过氧化尿素的合成研究

利用高浓度双氧水与尿素反应合成过氧化尿素 ,考察了过氧化氢与尿素的摩尔比 ,反应温度 ,反应时间 ,稳定剂品种对产品性能的影响 ,得出最佳的反应条件为 :反应温度 30°C,反应时间40 min,磷酸二氢钠作稳定剂 ,稳定剂用量为 1 g,过氧化氢和尿素的摩尔比为 1 .4∶ 1 ,此时产品过氧化尿素的收率可达到 77%以上 ,产品中过氧化氢含量可达 35 %以上 ,60°C储存 2 4 h后产品的稳定率可达 95 .5 %。     

Microstructural Change of Ni–GDC Cermet Anode in the Electrolyte‐supported Disk‐type SOFC upon Daily Start‐up and Shout‐down Operations

The daily start‐up and shut‐down operations were carried out for the 1 kW‐class solid oxide fuel cell stack composed of 46 electrolyte‐supported disk‐type planar cells made by Mitsubishi Materials Corporation and Kansai Electric Power Company. The representative Ni–gadolinia doped ceria cermet anodes in the deteriorated cells were analyzed by the dual‐beam focused ion beam‐scanning electron microscope. The anode microstructures were reconstructed and the microstructural parameters such as triple phase boundary (TPB) length were quantified. The surface area of nickel phase decreased with an increase in the deterioration rate, leading to a reduction in the TPB length. Furthermore, the TPB length had a strong correlation with the voltage deterioration rate.     

Degradation of surfactant used in iron mining by oxidation technique: Fenton,photo-Fenton,and H2O2/UV—A comparative study

Reuse of water in mining helps reduce the volume of tailings directed to dams, avoiding overloads and ruptures, as occurred in Brumadinho, Brazil. Water reuse in mining requires treatment mainly for removing the surfactant substances used. Photo-Fenton and UV/H₂O₂ showed 96% to 98% degradation results of anionic surfactants within 5 minutes, suggesting this technique is faster than biological systems that can take days. This paper aims to study the degradation of a surfactant used in the flotation process by UV/H₂O₂, Fenton, and photo-Fenton oxidation techniques. The compound was characterized by FTIR and MALDI-TOF. In degradation experiments, the variation in reactants concentrations was evaluated with hydrogen peroxide, iron sulphate heptahydrate, and oxalic acid. We used a synthetic solution of surfactant in the reverse flotation of ore with 180 mg/L. The reaction was monitored with TOC analysis and a spectrophotometer throughout the reaction. The UV/H₂O₂ and Fenton system were studied by varying peroxide and iron concentrations, with 120 minute tests. Additionally, photo-Fenton concentrations, the pH variation (1.5-8.0), temperature (15°C, 21°C, and 60°C), and time were evaluated. The results showed the most efficient degradation was that using photo-Fenton, which achieved total TOC removal using 4500 mg/L of peroxide and 364 mg/L of iron for 330 minutes, while the UV/H₂O₂ system achieved 29% and 49% TOC removal of the Fenton. It is verified that the oxidative processes can be applied to degrade the surfactants present in the water recovered from the flotation processes.     

Characterisation of the Major Synthetic Products of the Reactions Between Butanone and Hydrogen Peroxide

The reactions between butanone and hydrogen peroxide, both catalysed and un‐catalysed, were investigated and spectral and sensitiveness data reported. The major product of the un‐catalysed reaction, 2‐hydroxy,2‐hydroperoxybutane, displayed a Figure of Insensitiveness (F of I) of 10, Temperature of Ignition (T of I) of 132 °C, and initiated when 128 N of frictional force or an electrostatic discharge (ESD) of 4.5 J was applied. Differential scanning calorimetric analyses revealed an onset of decomposition at 128 °C, peak maximum of 140 °C, and decomposition energy of 203 J g⁻¹. The major product of the cooled (5 °C) acid catalysed reaction between butanone and hydrogen peroxide, 2,2′‐dihydroperoxy‐2,2′‐dibutyl peroxide, displayed a F of I of<10, T of I of 110 °C and initiated upon application of 5 N of friction or a 0.45 J ESD. Calorimetry showed a melt at 38.3 °C, an onset of exothermic decomposition at 127 °C and the evolution of 1292 J g⁻¹. The major product of the raised temperature (20 °C) acid catalysed synthesis, 1,4,7‐trimethyl‐1,4,7‐triethyl‐1,4,7‐cyclononatriperoxane, displayed F of I of<10 and initiated upon application of 5 N of friction or a 0.45 J ESD. Calorimetry revealed an onset to melting at 28.9 °C, an onset to thermal decomposition at 128 °C, and decomposition energy of 1438 J g⁻¹.     

