裂解C_9与溶剂之间汽液平衡数据的测定及溶剂筛选

裂解C9是乙烯装置的副产,产量很大,对其研究具有重要的经济意义.实验测定裂解C9汽液平衡数据,计算各组分之间相对挥发度,以确定精馏过程分离条件;测定裂解C9与溶剂之间汽液平衡数据,计算各主要组分之间的相对挥发度,通过气质联用色谱法分析实验结果,对比分析不同溶剂对相对挥发度的影响,筛选出甘油作为裂解C9萃取精馏实验的最佳溶剂.本文研究为进一步放大实验、裂解C9的精馏预处理及萃取精馏提取C9馏分提供依据.     

正己烷-甲基环戊烷-邻苯二甲酸二丁酯三元体系汽液平衡研究

测量了不同压力下正己烷-甲基环戊烷-邻苯二甲酸二丁酯三元体系等压汽液平衡数据，确定了该体系Wilson方程模型参数，并以Wilson方程为汽液平衡模型，采用微机模拟计算了以邻苯二甲酸二丁酯为溶剂，萃取精馏分离正己烷-甲基环戊烷混合物的分离结果，结果表明，萃取精馏分离该混合物效果良好。     

碳酸二甲酯-甲醇-糠醛三元体系汽液平衡数据的推算与关联

测定了DMC-CH_3OH,DMC-C_5H_4O_2,CH_3OH-C_5H_4O_2二元体系汽液平衡实验数据,利用二元体系的汽液平衡数据,运用C语言用NRTL状态方程模拟推算了碳酸二甲酯-甲醇-糠醛三元体系在常压下的汽液平衡,并对数据进行了关联。为建立精馏分离碳酸二甲酯-甲醇二元共沸体系的数学模型提供了必要的VLE数据。     

盐-水-乙醇-乙二醇体系汽液平衡的预测

电解质溶液汽液平衡的预测和计算是是热力学的一个重要研究领域,是加盐萃取精馏模拟计算的重要基础,精 确的推算电解质溶液的汽液平衡数据有着十分重要的理论和实际意义。本文改进了计算电解质溶液汽液平衡的LI- QUAC模型,用计算水-乙醇-乙二醇体系汽液平衡更为精确的NRTL模型代替lIQUAC模型中的UNIFAC模型来计 算溶剂分子间相互作用对超额Gibbs自由能的影响,并据此推算出两种盐-水-乙醇-乙二醇体系的汽液平衡数据, 与本文实验数据及文献数据比较,结果比较满意。该模型对电解质溶液汽液平衡的进一步研究以及加盐萃取精馏的工 程计算均具有一定的指导意义。     

二乙氧基甲烷-乙醇-水体系萃取精馏溶剂的筛选

由于二乙氧基甲烷-乙醇-水体系形成共沸物且共沸点接近,不能用普通精馏的方法分离,本文提出采用萃取精馏分离法。从二乙氧基甲烷、乙醇、水与溶剂分子之间存在的诱导力、静电力、色散力及氢键出发,分析和对比十二类溶剂,提出选用多元醇、水、胺类、酮作为萃取精馏溶剂;通过汽液平衡釜测定有所选溶剂存在时,各组分问的相对挥发度,确定乙二醇为分离二乙氧基甲烷一乙醇的良好溶剂;而乙二醇加盐作为复合溶剂,可提高二乙氧基甲烷-乙醇的分离效果。     

相平衡和平衡级分离专用计算软件VB设计

本软件系统包括4个子系统：（1）平衡数据关联子系统－含Van Laar,Margules,NRTL,UNIQUAC和Wilson模型以及Antione常数回归方程；（2）精馏子系统－含间歇精馏，普通精馏和萃取精馏；（3）液液萃取子系统－包括无水和含水溶剂体系；（4）数据库子系统－建成bpd.mdb数据文件，具有查询和管理各种烷烃，芳烃和溶剂等基础物性的功能。软件系统采用VB设计，界面友好，操作简便，可用于汽液和液液平衡数据模型参数的关联以及多元多级汽液和液液平衡级的分离计算。     

