等离子体原子荧光光谱法测定碳酸锂中钠、钾、钙、镁、铜、铁、钴、镍、锰、锌、镉

建立了用ICP-AFS同时测定碳酸锂中11种微量金属杂质元素的方法。加入甲烷可改善检出限,方法简便,样品分析结果与AAS法结果一致。     

气相色谱-质谱联用测定化妆品中硫酸二甲酯与硫酸二乙酯

建立了同时测定化妆品中硫酸二甲酯和硫酸二乙酯的气相色谱-质谱(GC-MS)联用法。样品经溶剂提取后采用GC-MS测定,外标法定量。水基类、乳液类、膏霜类、啫喱类和粉类化妆品的方法检出限均为1.5 mg/kg,定量下限均为5.0 mg/kg;蜡基类化妆品的检出限为3.0 mg/kg,定量下限为10.0 mg/kg;油状化妆品的方法检出限为5.0 mg/kg,定量下限为16.0 mg/kg。目标物在0.25~20.0 mg/L范围内线性良好,相关系数均大于0.99,硫酸二甲酯的平均回收率为83.8%~104.7%,相对标准偏差为2.7%~8.2%;硫酸二乙酯的平均回收率为84.7%~104.8%,相对标准偏差为3.5%~8.7%。方法前处理简单,灵敏度高,可满足水基类、乳液类、膏霜类、啫喱类、粉类和油状化妆品中硫酸二甲酯和硫酸二乙酯的检测要求。     

Optical,thermal and microstructural studies of epoxy-CoSO4.7H2O hybrid material

Organic–inorganic polymer hybrid films of epoxy polymer were prepared, using Cobaltous sulfate heptahydrate (CoSO₄.7H₂O) as a filler component, by physical blending method. UV–Vis optical absorption spectra were analyzed to determine optical band gaps (E_g) of the hybrid material. FTIR studies revealed the interaction of inorganic component with molecules of the polymer matrix. Glass transition temperature (T_g) and degradation temperature were determined by DSC. TG analysis showed the improvement in thermal stability of prepared hybrid films. XRD patterns revealed the amorphous nature of the pure epoxy polymer. Additional sharp peaks were seen for higher filler levels (FLs), indicating self formed nanostructures in the material, which was also evident from SEM analysis.     

Synthesis of Fucosylated Chondroitin Sulfate Nonasaccharide as a Novel Anticoagulant Targeting Intrinsic Factor Xase Complex

Fucosylated chondroitin sulfate (FuCS) is a structurally distinct glycosaminoglycan, and its oligosaccharides exhibit excellent anticoagulant activity with lower risks of adverse effects and bleeding. Herein we report a facile approach to the synthesis of FuCS hexa‐ and nonasaccharides on the basis of the enzymatic degradation of chondroitin over 12 linear steps. As compared with a clinical low‐molecular‐weight heparin drug (enoxaparin), the nonasaccharide synthesized in this study displayed similar APTT activity and selective intrinsic factor Xase complex inhibitory activity ((12.9±0.83) nm ) by binding to factor IXa with high affinity, thus offering promise for the development of new anticoagulant agents targeting the intrinsic coagulation pathway.     

Syntheses and characterization of nickel(II) dithiocarbamate complexes containing NiS4 and NiS2PN moieties: Nickel sulphide nanoparticles from a single source precursor

In this study, ammonium N-benzyldithiocarbamate was synthesized and used to prepare homoleptic Ni(II) bis(N-benzyldithiocarbamate) (1) and heteroleptic Ni(II) complexes involving isocyanate (2) and cyanide (3) ions. The complexes were characterized by elemental analysis, Fourier transform infra-red (FTIR), and NMR (¹H and ¹³C) spectroscopic techniques. Complex 2 was further characterized by single crystal X-ray diffraction analysis. The FTIR showed bidentate co-ordination for all the complexes as the v(CN) stretching frequency were in the 980–1050 cm^?1 region without any splitting. Thermal decomposition profile of the complexes showed decomposition resulting in the formation of nickel sulphides. The homoleptic complex 1 was utilized as single source precursor (SSP) to prepare Nickel sulphide nanoparticles. The synthesis of the nanoparticles was conducted using different capping molecules (with various alkyl chain lengths), and at different reaction temperature and time. Pure phase Heazlewoodite (Ni₃S₂) nanoparticles were obtained from the X-ray diffraction study. The TEM analysis showed that the type of capping agent, reaction temperature, and time of reaction have significant effect on the morphology and size of the nanoparticles. The optical properties of the nanoparticles were studied using absorption and fluorescence spectroscopies, and they displayed evidence of quantum confinement effect.     

