萃取精馏分离环己烷-环己烯溶剂的筛选

通过一个简单的汽液平衡装置,研究了N,N-二甲基甲酰胺、N,N-二甲基乙酰胺、N-甲基吡咯烷酮、二甲基亚砜、γ-丁内酯、N-甲酰基吗啉溶剂以及混合溶剂在萃取精馏分离环己烷-环己烯过程中的分离性能。结果发现二甲基亚砜单独作为溶剂时表现出最佳的分离性能。溶解性好的溶剂往往分离性能一般,而分离性能好的溶剂又存在溶解性差的问题。进一步通过萃取精馏实验证明了溶剂的实际分离效果由溶剂的分离性能与溶解性共同决定。结果表明:二甲基亚砜和N,N-二甲基甲酰胺混合溶剂表现最佳的实际分离效果。     

萃取精馏中二元混合溶剂的研究

通过实验找到了一个萃取精馏分离苯/环己烷近沸点体系的新的二元混合溶剂N,N-二甲基亚砜和N,N-二甲基甲酰胺,并确定了该溶剂的最佳组成,实验测定结果表明,该混合溶剂分离效果和溶剂性能均优于文献报道的溶剂,文中最后分析了混合溶剂优于单一溶剂分离效果的原因.     

间歇萃取精馏分离苯-环己烷的流程模拟及参数分析

苯和环己烷混合物是化工中非常典型的二元共沸物系。选用二甲基亚砜(DMSO)和N-甲基吡咯烷酮(NMP)的质量配比为DMSO∶NMP=1∶3作为混合溶剂,在前期实验验证基础上,采用ASPEN PLUS11.1化工模拟软件中的BatchFrac单元操作模块,采用UNIFAC物性计算方法,通过改变各操作参数,对苯和环己烷二元共沸物系的分离进行间歇萃取精馏模拟计算。模拟结果表明:常压操作条件下,塔顶环己烷质量分率可达到98%,模拟计算的运用能够为实验进一步研究提供很好的理论依据和设计参考。     

混合溶剂抽提甲基环己烷的溶剂性能

采用浊点法测定了甲基环己烷-庚烷-单-溶剂（N-甲基-吡咯烷酮,NMP）或混合溶剂（N-甲基-吡咯烷酮＋环西砜、苯甲醇＋环丁砜）的三元或四元体系在（25±0．1）℃下的液液分层曲线．结合体系的物性（如折光指数或比重）测定了各体系的结线数据．由实验数据计算得到的选择性系数、溶解度和容量等数据,可以初步评价单一溶剂以及混合溶剂体系萃取分离烷烃与环烷烃的基本性能．研究发现单一纯溶剂的选择性系数较小,但与环丁砜组成混合溶剂体系能在一定范围内提高选择性系数．苯甲醇与环丁砜混合溶剂体系的选择性系数、溶解度和容量优于相同质量组成的N-甲基-吡咯烷酮与环丁砜混合溶剂体系．     

N-甲基吡咯烷酮合成技术分析

N-甲基吡咯烷酮是一种性能优良的化工溶剂。该文简要分析了N-甲基吡咯烷酮的国内外市场情况,对比分析了γ-丁内酯与单甲基胺、混合甲基胺无催化及催化合成技术,以及丁二醇脱氢制γ-丁内酯γ一丁内酯胺化一体化制N-甲基吡咯烷酮技术,提出了N-甲基吡咯烷酮技术发展建议。     

萃取精馏分离乙酸甲酯-甲醇溶剂

用汽液平衡装置对萃取精馏分离乙酸甲酯-甲醇极性共沸体系的溶剂选择进行了实验研究.结果表明:被分离物系的分离效果随溶剂比(质量比)的增大而增大;二元混合溶剂(二甲基亚砜DMF+N,N-二甲基甲酰胺DMSO)和三元混合溶剂(N-甲基吡咯烷酮NMP+DMF+DMSO)的分离效果优于单一溶剂(DMF),且DMF和DMSO的摩尔...     

