TiSiW12O40/TiO2催化合成乙酸异戊酯的研究

以固载杂多酸盐TiSiW12O40/TiO2为多相催化剂，通过乙酸和异戊酯反应合成了乙酸异戊酯，并探讨了诸因素对产主的影响，结果表明，TiSiW12O40/TiO2具有良好的催化活性，醇酸摩尔比为1．2：1，催化剂用量为反应物料总量的1．0％，反应时间1．5h，反应温度11－122℃，产率可达96．3％。     

TiSiW12O40／TiO2催化合成氯乙酸正戊酯

首次以固载杂多酸盐TiSiW12O40/TiO2为多相催化剂,通过氯乙酸和正戊醇反应,合成了氯乙酸正戊酯,并探讨了诸因素对产率的影响,实验表明,TiSiW12O40/TiO2具有良好的催化活性,当醇酸物质的量比为1．3：1,催化剂用量为反应物料总量的1．5％,反应时间1．0h,反应温度108℃－126℃时,氯乙酸正戊酯的产率可达78．04％。     

TiSi W_(12)O_(40)/TiO_2催化合成乙酸正丙酯

首次报道了以固载杂多酸盐TiSiW12 O40 /TiO2 为多相催化剂 ,通过乙酸和正丙醇反应合成了乙酸正丙酯 ,并探讨了诸因素对产率的影响。实验表明 :TiSiW12 O40 /TiO2 具有良好的催化活性 ,醇酸物质的量比为1 60∶1,催化剂用量为反应物料总量的 1 0 % ,反应时间 1 5h ,反应温度 90℃～ 92℃时 ,产率可达 94 5 8%。     

TiSiW12O40/TiO2催化合成氯乙酸乙酯

首次以固载杂多酸盐TiSiW12O40/TiO2为多相催化剂，通过氯乙酸和乙醇反应合成了氯乙酸乙酯，并探讨了诸因素对产率的影响，实验表明：TiSiW12O40/TiO2具有良好的催化活性，醇酸物质的量比为1.4：1，催化剂用量为反应物料总质量的2.0%，反应时间2.0h，反应温度89～96℃，产率可达43.02%。     

TiSiW12O40/TiO2催化合成肉桂酸正戊酯

报道了以固载杂多酸盐TiSiW12O40/TiO2为多相催化剂，对以肉桂酸和正戊醇为原料合成肉桂酸正戊酯的反应条件进行了研究。实验表明：TiSiW12O40/TiO2是合成肉桂酸正戊酯的良好催化剂，最佳反应条件为：n（醇）：n（酸）＝4：1，催化剂用量为反应物料总质量的2．0％，反应时间1．5h，反应温度122℃－126℃。上述条件下，肉桂酸正戊酯的效率可达93．33％。     

TiSiW12O40/TiO2催化合成氯乙酸乙酯

介绍了固载杂多酸盐TiSiW12O40/TiO2催化剂的制备方法.首次以TiSiW12O40/TiO2为多相催化剂,通过氯乙酸和乙醇反应合成了氯乙酸乙酯,并探讨了反应因素对产率的影响.实验表明TiSiW12O40/TiO2具有良好的催化活性,醇酸物质的量比为1.41,催化剂用量为反应物料总量的2.0%,反应时间为2.0h,反应温度为89～96℃,产率可达49.84%.     

TiSiW12O40／TiO2催化合成苯甲酸戊酯

首次报道了以固载杂多酸盐TiSiW12O40/TiO2为多相催化剂,对以苯甲酸和正戊醇为原料合成苯甲酸戊酯的反应条件进行了研究,实验表明：TiSiW12O40/TiO2是合成苯甲酸戊酯的良好催化剂,最佳反应投机倒把为：醇酸摩尔比为4：1,催化剂用量为反应物料总量的1.5%,反应时间为2.5h。上述条件下,苯甲酸戊酸的产率可达96.7％。     

用环境友好催化剂合成丙酸异戊酯的研究

以固载杂多酸盐TiSiW12O40／TiO2为环境友好催化剂，对以丙酸和异戊醇为原料合成丙酸异戊酯的反应条件进行了研究。实验表明：TiSiW12O40／TiO2是合成丙酸异戊酯的良好催化剂，最佳反应条件为：n(醇)：n(酸)=1．3：1，催化剂用量为反应物料总质量的2．0％，反应时间1．0h，反应温度95—110℃。上述条件下，丙酸异戊酯的收率可达76．2％。     

TiSiW_(12)O_(40)/TiO_2催化合成辛酸乙酯

以正辛酸和乙醇为原料,用自制的环境友好固载杂多酸盐TiSiW12O40/TiO2为催化剂,催化合成辛酸乙酯。探讨TiSiW12O40/TiO2对酯化反应的催化活性,较系统地研究了醇酸量比,催化剂用量,反应时间诸因素对产率的影响。实验表明:TiSiW12O40/TiO2是合成辛酸乙酯的良好催化剂,在醇酸物质的量为1.3:1,催化剂用量为反应物料总量的2.0%,反应时间为1.5h,产率可达68.64%。     

