共查询到19条相似文献,搜索用时 70 毫秒
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以大黄为实验材料 ,利用半连续提取设备 ,分别采用简单提取和循环提取的方式 ,研究了溶剂流速对提取率和提取液浓度的影响。结果表明简单提取的速度快 ,极限提取率高 ,提取液浓度在初期很高 ,并随提取率增加而下降 ;循环提取溶剂用量和提取液浓度易控制 ,收率受级平衡限制而较低 ;适当增大溶剂流速可缩短提取时间 ,但会增加前者的溶剂消耗 ;在简单提取中引入回流对后期的提取有一定促进作用 ,回流的时间和回流强度值得研究。将简单提取和循环提取适当组合能够在保证效率的基础上使收率和提取液浓度有较大提高。 相似文献
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植物精油提取新技术的研究进展 总被引:1,自引:0,他引:1
随着化工分离技术研究的不断深入,植物精油的提取技术也得到了进一步发展,出现了很多新的提取技术和方法。介绍了植物精油的提取技术,包括超临界CO~2萃取、连续亚临界萃取、微波萃取、微胶囊双水相萃取、超声波萃取、分子蒸馏、酶法提取等方法,对这些技术进行了分析,同时展望了植物精油提取技术的发展前景。 相似文献
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针对目前国内外研究植物有效成分的常用提取、分离技术和方法,对比分析了各种常用的提取、分离技术和方法的适用性和局限性,通过多种提取方法的例举描述了现代植物有效成分的研究现状,并阐述了植物提取分离技术的发展前景。 相似文献
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采用以水为萃取剂、酒精为沉淀剂的方法,从芋头中提取植物胶,研究了萃取温度、萃取时间、沉淀液的用量对植物胶产量的影响,并确定了芋头植物胶的最佳提取条件。 相似文献
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综述了溶剂抽提的发展和现状,介绍了V(CS2)∶V(NMP)=1∶1的混合溶剂,对影响该混合溶剂抽提率的因素、抽提机理和相关理论计算研究进行了讨论,展望了该领域的研究方向。 相似文献
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Butyl hexanoate(BuHE) is an important long-chain ester that is widely used in the food, beverage and cosmetic industries. In this work, reactive extraction concept was proposed to intensify the BuHE formation in a biphasic system, in which deep eutectic solvent(DES) comprising 2-methylimidazole(2-MIm)and p-toluenesulfonic acid(PTSA) was used as dual solvent-catalyst. First, the effect of 2-MIm to PTSA molar ratio on esterification was investigated to determine the optimum DES of [2-MIm:2 PTSA], which was characterized by FT-IR and TGA. Then, the liquid–liquid equilibrium(LLE) and esterification experiments were carried out to confirm the extraction and catalytic effect of [2-MIm:2 PTSA], respectively.Afterwards, the pseudo-homogeneous kinetic model was employed to describe the esterification kinetics.Finally, the intensification mechanism of reactive extraction for BuHE formation was proposed according to the experiments and interaction effect analysis. 相似文献
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A solvent extraction process based on organophosphorus extractant EHEHPA has been developed to raise the purity of erbium from ~20 to >85% in the product solution. The challenging task of upgrading erbium value in a host of chemically similar heavy rare earths present in a concentrate (% composition: Dy2O3: 58.72, Er2O3: 21.45, Ho2O3: 13.33, Tm2O3: 0.67, Yb2O3: 4.74 and Y2O3: 1.09) was accomplished by careful selection of process parameters such as aqueous feed acidity, EHEHPA concentration, total rare earths concentration in feed solution, phase ratio, scrubbing agent, and so forth. Under optimised conditions, a multi-stage counter-current and scrubbing test runs raised the purity of erbium to >85% with >95% recovery in the product strip solution. Amongst the various scrubbing agent, 0.025M Er2O3 at 1.2M HCl was found to be superior. 相似文献
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分析了煤溶剂萃取的研究现状,对比了微波溶剂萃取、超临界流体萃取和超声波萃取3种新技术在萃取过程中的优劣及萃取结果,对如何有效、经济、合理地利用煤的问题给予启示.基于当前煤化工的发展状况,对煤的溶剂萃取研究前景进行了展望. 相似文献