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铷作为稀有碱金属常与钾共存,氯化铷在不同溶剂中的溶解度是对铷化合物结晶提纯的理论依据,因此,探究氯化铷在不同溶剂中的溶解规律对于实现铷钾分离具有指导意义。实验分别测定了常压条件下氯化铷在甲酸、冰乙酸、正丙醇和乙二醇中303.15—343.15 K条件下的溶解度。结果表明:氯化铷在上述4种有机溶剂中的溶解度均随温度的升高而增大,其中温度对氯化铷在甲酸中的溶解度影响最为明显;在4种溶剂中溶解度的排序为:甲酸乙二醇冰乙酸正丙醇,甲酸比较适合用于氯化铷的重结晶。同时对实验数据进行了拟合,实验数据与理论计算结果吻合,所得拟合方程可为氯化铷重结晶工艺路线的制定提供理论依据。 相似文献
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N-(2,6-二甲苯基)-2-(1-哌嗪基)乙酰胺合成过程中,会同时有产品及哌嗪双取代副产物生成,通过研究两者在常规溶剂中的溶解度,利用溶解度差异,选用乙醇对产品进行纯化,革除了原有不适于工业化规模生产的乙醚重结晶纯化工艺。 相似文献
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重结晶提纯碳酸二苯酯的溶剂选择 总被引:1,自引:0,他引:1
为了寻找重结晶法提纯碳酸二苯酯(DPC)的适宜溶剂,文章对DPC重结晶溶剂的选择及影响DPC纯度的因素进行了研究。结果表明:乙醇是重结晶纯化DPC的适宜溶剂,DPC在乙醇中溶解度在5—15℃的区间内变化缓慢,重结晶中止温度在15℃左右,DPC的收率高于89.0%。乙醇和DPC比率(质量比)采用8∶5为重结晶DPC时的适宜比率。通过对重结晶溶剂的进一步研究,发现采用水-乙醇的混合溶剂作为重结晶溶剂时,可以明显提高DPC的收率。水的质量分数在25.0%—35.0%范围内时,DPC的收率大于93.0%,纯度高于99.6%。其纯度符合合成聚碳酸酯的要求。 相似文献
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麦芽酚广泛应用于日化、饮料、医药、烟、酒等精细化工领域.其合成过程为:先进行格氏试剂的合成:卤代烷及Mg在苯、四氢呋喃溶剂存在下进行反应,然后与糠醛加成,再经水解得到糠基醇中间体,将制得的糠基醇在甲醇和水为溶剂的条件下用氯气氧化,最后在酸性介质中加热水解,得到麦芽酚粗产品,将制得的粗产品在乙醇等溶剂中进行结晶和重结晶,晶体干燥后包装. 相似文献
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丙交酯交替溶剂重结晶纯化法及其对聚合的影响 总被引:2,自引:1,他引:1
研究了交替溶剂重结晶丙交酯的纯化方法.首先优化了重结晶时间:在乙酸乙酯体系中,每百克溶剂中溶解丙交酯45 ~75 g,重结晶最佳时间为3~5 h;在乙醇体系中,每百克溶剂中溶解丙交酯30 ~45 g,重结晶最佳时间为1 ~3 h,结果表明,通过控制重结晶时间可达到最佳重结晶效果.以聚合效果比较了以上两种溶剂重结晶的结果,结果表明,乙醇体系重结晶率可高出乙酸乙酯体系约10%,但其纯化的丙交酯经聚合获得的产物分子量却远远低于乙酸乙酯体系.为此,采用交替溶剂重结晶法,即先使用乙醇重结晶丙交酯以获得高结晶率,再以乙酸乙酯重结晶则可在高得率的条件下获得高分子量聚丙交酯.用该法纯化得到的丙交酯经聚合后,产物的分子量可达43×104. 相似文献
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纯度标准物质HMX的制备及均匀性检验 总被引:1,自引:0,他引:1
以工业特级品HMX为基体,研究了HMX的纯化工艺,制备出军用纯度标准物质HMX.考察了用不同溶剂重结晶对HMX纯度的影响,选择用两种重结晶方法、分三步操作纯化HMX:首先用二甲基亚砜作溶剂,80℃溶解HMX,趁热过滤除去无机杂质和机械杂质后,用溶剂-非溶剂沉淀技术使HMX结晶析出;第二步以乙腈为溶剂重结晶纯化HMX,HMX的纯度达到99.60%以上;最后用MOS级无水乙醇煮洗,进一步去除有机杂质和溶剂残留.液相色谱分析、X射线粉末衍射分析和均匀性研究结果表明,所制备的纯度标准物质HMX纯度不小于99.70%,晶型为β型并且均匀性良好. 相似文献
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采用重量法测量了288.35~322.75 K温度范围内β-蒿甲醚在正丙醇、异丙醇、丙酮、乙酸乙酯及N, N-二甲基甲酰胺中的溶解度.结果表明β-蒿甲醚在五种有机溶剂中的溶解度均随温度的升高而增大,但在不同的溶剂中溶解度及其温度敏感性存在一定差异,在N,N-二甲基甲酰胺、乙酸乙酯和丙酮中的溶解度相对较大,而在正丙醇和异丙醇中的溶解度相对较小但对温度比较敏感.采用经验方程和理想溶液模型对实验数据进行了关联,计算值与实验值吻合良好.上述结果可为蒿甲醚结晶过程溶剂选择提供基础数据. 相似文献
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环氧树脂固化剂2—甲基咪唑的纯化 总被引:1,自引:0,他引:1
本文用重结晶法对环氧树脂固化剂2-甲基咪唑进行纯化,重点讨论了纯化过程中溶剂选择和溶剂用量确定两个问题,并对产物质量进行了标定。 相似文献
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MEASUREMENT AND CORRELATION OF TAXOL SOLUBILITY IN METHANOL,ETHANOL AND METHANOL-WATER SYSTEMS 下载免费PDF全文
Taxol is a unique antitumor drug that appears to exert its activity as a result of interference with microtubular structure and function. The Taxol solubility of in methanol, ethanol and methanol-water was measured by the equilibrium method in this paper. The data obtained were correlated by the regress equation and ANN model. The results showed that the both were in excellent agreement with the experimental data and the ANN model was more convenient than the regress equation. 相似文献
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The chemical composition, water activity, temperature and equilibrium moisture content (EMC) for 10 selected fruits were determined. Two methods of water sorption modeling, the GAB equation and the artificial neural network (ANN) method, were compared for their ability to predict water sorption behavior. Unlike the GAB equation, which uses only physical data for modeling, the ANN method uses both physical and chemical compositional data to make predictions. The ANN was superior, in most cases, to that of the GAB equation, in predicting EMC. This superiority was due to the availability of the additional chemical compositional information. The ANN method could predict EMC with a mean relative error of 9.85% and a standard error (Sx) of 1.59% EMC. The correlation coefficient (r2) of the relationship between the actual and predicted values of equilibrium moisture content obtained by the ANN was 0.9938. The ANN model was able to show a temperature dependent crossing of water sorption isotherms, due to the dissolution of sugar crystals in the fruit. The ANN was also able to predict the extent of crossing, depending upon differences in the individual fruit chemical composition. 相似文献