Development and thermal durability of an interfacial bond between electrolessly deposited metals and a fluorinated polyimide

The oxygen content of a fluorinated polyimide surface can be increased by exposure to an oxidant such as an alkaline permanganate solution. Deposition of an electroless metal layer on this oxidized surface results in the formation of an interfacial bond which is predominantly chemical in nature. The level of adhesion achieved depends both on the surface oxidation conditions and post-plating heating. Adhesion maxima are obtained by heating to 200°C for an electroless Cu deposit and to 300°C, the cure temperature for the polyimide film, for deposited electroless Ni. The fluorinated polyimide used in this study was derived from the reaction of 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane with pyromellitic dianhydride and was obtained from Ethyl Corporation as Eymyd® L30N resin.     

降低油脂中过氧化值方法的研究

以 Sn Cl2 为还原剂 ,降低油品的过氧化值 (POV)。通过一系列的试验研究表明 ,在非绝氧体系中 ,Sn Cl2 用量为 1%～ 2 % ,常温下 ,反应时间为 1h,去过氧化值效果显著 ,过氧化值由 5 0降为 0 .1,方法简单。     

Modelling mass transport in solid oxide fuel cell anodes: a case for a multidimensional dusty gas-based model

In this work the mass transport phenomena taking place in the fuel channel and the porous electrode of the anode of planar solid oxide fuel cells (SOFCs) are discussed. A comprehensive review of SOFC mass transport models in the literature is given and a new multidimensional, multicomponent, isothermal, dynamic model of the mass transport phenomena taking place in the fuel channel and the porous electrode of the anode of planar SOFCs is presented. The model can be used to predict species composition profiles and is based on the dusty-gas model (DGM) [Mason, E.A., Malinauskas, A.P., 1983. Gas Transport in Porous Media: The Dusty-Gas Model: Elsevier; Jackson, R., 1977. Transport in Porous Catalysts: Elsevier], which is considered to be the most accurate of the existing mass transfer models in porous media [Suwanwarangkul, R., Croiset, E., Fowler, M.W., Douglas, P.L., Entchev, E., Douglas, M.A., 2003. Performance comparison of Fick's, dusty-gas and Stefan-Maxwell models to predict the concentration overpotential of a SOFC anode. Journal of Power Sources 122, 9-18]. Our two-dimensional DGM is validated using experimental data [Yakabe, H., Hishinuma, M., Uratani, M., Matsuzaki, Y., Yasuda, I., 2000. Evaluation and modeling of performance of anode-supported solid oxide fuel cell. Journal of Power Sources 86, 423-431] and it is tested against a two-dimensional Stefan-Maxwell model (SMM) and against one-dimensional models (Fick's model, SMM and DGM) reported in the literature. It is shown that a detailed model is essential for the accurate prediction of concentration overpotentials especially at high fuel utilisation conditions, which are typical operating conditions for fuel cells [Hernández-Pacheco, E., Singh, D., Hutton, P.N., Patel, N., Mann, M.D., 2004. A macro-level model for determining the performance characteristics of solid oxide fuel cells. Journal of Power Sources 138, 174-186].     

温度对乳聚丁腈橡胶聚合的影响

采用中国石油兰州石化公司生产的丁腈橡胶N41乳液聚合配方,考察了不同聚合温度对反应时间的影响,测定了橡胶链化学结构组成、胶乳粒径、乳液机械稳定性和生胶门尼黏度等性能。结果表明:随着聚合温度的升高,反应时间缩短,丁腈橡胶链结构组成变化不明显。反应后期聚合温度的升高,导致胶乳粒径增大,机械稳定性降低,生胶门尼黏度升高。     

Performance analysis of K-based KEP-CO2P1 solid sorbents in a bench-scale continuous dry-sorbent CO2 capture process

Korea Institute of Energy Research (KIER) and Korea Electric Power Corporation Research Institute (KEPCORI) have been developing a CO₂ capture technology using dry sorbents. In this study, KEP-CO2P1, a potassium-based dry sorbent manufactured by a spray-drying method, was used. We employed a bench-scale dry-sorbent CO₂ capture fluidized-bed process capable of capturing 0.5 ton CO₂/day at most. We investigated the sorbent performance in continuous operation mode with solid circulation between a fast fluidized-bed-type carbonator and a bubbling fluidized-bed-type regenerator. We used a slip stream of a real flue gas from 2MWe coal-fired circulating fluidized-bed (CFB) power facilities installed at KIER. Throughout more than 50 hours of continuous operation, the temperature of the carbonator was maintained around 70-80 °C using a jacket-type heat exchanger, while that of the regenerator was kept above 180 °C using an electric furnace. The differential pressure of both the carbonator and regenerator was maintained at a stable level. The maximum CO₂ removal was greater than 90%, and the average CO₂ removal was about 83% during 50 hours of continuous operation.     

