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The solubility data of diosgenin in mixed systems of ethanol + 1-propanol (1 : 1), ethanol + 1-butanol (1 : 1), ethanol + isobutyl alcohol (1 : 1), methanol + isobutyl alcohol (1 : 1), methanol + isobutyl alcohol (1 : 4), ethanol + 1-pentanol (1 : 1) and carbon tetrachloride were measured over the temperature range from 289.15 K to 334.15 K by a laser monitoring observation technique at atmospheric pressure, with all mixtures mixed by volume ratio. The Apelblat equation, the ideal solution model, and the 2h equation are used to correlate the solubility data. The results show that the three models agree well with the experimental data, providing essential support for industrial design and further theoretical study. 相似文献
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This study investigated the hydrogenation of silicon tetrachloride (SIC14) in microwave plasma. A new launcher of argon (Ar) and hydrogen (Ha) plasma was introduced to produce a non-thermodynamic equilibrium activation plasma. The plasma state exhibited a characteristic temperature related to the equilibrium constant, which was termed "Reactive Temperature" in this study. Thus, the hydrogenation of SIC14 in the plasma could easily be handled with high conversion ratio and very high selectivity to trichlorosilane (SiHC13). The effects of SiC14/Ar and H2/Ar ratios on the conversion were also investigated using a mathematical model developed to determine the op- timum experimental parameters. The highest hydrogenation conversion ratio was produced at a H2/SiCl4 molar ratio of 1, with mixtures of SICl4 and H2 to Ar molar ratio of 1.2 to 1.4. In this plasma, the special system pressure and incident power were required for the highest energy efficiency of hydrogenating SIC14, while the optimum system pressure varies from 26.6 to 40 kPa depending on input power, and the optimum feed gas (He and SiCI4) molar en- ergy input was about 350 kJ. mo1-1. 相似文献
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A semi-empirical gas entrainment model was proposed for the ventilated cavity in vertical pipe, based on which, a complete numerical scheme was established by coupling with the Eulerian-Eulerian two-fluid model to predict the multiscale flow field created by ventilated cavity. Model predictions were validated against experimental measurements on void fraction and bubble size distributions. Simulations were carried out to explore the effect of ventilation rate and inlet turbulence intensity on the macroscale cavity shape and the bubbly flow downstream of the ventilated cavity. As the ventilation rate increasing, a reverse trend was observed for the void fraction and bub- ble size distributions. It is concluded that the average void fraction in the pipe flow region is determined by the volumetric ratio between liquid and gas. However, the bubble size evolution is dominated by the breakage effect induced by turbulence in the vortex region. Furthermore, simulations were conducted to analyze geometric scale effect based upon Froude similitude. The results imply that the velocity distributions were properly scaled. Slight scale effect was seen for the void fraction caused by faster dispersion of bubbles in the larger size model. The com- paratively greater bubble size was predicted in the smaller model, implying significant scale effects in terms of tur- bulence and surface tension effect. It reveals that empirical correlations valid in wide range are required for the ex- trapolation from small-size laboratory models. 相似文献
