甘油催化氧化合成二羟基丙酮研究进展

对甘油选择性催化氧化转化为二羟基丙酮的研究进行综述,介绍了负载型催化剂在不同条件下对产物选择性和反应物转化率的影响,以及催化剂的作用机理。阐述了甘油催化氧化存在的问题以及发展前景。从均相到非均相催化,从单金属到双金属负载催化,从金属到非金属催化,甘油氧化反应的研究不断在完善。研究发现用Bi改性的Pt负载催化剂可以有效地将甘油选择性催化氧化为二羟基丙酮,在最优条件下,可获得较高的甘油转化率和二羟基丙酮选择性,但催化剂稳定性较差,有待进一步提高。杂多酸催化剂以及非金属催化剂也存在稳定性差的问题。指出改善催化剂的稳定性将是未来研究的主要方向。     

Determination of glycerol by oxidation with periodic acid

Summary An acidimetric procedure for the determination of glycerol following oxidation with periodic acid has been described. This procedure has been successfully applied to C. P. grade glycerin, spent soap lyes, soap lye crudes, half crudes, saponification crudes, evaporator salt, and mixtures of glycerol with trimethylene glycol and polyglycerols. Factors that influence the determination, such as size of sample, presence of salt and the presence of organic compounds containing hydroxyl groups, have been discussed.     

锂辉石在玻璃纤维中的应用

1澳大利亚锂辉石简介 澳洲夸拉尔公司于1994年就通过了ISO9002国际质量认证体系的验证,该公司生产的各种规格锂辉石品质稳定;Li2O含量高、Fe2O3及TiO2等杂质含量低;经加工后粒度细而均匀;其质量和计量由世界著名的瑞士"SGS"质量检验机构验证,品质可以得到可靠保证;包装为GWALIA公司原装出口吨袋包装.它是替代品位不稳定的低锂高铁锂云母、昂贵Li2CO3的理想选择.     

Thermodynamic analysis of glycerol partial oxidation for hydrogen production

Thermodynamics of glycerol partial oxidation for hydrogen production has been studied by Gibbs free energy minimization method. The optimum conditions for hydrogen production are identified: reaction temperatures between 1000 and 1100 K and oxygen-to-glycerol molar ratios of 0.4-0.6 at 1 atm. Under the optimal conditions, complete conversion of glycerol, 78.93%-87.31% yield of hydrogen and 75.12%-87.97% yield of carbon monoxide could be achieved in the absence of carbon formation. The glycerol partial oxidation with O₂ is suitable for providing hydrogen-rich fuels for Molten Carbonate Fuel Cell and Solid Oxide Fuel Cell. The carbon-formed and carbon-free regions are found, which are useful in guiding the search for suitable catalysts for the reaction. Inert gases have a positive effect on the hydrogen and carbon monoxide yields.     

Reaction kinetics and modelling of the gold catalysed glycerol oxidation

The kinetics of the glycerol oxidation using a carbon supported gold catalyst was studied experimentally in a batch reactor at oxygen pressures up to 10 bar and at temperatures from 25 to 100 °C. The influence of the mass transfer on the reaction was estimated and confirmed with theoretical calculations. A kinetic model has been proposed on the basis of a Langmuir-Hinshelwood mechanism for the experiments carried out in the kinetic regime and the kinetic parameters (reaction rate and adsorption constants as well as activation energies) were calculated.     

Use of waste products in glass melting

Translated from Steklo i Keramika, No. 2, pp. 2–4, February, 1991.     

Use of electric power in glass melting

The advantages and disadvantages of electric furnaces for melting frits and enamels and glasses for special applications were examined. It was shown that low-efficiency electric furnaces are more economical than furnaces heated by organic fuel. The main advantage of electric furnaces is the reduction in harmful emissions.Translated from Steklo i Keramika, Nos. 3–4, pp. 8–10, March–April, 1994.