Kinetics of thiophene hydrodesulfurization over a supported Mo–Co–Ni catalyst

In this study, the kinetics of thiophene (TH) hydrodesulfurization (HDS) over the Mo–Co–Ni-supported catalyst was investigated. Trimetallic catalyst was synthesized by pore volume impregnation and the metal loadings were 11.5 wt % Mo, 2 wt % Co, and 2 wt % Ni. A large surface area of 243 m²/g and a relatively large pore volume of 0.34 cm³/g for the fresh Mo–Co–Ni-supported catalyst indicate a good accessibility to the catalytic centers for the HDS reaction. The acid strength distribution of the fresh and spent catalysts, as well as for the support, was determined by thermal desorption of diethylamine (DEA) with increase in temperature from 20 to 600 °C. The weak acid centers are obtained within a temperature range between 160 and 300 °C, followed by medium acid sites up to 440 °C. The strong acid centers are revealed above 440 °C. We found a higher content of weak acid centers for fresh and spent catalysts as well as alumina as compared to medium and strong acid sites. The catalyst stability in terms of conversion as a function of time on stream in a fixed bed flow reactor was examined and almost no loss in the catalyst activity was observed. Consequently, this fact demonstrated superior activity of the Mo–Co–Ni-based catalyst for TH HDS. The activity tests by varying the temperature from 200 to 275 °C and pressure from 30 to 60 bar with various space velocities of 1–4 h^?1 were investigated. A Langmuir–Hinshelwood model was used to analyze the kinetic data and to derive activation energy and adsorption parameters for TH HDS. The effect of temperature, pressure, and liquid hourly space velocity on the TH HDS activity was studied.     

First‐row transition metal–pyridine (py)–sulfate [(py)xM](SO4) complexes (M = Ni,Cu and Zn): crystal field theory in action

The crystal structures of three first‐row transition metal–pyridine–sulfate complexes, namely catena‐poly[[tetrakis(pyridine‐κN)nickel(II)]‐μ‐sulfato‐κ²O:O′], [Ni(SO₄)(C₅H₅N)₄]_n, (1), di‐μ‐sulfato‐κ⁴O:O‐bis[tris(pyridine‐κN)copper(II)], [Cu₂(SO₄)₂(C₅H₅N)₆], (2), and catena‐poly[[tetrakis(pyridine‐κN)zinc(II)]‐μ‐sulfato‐κ²O:O′‐[bis(pyridine‐κN)zinc(II)]‐μ‐sulfato‐κ²O:O′], [Zn₂(SO₄)₂(C₅H₅N)₆]_n, (3), are reported. Ni compound (1) displays a polymeric crystal structure, with infinite chains of Ni^II atoms adopting an octahedral N₄O₂ coordination environment that involves four pyridine ligands and two bridging sulfate ligands. Cu compound (2) features a dimeric molecular structure, with the Cu^II atoms possessing square‐pyramidal N₃O₂ coordination environments that contain three pyridine ligands and two bridging sulfate ligands. Zn compound (3) exhibits a polymeric crystal structure of infinite chains, with two alternating zinc coordination environments, i.e. octahedral N₄O₂ coordination involving four pyridine ligands and two bridging sulfate ligands, and tetrahedral N₂O₂ coordination containing two pyridine ligands and two bridging sulfate ligands. The observed coordination environments are consistent with those predicted by crystal field theory.     

硫酸铜催化下乙烯酮、乙酐与环酮、戊二酮及乙酰乙酸乙酯的反应

烯醇酯是合成高分子化合物的单体,较早由快烃与羧酸反应得到,1944年Bedoukian用醋酸钾为催化剂由异丁醛与乙酐反应得到乙酸异丁烯酯,Gwynn等在硫酸、磷酸等催化下由乙烯酮与酮反应合成了乙酸烯醇酯。我们曾由环戊酮、环己酮在硫酸铁催化下合成了环烯醇酯。本文在合成反应中改用硫酸铜为催化剂时提高了烯醇酯的产率。     

Partial Molar Volumes of Some of α-Amino Acids in Binary Aqueous Solutions of MgSO4·7H2O at 298.15 K

The apparent molar volume, V ^o _{φ, 2}, of glycine, alanine, α-amino-n-butyric acid, valine and leucine have been determined in aqueous solutions of 0.25, 0.5 and 1.0 mol⋅dm⁻³ magnesium sulfate, and the partial specific volume from density measurements at 298.15 K. These data have been used to calculate the infinite dilution apparent molar volume, V ^o _2,m , group contribution of amino acids and partial molar volume of transfer, Δ_tr V _2,m ^o, from water to aqueous magnesium sulfate solutions. The linear correlation of V _2,m ^o for a homologous series of amino acids has been utilized to calculate the contributions of charged end groups (NH₃ ⁺, COO⁻), CH₂ - groups and other alkyl chains of amino acids to V _2,m ^o. The results for Δ_tr V _2,m ^o of amino acids from water to aqueous magnesium sulfate solutions have been interpreted in terms of ion-ion, ion-polar, hydrophilic-hydrophilic and hydrophobic-hydrophobic group interactions. The values of the standard partial molar volume of transfer for the amino acids with different hydrophobic contents, from water to aqueous MgSO₄ are in general positive, indicating the predominance of the interactions of zwitterionic/hydrophilic groups of amino acids with ions of the salt. The hydration number decreases with increasing concentration of salt. The number of water molecules hydrated to amino acids decreases, further strengthening the predominance of ionic/hydrophilic interactions in this system.