TiSiW12 O40/Ti2催化合成葡萄糖五丁酸酯

报道了新型催化剂TiSiW12O40/TiO2催化酯化合成葡萄糖五丁酸酯的糖酸比、催化剂用量、反应时间、反应温度诸因素对产率的影响.实验表明TiSiW12O40/TiO2是合成葡萄糖五丁酸酯的良好催化剂.最佳反应条件为糖酸摩尔比16,催化剂的用量为反应物料总量的2.0%,酯化反应时间为2.0h,反应温度90～95℃,反应产率可达85.4%.     

Photocatalytic activity of Cu2O/TiO2, Bi2O3/TiO2 and ZnMn2O4/TiO2 heterojunctions

Cu₂O/TiO₂, Bi₂O₃/TiO₂ and ZnMn₂O₄/TiO₂ heterojunctions were studied for potential applications in water decontamination technology and their capacity to induce an oxidation process under VIS light. UV–vis spectroscopy analysis showed that the junctions-based Cu₂O, Bi₂O₃ and ZnMn₂O₄ are able to absorb a large part of visible light (respectively, up to 650, 460 and 1000 nm). This fact was confirmed in the case of Cu₂O/TiO₂ and Bi₂O₃/TiO₂ by photocatalytic experiments performed under visible light. A part of the charge recombination that can take place when both semiconductors are excited was observed when a photocatalytic experiment was performed under UV–vis illumination. Orange II, 4-hydroxybenzoic and benzamide were used as pollutants in the experiment. Photoactivity of the junctions was found to be strongly dependent on the substrate. The different phenomena that were observed in each case are discussed.     

ZrO2/SiO2- and La2O3/Al2O3-supported platinum catalysts for CH4/CO2 reforming

Surface-phase ZrO₂ on SiO₂ (SZrOs) and surface-phase La₂O₃ on Al₂O₃ (SLaOs) were prepared with various loadings of ZrO₂ and La₂O₃, characterized and used as supports for preparing Pt/SZrOs and Pt/SLaOs catalysts. CH₄/CO₂ reforming over the Pt/SZrOs and Pt/SLaOs catalysts was examined and compared with Pt/Al₂O₃ and Pt/SiO₂ catalysts. CO₂ or CH₄ pulse reaction/adsorption analysis was employed to elucidate the effects of these surface-phase oxides.

The zirconia can be homogeneously dispersed on SiO₂ to form a stable surface-phase oxide. The lanthana cannot be spread well on Al₂O₃, but it forms a stable amorphous oxide with Al₂O₃. The Pt/SZrOs and Pt/SLaOs catalysts showed higher steady activity than did Pt/SiO₂ and Pt/Al₂O₃ by a factor of three to four. The Pt/SZrOs and Pt/SLaOs catalysts were also much more stable than the Pt/SiO₂ and Pt/Al₂O₃ catalysts for long stream time and for reforming temperatures above 700 °C. These findings were attributed to the activation of CO₂ adsorbed on the basic sites of SZrOs and SLaOs.     

Al_2(SO_4)_3/FeCl_3催化合成乙酸异戊酯

以冰乙酸和异戊醇为原料,Al_2(SO_4)_3/FeCl_3为催化剂,对催化合成乙酸异戊酯的条件进行研究。考察催化剂用量、乙酸与异戊醇物质的量比以及反应时间对乙酸酯化率的影响。结果表明,Al_2(SO_4)_3/FeCl_3具有良好的催化活性,在乙酸物质的量为0.1 mol、乙酸与异戊醇物质的量比为1∶4、催化剂用量1.0 g、反应时间2.0 h和带水剂环己烷用量10 m L反应条件下,重复实验3次,平均乙酸酯化率为93.50%。     

稀土固体超强酸SO2-4/TiO2/La3+催化合成醋酸丁酯

研究了以固体超强酸SO24-/TiO2/La3+催化剂,醋酸和正丁醇为原料合成醋酸丁酯,并考察了影响反应的因素.结果表明醇酸物质的摩尔比为1.61、催化剂用量0.6 g、带水剂甲苯7 mL、反应时间2.5 h是最适宜的反应条件,其酯化率可达96.2%.     

