Kinetics of the peracetic acid decomposition: Part II: pH effect and alkaline hydrolysis

The effect of pH on the decomposition of peracetic acid in an aqueous solution was studied. It was found that three potential reactions, namely i) the spontaneous decomposition, ii) the hydrolysis and iii) the transition metal catalysed decomposition, are responsible for the consumption of peracetic acid. The spontaneous decomposition reaches its maximum at pH 8.2, while both the hydrolysis and metal ion catalysed decomposition increase as the pH increases. At pH 10.5 and higher, the hydrolysis becomes dominant when the metal ion catalysed decomposition is minimized by the addition of DTMPA. The kinetics of the peracetic acid hydrolysis was developed, which can very well predict the development of peracetic acid and hydrogen peroxide during the decomposition reaction.     

SOLUBILITY OF CO2 AND H2S IN A HINDERED AMINE SOLUTION

The solubility of H₂S and CO₂ in aqueous solutions of the sterically hindered amine, 2-amino-2-methyl-1-propanol (AMP), was determined at 40 and 100°C. Partial pressures of C)₂ ranged from approximately 2 to 6000 kPa and of H₂S from 2 to 2200 kPa. The solubility results were compared with previously reported acid gas solubilities in aqueous monoethanolamine (MEA) solutions.     

实验室用超高温氢气钼丝炉的研制

通过结构设计和负荷计算，研制出适合于实验室使用的以钼丝为电热体，电熔镁砂或镁铝尖晶石为沪芯材料，H2－N2混合气体为保护气氛和最高使用温度达1950℃的内挂式氢气钼丝炉。     

甲苯稀释对AlCl3-EMIC型离子液体电镀铝工艺氢脆性的影响

采用甲苯作为AlCl3-EMIC(1-乙基-3-甲基咪唑)型离子液体的稀释剂,其中纯态离子液体由物质的量比为2∶1的无水AlCl3和EMIC组成。对比了纯态和按稀释剂与离子液体体积比为1∶1稀释后电镀铝的外观、微观形貌和氢脆性。结果表明,采用甲苯稀释离子液体虽然可以降低镀液的黏度,改善镀层外观和微观形貌,但对离子液体电镀铝工艺的氢脆性有负面影响。     

Polymerization of liquid propylene with a fourth‐generation Ziegler–Natta catalyst: Influence of temperature,hydrogen, monomer concentration,and prepolymerization method on powder morphology

Liquid propylene was polymerized in a 5‐L autoclave batch reactor using a commercially available TiCl₄/MgCl₂/Al(ethyl)₃/DCPDMS Ziegler–Natta catalyst, with a phthalate ester as internal electron donor. The powders from these polymerizations were characterized using laser diffraction particle size distribution (PSD) analysis, scanning electron microscopy (SEM), and bulk density measurements. These characteristics were analyzed as a function of the process conditions, including hydrogen and monomer concentration, polymerization temperature, and the prepolymerization method. It was shown that polymerization temperature influences the powder morphology to a large extent. At low temperatures, high‐density particles were obtained, showing regular shaped particle surfaces and low porosities. With increasing temperature, the morphology gradually was transferred into a more open structure, with irregular surfaces and poor replication of the shape of the catalyst particle. When using a prepolymerization step at a relatively low temperature, the morphology obtained was determined by this prepolymerization step and was independent from conditions in main polymerization. The morphology obtained was the same as that observed after a full polymerization at temperature. Even when using a short polymerization at an increasing temperature, the morphology was strongly influenced by the initial conditions. The effect of variation in hydrogen concentration supported the conclusion that the initial polymerization rate determines the powder morphology. In the absence of hydrogen, high bulk densities, and regularly shaped particles were obtained, even at high temperatures. With increasing hydrogen concentration, the reaction rates increased rapidly, and with that changed the morphology. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1421–1435, 2003     

Combustion of a gasoline-hydrogen-air mixture in a reciprocating internal combustion engine cylinder and determining the optimum gasoline-hydrogen ratio

This paper reports results of an analysis of experimental data on the combustion of a gasoline-hydrogen-air mixture in a reciprocating internal combustion engine cylinder. The completeness of combustion of the mixture is shown to depend on the amount of hydrogen in the fuel mixture and the composition and physicochemical properties of the mixture. In particular, the conditions of addition of hydrogen to the gasoline-air mixture with active chemical action on the combustion process and the action of hydrogen as an additional fuel component are determined. A dimensionless universal relation is proposed that allows one to uniquely determine the initial composition of the fuel mixture (hydrogen to gasoline ratio) to accomplish combustion of the fuel mixture at the lean combustion limit. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 4, pp. 8–14, July–August, 2007.     

Time-of-flight studies on catalytic model reactions

Time-of-flight spectroscopy (TOF) and REMPI-TOF (resonance enhanced multi-photon ionization-TOF) were applied to measure the angular and translational energy distribution, as well as the internal state resolved energy distribution of desorption and reaction products on some model systems. Desorption of hydrogen and deuterium from clean and modified Pd(111) surfaces was studied, where the palladium sample was part of a permeation source. Water formation by reaction of oxygen with hydrogen on palladium was investigated by using different types of hydrogen supply: molecular H₂ exposure and atomic H exposure from the gas phase, as well as H exposure by permeating hydrogen. Vanadium oxide nanostructures on Pd(111) were prepared and the influence on D₂ desorption and D₂O production was investigated with the permeation technique. Additionally, deuterium desorption from sulfur and oxygen covered V(111) and V(100) surfaces was studied by TOF and REMPI-TOF spectroscopy. From the TOF spectra information concerning the reaction and desorption dynamics (activation barriers) could be gained.     

一步法合成硫化剂双25的新方法

报道一种有机过氧化物 2 ,5 -二甲基 -2 ,5 -双 (叔丁过氧基 )己烷 (简称双 2 5 )的合成新方法。研究了反应温度、过氧化氢浓度、反应物摩尔比以及反应物加入顺序对产品产率、品质的影响。该双2 5与硅橡胶硫化后的混炼胶物经各种性能测试 ,结果表明具有优良的性能     

利用厌氧折流反应系统进行有机废水发酵制氢

以厌氧折流形式的发酵生物制氢反应器进行了连续流有机废水发酵产氢试验研究。反应器由有机玻璃制成,三格室,单格有效容积9.16L。以好氧生物处理系统剩余污泥为种泥,在容积负荷为8.89kg COD·(m~3·d)~(-1),水力停留时间为13.5 h,温度(35±1)℃等条件下,系统启动运行25 d后达到稳定运行状态。系统稳定运行时,总产气量和产氢量分别稳定在59.0 L·d~(-1)和32.0 L·d~(-1)左右。其中,第一格室、第二格室和第三格室的平均产气量及其氢含量分别为14 L·d~(-1)、25 L·d~(-1)、20 L·d~(-1)和50％、60％、50％。系统污泥的比产氢速率为76.64 L·(kg VSS·d)~(-1)。与同类生物制氢反应器相比,厌氧折流发酵生物制氢反应器具有结构简单、运行稳定、操作灵活、容积利用率高、生物持有量高以及运行费用较低等优点,在发酵生物制氢技术领域有很好的开发前景。     

蒽醌法生产过氧化氢研究进展

过氧化氢是一种重要的无机化工产品，在工业上有着广泛的应用。而蒽醌法以其相对成熟的工艺成为当今世界过氧化氢的主要生产方法。综述了近些年来蒽醌法生产过氧化氢在工作液、氢化催化剂、氧化过程等方面的进展情况，并对其发展方向作一展望。