丁烷催化脱氢催化剂及技术研究进展

综述了国内外丁烷催化脱氢催化剂及工艺技术的研究进展.论述了丁烷催化脱氢用Pt系、V系和Cr系催化剂的主要制备方法及催化性能,并对比了国外异丁烷催化脱氢制异丁烯工业化技术的主要工艺特点.指出丁烷脱氢主流技术为催化脱氢,优选Cr系催化剂及FBD-4工艺.     

Enhanced magnetic and antifungal characteristics on wool with Fe3O4 nanoparticles and BTCA: a facile synthesis and RSM optimization

A facile route for the synthesis of high-quality Fe₃O₄ nanoparticles (FNPs) has been successfully confirmed by employing a co-precipitation technique and then was stabilized onto wool fabric through a simple “impregnating” process. Here, the synergistic effect of BTCA and synthesized FNPs on magnetic and antifungal characteristics of the wool fabric was investigated. The FNPs was stabilized on the wool surface using BTCA cross-linking agent. The role of both FNPs and BTCA concentrations on magnetic and antifungal properties of samples was optimized using response surface methodology. The magnetization properties and uniform distribution of FNPs on the wool surface were characterized by vibrating sample magnetometry, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The saturation magnetization and antifungal activity against Candida albicans of BTCA/FNPs-optimized wool was 7.8 emu g^?1 and 98.31%, respectively. Subsequently, treated wool fabric with optimum concentration of FNPs and BTCA enhanced magnetic and antifungal properties.     

正丁烷氧化制顺丁烯二酸酐VPO催化剂活性相性质的研究

采用三种典型的还原方法制备VPO催化剂 ,并且进行了XRD、IR、TG和DTA的表征测试及其由正丁烷、丁烯选择性氧化制顺丁烯二酸酐的评价试验。研究了VPO催化剂活性相的生成与其性质 ,探讨了活性相结构对其催化性能的影响。结果表明 ,不同的还原方法可以制备具有不同性质的活性相 (VO) 2 P2 O7,( 0 2 0 )晶面适宜失序变形的(VO) 2 P2 O7,对于促进催化性能的提高具有重要的作用。     

正丁烷氧化制顺酐流化床催化剂性能

实验考察了以正戊醇为还原剂的前驱体制备过程中磷酸浓度对催化剂性能的影响.在较高的磷酸浓度范围内制得的催化剂,V⁴⁺相(VO)₂P₂O₇的量较大,正丁烷的转化率都较高.磷酸浓度减少,V⁵⁺相δ-VOPO₄的相对量逐渐增大,正丁烷的转化率随之升高,而对顺酐的选择性开始时升高,达到最大点后则逐渐降低.在最佳磷酸浓度101.7% 时制备出的催化剂,在进气丁烷浓度为4.0 %、空速为500h^-1的反应条件下,顺酐的最高收率为47.67%(mol).     

Oxidation of butane over vanadium–phosphorus oxides of P/V≥2

Two mixed oxides of vanadium and phosphorus, with phosphorus to vanadium atomic ratio (P/V) about 2 and 2.4, were studied as catalysts for selective oxidation of butane to maleic anhydride. The sample with P/V about 2 was poorly crystalline, contained a small amount of V(V), and oxidized butane to maleic anhydride with about 50% selectivity. The sample with P/V about 2.4 contained well crystalline VO(PO₃)₂ phase, but it deactivated with time-on-stream with the formation of V(PO₃)₃. The results suggested that the two samples differed greatly in their rates of oxidation of the vanadium ions.     

Tribomechanical pretreatment of vanadium phosphates: structural and catalytic effects

The influence of the tribomechanical pretreatment of the precursor vanadyl hydrogenphosphate hemihydrate, VOHPO₄·0.5H₂O, prepared in aqueous medium and of the catalyst vanadyl pyrophosphate, (VO)₂P₂O₇, on the structural and catalytic properties of (VO)₂P₂O₇ in the oxidation of n-butane to maleic anhydride was investigated. Due to the pretreatment the activity and selectivity of the catalyst were markedly increased. The increase in catalytic performance is explained as an effect of the particle size in connection with lattice imperfections. This revised version was published online in July 2006 with corrections to the Cover Date.     

The effects of a potassium overlayer on the reaction pathway of CH2 and C2H5 on Rh(111)

The effect of potassium on the reaction pathways of adsorbed CH₂ and C₂H₅ species on Rh(111) was investigated by means of reflection absorption infrared spectroscopy (RAIRS) and temperature programmed desorption (TDS). Hydrocarbon fragments were produced by thermal and photo-induced dissociation of the corresponding iodo compounds. Potassium adatoms markedly stabilized the adsorbed CH₂ and converted it into C₂H₄, the formation of which was not observed for K-free Rh(111). New routes of the surface reactions of C₂H₅ have been also opened in the presence of potassium, namely its transformation into butane and butene.     

Equations for Thermal Conductivity of Natural Refrigerants

Experimental results for the thermal conductivity of ammonia, propane, butane, isobutane, and propylene are reviewed, with special attention given to the liquid phase. New equations for the thermal conductivity of these five substances applicable for practical use over wide ranges of temperature and pressure including the critical region are proposed based on the experimental data. The present equations as well as the existing equations are compared with the experimental data. Compared with existing equations for ammonia, isobutane, and propylene, which are not reliable in the liquid phase, the behavior of the thermal conductivity for these substances is much improved using the present equations.     

Thermal conductivity of a shearing molecular fluid

We have investigated the thermal conductivity tensor of strongly sheared atomic and molecular liquids by computer sinudation methods. According to linear nonequilibrium thermodynamics. licat and transverse momentum transport are uncoupled in the linear reginx. We also expect the thermal conductivity to he independent of the zero-wavevector strain rate in the linear regime. Away from the linear regime. the Situation is dillcrent. Although even a large zero-wavevector strain rate cannot induce a heat flux. the thermal conductivity can become strain-rate dependent. Furthermore, the thermal conductivity becomes a lensor because a strong velocity prolile can destroy the isotropy of a fluid. These effects are only apparent at extremely high strain rates for atomic liquids, but are experimentally observable for polymeric liquids.Paper presented at the Twelfth Symposium on Thermophysical Properties. June 19-24. 1994, Boulder, Colorado. U.S.A.     

老化工艺对丁烷氧化催化剂结构与性能的影响

通过丁烷氧化催化剂第一先驱体老化过程的研究发现，老化介质的ｐＨ值对催化剂第二先驱体和催化剂的晶体结构以及催化剂的化学反应性能有显著的影响。老化介质ｐＨ值影响催化剂第二先驱体中结晶水的数量。在ｐＨ＝３．０时，老化的催化剂先驱体具有最高的顺酐选择性和顺酐质量收率。在不同ｐＨ值老化的催化剂先驱体，经活化后对丁烷的转化率基本相同。