共查询到19条相似文献,搜索用时 62 毫秒
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为了给醋酸仲丁酯的工业生产提供动力学支持,研究了醋酸和丁烯在液相中直接酯化合成醋酸仲丁酯的本征动力学。在间歇搅拌釜式反应器中,以阳离子交换树脂为催化剂,采用MTBE后续工段中除去异丁烯后的C4混合组分和醋酸发生酯化加成反应生成醋酸仲丁酯。在消除内外扩散的影响下考察了催化剂用量、反应温度对反应速率的影响。得到其酯化反应正反应速率常数及活化能分别为65.23 L/(mol.min)和325.17 J/mol;其酯化反应负反应速率常数及活化能分别为0.239 L/(mol.min)和900.47 J/mol。得到了合成醋酸仲丁酯的反应动力学方程,为反应精馏的模拟优化提供了基础数据。 相似文献
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用电导和粒度测试两种方法研究了壳聚糖在醋酸溶液中的溶解行为。结果显示:醋酸浓度、溶解温度和壳聚糖样品本身的脱乙酰度及分子量都会影响壳聚糖的溶解,但溶解初期壳聚糖因吸附醋酸根离子而产生聚集现象。一般情况下,温度高有利于壳聚糖的溶解。当壳聚糖脱乙酰度非常高,分子量差距又并不是非常大时,前者将对溶解起主导作用,同时脱乙酰度越高越有利于其溶解。 相似文献
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传统铬盐行业生产过程中铬的价态需经过三价到六价再到三价的转化。六价铬的高毒性导致铬成为国家重点防控的重金属。铬盐行业的可持续发展亟需开发避免六价铬产生的新技术,含铬原料的酸浸为可行的途径。本文提出以高碳铬铁合金为原料,盐酸为浸出剂的酸性浸出制备三价铬盐新工艺。浸出后的氯化铬和氯化亚铁可制备出三价铬盐产品,其可作为铁铬液流电池的电解液。本文在对高碳铬铁元素含量、物相组成及形貌等分析的基础上,系统研究了反应温度、盐酸浓度、搅拌速率和反应时间对铬和铁浸出率的影响规律。结果表明,在反应温度100℃、盐酸浓度9mol/L、搅拌速率250r/min、反应时间6h的条件下,铬浸出率为92%,铁浸出率为95%。进一步研究了高碳铬铁在盐酸中浸出的动力学。高碳铬铁的浸出过程符合未反应收缩核模型,铬浸出过程受化学反应控制,表观活化能Ea=65.95kJ/mol;铁浸出过程受化学反应控制,表观活化能Ea=63.85kJ/mol。 相似文献
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钛铁矿硫酸浸出动力学研究 总被引:8,自引:1,他引:7
研究了攀枝花钛铁矿在硫酸溶液中浸取反应的动力学行为,发现在温度为100℃-198℃、酸矿比为500:15时,钛精矿在85%硫酸溶液中的反应速率同时受矿粒表面反应和表面产物层传质阻力影响,表观反应活化能约68.4kJ/mol。浸出反应动力学方程为t=「0.00766/(2.74*10^7e^-68400/RT)」「1-x)^1/3」{1+(11-0.016T)「1+(1-x)^1/3-2(1-x)^2/3」}在酸矿比更低的非等温和准绝热实验中,该方程式可以很好地模拟反应的动力学特性。 相似文献
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The oxidation of CH4 over Pt–NiO/δ-Al2O3 has been studied in a fluidised bed reactor as part of a major project on an autothermal (combined oxidation–steam reforming) system for CH4 conversion. The kinetic data were collected between 773 and 893 K and 101 kPa total pressure using CH4 and O2 compositions of 10–35% and 8–30%, respectively. Rate–temperature data were also obtained over alumina-supported monometallic catalysts, Pt and NiO. The bimetallic Pt–NiO system has a lower activation energy (80.8 kJ mol−1) than either Pt (86.45 kJ mol−1) and NiO (103.73 kJ mol−1). The superior performance of the bimetallic catalyst was attributed to chemical synergy. The reaction rate over the Pt–NiO catalyst increased monotonically with CH4 partial pressure but was inhibited by O2. At low partial pressures (<30 kPa), H2O has a detrimental effect on CH4 conversion, whilst above 30 kPa, the rate increased dramatically with water content. 相似文献
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The effects of surfactant on the solvent extraction in leaching sphalerite were investigated. It is found that sodium dodecyl sulfonate is the effective surfactant in improving the zinc recovery from sphalerite in the aqueous FeCl3-HCl-tetrachloroethylene system. Through the measurements of surface tension and viscosity of the sphalerite slurry modified with different surfactants, it is concluded that sodium dodecyl sulfonate in the concentration range of 0.05 to 0.2g L-1 can improve the viscosity of sphalerite slurry in the water, decrease the surface tension of leaching solution, prevent the aggregation of ore particles, and give very high zinc extraction . 相似文献