Degradation of poly(vinyl alcohol) in strongly alkaline solutions of hydrogen peroxide

The action of hydrogen peroxide and sodium hydroxide independently as well as in combination together with stabilizer formulation–consisting of magnesium sulphate (5 g/L), ethylenediamine tetraacetic acid (2 g/L), gluconic acid (2 g/L), and nonionic/anionic wetting agent (1.5 g/L)–on poly(vinyl alcohol) (PVA) was investigated at 30°C and 95°C. The effect of sodium hydroxide (5–25 g/L) alone was to bring about an enhancement in the viscosity of PVA most probably due to gel formation. The latter was favored at higher sodium hydroxide concentrations and longer duration (30 min) of treatment. The opposite holds true when hydrogen peroxide (35% w/v) was used alone at concentrations ranging from 2 to 20 mL/L. The viscosity of PVA decreased as the hydrogen peroxide concentration increased. Nevertheless, hydrogen peroxide alone could not cause complete dissolution of PVA even at 95°C for 30 min. On the other hand, complete dissolution of PVA could be achieved under the influence of stabilized alkaline solutions of hydrogen peroxide at 95°C in less than 10 min. It was postulated that, under the conditions used, oxidation of PVA by hydrogen peroxide prevailed over gel formation under the influence of sodium hydroxide.     

变频式自动真空滤油机在电网中的应用

分析了用于高压电网的变电设备尤其是进口设备的发展趋势 ,列举了二滩电网大溪沟电站变压器真空注油实例 ,以及台湾电力公司真空注油设备的控制系统原理 ,阐述了三级真空、全自动、变频技术在国际上的应用趋势和优点     

Physicochemical and Oxidative Changes in Sonicated Interesterified Soybean Oil

The effect of power ultrasound on physicochemical properties and oxidative stability of an interesterified soybean oil (IESBO) was investigated. IESBO was crystallized at 32 °C and sonicated for 10 s with acoustic power of 101 W. The sonicated IESBO was tested for melting behavior and chemical composition and compared to those of non sonicated IESBO to determine physical and chemical changes originated as a consequence of sonication. Application of power ultrasound affected the melting behavior of the crystallized fat and did not affect its chemical composition. Oxidation stability of the sonicated IESBO was measured using peroxide value (PV) and compared to that of non sonicated IESBO and liquid soybean oil (SBO) when stored at 25 °C for 105 days followed by storage at 40 °C for 42 days. Power ultrasound did not cause accelerated oxidation in SBO or IESBO until they were highly oxidized (PV > 10 mequiv/kg). At high levels of oxidation, non‐sonicated IESBO had significantly higher PV than sonicated IESBO, while non‐sonicated SBO had significantly lower PV than sonicated SBO.     

Azoperoxide. VI. Selektive Spaltungen von β-Azo-acylperoxiden

Azoperoxides. VI. Selective Decomposition of β-Azoacylperoxides The selective decomposition of the O O-Groups in the azoperoxides 1 and 2 is possible by reaction with dimethylaniline at 35°C. Rate constants were measured and the decomposition products were analyzed. Intermediates are azoalkyl radicals. The radical yield of the amine induced decomposition of 2 in ethylbenzene is 8.2% at 35°C. UV irradiation of the azoperoxides 1 and 2 at 20°C in ethylbenzene results in a quantitative and selective decomposition of the azo groups. Intermediates are C-radicals with intact peroxide groups. The reaction of 1 and 2 with triethylstannane yields reduction products of the O O-groups and the NN-groups, respectively.     

Effect of bed height on the carbon dioxide capture by carbonation/regeneration cyclic operations using dry potassium-based sorbents

The effect of bed height on CO₂ capture was investigated by carbonation/regeneration cyclic operations using a bubbling fluidized bed reactor. We used a potassium-based solid sorbent, SorbKX35T5 which was manufactured by the Korea Electric Power Research Institute. The sorbent consists of 35% K₂CO₃ for absorption and 65% supporters for mechanical strength. We used a fluidized bed reactor with an inner diameter of 0.05 m and a height of 0.8 m which was made of quartz and placed inside of a furnace. The operating temperatures were fixed at 70 °C and 150 °C for carbonation and regeneration, respectively. The carbonation/regeneration cyclic operations were performed three times at four different L/D (length vs diameter) ratios such as one, two, three, and four. The amount of CO₂ captured was the most when L/D ratio was one, while the period of maintaining 100% CO₂ removal was the longest as 6 minutes when L/D ratio was three. At each cycle, CO₂ sorption capacity (g CO₂/g sorbent) was decreased as L/D ratio was increased. The results obtained in this study can be applied to design and operate a large scale CO₂ capture process composed of two fluidized bed reactors. This work was presented at the 7 ^th China-Korea Workshop on Clean Energy Technology held at Taiyuan, Shanxi, China, June 26–28, 2008.     

