good crystal cubic zinc blended with average size of 50 nm, possess good IR transmittance in the range of 400-4000 cm and good thermal stability.
ZnS nanoparticles were prepared with normal ZnO and Na2S by solid-liquid chemical reaction under ultrasonic condition and characterized by XRD, TEM, SEM, IR and TG-DTG. The results showed that these particles were good crystal cubic zinc blended with average size of 50 nm, possess good IR transmittance in the range of 400-4000 cm and good thermal stability.
2007, 18(4): 487-490
doi: 10.1016/j.cclet.2007.01.042
Abstract:
Carbon encapsulated magnetic nanoparticles (CEMNs) were synthesized by heating an aqueous glucose solution containing Fe-Au (Au coated Fe nanoparticles) nanoparticles at 160-180℃ for 2 h. This novel hydrothermal approach is not only simple but also provides the surface of CEMNs with functional groups like -OH. The formation of carbon encapsulated magnetic nanoparticles was not favored when using pure Fe nanoparticles as cores because of the oxidation of Fe nanoparticles by H2O during the reaction and,therefore, the surfaces of the naked Fe nanoparticles had to be coated by Au shell in advance. TEM, XRD, XPS and VSM measurments characterized that they were uniform carbon spheres containing some embedded Fe-Au nanoparticles, with a saturation of 14.6 emu/g and the size of the typical product is~350 nm.
Carbon encapsulated magnetic nanoparticles (CEMNs) were synthesized by heating an aqueous glucose solution containing Fe-Au (Au coated Fe nanoparticles) nanoparticles at 160-180℃ for 2 h. This novel hydrothermal approach is not only simple but also provides the surface of CEMNs with functional groups like -OH. The formation of carbon encapsulated magnetic nanoparticles was not favored when using pure Fe nanoparticles as cores because of the oxidation of Fe nanoparticles by H2O during the reaction and,therefore, the surfaces of the naked Fe nanoparticles had to be coated by Au shell in advance. TEM, XRD, XPS and VSM measurments characterized that they were uniform carbon spheres containing some embedded Fe-Au nanoparticles, with a saturation of 14.6 emu/g and the size of the typical product is~350 nm.
2007, 18(4): 491-494
doi: 10.1016/j.cclet.2007.01.041
Abstract:
The Gd(OH)3 nanorods with diameters of ca. 40-60 nm and lengths of more than 400-550 nm have been prepared by a novel hydrothermal technique. The structural features and chemical composition of the nanorods were investigated by X-ray diffraction(XRD), transmission electron microscopy (TEM), and field emission scanning electron microscope (FESEM), selected area electron diffraction (SAED), and high resolution transmission electron microscopy (HRTEM). The possible mechanism for the formation of Gd(OH)3 nanorods was proposed.
The Gd(OH)3 nanorods with diameters of ca. 40-60 nm and lengths of more than 400-550 nm have been prepared by a novel hydrothermal technique. The structural features and chemical composition of the nanorods were investigated by X-ray diffraction(XRD), transmission electron microscopy (TEM), and field emission scanning electron microscope (FESEM), selected area electron diffraction (SAED), and high resolution transmission electron microscopy (HRTEM). The possible mechanism for the formation of Gd(OH)3 nanorods was proposed.
2007, 18(4): 495-498
doi: 10.1016/j.cclet.2007.02.003
Abstract:
Non-negative matrix factorization (NMF) is a technique for dimensionality reduction by placing non-negativity constraints on the matrix. Based on the PARAFAC model, NMF was extended for three-dimension data decomposition. The three-dimension nonnegative matrix factorization (NMF3) algorithm, which was concise and easy to implement, was given in this paper. The NMF3 algorithm implementation was based on elements but not on vectors. It could decompose a data array directly without unfolding,which was not similar to that the traditional algorithms do. It has been applied to the simulated data array decomposition and obtained reasonable results. It showed that NMF3 could be introduced for curve resolution in chemometrics.
Non-negative matrix factorization (NMF) is a technique for dimensionality reduction by placing non-negativity constraints on the matrix. Based on the PARAFAC model, NMF was extended for three-dimension data decomposition. The three-dimension nonnegative matrix factorization (NMF3) algorithm, which was concise and easy to implement, was given in this paper. The NMF3 algorithm implementation was based on elements but not on vectors. It could decompose a data array directly without unfolding,which was not similar to that the traditional algorithms do. It has been applied to the simulated data array decomposition and obtained reasonable results. It showed that NMF3 could be introduced for curve resolution in chemometrics.