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The synthesis and structure of (CH3CH[NH3]CH2NH3)1/2·ZnPO4, an organically templated zincophosphate (ZnPO) analogue of aluminosilicate zeolite thomsonite (THO), are described. The ZnPO framework is built up from an alternating, vertex-sharing, network of ZnO4 and PO4 groups (dav(Zn–O)=1.944 (8) Å, dav(P–O)=1.535 (9) Å, θav(Zn–O–P)=130.5°) involving distinctive 4=1 secondary building units. The 1,2-diammonium propane cations are highly disordered in the [0 0 1] 8-ring channels. Crystal data: (CH3CH[NH3]CH2NH3)1/2·ZnPO4, Mr=198.42, orthorhombic, space group Pncn (no. 52), a=14.119 (6) Å, b=14.136 (5) Å, c=12.985 (5) Å, V=2591 (3) Å3, Z=10, R(F)=0.057, Rw(F)=0.061 (for a twinned crystal). 相似文献
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Bohdan Schneider Jan Štokr Pavel Schmidt Marian Mihailov Stoil Dirlikov Nadezhda Peeva 《Polymer》1979,20(6):705-712
Infrared and Raman spectra of atactic PMMA and infrared spectra of stereoregular PMMA and of its four deuterated derivatives , were measured. They were used to assign the bands of stretching and deformation vibrations of CH2, CCH3 and OCH3 groups in the infrared and Raman spectra and to discuss the effect of stereoregularity on these bands in the infrared spectra. 相似文献
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《分离科学与技术》2012,47(8):1816-1828
Abstract Electric arc furnace (EAF) flue dust is generated during EAF steelmaking from iron-containing scrap such as recycled automobile bodies. The relatively high level of Zn (20–30 wt%) in EAF dusts provides a potentially valuable resource, even though the zinc is present as oxide phases such as zincite (ZnO) and zinc ferrite (ZnFe2O4). In this work, a method to deflocculate and disperse ZnO and ZnFe2O4 particles in aqueous suspension of EAF dust is developed and the efficiency of Zn recovery by the classification method was evaluated. Major findings of this study indicate that citric acid, a tetradendate chelating agent, demonstrates the best liberation and dispersion efficiency for EAF dust. Elutriating at 0.01 cm/min fluid velocity we recover 10 wt% of EAF dust (mostly ZnO particles) at a grad of 70 wt% Zn from a well-liberated and dispersed suspension of EAF dust. About 30 wt% of Zn recovery may be achieved using only simple classification. 相似文献
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Juan Fernández Jessely Molina Tamara Rajmankina José Arévalo álvaro Parada 《Polymer Bulletin》2007,59(5):629-636
Summary (C5H5)2Zr(O2C)CH3 and (C5H5)2Zr(O2C)CH2CH3 complexes were synthesized, characterized and activated with MAO for ethylene polymerization. The highest catalytic activity
was achieved at Al/Zr molar ratio of 3000 for both systems. The effects of the size of the R group in the carboxylate ligands,
the Al/Zr molar ratio and reaction temperature on the catalytic activity and polymer properties were studied and discussed. 相似文献