A Facile Synthesis of 3,5—Diaryl 1,2,4—Selenadiazoles from Aryl Selenoamides

A facile synthesis of 3,5-diaryl 1,2,4-selenadiazoles was provided by treatment of aryl selenoamides with p-methylphenyl sulfonyl chloride in chloroform.     

New polyfunctional silicon-containing amines C6[CH2CH2SiMe(OCH2CH2NR2)2]6 (R = H,Me) and their reactions with cobalt(ii) chloride and dicobalt octacarbonyl

Hexakis[bis(2-aminoethoxy)methylsilylethyl]benzene and hexakis[bis(N,N-dimethyl-2-aminoethoxy)methylsilylethyl]benzene C₆[(NR₂CH₂CH₂O)₂SiMeCH₂CH₂]₆ (4, R = H; 5, R = Me) were prepared from hexakis(methyldichlorosilylethyl)benzene C₆(Cl₂MeSiCH₂CH₂)₆ and 2-aminoethanol or N,N-dimethyl-2-aminoethanol, respectively. Compounds 4 and 5 react with anhydrous cobalt (ii) chloride to give poorly soluble dodecachloro{hexakis[bis(2-aminoethoxy)methylsilylethyl]benzene}hexacobalt and dodecachloro{hexakis[bis(N,N-dimethyl-2-aminoethoxy)methylsilylethyl]benzene}hexacobalt {Co₆[(NR₂CH₂CH₂O)₂SiMeCH₂CH₂]₆C₆}Cl₁₂ (R = H or Me), respectively. Polyfunctional amine 4 reacts with dicobalt octacarbonyl to produce hexakis[bis(2-aminoethoxy)methylsilylethyl]benzenedicobalt(ii) tetrakis(tetracarbonylcobaltate) {Co₂[(NH₂CH₂CH₂O)₂SiMeCH₂CH₂]₆C₆}[Co(CO)₄]₄. N,N-Dimethyl-substituted polyfunctional amine 5 is lowly reactive in the reaction with Co₂(CO)₈, whereas the simplest model of this compound, viz., bis(N,N-dimethyl-2-aminoethoxy)dimethylsilane (NMe₂CH₂CH₂O)₂SiMe₂, slowly reacts with Co₂(CO)₈ to give tris[bis(N,N-dimethyl-2-aminoethoxy)dimethylsilane]cobalt(ii) bis(tetracarbonylcobaltate) {Co[(NMe₂CH₂CH₂O)₂SiMe₂]₃}[Co(CO)₄]₂. Thermal decomposition and transformations of the resulting complexes under the action of oxygen and water were studied.     

高效毛细管电泳测定混合氯化稀土中的稀土元素

研究了在以含有紫外吸收的咪唑为背影电解质和以α－羟基异丁酸为络合剂的缓冲液体系中，用毛细管电泳间接外法检测和然土离子的方法，讨论了各操作条件对稀土离子分离泊影响。     

Ions with a strong symmetrical H bond in the HCl−BuiOH system by IR spectroscopy data

Ion-molecular interactions in the HCl−BuⁱOH system with different compositions (from neat isobutyl alcohol to 37 mol.% HCl) were studied by Multiple Attenuated Total Reflectance (MATR) IR spectroscopy at 30 °C. Proton disolvates (Buⁱ(H)O…H…O(H)Buⁱ)⁺ with strong symmetrical H bonds are formed upon the addition of HCl to BuⁱOH. At high concentrations of HCl (C ⁰ _HCl>33 mol.%), (Cl…H…Cl)⁻ ions are formed along with (BuⁱOH)₂H⁺. The spectra of positively and negatively charged proton disolvates were compared to those of similar ions in the HCl−PrⁱOH and HCl−MeOH systems. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2496–2500, December, 1998.     

Electrical conductivity of poly(vinyl chloride) obtained by photodehydrochlorination from laminated poly(vinyl chloride)/polypyrrole films

Poly(vinyl chloride) (PVC) has been converted to an electrically conductive structure by combined electrochemical and photochemical methods. PVC was cast on a polypyrrole (PPy) film electrode which had been electrochemically prepared. The PVC layer in the laminated PVC/PPy films was first dehydrochlorinated under the illumination of UV light, and the generated polyenes were subsequently doped with I₂ and FeCl₃. The maximum electrical conductivity achieved for such PVC film was 2.51 X 10^?2 and 8.63 10^?2 S cm^?1 after I₂ and FeCl₃ doping, respectively. The temperature dependence of the electrical conductivity showed different behavior in higher and lower temperature ranges. In the former (T > 243 K), the T^?1 law held, and the activation energy and bandgap were estimated as 0.25 and 0.49 eV, respectively. In the latter (T < 243 K), the conductivity mechanism followed the variable range hopping model (T^?1/4 law) in which the radius of the localized state wave function and the density of the localized states at the Fermi level were 1.25 × 10³ Å and 1.03 X 10¹⁵ eV^?1 cm^?3, respectively. © 1995 John Wiley & Sons, Inc.     

