The formation of cation-ligand complexes of tributylammonium cation with diethyl carbonate,ethylene carbonate,propylene carbonate, 4-butyrolactone,ethyl acetate,and cyclopentanone ino-dichlorobenzene at 25°C

The effects of adding millimolar quantities of a series of compounds containing the carbonyl function on the conductances of solutions (0.2 mM) of tri-n-butylammonium picrate ino-dichlorobenzene solvent at 25°C have been measured. Values of the complex formation constants K ₁ ⁺ for 1:1 cation-ligand complexes are derived from these data. The corresponding values of –G ₁ ⁰ at 25°C are (in kcal-mole ^–1 ): 4-butyrolactone, 4.29; propylene carbonate, 3.87; ethylene carbonate, 3.59; cyclopentanone, 3.42; ethyl acetate, 2.84; and diethyl carbonate, 2.78. These results together with earlier results from this laboratory are discussed in terms of the effects of structure on cation-ligand affinity.     

Propane/propylene separation by selective olefin adsorption on Cu/SBA-15 mesoporous silica

Samples of mesoporous silica, SBA-15, were prepared under hydrothermal conditions and Cu cations were incorporated into the framework by two different impregnation techniques. The corresponding adsorption/desorption isotherms of propylene, propane, and N₂ were measured to evaluate the material's effectiveness in the separation of propane/propylene mixtures. Adsorption uptake of propylene increased and that of propane decreased in Cu containing samples as compared to the uptakes observed in undoped SBA-15 samples. It was demonstrated that the presence of Cu atoms in the adsorbent lattice led to a greater selectivity towards propylene. Furthermore, the highest level of Cu(I) were obtained in samples prepared by equilibrium impregnation, which in turn improved the olefin/paraffin uptake ratio. Under some working conditions, the amount of propylene adsorbed in selected samples is totally reversible while propane uptake was negligible.     

均相催化剂催化合成碳酸亚丙酯

分别就单组为催化剂和双组分催化剂对二氧化碳与环氧丙烷合成碳酸亚丙酯的催化活性进行了研究。实验结果表明，在单组分催化体系中，相转移催化剂，如十六烷基三甲基漠化按、四丁基演化铵对上述酯化反应具有较高的催化活性此外，盐酸羟胺、三苯基磷也有一定的催化活性；在双组分催化体系中，KI／PEG（聚乙二醇）体系具有很高的催化活性，能在较短时间内、较低的压力下高产率地得到碳酸亚丙酯，而某些金属盐、有机碱、季接盐的适当红合，也能有效地催化该反应。     

Kinetics of catalytic combustion in air over Pt/Al2O3/Al catalyst

Summary Catalytic combustion of toluene, propylene and CO over Pt/Al₂O₃ /Al catalyst was investigated. Strong inhibition effects are observed when the mixture of toluene, propylene and CO is oxidized. A reaction mechanism of catalytic combustion over Pt/Al₂O/Al is proposed. The results from kinetic models are in good agreement with the experimental data.     

Binding Reaction of Hemin with Chloroquine, Quinine and Quinidine in Water-propylene Glycol Mixture

the interaction of hemin with chloroquine,quinine and quinidine was investigated in 50% water-propylene glycol mixture at pH=9,8.1,7.4 and 6.8using a spectrophotometric method.The data could be well fitted into a model consistent with the formation of a 1:1 complex between the reacting partners.In addition,the results indicated that hemin complexed more strongly with quinidine than with chloroquine and quinine,and the binding constants were pH-dependent.Moreover,it was proved that the water-propylene glycol mixture is well suitable to the study of the systems containing hemin and quinolinebased drugs.     

Catalytic activity of tetracoordinated stereochemically flexible Ni(II) bis(5-thiopyrazol-4-aldiminates) in the dimerization of propylene

The catalytic activity of Ni(II) bis-(5-thiopyrazol-4-aldiminates) was found to be related to the stereochemical flexibility of these compounds in the dimerization of propylene. The propylene conversion decreases with decreasing stereochemical flexibility of the complexes resulting from an increase in the bulk of the substituent at the coordinated nitrogen atom of the NiN₂S₂ chelate ring.Institute of Inorganic and Physical Chemistry, Academy of Sciences of Azerbaidjan, 370143 Baku. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2667–2670, November, 1992.     

