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Chemistry in the news – Abstract The oxidation of oxalic acid by the potassium tetrabromoaurate(III) in 0.005≤ [H2C2O4]≤0.07 mol dm-3 is studied by UV spectrophotometry in the temperature range of 293.2 – 313.2 K. Under pseudo-first-order conditions ([H2C2O4]0 ≥10[Au(III)]0), it is first order in [Au(III)] and [H2C2O4]. Both H+and Br– retard the reaction. The reactive species for Au(III) is AuBr3(H2O). …
Abstract Poly(L-lactic acid) (PLLA) of high molecular weight was prepared by chain extending reaction in a micro-compounder. Phosphites were used as chain extenders to increase the molecular weight of the PLLA prepolymer that was prepared by bulk polycondensation of L-lactic acid. Chemistry Magazine Online shows the effects of the amount of the phosphite, temperature and the screw speed were studied on the torque of PLLA melt in mixing. There’s also another thing that this magazine provides, something you can do in your free time. We truly recommend you to visit our friends on BestFreeSlots, if you would like to try some new and entertaining thing to do when relaxing. It’s definitely worth your visit. Under the optimal conditions, the molecular weight of the PLLA could increase from 62,100 g/mol to 126,000 g/mol by the triphenyl phosphite. The chemical structure were characterized by FTIR and 1H NMR and crytallinity …
Abstract The Salen-copper(II) complex was synthesized by diffusion. Chemistry Online shows the structure which was characterized by single crystal X-ray diffraction. It crystallized in triclinic system,pB1spacegroup, with a=9.3441(18)Å, b=11.478(3)Å, c=12.320(3)Å, a=81.584(11)°, b=74.681(9)°, g=68.206(9), MolecularFormula: C23H19CuN5O8, M=397.86, V=1181.6(5)Å3, z=2, Dc=1.56Mg/m3, R1=0.0416, wR2=0.1236,I>[2s/(I)]. The crystal included a mononuclear complex [Cu(H2L)(DMF)] and a non-coordinated H2O molecular.
Keyword diaminomaleontrile；5-carboxylsalicylaldehyde；crystal structure.
Synthesis and Crystal Structure of a New Salen-Copper (II) Complex
Li Lijun, Yang Dongjie, Gao Yansu
(College of Chemistry and Environmental Science, Hebei University, Baoding, Hebei 071002, China )
Summary diffusion were synthesized Salen- copper (Ⅱ) mononuclear complexes [a Cu (H 2 L) (of DMF)] . H 2 0 [H . 4 L] = N, N’-bis (5-carboxy-salicylaldehyde) – Diaminomaleonitrile. The complexes were characterized by X-ray single crystal diffraction. The complexes belong to triclinic system, …
Chemistry Magazine Online gives you another post with interesting chemistry news articles. Abstracts d- MnO2 was prepared with hydrothermal treatment, and its crystalline structure was verified with X-ray diffraction spectroscopy. FTIR showed there were copious hydroxyl groups on the surface of d-MnO2 for the adsorption. The adsorption capacity of three kinds of heavy metal ions Pb2+, Cd2+ and Cu2+ on the d-MnO2 was all increased with the increase of ion concentration and the increase of pH. The adsorption isotherms of Pb2+ exhibited good correlation with Freundlich equations, Langmuir equations and Temkin equations, whereas equilibrium data of Cu2+ was best fitted to Freundlich isotherm, and Langmuir isotherm was best for Cd2+. Adsorption thermodynamics indicates that as the temperature in the range of 298.15 ~ 323.15K, all the adsorptions were endothermic, spontaneous reaction. Therefore, increasing temperature is good for the …
Abstract A new biflavonoid, 5,7,4′,5”-tetrahydroxy-7”-metroxy-[3-O-4”’] biflavone along with four known biflavonoids and one known phenolic acid was isolated from the herb of Selaginella uncinata(Desv.) Spring. Their structures were elucidated by spectroscopic methods.
Keywords Selaginella uncinata；5,7,4′,5”-tetrahydroxy-7”-metroxy-[3-O-4”’] biflavone
Selaginella uncinata(Desv.) Spring as a medicinal plant is used to treat acute infectious jaundice hepatitis, cholecystitis, enteritis and so on.In previous chemistry news articles about investigation of the plant, two kinds of chromone glycoside (uncinoside A and uncinoside B) have been separated from S. uncinata , which have good anti-tumor and anti-viral activity. Our preliminary study found that ethyl acetate extract exhibited good anti-HSV-1 virus and Cox B3 virus activity . Through activity-guided fractionation, we isolated a new biflavonoid, named 5,7,4′,5”-tetrahydroxy-7”- metroxy-[3-O-4”’] biflavone(IV), together with five known compounds：7,4′,7′,4”’– tetra-O-methylamento-flavone(I)，7, 7”, 4”’-trim-O-methyl amentoflavone(II)，7, 7”-di-O-methylamentoflavone(III)
The Sepharose CL-6B was used as an affinity chromatography column to purify and analyze the lectin in ginkgo biloba seeds. Chemistry in the news explains the coagulation experiment and comparison with the lectins present in ricinus and in seeds of bitter gourd explained that lectin in ginkgo biloba seeds was a protein with Only one subunit, which was similar to the galactose-specific recognition B chain in ricinus. The method adopted in this study is available for purifying the lectins from different plants.