萃取精馏分离乙腈-正丙醇的研究

采用萃取精馏的方法分离乙腈-正丙醇的共沸物系。首先利用溶剂选择原理和UNIFAC基团贡献法选出N-甲基吡咯烷酮作为萃取精馏的萃取剂,同时采用NRTL模型对常压下乙腈-正丙醇物系和加入萃取剂N-甲基吡咯烷酮后的汽液平衡进行模拟和实验验证,模拟结果与实验数据吻合较好。然后通过间歇萃取精馏实验进一步考察所选萃取剂的分离效果。结果表明,N-甲基吡咯烷酮能够打破共沸,有效分离乙腈-正丙醇共沸物系。采用有28块理论板的填料塔,萃取剂进料位置为第4块板,溶剂比为1.0,回流比为3,可以从塔顶得到质量分数为98.6%的乙腈产品。最后,用Aspen Plus软件对乙腈-正丙醇物系的连续萃取精馏流程进行了模拟,得出的参数为进一步的工业应用奠定基础。     

萃取精馏技术在环己醇生产中的应用

介绍了萃取精馏的基本原理,萃取剂选择时要考虑的几个影响因素,在环己醇生产中应用N,N-二甲基乙酰胺作萃取剂,通过萃取精馏将苯加氢反应后的混合物料中的苯、环己烯、环己烷有效分离为纯组分,并对萃取精馏过程中蒸汽温度、塔的操作压力和混合物中水分等因素对系统的影响作了简要分析.     

γ-丁内酯（GBL）下游产品需求预测

◆N-甲基吡咯烷酮（NMP） 由γ-丁内酯与甲胺经过缩合而得。该品作为一种高效选择性溶剂，主要用于有机原料的回收、润滑油精制和聚合反应的溶剂。另外还可以合成医药，颜料、香料及清洗剂等精细化学品的合成。2005年，我国N-甲基吡咯烷酮产量约为2．5万吨，随着我国石油化工和塑料工业的发展，N-甲基吡咯烷酮的需求量将呈现年均8％的增长速度。     

低共熔溶剂萃取精馏分离苯/环己烯共沸物研究

以四丁基溴化铵(TBAB)、氯化胆碱(ChCl)为氢键受体,乙二醇(EG)、乙酰丙酸(LA)为氢键供体合成的TBAB:EG (1:2), TBAB:LA (1:2), ChCl:LA (1:2)三种低共熔溶剂(DES)作为萃取剂,通过萃取精馏分离苯-环己烯共沸体系。实验测量了环己烯-苯-DES三元体系气液相平衡,并对DES组成中氢键供体和氢键受体对分离性能的影响进行探讨。结果表明,DES的分离性能由高到低依次为ChCl:LA (1:2)>TBAB:LA (1:2)>TBAB:EG (1:2);采用NRTL模型关联环己烯-苯-DES三元体系的气液相平衡数据,拟合得到体系二元交互参数;在Aspen Plus V7中针对ChCl:LA (1:2)为溶剂的萃取精馏过程进行建模计算,并将其分离效果与传统溶剂N,N-二甲基乙酰胺(DMAC)进行对比,以DES为溶剂的萃取精馏过程相比于DMAC,回流比由3.8降至0.30,流程整体热负荷减少了16.57%。     

混合溶剂对TiO2/PVDF平板超滤膜性能和结构的影响

采用N,N-二甲基乙酰胺(DMAC)和N-甲基吡咯烷酮(NMP)为混合溶剂制备PVDF超滤膜。考察了不同混合比例的DMAC和NMP对膜性能及膜结构的影响,同时利用扫描电子显微镜(SEM)对膜表面及断面结构进行分析,原子力学显微镜(AFM)对膜表面粗糙度进行了分析,利用接触角测量仪对膜表面接触角进行了测量。结果表明,使用混合溶剂对膜孔径和膜亚层结构影响较大,但混合溶剂对膜孔隙率和接触角基本没有影响。当混合溶剂DMAC/NMP为1:2时,膜性能达到最优,孔隙率为70%,平均孔径为0.24μm,水通量为373 L.m-2.h-1,截留率为88%。     

Phase separation in polyetherimide/solvent/nonsolvent systems and membrane formation

Phase separation phenomena of polyetherimide (PEI)/solvent/nonsolvent systems were investigated by measuring their precipitation values over the temperature range from 20 to 50°C. The solvents used are N‐methyl‐2‐pyrrolidone (NMP), dimethylacetamide (DMAC), and dimethylformamide (DMF). Nine nonsolvents were employed including water, methanol, ethanol, 1‐propanol, 2‐propanol, acetic acid, propionic acid, ethylene glycol, and diethylene glycol. Based on the measured precipitation values, critical solubility parameters for PEI were calculated, and the partial solubility boundary for PEI was obtained in a two‐dimensional solubility parameter coordinate graph. The relationship between solvent strength and membrane structure was examined using PEI hollow‐fiber membranes prepared from binary polymer solutions containing NMP, DMAC, and DMF as solvents. Water was used both as internal and external coagulants. The cross‐sectional structure and gas permeation properties of these hollow fibers were examined. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1789–1796, 1999     

Preparation and characterization of polysulfone–cyclodextrin composite nanofiltration membrane: Solvent effect

