复合金属氧化物催化剂用于甘油氧化制丙烯酸的研究进展

随着化石燃料的短缺及其利用所产生的环境问题,可再生生物质资源逐渐成为生产燃料以及化学品的重要来源。近年来,甘油作为生物柴油生产的主要副产物受到了人们的广泛关注,利用其生产高附加值产品以及开发相关的转化技术也成为了国内外学者研究的热点。在诸多转化技术中,甘油选择性氧化制丙烯酸展现出了广阔的发展前景,对该反应尤其是催化剂开展研究具有重要的经济意义和社会意义。文中综述了用于甘油选择性氧化制丙烯酸复合金属氧化物催化剂的研究现状,介绍了当前用于该反应的催化体系类型以及对甘油氧化制丙烯酸催化反应机理的认识,分析并提出了存在的问题以及对未来的展望。     

Behaviors of flow mechanisms and heat transfer of non-Newtonian fluids through a spinneret

This investigation examines non-Newtonian flow mechanisms and heat transfer characteristics for a micro spinneret. The working fluid, Polyethylene terephthalate (PET), is the raw material of micro fiber, and a large-scale experimental test model was designed to visualize the complex viscous flow system in the micro spinneret. To visualize the complex convective flow system, an experimental test model was constructed, using glycerin instead of PET. The related parameters of PET were compared with those of glycerin. The power law correlates the shear strain with PET viscosity at various temperatures. The pressure distribution along the flow direction was measured and the flow pattern was visualized using polyethylene (PE) powder of 20–40 m. Similar configurations were calculated for micro spinneret physical parameters to determine the thermal flow characteristics. The Reynolds number in the test model is not less than 10^–2. In the non-Newtonian PET working fluid of practical micro spinneret, flows with Re = 10⁴ to 10^–2 are in the same low Reynolds number flow regime. Therefore, the working fluid is expected to have the same flow characteristic. A numerical solution covering the range of approximately Re = 10^–4 at PET confirms that the flow characteristics of glycerin are constant for Re = 1.228 × 10^–2. The Peclet number in the test model can be adjusted to a value similar to that in the micro spinneret. The flow visualization was compared with that of the numerical solution, and the friction factor and Nusselt number in the micro spinneret were analyzed. Finally, numerical results and friction factor with various exit angles of micro spinneret in a triangular zone flow system were also summarized.     

Enhanced multiple ultrasonic shear reflection method for the determination of high frequency viscoelastic properties

In this work, we propose a study dedicated to the influence of the delay line nature in transverse ultrasonic sensors, dedicated to dynamic high frequency elastic moduli of viscoelastic materials estimation. In literature, these shear ultrasonic rheometers are using delay lines in glass or quartz and normal or oblique incidence of ultrasonic rays. The oblique incidence is used in order to improve the sensitivity of the measurements. We theoretically demonstrate in this work that the use of delay lines in polymers is recommended to improve the sensitivity. Due to modifications, performed on a 10 MHz commercial ultrasonic sensor, we experimentally show on glycerin (which is a Newtonian material) that it is possible to multiply by a factor 10 the sensitivity; compared to delay lines in quartz using a normal incidence of rays. Hence, we overpass the accuracy of the oblique incidence approach with a simpler experimental setup.     

高碘酸钠氧化甘油的动力学研究及应用

本文利用紫外分光光度法研究了高碘酸钠氧化甘油的动力学，测定了其动力学方程，探讨了反应机理，同时建立了甘油氧化动力学的紫外分光光度法，该法简单、重现性好、准确度高。     

气相色谱法分析碳酸甘油酯

采用气相色谱法测定碳酸甘油酯粗产品中碳酸甘油酯和残余甘油的含量。选择HP1701毛细管柱,程序升温及四甘醇内标物作为色谱条件,在此条件下碳酸甘油酯和残余甘油能很好地分离。碳酸甘油酯和甘油的线性范围分别为23.30～116.6 g.L-1和3.70～18.40 g.L-1。方法的回收率在99.1%～100.9%之间,相对标准偏差(n=6)在0.61%～1.93%之间。     

Equilibrium Phase Behavior of Ethylene Glycol/Glycerin＋RbNO3/CsNO3＋H2O at 288.15 and 298.15 K

The solubilities, densities and refractive indices for the four ternary systems ethylene glycol/glycerin＋ RbNOJCsNO3＋H20 were measured with mass fractions of ethylene glycol or glycerin in a range of 0 to 1.0 at 288.15 and 298.15 K. In all the cases, the presence of either ethylene glycol or glycerin significantly reduces the solubilities of the rubidium nitrate and cesium nitrate in aqueous solution, but the refractive indices increase with the increase of mass fraction of either ethylene glycol or glycerin. The density, refractive index and solubility of the saturated ternary systems were correlated with each other via polynomial equations. In addition, the refractive indices and densities of unsaturated solutions were also determined for the four ternary systems with different salt concentrations, which were correlated with the salt concentration and proportion of ethylene glycol or glycerin in the solution.     

离子交换法提纯甘油的研究

本文通过模拟工业生产提纯甘油恒温、恒速条件，用离子交换法提纯甘油，选择出最佳提纯工艺。