Advanced Materials Research Vols. 233-235

Abstract: Highly uniform and monodisperse comet-likeYF₃:Eu³⁺ nanocrystals has been successfully prepared by a sonochemical method under ambient air without any template. The as-prepared YF₃:Eu³⁺ sample was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) spectra.

Abstract: Support effects of PW/SiO₂ on MPA (p-methoxyacetophenone) synthesis from toluene and acetic anhydride were carefully studied, and catalysts were carefully characterized by BET, XRD and NH₃-TPD. The charactrerized results displayed that the interaction between PW and SiO₂ prevented the loss of acidic protons from PW to form the weak acid PW₁₂O_38.5 over PW/SiO₂. The weak acid site PW₁₂O_38.5 over PW/SiO₂ came into being only in case of much more PW being loaded onto SiO₂, and the appearance of PW₁₂O_38.5 over PW/SiO₂ resulted in MPA yield decline.

Abstract: Disulfides play important roles in biological and chemical processes. Oxidation of thiols is the most exploited method for disulfide synthesis. Trichloromonoxomolybdenum (V) has been found to be a superior oxotransfer reaction catalyst for the conversion of thiols to the corresponding disulfides in excellent yields under mild reaction conditions. A viable kilo-scale synthesis of the symmetrical disulfide was described. Simple workups, economical and practical are the some advantages of this method.

Abstract: A convenient method for the chlorination of p-methoxybenzyl 2-(3- phenylacetamido-4- benzenesulfonylthio-2-azetidinone-1-yl)-3-methyl-3-butenate from penicillin G with sulfuryl chloride ( SO₂Cl₂) , which is subsequently converted to p-methoxybenzyl 2-(3- phenylacetamido-4- benzenesulfonylthio-2-azetidinone-1-yl)-3-chloromethyl-3-butenate, versatile intermediates for the synthesis of cephalosporin antibiotics was developed. The method has the advantage of cheap reagents, mild reaction conditions and convenient operation. The quantity and the feeding rate of the chlorination reagent can be controlled easily. The method is particularly suitable for the chlorination in an industral process.

Abstract: The recent development of carbon fiber sizing agent was introduced in this article. The sizing agent used in carbon fiber was synthesized at a temperature range of 55-60°C using epoxy resin and vinyl acetate as a monomer together, octyl phenol ethoxylated(OP-10) as the emulsion agent, ammonium peroxydisulfate as the solicitation agent and water as the dispersant. At the same time, the optimum composition, the optimum process condition and the effects affecting the emulsion stability were discussed. The characterizations were measured by Scanning Electron Microscopy and TG. The results show that the synthesis process is simple, low cost, less polution and remarkbably stable. The diameter of the particle is 1.8μm and the decomposition temperature is 260°C.

Abstract: Fir char sulfonic acid was prepared by pyrolysis at 350°C and sulfonation from fir processing residues. FT-IR、XRD and XPS analysis showed that fir pyrocarbon retains the benzene ring structure of lignin, with the active hydrogen for sulfonation. And sulfonic groups successfully bonded with the charcoal skeleton. The catalytic properties of fir char sulfonic acid were investigated in the ring-opening addition reactions of styrene oxide with five alcohols. The results showed that fir char sulfonic acid has good catalytic activity in these alcoholysis reactions. The catalyst is also security, stability and environment friendly.

Abstract: 2, 6-Deoxyfructosazine (1) was synthesized from glucose and ammonium formate and isolated from the reaction mixture by membrane technology. The compound was characterized by HRMS, ¹HNMR, and ¹³CNMR. Thermal analysis of the product showed that it began to decompose at 220 °C, and its weight loss was about 50 % at 320 °C. GC/MS analysis of the tobacco smoke showed that it decomposed to produce 2-methylpyrazine, 2, 6-dimethylpyrazine and 2-ethyl-6-methylpyrazine in the smoke upon smoking.

Abstract: The insecticidal and repellent activities of essential oil from leaves of Eucalyptus grandis against Culex pipiens quinquefasciatus were investigated. The essential oil was obtained by hydro-distillation and analyzed by gas chromatography-mass spectrometry (GC-MS). The principal constituents in the essential oil were p-cymene (26.794%), α-pinene (15.864%), eucalyptol (6.281%), α-terpineol (4.100%), limonene (3.614%) and borneol (2.519%). The results indicated that the essential oil of Eucalyptus grandis leaves hold insecticidal and repellent activities against Culex pipiens quinquefasciatus. The complete protection time for people against Culex pipiens quinquefasciatus was correlative with its concentration. It could protect people for 7h when its concentration was 50%. Fumigating insecticidal activity was evaluated by airtight fumigation in conical flask. The LC₅₀ values of the essential oil for adults of Culex pipiens quinquefasciatus were 4.5%(0.5h), 3.6%(1h), 2.6%(2h), 2.1%(4h), 0.56%(8h) and 0.56%(24h). The LT₅₀ value of the essential oil was 19.1 min when its concentration was 6.4%.

Abstract: In this study, the utral-performance liquid chromatography (UPLC) method with UV-PDA was utilized to develop a rapid, sensitive reliable method for analysis of 5 penicillin antibiotics in cosmetics productions which the presence of these penicillin in commercial cosmetics samples is prohibited. The samples was prepared by liquid-liquid extraction and then the analyses was carried out on UPLC-PDA. The chromatographic column used was Acquity UPLC^TM BEH C18 (100 mm ×2.1 mm,1.7μm) and the mobile phase is Acetonitrile and potassium dihydrogen phosphate(PBS) Buffer solution pH 5.5. Chromatographic separation was obtained by gradient elution.

Abstract: The adsorption equilibrium and thermodynamics of pigment extracted from Fenugreek after degumming on macroporous resins was investigated under differentinitial concentrations. The suitability of the Freundlich and Langmuir adsorption models to the equilibrium data was investigated. The model fitness was determined by R² . Thermodynamic parameters were calculated by the Van’t Hof equation.The results showed that Freundlich model gave a better fit of adsorption isotherms than Langmuir models. The positive value of enthalpy(∆H) indicated that the adsorption was endothermic, the negative value of Gibbs free energy (∆G) showed the spontaneous and favoured nature of adsorption, and the entropy(∆S) was positive.The resins LS-46 showed an effective adsorbtion for Fenugreek yellow pigment.