2007 Volume 18 Issue 4

Synthesis of two derivatives of tigogenyl disaccharides containing N-acetylglucosamine and the long range shielding effect of benzoyl groups
Shu Jie Hou , Liang Zhou , Ping Sheng Lei , De Quan Yu
2007, 18(4): 373-376  doi: 10.1016/j.cclet.2007.02.012
[Abstract](157) [FullText HTML] [PDF 240KB](0)
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.
Solid-phase synthesis of (Z)-allyl iodides from 3-acetoxy-2-methylene-alkanoates with recyclable polymer-supported selenium bromide
Shou Ri Sheng , Ming Gang Hu , Qin Xin , Xiao Ling Liu , Xian Huang
2007, 18(4): 377-379  doi: 10.1016/j.cclet.2007.01.045
[Abstract](158) [FullText HTML] [PDF 249KB](1)
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.
Synthesis of 2-aryl-5-alkyl-7-methoxylbenzo[b]furan derivatives
Xue Fei Yan , Ling Yi Kong
2007, 18(4): 380-382  doi: 10.1016/j.cclet.2007.01.018
[Abstract](157) [FullText HTML] [PDF 476KB](0)
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.
Pd(OAc)2 catalyzed synthesis of heteroaryl-substituted 1,8-naphthyridine derivatives via C-N-coupling reactions of chloronaphthyridines
Shou Wen Jin , Bin Liu , Wan Zhi Chen
2007, 18(4): 383-386  doi: 10.1016/j.cclet.2007.01.024
[Abstract](168) [FullText HTML] [PDF 343KB](0)
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.
A facile approach to asymmetrical biaryls via coupling reaction of aryl halides with sodium tetraphenylborate catalyzed by MCM-41-supported sulfur palladium(0) complex
Qiu Hua Xu , Ping Ping Wang , Ming Zhong Cai
2007, 18(4): 387-389  doi: 10.1016/j.cclet.2007.01.046
[Abstract](170) [FullText HTML] [PDF 202KB](0)
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.
Microwave-prompted rapid and efficient synthesis of 3-alkyl substituted imidazo[1,5-a] pyridines
Lai Bao Wang , Jia Pan , Can Ling Tang , Xiu Ren Bu , Jie Wang
2007, 18(4): 390-392  doi: 10.1016/j.cclet.2007.02.015
[Abstract](161) [FullText HTML] [PDF 214KB](0)
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.
An efficient way to coupling amine with derivatives of steric N-Boc-pyrrolidine-2-carboxylic acid
Feng Zhi Liu , Hao Fang , Wen Fang Xu
2007, 18(4): 393-396  doi: 10.1016/j.cclet.2007.01.048
[Abstract](157) [FullText HTML] [PDF 356KB](0)
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.
Novel synthesis of a strained para-cyclophane derivative
Zhi Hao Shi , Yun Yang Wei
2007, 18(4): 397-399  doi: 10.1016/j.cclet.2007.02.006
[Abstract](169) [FullText HTML] [PDF 235KB](4)
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.
Synthesis of a new series of anti-rhinovirus compounds
Shi Yong Fan , Chun Lai Mi , Jun Yang , Song Li , Zhi Bing Zheng
2007, 18(4): 400-402  doi: 10.1016/j.cclet.2007.02.008
[Abstract](156) [FullText HTML] [PDF 182KB](0)
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.
Synthesis and characterization of a novel series of pyrimidinylthiaalkoxycalix[4]arenes
Bing Zhao , Ya Qing Feng , Yu Kun Li
2007, 18(4): 403-406  doi: 10.1016/j.cclet.2007.02.007
[Abstract](161) [FullText HTML] [PDF 217KB](0)
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 convenient synthesis of 6-demethoxycapillarisin
Yuan Feng Tong , Shuai Chen , Yong Hao Cheng , Song Wu
2007, 18(4): 407-408  doi: 10.1016/j.cclet.2007.01.049
[Abstract](157) [FullText HTML] [PDF 189KB](0)
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.
Two new C18-norditerpenoid alkaloids from Aconitum delavayi
Shan Hao Jiang , Hai Qing Wang , Yi Ming Li , Shuang Jun Lin , Jun Jie Tan , Da Yuan Zhu
2007, 18(4): 409-411  doi: 10.1016/j.cclet.2007.01.031
[Abstract](160) [FullText HTML] [PDF 210KB](0)
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.