基于UNIFAC模型的碳酸二甲酯-甲醇-恒沸剂三元体系汽液平衡数据的推算

运用Visual Basic计算机语言，用UNIFAC方程模拟推算了碳酸二甲酯－甲醇－恒沸剂（分别为正己烷、环己烷、正庚烷、正辛烷）三元体系在常压下的汽液平衡。为采用恒沸精馏法分离DMC与甲醇共沸体系提供了汽液平衡数据。     

三塔萃取分离叔丁醇-异丙醇-水混合液的模拟及优化研究

叔丁醇、异丙醇和水易形成二元和三元共沸,此共沸体系无法采用常规精馏等方法进行分离。本文分别以乙二醇、环丁砜和乙二醇为萃取剂,NRTL为平衡模型,采用Aspen Plus软件对叔丁醇-异丙醇-水分离的三塔萃取精馏过程进行模拟。分别考察了三塔的塔顶出料量、回流比、溶剂比、塔板数及原料进料位置等因素对分离效果的影响。并设计正交实验方案,对分离过程进行进一步优化,确定过程条件对叔丁醇和异丙醇的纯度及收率的影响,为叔丁醇-异丙醇-水体系分离提供基础数据。结果表明,在优化条件下,可得到纯度和收率为99.87%和94.29%的叔丁醇、纯度和收率为98.69%和89.38%的异丙醇。     

萃取抽提混合二乙苯中间二乙苯的研究

采用单级循环汽液平衡釜测定混合二乙苯不同组分与溶剂之间的汽液平衡数据,计算间二乙苯与主要组分之间的相对挥发度,并与模拟结果进行对比,确定萃取精馏分离的最佳溶剂。采用Aspen Plus软件进行模拟研究,考察了理论板数、塔顶采出比、溶剂比、回流比等因素对分离过程的影响。模拟结果表明,在理论板数为80块、进料位置为第40块、塔顶采出料比为0.7:1、溶剂比为5:1及回流比为5:1的优化条件下,间二乙苯质量含量由59.00%提高到79.00%,收率达到93.73%以上。本文研究为进一步萃取和结晶提取间二乙苯提供条件。     

NFM-MEK混合溶剂萃取精馏分离正丁烯/丁烷的流程模拟与参数分析

近年来,利用N-甲酰吗啉(NFM)及其混合溶剂萃取精馏分离正丁烯与丁烷的工艺逐渐得到工业应用。然而有关该体系汽液平衡数据的文献报道极少,尚未见到该工艺流程模拟方法的报道。本文利用PRO／Ⅱ模拟软件,采用经过UNIFAC修正的NRTL方程作为热力学方法,对NFM-MEK(甲乙酮)混合溶剂萃取精馏分离正丁烯／丁烷的工业装置进行了流程模拟,结果表明,该方法对于预测NFM-MEK-C4体系的汽液平衡具有相当的准确性。在此基础上,考察了溶剂比、回流比及溶剂组成等参数对工艺过程的影响,结果表明,合理溶剂比、溶剂组成的选择应基于经济权衡,而回流比则存在一个最佳值。     

醋酸与醋酸叔丁酯的汽液平衡数据测定及分离

测定醋酸叔丁酯-醋酸的汽液平衡数据,用最小方差法关联拟合;采用共沸蒸馏法从醋酸叔丁酯和醋酸混合溶液中提取醋酸叔丁酯,研究共沸蒸馏过程中,温度及回流比对分离效果的影响;由甲醇-水标准体系确定共沸蒸馏塔的等板高度、塔高及塔板效率;研究结果为进一步放大实验提供依据.     