复合半导体负载金属材料光催化性能研究

CO₂和烃类光催化直接合成烃类氧化物在合成化学、碳资源利用和环境保护等方面均有重大意义。用溶胶-凝胶和浸渍-还原相结合的方法制得M/V₂O₅-TiO₂(M=Pd、Cu、Ni和Ag)光催化剂。利用XRD、TPR、IR、TPD、UV-Vis DRS和光反应器等技术研究了负载金属复合半导体的物相结构、吸附性能、光吸收性能和光催化反应性能。结果表明：金属负载在复合半导体上延迟了TiO₂由锐钛矿向金红石相的转化,增强了V与载体TiO₂的相互作用,使TiO₂光吸收限发生蓝移,对可见光部分的吸收明显增加,拓宽了催化剂的光响应范围;材料吸光性能强弱顺序Pd/V₂O₅-TiO₂ >Cu/V₂O₅-TiO₂ >Ag/V₂O₅-TiO₂>Ni/V₂O₅-TiO₂;材料的吸附性能及反应物的吸附态是反应发生的关键,CO₂在Ag/V₂O₅-TiO₂表面无法形成卧式吸附态,没有目的产物甲基丙烯酸(MAA)生成,光量子效率低;光吸收性能较好的Pd/V₂O₅-TiO₂对CO₂吸附能力过强,卧式吸附态脱附温度高,光催化效率不高;Cu/V₂O₅-TiO₂对CO₂吸附能力适中,CO₂与C₃H₆脱附温度较接近,实现了“光-表面-热”的协同作用,光量子效率最高,达15.1%。     

聚碳酸亚丙酯对聚(β-羟基丁酸酯-β-羟基戊酸酯)结晶行为的影响

用FTIR和DSC研究了PHBV及其与聚碳酸亚丙酯(PPC)熔融共混样的熔融结晶行为和等温结晶动力学.结果表明,PHBV与PPC熔融共混过程中发生了酯交换反应,两组分间存在一定的相互作用.PPC虽然能降低PHBV结晶折迭链的表面自由能,但同时也能够降低PHBV的结晶度、球晶径向生长速率、平衡熔点和结晶能力.     

Laponite clay in homopolymer and tri-block copolymer matrices

Macromolecule/laponite nanomaterials were studied by DSC and X-ray diffraction techniques. The matrices are poly(ethylene) glycols at various molecular masses and poly(ethylene oxides)-poly(propylene oxides)-poly(ethylene oxides) tri-block copolymers. The latter were tuned by modulating the molecular masses, at constant hydrophilic/hydrophobic ratio, and the hydrophilicity. For all the investigated systems, the enthalpy of melting (ΔH _m) is nearly constant up to a given composition thereafter it increases monotonically reaching the value of the pure macromolecule. We proposed a model to interpret the DSC data. Briefly, it was invoked a mechanism of interaction following which some segments of the adsorbed macromolecule are anchored to the laponite (RD) particles and the remaining segments are radiating away from the surface. The portion of the macromolecule in contact with RD does not contribute to ΔH _m whereas that radiating away from the clay does. Once that the RD surface is saturated, the excess of the macromolecule behaves like the pure one. The proposed model allowed to compute successfully the ΔH _m values. The X-ray diffraction experiments ruled out the polymer intercalation between the silicate sheets.     

Cu/SO42-/La2O3-ZrO2-Al2O3催化剂的制备及其对C3H6选择还原NO的催化性能

以Al₂O₃为基质，添加ZrO₂和La₂O₃，制成La₂O₃-ZrO₂-Al₂O₃复合载体，然后采用SO₄^2-进行改性，再负载上Cu²⁺，制备了铜基SO₄^2-改性的复合载体催化剂(Cu/SO₄^2-/La₂O₃-ZrO₂-Al₂O₃)。考察了它在富氧条件下对丙烯选择还原NO的催化性能，并借助XRD、SEM、TG、Py-IR、NH₃-TPD、FTIR和TPR等方法研究了Cu/SO₄^2-/La₂O₃-ZrO₂-Al₂O₃的结构和性能的关系。结果表明，ZrO₂的加入主要有利于提高催化剂的低温活性；La₂O₃的加入则主要有利于提高催化剂的热稳定性和还原性能；SO₄^2-能够与Zr形成螯合双配位结构，大幅度促使催化剂表面酸量增加并且酸性增强；因此，有效地提高了Cu/SO₄^2-/La₂O₃-ZrO₂-Al₂O₃在富氧条件下对丙烯选择还原NO的催化活性和水热稳定性。在无水条件下，Cu/SO₄^2-/La₂O₃-ZrO₂-Al₂O₃能使NO的最大转化率高达84.3%，即使在275 ℃ 10%水蒸气存在的情况下，仍能使NO的转化率高达81.2%。