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《Drying Technology》2013,31(8):1543-1554
The chemical composition, water activity, temperature and equilibrium moisture content (EMC) for 10 selected fruits were determined. Two methods of water sorption modeling, the GAB equation and the artificial neural network (ANN) method, were compared for their ability to predict water sorption behavior. Unlike the GAB equation, which uses only physical data for modeling, the ANN method uses both physical and chemical compositional data to make predictions. The ANN was superior, in most cases, to that of the GAB equation, in predicting EMC. This superiority was due to the availability of the additional chemical compositional information. The ANN method could predict EMC with a mean relative error of 9.85% and a standard error (S x ) of 1.59% EMC. The correlation coefficient (r 2) of the relationship between the actual and predicted values of equilibrium moisture content obtained by the ANN was 0.9938. The ANN model was able to show a temperature dependent crossing of water sorption isotherms, due to the dissolution of sugar crystals in the fruit. The ANN was also able to predict the extent of crossing, depending upon differences in the individual fruit chemical composition. 相似文献
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Drying rate data were generated for training of an ANN model using a liquid diffusion model for potato slices of different thicknesses using air at different velocities, humidities and temperatures. Moisture content and temperature dependence of the liquid diffusivity as well as the heat of wetting for bound moisture were included in the diffusion model making it a highly nonlinear system. An ANN model was developed for rapid prediction of the drying rates using the Page equation fitted to the drying rate curves. The ANN model is verified to provide accurate interpolation of the drying rates and times within the ranges of parameters investigated. 相似文献
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咖啡因在水和乙醇中的溶解度及其关联 总被引:7,自引:0,他引:7
The solubility of caffeine in water and ethanol at 0—50 ℃ was measured using the laser method. The results were regressed with an empirical equation and simplified EOS correlation. A 2 - 2 - 1 backpropagation (BP) artificial neural network (ANN) model was selected from many other models. The prediction of interpolation and extrapolation of the data was made with trained 2 - 2 - 1 BP ANN model. The result was satisfactory. 相似文献
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《Drying Technology》2013,31(9):1867-1884
Abstract Drying rate data were generated for training of an ANN model using a liquid diffusion model for potato slices of different thicknesses using air at different velocities, humidities and temperatures. Moisture content and temperature dependence of the liquid diffusivity as well as the heat of wetting for bound moisture were included in the diffusion model making it a highly nonlinear system. An ANN model was developed for rapid prediction of the drying rates using the Page equation fitted to the drying rate curves. The ANN model is verified to provide accurate interpolation of the drying rates and times within the ranges of parameters investigated. 相似文献
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