Influence of pH on particle size and sensing response of chemically synthesized chromium oxide nanoparticles to alcohols

Nanoparticles of chromium oxide have been synthesized by following a co-precipitation route at various pH values of the precursor solution. Structural and morphological analysis were carried out by using XRD and TEM techniques which revealed that the size of nanoparticles synthesized at pH 9 was smaller as compared to those synthesized at other pH values. The thick films of synthesized samples were deposited on alumina substrate and their sensing response to methanol, ethanol and isopropanol was investigated at different operating temperatures. It was observed that all the sensors gave optimum response at 250 °C. It has been observed that sample prepared at pH 9, being a collection of smallest particles as compared to other samples, exhibited high sensing response to alcohol vapour. Sensor response of all the samples tested was significantly higher towards isopropanol vapour than towards methanol or ethanol.In the present study the effect of particle size on intergranular activation energy has been studied as well. It was found that smaller particles possess high activation energy and exhibit higher sensing response as compared to that of larger particles. This type of study may help in the selection of particle suitable for gas sensing.     

Sensing characteristics of the organic vapors according to the reflectance spectrum in the porous silicon multilayer structure

We fabricated a porous silicon multilayer and investigated its reflectance spectra before, during, and after exposure to various organic vapors. During exposure of the porous silicon multilayer to isopropanol, ethanol, methanol, and acetone vapors, the reflectance peak shifted toward longer wavelengths by about 5, 12, 26, and 39 nm, respectively. The shift of the reflectance peak arises from refractive index changes induced by capillary condensation of the organic vapor in the pores of the porous silicon multilayer. In addition, we observed that the shift value of the reflectance peak increased with increasing organic solvent concentration in the organic solvent-water mixture. After removing the organic vapor, the reflectance spectrum returned completely to its original state.     

Application of sulfuric acid doped poly (m-aminophenol) as aliphatic alcohol vapor sensor material

Chemically synthesized processable poly (m-aminophenol) (PmAP) film was cast from dimethyl sulfoxide solution and doped with sulfuric acid by solution doping technique. This sulfuric acid doped PmAP film shows a good electrical conductivity. The response of doped film under continuous flow of various aliphatic alcohols vapor and air mixture was examined at room temperature (30 °C) and humidity (65% RH). The doped polymer only showed good result for methanol and ethanol vapor and some week response for the isopropanol vapor. A decrease in resistivity of the doped PmAP film was separately observed in air–alcohol vapor at different concentrations. The response of the film increases as the concentration of the alcohol vapor increases in air–alcohols vapor mixture. The kinetics of the response with respect to the alcohol concentration was studied for methanol and ethanol. Sulfuric acid doped and methanol vapor absorbed doped films were characterized by ultraviolet–visible spectroscopic, attenuated total reflectance Fourier transformed infrared spectroscopic and X-ray diffraction analyses. The mechanism of alcohol vapor sensing by sulfuric acid doped PmAP film has been explained on the basis of the above characterizations. All the above facts are trying to explain from the proposed mechanistic point of view.     

Molecular dynamics simulations of alpha-D-Manp-(1-->3)-beta-D-Glcp-OMe in methanol and in dimethyl sulfoxide solutions.

Molecular dynamics simulations have been performed of the disaccharide alpha-D-Manp-(1-->3)-beta-D-Glcp-OMe in two different solvents, namely in methanol and in dimethyl sulfoxide. The conformation of the disaccharide is similar to that previously determined in water. The three-dimensional structure around the solute was investigated by geometric hydrogen bonding criteria, radial distribution functions, coordination number analysis, residence times for hydrogen bonds, and spatial distribution functions. Differences and similarities between methanol and the aprotic dimethyl sulfoxide as solvent are analyzed.     

稀醋酸共沸精馏脱水工艺的模拟

醋酸是一种重要的化工原料,其水溶液广泛存在于各类工业过程中。由于醋酸与水会缔合使得两者的相对挥发度不大,生产中用于分离醋酸/水的工艺能耗较高,因此研究者和工业界都在寻求更好的分离方法。本文以醋酸正丙酯做挟带剂,应用Aspen Plus流程模拟软件,汽相逸度采用Hayden-O’Connell方程,液相活度系数采用NRTL方程计算,实现了稀醋酸共沸精馏脱水工艺的模拟。本文详细讨论了全塔理论板数、进料位置、回流比等因素对脱水塔性能的影响。结果表明,在理论板数50块,回流比3.2,醋酸进30块板,挟带剂与进料比0.15条件下,塔釜得到醋酸浓度高于95%。模拟结果对醋酸脱水工艺的设计和改造具有重要的指导意义。     

