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31.
Solid state M-4-Me-BP compounds, where M stands for bivalent Mn, Fe, Co, Ni, Cu, Zn, Pb and 4-Me-BP is 4-methylbenzylidenepyruvate, have been synthesized. Simultaneous thermogravimetry-differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy, elemental analysis, and complexometry were used to characterise and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, thermal stability and thermal decomposition of the isolated complexes. 相似文献
32.
在电极袭面反应物浓度均匀的近似假设下,得到了微圆盘电极上暂态可逆反应的一般解.然后利用该一般解得到了微圆盘电极上耦合一级均相反应的可逆电极反应CE、EC、EC′和ECE 的稳态电流计算公式. 相似文献
33.
非水层状液晶的稳定性与相行为 总被引:3,自引:1,他引:3
水体系层状液晶已研究较久,非水层状液晶则是近十年来才得到发展。本文以层状液晶的相行为和~2H NMR测量,研究并比较了非水层状液晶十二烷基硫酸钠/正癸醇溶剂以甘油或甲酰胺为溶剂时体系的结构与稳定性。 表面活性剂十二烷基硫酸钠(BDH,简写SDS)经无水乙醇重结晶两次提纯。用铂环法测 相似文献
34.
In developing a method for possible low level isotopic enrichment, which uses to advantage the equilibrium isotope effect
observed during U(1V)-U(VI) electron exchange reaction in sulphate solutions, details of a solvent extraction process involving
high concentration of a mixture of U(IV) and U(VI) and at low acid concentrations, are described. The extraction behaviour
of uranium under these conditions is discussed. During the extraction with amines, U(IV) tended to get oxidised in sulphate
solutions. 相似文献
35.
G Bannach E Schnitzler O Treu
Filho V H S Utuni M Ionashiro 《Journal of Thermal Analysis and Calorimetry》2006,83(1):233-240
Solid-state
compounds of general formula LnL3⋅nH2O,
where Ln represents heavier lanthanides
and yttrium and L is 2-chlorobenzylidenepyruvate,
have been synthesized. Chemical analysis, simultaneous thermogravimetry-differential
analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry,
elemental analysis and infrared spectroscopy have been employed to characterize
and to study the thermal behaviour of these compounds in dynamic air atmosphere.
On heating these compounds
decompose in four (Gd, Tb, Ho to Lu, Y) or five (Eu, Dy) steps. They lose
the hydration water in the first step and the thermal decomposition of the
anhydrous compounds up to 1200°C occurs with the formation of the respective
oxide, Tb4O7 and Ln2O3
(Ln=Eu, Gd, Dy to Lu and Y) as final residue.
The dehydration enthalpies found for these compounds (Eu, to Lu and Y) were:
65.77, 55.63, 86.89, 121.65, 99.80, 109.59, 131.02, 119.78, 205.46 and 83.11
kJ mol-1, respectively. 相似文献
36.
通过1-环庚烯基锂与6,6-二烷基富烯发生环外双键的加成反应形成的大取代茂锂试剂与MCl4(M=Ti,Zr)反应,合成了12个含或不含手性碳的大位阻取代茂金属有机化合物,并研究了它们的1HNMR,EIMS和IR. 相似文献
37.
Y. BallesterosM.J. Gonzalez de la Huebra M.C. QuintanaP. Hernandez L. Hernandez 《Microchemical Journal》2003,74(2):193-202
The electrochemical behaviour of kinetin (6-furfurylaminopurine) on a carbon paste modified with OV-17 silicone electrode, is studied. The determination of kinetin is possible working in square wave voltammetric techniques, reaching limits of determination of 38.7 ng ml−1. The proposed method was successfully applied to determine the cytokinin in extracts of apples (previously spiked with kinetin) and the obtained results were in accordance with the results obtained with HPLC-UV. 相似文献
38.
On the basis of a better analytical exploitation of acid-induced cloud point approach, a systematic study on the phase behaviour of acid aqueous solutions of anionic surfactants and factors affecting anionic surfactant-mediated extractions was performed. The anionic surfactants investigated were alkylsulphonates (ASS) with alkylchain lengths comprised between 8 and 16 carbon atoms. The critical hydrochloric acid concentration (minimal acid concentration required to separation in two liquid phases) was found to increase as alkylchain length of the anionic surfactant increased from 10 to 14. Non-acid-induced liquid-liquid phase separation was observed for sodium octanesulphonate (SOS) or sodium hexadecyl sulphonate (SHS) in the hydrochloric concentration range 0-10 M. Acid aqueous solutions of sodium decylsulphonate (SDeS) and sodium dodecylsulphonate (SDoS) separated into two liquid phases at temperatures ranging between 10 and 80 °C, while temperatures >35 °C were required for sodium tetradecylsulphonate. The influence on extraction efficiency and concentrating ability of experimental variables such as hydrophobicity and concentration of surfactant, nature and concentration of analyte, hydrochloric acid concentration, time and temperature of extraction and time of equilibration and centrifugation was examined. Advantages provided by anionic surfactant-mediated extractions over the use of non-ionic surfactants (cloud point extractions) are discussed. 相似文献
39.
40.
Matthias Weil 《无机化学与普通化学杂志》2004,630(7):1048-1053
Single crystals of HgII(H4TeVIO6) (colourless to light‐yellow, rectangular plates) and HgI2(H4TeVIO6)(H6TeVIO6)·2H2O (colourless, irregular) were grown from concentrated solutions of orthotelluric acid, H6TeO6, and respective solutions of Hg(NO3)2 and Hg2(NO3)2. The crystal structures were solved and refined from single crystal diffractometer data sets (HgII(H4TeVIO6): space group Pna21, Z = 4, a =10.5491(17), b = 6.0706(9), c = 8.0654(13)Å, 1430 structure factors, 87 parameters, R[F2 > 2σ(F2)] = 0.0180; HgI2(H4TeVIO6)(H6TeVIO6)·2H2O: space group P1¯, Z = 1, a = 5.7522(6), b = 6.8941(10), c = 8.5785(10)Å, α = 90.394(8), β = 103.532(11), γ = 93.289(8)°, 2875 structure factors, 108 parameters, R[F2 > 2σ(F2)] = 0.0184). The structure of HgII(H4TeVIO6) is composed of ribbons parallel to the b axis which are built of [H4TeO6]2— anions and Hg2+ cations held together by two short Hg—O bonds with a mean distance of 2.037Å. Interpolyhedral hydrogen bonding between neighbouring [H4TeO6]2— groups, as well as longer Hg—O bonds between Hg atoms of one ribbon to O atoms of adjacent ribbons lead, to an additional stabilization of the framework structure. HgI2(H4TeVIO6)(H6TeVIO6)·2H2O is characterized by a distorted hexagonal array made up of [H4TeO6]2— and [H6TeO6] octahedra which spread parallel to the bc plane. Interpolyhedral hydrogen bonding between both building units stabilizes this arrangement. Adjacent planes are stacked along the a axis and are connected by Hg22+ dumbbells (d(Hg—Hg) = 2.5043(4)Å) situated in‐between the planes. Additional stabilization of the three‐dimensional network is provided by extensive hydrogen bonding between interstitial water molecules and O and OH‐groups of the [H4TeO6]2— and [H6TeO6] octahedra. Upon heating HgI2(H4TeVIO6)(H6TeVIO6)·2H2O decomposes into TeO2 under formation of the intermediate phases HgII3TeVIO6 and the mixed‐valent HgIITeIV/VI2O6. 相似文献