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The kinetics for production of ethyl levulinate from glucose in ethanol medium was investigated. The experiments were performed in various temperatures (433-473 K) and initial glucose concentrations (0.056-0.168 mol·L-1) with extremely low sulfuric acid as the catalyst. The results show that higher temperature can improve the conversion of glucose to ethyl levulinate, with higher yield of ethyl levulinate (44.79%, by mole) obtained at 473 K for 210 min. The kinetics follows a simplified first-order kinetic model. For the main and side reactions, the values of activation energy are 122.64 and 70.97 kJ·mo1-1, and the reaction orders are 0.985 and 0.998, respectively. 相似文献
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Molecular dynamics simulation with an all-atom force field has been carded out on the two binary sys- tems of [bmim][PF6]-CO2 and [bmim][NO3]-CO2 to study the transport properties, volume expansion and micro- structures. It was found that addition of CO2 in the liquid phase can greatly decrease the viscosity of ionic liquids (ILs) and increase their diffusion coefficient obviously. Furthermore, the volume expansion of ionic liquids was found to increase with the increase of the mole fraction of CO2 in the liquid phase but less than 35% for the two simulated systems, which had a significant difference with CO2 expanded organic solvents. The main reason was that there were some void spaces inter and intra the molecules of ionic liquids. Finally, site to site radial distribution functions and corresponding number integrals were investigated and it was found that the change of microstructures of ILs bv addition CO2 had a great influence on the orooerties of ILs. 相似文献
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以乙醇和乙二醇用直接法合成乙二醇单乙醚,探索了催化剂种类、反应温度、压力等因素对反应的影响,结果表明:以无水AlCl3为催化剂,乙二醇与乙醇的摩尔比为1:4,在240℃,压力7 MPa的条件下反应4 h,当催化剂用量为反应物总量的4%时,乙二醇的转化率35.8%,乙二醇单乙醚的选择性59.5%。通过单因素正交实验优化后,仍以无水AlCl3为催化剂,乙二醇与乙醇的摩尔比为1:4,在260℃,压力6 MPa的条件下反应4 h,乙二醇的转化率提高到38.8%,乙二醇单乙醚的选择性提高到59.9%。此外,考察了AlCl3/Na2HPO4复合催化剂在不同比例时对反应的影响。当无水AlCl3与Na2HPO4的摩尔比为1:3时,乙二醇的转化率为25.1%,乙二醇单乙醚的选择性为72.3%。 相似文献
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草酸二甲酯的气相加氢具有高水平的活性,采用共沉淀法制备需要不同特性规格的沉淀剂,催化剂的组合和反应条件都对乙二醇的合成性质具有明显的性能影响。通过采用独特的吸附方法表征制备的催化剂,以及通过试验获得的值表明草酸二甲酯的独特氢化反应与铜离子的独特活性状态密切相关。此外,通过气相催化得到的乙二醇,草酸二甲酯的比转化率可超过97%;乙二醇的选择性特征高达85%;制备的催化剂突出了最佳的稳定性能。 相似文献
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采用超声波萃取方法和气相色谱质谱联用技术(GC-MS),对油漆涂层中的乙二醇单甲醚和乙二醇单乙醚残留量进行定性定量检测技术研究,得到乙二醇单甲醚的仪器定性检出限为0.075 mg/L,方法的定量检出限最低为25 mg/kg;乙二醇单乙醚的仪器定性检出限为0.033 mg/L,方法的定量检出限最低为11 mg/kg。两者的标准工作溶液(2~50 mg/L)线性相关系数r均为0.999以上,连续进行6次测试各浓度响应峰面积的RSD在10%以内。进行前处理的正交实验,最佳萃取条件是使用甲醇在1130 W超声波萃取30分钟。 相似文献
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乙二醇合成方法研究探讨 总被引:1,自引:0,他引:1
文章分别对乙二醇的催化水合法、碳酸乙烯酯法和合成气法进行了阐述,不仅详细给出了合成的主要原材料、反应过程,而且对每种方法的优缺点进行了系统分析,并提出了自己的观点,以期为乙二醇的进一步研究提供参考。 相似文献
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综述乙二醇装置原料气、产品气以及系统废气的优化利用及综合回收利用,使煤制乙二醇及关联装置在气体利用上更加节能环保。 相似文献
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环氧乙烷催化法合成乙二醇的研究进展 总被引:2,自引:1,他引:1
对环氧乙烷催化法合成乙二醇研究的最新进展作了综述。阐述了用于环氧乙烷催化水合反应中的多羧酸衍生物催化体系、离子交换树脂催化体系、大环螯合物催化体系、季鏻盐催化体系、多相水滑石型催化体系及其他催化体系近年来的研究进展;同时阐述了用于碳酸亚乙酯法合成乙二醇反应中的催化体系的新进展。 相似文献
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简述了低压闪蒸系统的工艺流程和低压闪蒸塔的主要结构,简介了低压闪蒸系统投用后的运行概况和经济效益,表明通过新增低压闪蒸塔可有效地回收合成氨生产中的低压尾气,达到降低生产成本和保护环境的双重目的。 相似文献