K_2SO_4对V_2O_5/TiO_2脱硝催化剂表面形态的影响

采用XRD和XPS对新鲜的和K2SO4掺杂的V2O5/TiO2脱硝催化剂的表面形态进行了分析。结果表明,K2SO4的掺杂未对V与Ti之间的相互作用造成显著的影响,但是引起催化剂表面V和Ti的浓度降低,V5+在催化剂表面消失。K与钒氧物种上的晶格氧发生了强烈的相互作用。     

Electrocatalyst materials for fuel cells based on the polyoxometalates—K7 or H7[(P2W17O61)Fe(H2O)] and Na12 or H12[(P2W15O56)2Fe4(H2O)2]

Free acids of the iron substituted heteropoly acids (HPA), H₇[(P₂W₁₇O₆₁)Fe^III(H₂O)] (HFe1) and H₁₈[(P₂W₁₅O₅₆)₂Fe^III₂(H₂O)₂] (HFe2) were prepared from the salts K₇[(P₂W₁₇O₆₁)Fe^III(H₂O)] (KFe1) and Na₁₂[(P₂W₁₅O₅₆)₂Fe^III₄(H₂O)₂] (NaFe4), respectively. The iron-substituted HPA were adsorbed on to XC-72 carbon based GDLs to form HPA doped GDEs after water washing with HPA loadings of ca. 1 μmol. The HPA was detected throughout the GDL by EDX. Solution electrochemistry of the free acids are reported for the first time in sulfate buffer, pH 1-3. The hydrogen oxidation reaction was catalyzed by KFe1 at 0.33 V, with an exchange current density of 38 mA/cm². Moderate activity for the oxygen reduction reaction was observed for the iron substituted HPA, which was dramatically improved by selectively removing oxygen atoms from the HPA by cycling the fuel cell cathode under N₂ followed by reoxidation to give a restructured oxide catalyst. The nanostructured oxide achieved an OCV of 0.7 V with a Tafel slope of 115 mV/decade. Cycling the same catalysts in oxygen resulted in an improved catalyst/ionomer/carbon configuration with a slightly higher Tafel slope, 128 mV/decade but a respectable current density of 100 mA/cm² at 0.2 V.     

Properties of char particles obtained under O2/N2 and O2/CO2 combustion environments

Pulverized coal combustion in O₂/N₂ and O₂/CO₂ environments was investigated with a drop tube furnace. Results present that the reaction rate and burn-out degree of O₂/CO₂ chars (obtained in O₂/CO₂ environments) are lower than that of O₂/N₂ chars (obtained in O₂/N₂ environments) under the same experimental condition. It indicates that a higher O₂ concentration in O₂/CO₂ environment is needed to achieve the similar combustion characteristic to that in O₂/N₂ environment. The main differences between O₂/N₂ and O₂/CO₂ chars rely on the pore structure determined by N₂ adsorption and chemical structure measured by FT-IR. For O₂/CO₂ char, the surface is thick and the pores are compact which contribute to the fragmentation reduction of particles burning in O₂/CO₂ environment. The organic functional group elimination rate from the surface of O₂/CO₂ chars is slower or delayed. The present research results might have important implications for further understanding the intrinsic kinetics of pulverized coal combustion in O₂/CO₂ environment.     

New acrylic monolithic carbon molecular sieves for O2/N2 and CO2/CH4 separations

The modification of activated carbon fibres prepared from a commercial textile acrylic fibre into materials with monolithic shape using phenolic resin as binder was studied. The molecular sieving properties for the gas separations CO₂/CH₄ and O₂/N₂ were evaluated from the gas uptake volume and selectivity at 100 s contact time taken from the kinetic adsorption curves of the individual gases. The pseudo-first order rate constant was also determined by the application of the LDF model. The samples produced show high CO₂ and O₂ rates of adsorption, in the range 3-35 × 10⁻³ s⁻¹, and in most cases null or very low adsorption of CH₄ and N₂ which make them very promising samples to use in PSA systems, or similar. Although the selectivity was very high, the adsorption capacity was low in certain cases. However, the gas uptake in two samples reached 23 cm³ g⁻¹ for CO₂ and 5 cm³ g⁻¹ for O₂, which can be considered very good. The materials were heat-treated using a microwave furnace, which is a novel and more economic method, when compared with conventional furnaces, to improve the molecular sieves properties.     

Solid state metathesis synthesis of BaTiO3, PbTiO3, K0.5Bi0.5TiO3 and Na0.5Bi0.5TiO3

A solid state metathesis approach has been applied to synthesize perovskite oxides such as BaTiO₃, PbTiO₃, K_0.5Bi_0.5TiO₃ and Na_0.5Bi_0.5TiO₃, these were characterized by powder XRD, IR and energy dispersive spectra (EDS). Potassium titanium oxalate and metal chlorides are used as the starting materials. X-ray analysis shows the formation of a single phase with tetragonal structure for BaTiO₃, PbTiO₃, K_0.5Bi_0.5TiO₃ and a monoclinic structure for Na_0.5Bi_0.5TiO₃. The Infrared spectra of these compounds show the characteristic band due to Ti–O octahedron for all the compounds. The EDS spectra show the relative ratio of the metal ions. The morphology of synthesized compounds was obtained from SEM measurements.