New anthraquinone derivatives from the roots of Berchemia floribunda
Xin Wei , Jian Shuang Jiang , Zi Ming Feng , Pei Cheng Zhang
2007, 18(4): 412-414  doi: 10.1016/j.cclet.2007.02.001
[Abstract](160) [FullText HTML] [PDF 246KB](0)
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 C21-steroidal glycoside from Cynanchum stauntonii
Mei Hong Fu , Zhu Ju Wang , Hong Jun Yang , Mayila Maimai , Jing Fang , Li Ying Tang , Lan Yang
2007, 18(4): 415-417  doi: 10.1016/j.cclet.2007.01.047
[Abstract](163) [FullText HTML] [PDF 214KB](0)
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 cycloartane triterpenoid from the leaves and stems of Fritillaria hupehensis
Hui Fang Pi , Peng Zhang , Tian Zhu , Han Li Ruan , Yong Hui Zhang , Han Dong Sun , Ji Zhou Wu
2007, 18(4): 418-420  doi: 10.1016/j.cclet.2007.02.005
[Abstract](162) [FullText HTML] [PDF 207KB](0)
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.
Design,synthesis of novel antifungal triazole derivatives with high activities against Aspergillus fumigatus
Qiu Qin He , Chao Mei Liu , Ke Li , Yong Bing Cao
2007, 18(4): 421-423  doi: 10.1016/j.cclet.2007.02.011
[Abstract](158) [FullText HTML] [PDF 226KB](0)
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.
Study on the effects of cefotaxime on intracellular Ca2+ in human peripheral lymphocytes by fluoremetry
Dan Dan Wang , Hai Yan Wang , Ye Hong Zhou , Chun Gui Zhao , Chuan Dong , Shao Min Shuang
2007, 18(4): 424-426  doi: 10.1016/j.cclet.2006.12.044
[Abstract](179) [FullText HTML] [PDF 323KB](0)
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.
Determination of captopril in pharmaceutical preparation and biological fluids using two- and three-way chemometrics methods
Nahid Ghasemi , Ali Niazi
2007, 18(4): 427-430  doi: 10.1016/j.cclet.2007.02.019
[Abstract](171) [FullText HTML] [PDF 262KB](0)
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.
Determination of chlorogenic acid by flow injection irreversible biamperometry
Li Jun Li , Qi Feng Chen , Lai Bo Yu , Zhao Heng Zhong , Jun Feng , Hao Cheng , Hong Xing Kong , Jian Ling Wu
2007, 18(4): 431-434  doi: 10.1016/j.cclet.2007.02.018
[Abstract](164) [FullText HTML] [PDF 200KB](0)
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.
High extraction ability of 1,3-dialkynyl calixarene towards mercury(Ⅱ) ion
Lin Bo Gong , Shu Ling Gong , Qin Zheng , Xiong Li , Yuan Yin Chen
2007, 18(4): 435-436  doi: 10.1016/j.cclet.2007.01.015
[Abstract](165) [FullText HTML] [PDF 221KB](0)
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.
Organic photovoltaic devices with high open-circuit voltage based on oligothiophene derivatives
Ping Liu , Jia Le Huang , Wan Zhang Pan , Ming Sheng Huang , Wen Ji Deng , Yu Liang Mai , An Bo Luan
2007, 18(4): 437-440  doi: 10.1016/j.cclet.2007.01.030
[Abstract](163) [FullText HTML] [PDF 275KB](0)
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.
A novel detection of single-stranded DNA binding protein based on ss-DNA modified chip using surface plasmon resonance microscopy
Jian Quan Lu , Ming Bo Xu , Xing Wang Zhou , Jin Guang Xu , Qing Tao
2007, 18(4): 441-444  doi: 10.1016/j.cclet.2007.01.012
[Abstract](150) [FullText HTML] [PDF 253KB](0)
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.
Study on biomass catalytic pyrolysis for production of bio-gasoline by on-line FTIR
Chang Bo Lu , Jian Zhong Yao , Wei Gang Lin , Wen Li Song
2007, 18(4): 445-448  doi: 10.1016/j.cclet.2007.01.005
[Abstract](144) [FullText HTML] [PDF 513KB](0)
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.
A new method for determination of antithrombotic activity of egg white protein hydrolysate by microplate reader
Wan Gen Yang , Zhang Wang , Shi Ying Xu
2007, 18(4): 449-451  doi: 10.1016/j.cclet.2007.02.014
[Abstract](160) [FullText HTML] [PDF 287KB](1)
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.