Structures and Mechanical Properties of PVC／Na^＋—Montmorillonite Nanocomposites

Poly(viyl chloride)/Na^ -montmorillonite(PVC/MMT)nanocomposites with different MMT contents were prepared via melt blending.Wide-angle X-ray diffraction(WAXD)and transmission electron microscopy(TEM)were used to characterize the structures.Effects of MMT content on the mechanical properties were also studied.It is found that PVC molecular chains can intercalate into the gallery of MMT layers during melt blending process,the stiffiness and toughness of the composites are inproved simultaneously within 0.5-7wt% MMT content,and the transparency and mechanical properties decrease as MMT conten further increases.     

Volumetric properties of dilute aqueous solutions of cobalt amine type salts. Part 2. Densities at 15 and 5°C

Apparent molar volumes have been determined by density measurements of aqueous solutions for a series of salts [Co(L)₃]X₃, where X=Cl^– and Br^– and L¹=1,2-diaminoethane (en), L²=1,2-diaminopropane (pn) and L³=1,3-diaminopropane (tn) at 15°C and 5°C. Apparent molar volumes at infinite dilution for the complex cations at 0°C are estimated. The resulting values are related to the structure of solvent water molecules around the ions.     

Spectrophotometric determination of Fe(III) with tiron in the presence of cationic surfactant and its application for the determination of iron in Al-alloys and Cu-based alloys

A sensitive Spectrophotometric method for the determination of iron with tiron and a cationic surfactant, cetylpyridinium chloride, at pH 5.6 is reported. The complex is extracted into a chloroform-propan-2-ol (41) mixture and shows maximum absorbance at 520 nm. Beer's law is obeyed in the range 1–14 g/ml with an average molar absorptivity of 15800 l mol^–1 cm^–1. The molar ratio as determined by Job's method for Fe:tiron:CPC is 143. Interferences by various ions are examined. Zr, Ti and Mo interfere heavily. The method is applied for the determination of iron in Al-based and Cu-based alloys, using appropriate masking agents.     

Precipitation and association in a mixture of dodecylammonium chloride and sodium dodecyl sulfate in aqueous medium

The precipitation boundary in aqueous mixtures of dodecylammonium chloride (DDACl) and sodium dodecyl sulfate (NaDS) was determined in the absence and in the presence of 1 mol dm^–3 NaCl. The structure and the composition of the solid phase was characterized by x-ray and chemical analysis, respectively. Activities of Cl^– and Na⁺ ions in the aqueous phase were measured by ion-selective electrodes. As determined by calorimetry, precipitation is an exothermic process.The DDA·DS precipitate was formed in the equimolar region of the precipitation components. Its crystallographic structure is described. In an excess of sodium dodecyl sulfate, the precipitate incorporated substantial amounts of NaDS, as detected by analyses of both solid and liquid phases. X-ray analysis of the dry sample showed peaks of crystalline NaDS. According to the polarization microscopy of wet samples, one may conclude that liquid crystals, containing an excess of NaDS, are incorporated in the solid DDA·DS phase. The same was found in the case of an excess of DDACl; mixed liquid crystals with an excess of DDACl were incorporated in the solid DDA·DS.Interpretation of the solubility boundary points to the presence of DDA⁺·DS^– ion pairs. Formation of these species at low ionic strengths is characterized by the equilibrium constantK _a ⁰ 10⁶. However, in the 1 mol dm^–3 NaCl, the association of DDA⁺ and DS^– ions into pairs is inhibited (K _a ⁰ 0). This finding can be explained in terms of ionic clouds around the charged surfactant heads: if these heads are not in close contact, but separated due to structural effects of the chains, the dense distribution of counterions around them at high ionic strengths may compensate for electrostatic attraction and, thus, inhibit ion-pairing.     

异丁烯聚合催化体系研究 Ⅰ.均聚与共聚反应

用苯甲酰氯(BC)／TiCl4引发异丁烯(IB)聚合及与苯乙烯(St)的共聚反应，得到分子量高、分布窄的聚异丁烯及其共聚物，并控制了BC的高活性。对IB均聚及其与ST共聚反应影响因素(体系浓度、残余水、第3组分三乙胺(TEA))进行优化，得到最佳条件为：[BC]=2．6mmol／L、[TEA]／[BC]=1.0(均聚)和n(TiCl4)／n(BC)=80、[TEA]／[BC=4．0(共聚)，BC／TiCl4／TEA是最佳体系，对水不敏感，可以制备分子量高及分子量分布(MWD)为1．5(均聚)和2．0(共聚)的窄分布聚合物(GPC曲线均为单峰)。