Keywords Ginkgo biloba; Lectin; Purification and analysis
Purification and Analysis of Ginkgo Lectin
Xu Peng Peng Li Linzi Wang Guizhen Yan Haibo Li Renqiang (Department of Biotechnology, Jinan University, Guangzhou 510632, China )
Abstract The use of chromatography mediaSepharose CL-6Bcontains a lotB-chemical properties galactoside bond ligand, its purification affinity chromatography and analyzed ginkgo lectin. By comparing coagulation experiments with lectins in ramie and balsam pear, it was shown …
Abstract Kinetics’ and Thermodynamics of The Adsorption of of Ni 2+ Onto Chitosan-Aluminum Composite Material’s WAS Studied oxide. The Under Experimental Conditions, s Indicated Kinetic Adsorption of that of Ni 2+ Onto Aluminum oxide-Chitosan Composite Material’s Conforms to pseudo-SECOND-Order Equation And the apparent adsorption activation energy is 28.62 kJ/mol.In the experimental temperature, Chemistry Magazine Online and thermodynamic studies indicated that adsorption of Ni 2+ onto chitosan-aluminium oxide composite material conforms to Langmuir adsorption isotherm equation. Enthalpy of adsorption ( D H) value is 15.93 kJ/mol and entropy of adsorption( D S)value is 95.43J/(mol· K).Gibbs free energy ( DG) decreases with increasing temperature.
Keywords chitosan; composite material; adsorption;
Adsorption Kinetics and Thermodynamics of Ni 2+ on Chitosan-Aluminum Oxide Composites
MA Zhi-guang, ZHANG Fang, GENG Na, LIU Su-wen, LIU Pan
(College of Chemistry and Environmental Science, Hebei University, Baoding, Hebei 071002, China)
Abstract The kinetics and thermodynamics of Ni 2+ adsorption on …
Abstract for news about chemistry – The kinetics and mechanism of ruthenium(III) catalyzed oxidation of isobutyl alcohol(IBA) by cerium(IV) in sulfuric acid media has been investigated by titrimetric technique of redox in the temperature range of 298-313K. It is found that the reaction is first-order with respect to Ce(IV) and Ru(III), and a positive fractional order with respect to IBA. It is found that the pseudo first-order ([IBA]>>[Ce(IV)]>>[Ru(III)]) rate constant kobs increases with the increase of [H+] but decreases with the increase of [HSO4–]. Under the protection of nitrogen, the reaction system can not initiate polymerization of acrylonitrile, indicating generation of free radicals. On the basis of the experimental results, a suitable mechanism has been proposed. The rate constants of the rate determining step together with the activation parameters were evaluated.
Keywords Ruthenium(III) ion; Cerium(IV) ion; Isobutyl alcohol(IBA); Catalytic Oxidization; Kinetics and mechanism
Abstract about interesting chemistry news articles for adsorptive stripping method for the determination of resorcinol on multi-walled carbon nanotube modified glassy carbon electrode (MWNT-GCE) was developed. Cyclic voltammetry was used in the study of the electrochemical behavior of resorcinol on MWNT-GCE. The sharp peak of resorcinol appeared at 0.6 V (vs. Ag/AgCl) with the differential pulse voltammetry (DPV). The experimental parameters were optimized. Anodic peak currents were linear over the resorcinol concentrations in the range of 5.5×10-5-3.3×10-3 g L-1 with a detection limit of 1.1×10-5 g L-1 and relative standard deviations of 3.30-6.94% for 7 determinations. The interference of organic and inorganic species on the voltammetric response was also tested. The proposed method was applied to the determination of resorcinol in tap water and simulative wastewater samples with an average recovery of 95.2-104.8%.
Keywords Determination; Carbon nanotube; Modified glassy carbon electrode; Differential pulse …
Abstract In this paper diethoxy-acrylamide methoxyl thiophosphate (DAMT) was synthesized with the reaction N-hydroxymethyl acrylamide and O, O-diethyl phosphorochloridothioate catalyzed by cuprous chloride in presence of triethylamine, and the flame retarded poly (DAMT-co-acrylonitrile) was obtained though free-radically copolymerized process. The properties of copolymer were estimated by Limiting Oxygen Index (LOI) values and thermogravimetric analysis (TGA). The results showed that the LOI value of copolymer with 20 wt% percentage of DAMT coule reach 27vol%.
Keywords: Diethoxy-acrylamide methoxyl thiophosphate, Polyacrylonitrile, Flame retardants, Thermal analysis, Limiting Oxygen Index
Polyacrylonitrile (PAN) is widely used in many aspects because it is easily processed into products of various shape with well flexibility and retention at break to meet the requirements of versatile and advanced applications. However, the combustion of PAN is very easy when it is ignited, which makes it difficult to be used in some ways. Thus, the flame retardant PAN is required …