Self-formation of nanoporous polymeric materialsin photopolymerizable composition with nonpolymerizable components

The morphology of polymers prepared through the photoinduced polymerization of oligo(carbonate dimethacrylate) in the presence of different nonpolymerizable additives is studied via the method of atomic force microscopy. Depending on the nature and concentration of an additive, the photoinduced polymerization of the above composite systems is shown to be accompanied by microphase separation and formation of a porous polymeric material. In the case of methanol, homogeneous porous structures with characteristic pore sizes of several hundred nanometers are formed. In the case of dinonyl phthalate, the characteristic pore sizes lie below 100 nm. The synthesized porous polymers can sorb both polar and nonpolar solvents. The photoinduced polymerization of an oligomer in the medium of toluene, benzene, or carbon tetrachloride leads to the formation of polymer nano-particles whose dimensions are controlled by the nature of a solvent.     

茄尼醇萃取结晶提纯的实验及关联研究

茄尼醇(Sol)是一种不饱和的聚异戊二烯醇,属四倍半萜醇,具有较强的抗癌生物活性。由于茄尼醇的粘度很大、熔点低,无法用传统的方法分离纯化,针对其分离难问题,本文提出采用乙酸乙酯为萃取溶剂,甲醇为结晶溶剂,利用两级萃取结晶装置分离提纯茄尼醇。实验数据用最小方差法进行关联,用NEWTON-LAPUSON法进行迭代,实验及关联的结果表明5g茄尼醇粗品和20 mL乙酸乙酯充分混合均匀后,在30 mL甲醇中结晶,控制结晶温度为54℃,抽滤时间为40 min,可得到60%以上的茄尼醇粗品,本文工作为进一步试验研究提供了依据。     

Solvent-based bonding of PMMA–PMMA for microfluidic applications

Solvent bonding is a simple, inexpensive and quick technique used for joining microfluidic parts made of thermoplastic polymers that results in high bonding strength and good optical clarity. However, selecting the right solvent as well as the curing conditions is an important step in providing a successful bond that ensures an appropriate bonding without squeeze-out and clogging of microchannels. In this study, different solvent mixtures and solvent phases (i.e., liquid vs. vapor), as well as a range of curing times and temperatures, were tested to bond poly(methyl methacrylate) samples. Additionally, effect of corona surface modification was also examined on bonding quality. Results were compared in terms of bonding strength and optical clarity. A solvent mixture of 20% dichloromethane and 80% isopropanol showed the greatest bonding strength (4.2 MPa, based on tensile test), while vaporized dichloromethane had the best optical clarity (only 2.22% reduction in power transmittance). Coronal surface modification also showed a 25% increase in bonding strength and 2% improvement on optical clarity, for 20% dichloromethane and 80% isopropanol solution at room temperature and curing time of 15 min.

     

Novel e-nose for the discrimination of volatile organic biomarkers with an array of carbon nanotubes (CNT) conductive polymer nanocomposites (CPC) sensors

We report the original design of a new type of electronic nose (e-nose) consisting of only five sensors made of hierarchically structured conductive polymer nanocomposites (CPC). Each sensor benefits from both the exceptional electrical properties of carbon nanotubes (CNT) used to build the conductive architecture and the spray layer by layer (sLbL) assembly technique, which provides the transducers with a highly specific 3D surface structure. Excellent sensitivity and selectivity were obtained by optimizing the amount of CNT with five different polymer matrices: poly(caprolactone) (PCL), poly(lactic acid) (PLA), poly(carbonate) (PC), poly(methyl methacrylate) (PMMA) and a biobased polyester (BPR). The ability of the resulting e-nose to detect nine organic solvent vapours (isopropanol, tetrahydrofuran, dichloromethane, n-heptane, cyclohexane, methanol, ethanol, water and toluene), as well as biomarkers for lung cancer detection in breath analysis, has been demonstrated. Principal component analysis (PCA) proved to be an excellent pattern recognition tool to separate vapour clusters.