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81.
Ryashentseva M. A. Egorova E. V. Trusov A. I. Antonyuk S. N. 《Russian Chemical Bulletin》2002,51(9):1698-1701
The activity and selectivity of mono- and bimetallic catalysts containing copper and rhenium on sibunite were studied in the decomposition of methanol to methyl formate (MF), water, H2, CO, and CO2at 200—400 °C. Methane is also formed on rhenium-containing catalysts at 300—400 °C. The dehydrogenating activity and selectivity to form MF are higher on the copper-sibunite catalysts than on the rhenium-sibunite samples. The introduction of 0.25% Re into the 4% copper-containing catalyst enhances its total activity and stability. 相似文献
82.
83.
Noëlle Martine Gosselet Horacio NaranjoEstelle Renard Catherine AmielBernard Sebille 《European Polymer Journal》2002,38(4):649-654
An acrylic polymer with pendent adamantyl groups was synthesized and its properties in an aqueous solution with a β-cyclodextrin (βCD) epichlorhydrin polymer examined. Viscosity properties of precursor and modified polymers show differences at low concentrations, but not at higher concentration probably due to very important hydrogen bonds which prevent the formation of intermolecular hydrophobic bonds. The association of both complementary polymers through the inclusion of adamantyl groups is evidenced by phases separation occurrence. Phase diagrams were established at two different concentrations of polymers. We have shown a maximal association of both polymers at these two concentrations, for the same ratio βCD moles/adamantyl groups: 2.4. Salt addition favors this association and displaces the two phases zone to smaller concentrations of modified polymer. Further, 4-nitrophenol can be extracted by the concentrated phase resulting from mixture of solutions of guest and host polymers, pointing out the availability of the associated phase to trap organic molecules. 相似文献
84.
以糠酸、甲醇、氢气为原料,采用连续流动固定床微反应器,Pd-Ni/γ-Al2O3为催化剂,使糠酸一步加氢甲酯化生成α-四氢糠酸甲酯.研究了反应的温度,压力,气、液体流速,进料流量等因素对催化反应的影响.结果表明:在1.5MPa,250℃,氢气空速3300 h-1,液体空速3.0 h-1(氢油比为50)时,糠酸转化率为96.6%,四氢糠酸甲酯的选择性97.2.0%,产率94.0%.催化剂稳定性较好,连续运转280小时后未见活性下降.该反应体系活性高,选择性好,反应压力低,催化剂性能稳定,操作简单,产物易分离. 相似文献
85.
The first part of the paper deals with a critical discussion of the methodical basis of essential work of fracture (EWF) concept with respect to the specimen geometry (especially the notch depth) and application to polymers. In the second part, an in situ testing device, which combines a tensile testing machine with an optical strain-field measuring system, has successfully demonstrated possibility of characterization of fracture behaviour of polystyrene-polybutadiene block copolymers and block copolymer/homopolymer blends as examples of nanostructured polymer materials. It has been shown that knowledge of the time evolution of the strain field close to the crack tips leads to a simple verification of the basic precondition for the applicability of the EWF concept, the precondition “plastic zone coalescence-before-stable crack propagation”. 相似文献
86.
含间苯基聚芳醚酮的合成与性能研究 总被引:3,自引:0,他引:3
含间苯基聚芳醚酮的合成与性能研究林权,张万金,吴忠文,尹玖梅(吉林大学化学系,长春,130021)(中国科学院长春应用化学研究所)关键词聚芳醚酮,间苯基,熔点,结晶度聚芳醚酮作为一类耐高温特种工程塑料,由于具有优异的热、电、机械性能,已被广泛应用于电... 相似文献
87.
S. F. Malysheva N. K. Gusarova N. A. Belogorlova A. V. Afonin S. N. Arbuzova B. A. Trofimov 《Russian Chemical Bulletin》1997,46(10):1799-1801
Diorganylvinylphosphine oxides were synthesized in 31–38% yields on heating (50°C) diorganylphosphine oxides with vinyl sulfoxides
or divinyl sulfone in the presence of KOH.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1895–1896, October, 1997. 相似文献
88.
89.
90.
Dwayne R. Senn 《Journal of polymer science. Part A, Polymer chemistry》1994,32(6):1175-1183
Random copoly(p-phenylene sulfide sulfone/ketone)s (PPSS/K) are prepared in high yield by the polycondensation of sodium hydrosulfide (NaSH) with bis(4-chlorophenyl) sulfone (BCPS) and 4,4′-dichlorobenzophenone (DCBP). The polymerization is conducted between 200–220°C, depending on the composition of the copolymer, and in the presence of water without any detrimental effects to the molecular weight. The copolymers with sulfone/ketone mole ratios (S : K) > 25 : 75 are amorphous, while the copolymers with S : K ratios ≤ 25 : 75 are crystalline. These materials form tough, creaseable films and exhibit a linear increase in the glass transition temperature with increasing sulfone content. Sulfuric acid solutions of the copolymers are dark orange to red and display an increasing λmax in the uv-visible spectra as the S:K ratio of the copolymers decreases. © 1994 John Wiley & Sons, Inc. 相似文献