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71.
Surface modification of highly dispersed rubber fillers and pigments by titanate proadhesive and hydrophobic compounds 总被引:1,自引:0,他引:1
A method of modifying silicate and carbonate fillers with titanate coupling agents and proadhesive agents was worked out. The modification aimed at hydrophobization of filler surface by introduction to the surface of functional groups with chemical affinity to polymers. Optimum amounts of modifying substances and appropriate conditions for performing the modification process were established. The obtained fillers showed a high degree of hydrophobicity.The modified fillers were applied in rubber mixtures based on butadienestyrene or natural rubber, in polyurethanes, in PVC, and as pigments in oil dyes of high corossive resistance. 相似文献
72.
Dany Brouillette Gérald Perron Jacques E. Desnoyers 《Journal of solution chemistry》1998,27(2):151-182
Lithium bis(trifluoromethylsulfone)imide (LiTFSI) is a promising electrolyte for high-energy lithium batteries due to its high solubility in most solvents and electrochemical stability. To characterize this electrolyte in solution, its conductance and apparent molar volume and heat capacity were measured over a wide range of concentration in glymes, tetraethylsulfamide (TESA), acetonitrile, -butyrolactone, and propylene carbonate at 25°C and were compared with those of LiClO4 in the same solvents. The glymes or n(ethylene glycol) dimethyl ethers (nEGDME), which have the chemical structure CH3–O–(CH2–CH2–O)
n
–CH3 for n = 1 to 4, are particularly interesting since they are electrochemically stable, have a good redox window, and are analogs of the polyethylene oxides used in polymer-electrolyte batteries. TESA is a good plasticizer for polymer-electrolyte batteries. Whenever required, the following properties of the pure solvents were measured: compressibilities, expansibilities, temperature and pressure dependences of the dielectric constant, acceptor number, and donor number. These data were used in particular to calculate the limiting Debye-Hückel parameters for volumes and heat capacities. The infinite dilution properties of LiTFSI are quite similar to those of other lithium salts. At low concentrations, LiTFSI is strongly associated in the glymes and moderately associated in TESA. At intermediate concentrations, the thermodynamic data suggests that a stable solvate of LiTFSI in EGDME exists in the solution state. At high concentrations, the thermodynamic properties of the two lithium salts approach those of the molten salts. These salts have a reasonably high specific conductivity in most of the solvents. This suggests that the conductance of ions at high concentration in solvents of low dielectric constant is due to a charge transfer process rather than to the migration of free ions. 相似文献
73.
New Ternary Phosphides and Arsenides of Cesium and Element of the 8th Transition Metal Group In the ternary systems Cesium/8th transition metal group/5th main group some new compounds were found and investigated. By single crystal measurements CsRh2P2 was found to crystallize in the space group 14/mmm with the lattice constants a = 390.11 pm and c = 1429.36 pm. The new compounds with the formula CsM2X2 (M = Fe, Co, Ru, Rh, Ir; X = P or As) crystallize in the ThCr2Si2-type structure, compounds of the formula Cs2MX2 (M = Ni, Pd, Pt; X = P or As) can be placed in a line with the K2PdP2-type structure. 相似文献
74.
Feng Xian Liu-Cai Charlotte Pham Farida Bey Gilbert Hervé 《Reaction Kinetics and Catalysis Letters》2002,75(2):305-314
Effects of Cs+, H+ and Cu2+ counterions in the vanadium containing heteropoly compounds CsxH1-xVO[PMo12O40] and CsyH0.5-yCu0.25VO[PMo12O40] on the catalytic oxidation of isobutane and characterization by TGA, IR and ESR spectroscopies are reported. A high selectivity of 76% for methacrylic acid and methacrolein together has been obtained with Cs0.75H0.25VO[PMo12O40] catalysts at a reactivity of 5.3x10-1 mmol/h cm3. 相似文献
75.