Chemo‐enzymatic epoxidation of linoleic acid: Parameters influencing the reaction

The effect of reaction parameters on lipase‐mediated chemo‐enzymatic epoxidation of linoleic acid was investigated. Hydrogen peroxide was found to have the most significant effect on the reaction rate and degree of epoxidation. Excess of hydrogen peroxide with respect to the amount of double bonds was necessary in order to yield total conversion within a short time period, as well as at temperatures above 50 °C to compensate for hydrogen peroxide decomposition. However, prolonged incubation with high excess of hydrogen peroxide leads to the accumulation of peracids in the final product. The reaction rate increased also with increasing hydrogen peroxide concentration (between 10 and 50 wt‐%); however, at the expense of enzyme inactivation. Linoleic acid was completely epoxidized when used at a concentration of 0.5–2 M in toluene at 30 °C, while in a solvent‐free medium, the reaction was not complete due to the formation of a solid or a highly viscous oily phase, creating mass transfer limitations. Increasing the temperature up to 60 °C also improved the rate of epoxide formation.     

气相法聚丙烯生产工艺技术研究进展

从生产工艺特点、催化剂、反应条件和产品特点方面详细介绍了气相法聚丙烯生产工艺,如Ineos公司的Innovene工艺、Dow公司的Unipol工艺、NTH公司的Novolen工艺、Lyondell Basell公司的Spherizone工艺、JPP公司的Horizone工艺、住友化学公司的Sumitomo工艺。概述了我国近几年气相法聚丙烯生产工艺的应用现状,并对我国气相法聚丙烯生产工艺的未来发展提出了建议。     

Effect of degradative treatments on cotton graft copolymers. Part V. Behavior of poly(acrylamide)-cotton graft copolymers toward acid treatments

Polyacrylamide (Aam)-cotton graft copolymers having 9, 14.5, and 20% graft were synthesized using ferrous cellulose thiocarbonate-hydrogen peroxide redox system. These copolymers as well as ungrafted and initiator-treated cottons were subjected to acid treatments (0.5 N HCl) at 40°, 60°, and 80°C for 15-90 minutes. Hydrolytic susceptibility of the five substrates was assessed by monitoring carboxylic groups, copper, number, nitrogen content (in case of the copolymers), and tensile strength. Results obtained concluded that the copolymers exhibit higher resistance to acid hydrolysis than the ungrafted and initiator-treated cottons. This was explained in terms of involvement of the ? CONH₂ groups of the graft in an interaction with HCl.     

Degradation and cross-linking of ethylene-propylene copolymer rubber on reaction with maleic anhydride and/or peroxides

The reaction of EPR with dicumyl peroxide at 180°C or t-butyl perbenzoate at 140°C resulted in the formation of a fraction insoluble in cyclohexane at 22°C. The presence of maleic anhydride (MAH) in the EPR-peroxide reaction mixture increased the amount of insoluble polymer, whose concentration decreased as the peroxide concentration increased. The [η] of the cyclohexane-soluble polymer decreased and the MAH content increased as the peroxide concentration increased at constant MAH concentration. The [η] and the MAH content of the soluble polymer increased as the MAH concentration increased at constant peroxide concentration. The EPR-peroxide and EPR-MAH-peroxide reaction products were soluble in refluxing xylene and could be fractionated by precipitation with acetone. The presence of stearamide in the EPR-MAH-peroxide reaction mixture decreased the amount of cyclohexane-insoluble polymer, indicative of decreased cross-linking, but the [η] of the soluble EPR-g-MAH increased, indicative of decreased degradation, analogous to the effect of stearamide in the MAH-peroxide reactions with LDPE and PP, respectively.     

米氏醇的绿色合成工艺研究

以4,4’-双二甲氨基二苯甲烷(甲烷贝司)为原料,水做溶剂,在负载铁酞菁四磺酸的NaY沸石催化剂作用下,用双氧水氧化制得4,4’-双二甲氨基二苯甲醇(米氏醇),优化工艺参数为:甲烷贝司浓度1 mol/L,双氧水用量为甲烷贝司摩尔质量的2倍,催化剂用量为甲烷贝司质量的4％,室温反应2小时,催化剂可以回收再利用,米氏醇收率94％,产品纯度96％.