α-Cyclodextrin membranes were prepared by the phase inversion method using four types of casting solvents such as N-methyl pyrrolidone (NMP), dimethyl sulfoxide (DMSO), dimethyl acetamide (DMAc), and dimethyl formamide (DMF) herein-after termed as α-CD-NMP, α-CD-DMSO, α-CD-DMAc, and α-CD-DMF, respectively. The membranes were characterized by IR, XRD, TGA-DTA, DSC, and SEM analysis and show that solvents like NMP, DMA, DMF give good uniform morphological membranes and are better than that of DMSO. Thermal decompositions of the pure polymer and composite membranes indicate different range of thermal degradation of the membrane. This study reveals that the casting solvents NMP, DMF, DMAC have nearly same significant effect on morphology and other properties of the membranes. This is explained in terms of demixing behavior of the polymer and the combined effect of solvent volatility and polymer–solvent interactions as estimated from Hansen solubility parameter. Solvent hydrophobicity also affects the performance of the membrane and can be determined in terms of water permeability. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

萃取精馏分离苯-环己烷三元混合溶剂的效应

引言环己烷是一种性能较好的溶剂,可用来取代苯作脱油脂剂及脱漆剂等,因其一般通过苯催化加氢或汽油分馏来制备,在其产物中通常存在苯和环己烷的混合物,由于二者沸点相近,能形成最低共沸混合物,所以如何对苯和环己烷混合物系进行分离,许多研究人员对此进行了研究。     

Influence of solvent,Lewis acid–base complex,and nanoparticles on the morphology and gas separation properties of polysulfone membranes

A series of polysulfone (PSF) membranes were prepared using different solvents: dimethylformamide (DMF), tetrahydrofuran, dimethylacetamide, and n-methyl-2-pyrrolidone (NMP). The PSF membrane prepared by NMP showed the highest gas permeability. The influence of propionic acid as a Lewis acid on gas separation properties of the PSF was explored. The PSF membrane prepared by the casting solution containing 25 wt% PSF, 35 wt% propionic acid, and 40 wt% NMP showed a superior gas separation performance. The gas permeation measurements indicated that incorporating 30 wt% γ-alumina nanoparticles into the PSF matrix resulted in about the respective 43% and 41% increase in CO₂ and O₂ permeability together with a rise in CO₂/CH₄ and O₂/N₂ selectivities (13% and 7%, respectively). Furthermore, by rearranged modified Maxwell model, the role and nature of the interfacial layer in the PSF-based mixed matrix membranes were mathematically analyzed considering a reduced permeability factor.     

Solution thermodynamic study of several hydrocarbons in γ-butyrolactone and ethylene glycol mixtures by GLC

The gas—liquid chromatographic technique was used to determine the thermodynamic properties of solutions at infinite dilution for binary and ternary systems of five normal paraffins (C₅–-C₉), cyclohexane, benzene and toluene with γ-butyrolactone and ethylene glycol mixtures. A combination solvent of 50 mol % of γ-butyrolactone and ethylene glycol was shown to have the highest selectivity towards aromatic hydrocarbons.     

聚偏氟乙烯膜的制备及其影响规律的研究

以聚偏氟乙烯(PVDF)为膜材料,LiCl为添加剂,NMP,DMF,DMAC为溶剂进行正交试验,确定不同的溶剂种类,聚合物浓度,添加剂浓度对膜结构和性能的影响,并通过正交实验分析出最佳的制膜液组成:18%PVDF/3%LiCl/DMAC,经表征后纯水通量为223.73L/m2h,对牛血清白蛋白(M=67000)截留率为78%,孔径为44nm。     

萃取精馏复合溶剂的复配选择

提出按溶剂之间复配形成氢键的情况和修正的UNIFAC模型相结合的方法选择分离共沸体系的萃取精馏复合溶剂。准确测量了共沸体系与萃取精馏单溶剂和复合溶剂的汽液平衡数据,结果表明采用的萃取精馏单溶剂和复合溶剂的选择方法具有较好的准确度,模拟值与实验值比较,相对偏差均小于9%。通过综合比较得到分离乙酸乙酯-乙醇、乙醇-水和环己烷-苯3个共沸体系的最佳复合溶剂及配比。在最佳复合溶剂组成下,原共沸体系的相对挥发度达到最大值,该值优于组成复合溶剂的单溶剂所达到的分离效果。在最佳复合溶剂组成下,改变原料体系组成,复合溶剂组成对原料体系相对挥发度的影响趋势基本相同,这表明复合溶剂在萃取精馏塔内不同原料组成下均能较好地增加体系的相对挥发度,为工业上在萃取精馏过程中使用复合溶剂提供了理论依据。