Capillary electrophoresis with direct chemiluminescence detection for the analysis of catecholamines in human urine
Cheng Quan Wang , Hui Wang , Yan Ming Liu
2007, 18(4): 452-454  doi: 10.1016/j.cclet.2007.02.009
[Abstract](151) [FullText HTML] [PDF 335KB](0)
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.
Novel preparation of NaA/carbon nanocomposite thin films with high permeance for CO2/CH4 separation
Zhi Hui Zhou , Jian Hua Yang , Li Feng Chang , Yan Zhang , Wei Guo Sun , Jin Qu Wang
2007, 18(4): 455-457  doi: 10.1016/j.cclet.2007.01.039
[Abstract](154) [FullText HTML] [PDF 914KB](0)
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.
ZrCl4/Hantzsch 1,4-dihydropyridine as a new and efficient reagent combination for the direct reductive amination of aldehydes and ketones with weakly basic amines
Zhen Gang Liu , Nan Li , Li Yang , Zhong Li Liu , Wei Yu
2007, 18(4): 458-460  doi: 10.1016/j.cclet.2007.02.013
[Abstract](161) [FullText HTML] [PDF 181KB](0)
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.
Synthesis of novel chiral stationary phases for high-performance liquid chromatography
Xu Lin Tan , Shi Cong Hou , Qing Hua Bian , Min Wang
2007, 18(4): 461-464  doi: 10.1016/j.cclet.2007.02.010
[Abstract](149) [FullText HTML] [PDF 287KB](0)
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.
Electrospun nanofibers of poly(vinyl pyrrolidone)/Eu3+ and its photoluminescence properties
Shan Shan Tang , Chang Lu Shao , Shou Zhu Li
2007, 18(4): 465-468  doi: 10.1016/j.cclet.2007.01.040
[Abstract](148) [FullText HTML] [PDF 2378KB](0)
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.
Synthesis and characterization of novel multifunctional epoxy resin
Jue Cheng , Jing Chen , Wan Tai Yang
2007, 18(4): 469-472  doi: 10.1016/j.cclet.2006.12.033
[Abstract](139) [FullText HTML] [PDF 777KB](0)
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.
Mechanism study on UV-induced photodegradation of nonylphenol ethoxylates by intermediate products analysis
Ling Chen , Hai Yun Zhou , Lan Liu , Qin Ying Deng
2007, 18(4): 473-475  doi: 10.1016/j.cclet.2007.02.004
[Abstract](155) [FullText HTML] [PDF 260KB](0)
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.
KNaY-zeolite catalyzed dehydration of methyl lactate
Hai Feng Shi , Yao Chi Hu , Yang Wang , He Huang
2007, 18(4): 476-478  doi: 10.1016/j.cclet.2007.01.043
[Abstract](174) [FullText HTML] [PDF 237KB](0)
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.
Non-oxidative aromatization of C1 to C3 hydrocarbons over Pd-promoted Ga/HZSM-5 catalyst under mild conditions
Xiao Chun Shen , Hui Lou , Kai Hu , Xiao Ming Zheng
2007, 18(4): 479-482  doi: 10.1016/j.cclet.2007.01.044
[Abstract](142) [FullText HTML] [PDF 196KB](0)
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.
A new way to synthesize ZnS nanoparticles
Heng Zhi Zeng , Ke Qiang Qiu , Yuan Yuan Du , Wen Zhang Li
2007, 18(4): 483-486  doi: 10.1016/j.cclet.2007.02.002
[Abstract](152) [FullText HTML] [PDF 1625KB](0)
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.
Carbon encapsulated magnetic nanoparticles produced by hydrothermal reaction
Nong Yue He , Ya Fei Guo , Yan Deng , Zhi Fei Wang , Song Li , Hong Na Liu
2007, 18(4): 487-490  doi: 10.1016/j.cclet.2007.01.042
[Abstract](143) [FullText HTML] [PDF 729KB](0)
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.
Preparation and characterization of gadolinium hydroxide single-crystalline nanorods by a hydrothermal process
Yi Dong Yin , Guang Yan Hong , Bai Fu Xin
2007, 18(4): 491-494  doi: 10.1016/j.cclet.2007.01.041
[Abstract](147) [FullText HTML] [PDF 940KB](1)
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.
A novel trilinear decomposition algorithm:Three-dimension non-negative matrix factorization
Hong Tao Gao , Dong Mei Dai , Tong Hua Li
2007, 18(4): 495-498  doi: 10.1016/j.cclet.2007.02.003
[Abstract](152) [FullText HTML] [PDF 281KB](2)
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.
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