ChuanChunZOU ShuJieHOU PingShengLEI XiaoTianLIANG 《中国化学快报》2003,14(4):361-364
Two spirostanol saponins(gracillin and dioscin)which have the typical sugar moieties were synthesized facilely by a general approach. 相似文献
76.
Conductometric measurements of tetrabutylammonium perchlorate in propylene carbonate-acetonitrile and propylene carbonate-toluene mixtures at 25°C are reported. Limiting molar conductances, association constants and distance of closest approach of ions are calculated. The experimental data were analyzed by means of the Lee-Wheaton equation. The Gilkerson's solvent-solute interaction energy term was calculated from a plot of association constant logarithmvs. reciprocal dielectric constant. 相似文献
77.
CsOH-promoted epoxide ring-opening with phosphines: mild and efficient synthesis of monohydroxyphosphines 总被引:1,自引:0,他引:1
Daniel L. FoxAshlee A. Robinson James B. FrankRalph Nicholas Salvatore 《Tetrahedron letters》2003,44(41):7579-7582
A mild and convenient synthesis of monohydroxyphosphines has been achieved by epoxide ring-opening using primary or secondary phosphines in the presence of cesium hydroxide, 4 Å molecular sieves and DMF at room temperature. These reaction conditions were found to be highly regio- and stereoselective producing various monohydroxyphosphines exclusively in moderate to high yields. 相似文献
78.
Ji-Guang LiTakayasu Ikegami Yarong WangToshiyuki Mori 《Journal of solid state chemistry》2002,168(1):52-59
A novel carbonate (co)precipitation method, employing nitrates as the starting salts and ammonium carbonate as the precipitant, has been used to synthesize nanocrystalline CeO2 and Ce1−xYxO2−x/2 (x≤0.35) solid-solutions. The resultant powders are characterized by elemental analysis, differential thermal analysis/thermogravimetry (DTA/TG), X-ray diffractometry (XRD), Brunauer-Emmett-Teller (BET) analysis, and high-resolution scanning electron microscopy (HRSEM). Due to the direct formation of carbonate solid-solutions during precipitation, Ce1−xYxO2−x/2 solid-solution oxides are formed directly during calcination at a very low temperature of ∼300°C for 2 h. The thus-produced oxide nanopowders are essentially non-agglomerated, as revealed by BET in conjunction with XRD analysis. The solubility of YO1.5 in CeO2 is determined via XRD to be somewhere in the range from 27 to 35 mol%, from which a Y2O3-related type-C phase appears in the final product. Y3+-doping promotes the formation of spherical nanoparticles, retards thermal decomposition of the precursors, and suppresses significantly crystallite coarsening of the oxides during calcination. The activation energy for crystallite coarsening increases gradually from 68.7 kJ mol−1 for pure CeO2 to 138.6 kJ mol−1 for CeO2 doped with 35 mol% YO1.5. The dopant effects on crystallite coarsening is elaborated from the view point of solid-state chemistry. 相似文献
79.
Farajollah?MohanazadehEmail author Mostafa?Hosini Mahmoud?Tajbakhsh 《Monatshefte für Chemie / Chemical Monthly》2005,136(12):2041-2043
Summary. Reduction of aldehydes and ketones to the corresponding alcohols was achieved in a simple procedure using the system sodium
borohydride and ammonium carbonate. This system needs lower excesses of reducing agent and leads to significantly shortened
reaction times. 相似文献
80.
Promotion of Ionic Liquid to Dimethyl Carbonate Synthesis from Methanol and Carbcn Dioxide 总被引:2,自引:0,他引:2
Promotion of ionic liquid, 1-ethyl-3-methylimidazolium bromide (emimBr), to the synthesis of dimethyl carbonate (DMC) from methanol and carbon dioxide in the presence of potassium carbonate and less amount of methyl iodide under mild conditions was investigated. The results showed that the high selectivity and raised yield of DMC was achieved due to the addition of emimBr in the reaction system. And effect of several reaction conditions such as temperature, pressure and amount of emimBr was discussed. 相似文献