UNIFAC基团贡献法预测加压下的二元共沸点

本文实测了乙醇－环己烷，乙醇－乙酸乙酯、乙醇－丁酮，异丙醇－正己烷，丙酮－环己守五组二元体系在１０１．３－９１１．０ｋＰａ压力下的加压共沸数据。研究了二元共混点随压力变化的规律。并和ＵＮＩＦＡＣ基团法预测了这五组二元体系在相应压力下的共沸数据，与实测值作了比较，两者符合良好。     

分离环己烷-乙醇的离子液体萃取剂的筛选

基于COSMO-RS理论模型,以乙醇的选择性系数和容量为评价指标,研究了离子液体萃取剂在强化分离环己烷-乙醇共沸体系中的应用。首先,通过与实验数据的对比分析,验证了该模型预测环己烷-乙醇体系汽液相平衡行为的可靠性。其次,从由27种阳离子和26种阴离子组合设计出的702种离子液体中筛选出性能优良的萃取剂C5A20,并考察了其对环己烷-乙醇体系汽液相平衡的影响,结果表明,在C5A20的摩尔含量仅为0.03时,即可打破该体系的共沸,用于环己烷-乙醇体系的强化分离。在此基础上,从微观分子相互作用的角度,分析了萃取剂对乙醇选择性作用机理,为进一步设计性能优异的离子液体萃取剂提供了理论依据及数据支撑。     

加碱萃取精馏制取无水乙醇

乙醇-水体系存在共沸点,难以通过普通精馏方法制取高纯度乙醇,萃取精馏是分离共沸体系的有效途径。目前常用的萃取溶剂是乙二醇。在分离乙醇-水体系的过程中,将适当的盐类(醋酸钾)溶于乙二醇形成溶盐萃取剂,会有效提高溶剂的选择性。本文用萃取精馏方法并加入乙二醇分离效果更明显。     

Gaussian与Aspen Plus在化工原理课程设计中的应用*

在化工原理课程设计中将某药厂委托的科研项目“二甲硫醚、甲醇和水分离设计项目”转化为典型教学案例,结合现代计算机辅助技术,引入量化计算软件Gaussian和化工模拟软件Aspen Plus分别从微观和宏观上进行萃取精馏分离共沸物的设计。通过Gaussian软件,基于密度泛函理论证实了待分离体系中已有的组分水可改变二甲硫醚与甲醇二元共沸物的相对挥发度,消除2者之间的共沸。继而采用Aspen Plus软件对待分离混合液进行萃取精馏工艺模拟与优化,最后开展工业设计与设备选型。上述实际案例的设计过程,创造性地使用了混合液已有的组分作为萃取剂,通过萃取精馏工艺实现共沸物的分离,弥补了传统萃取精馏因引入萃取剂导致产品携带少量第三组分的缺点,极大地激发了学生学习的兴趣,丰富了课程教学内容,将复杂的萃取精馏过程讲解透彻,促进教学质量的提升,增强学生的工程设计能力,学生多次参加全国大学生化工设计竞赛并取得了优异成绩。     

水-乙醇二元体系共沸混合物的热力学研究

用全自动低温绝热量热计测定了水、乙醇以及水和乙醇组成的共沸混合物在不同温区的摩尔热容Cp,m. 建立了共沸混合物Cp,m与温度T的函数关系.结果表明,水和乙醇组成的共沸混合物在98.496 K发生玻璃态转化,在158.939 K 和270.95 K发生固-液相变.获得了其相应的相变焓和相变熵.计算了以298.15 K为基准的该共沸混合物的热力学函数和超额热力学函数.     

糠醛水溶液的液-液萃取分离

糠醛是重要的化工溶剂和中间体,传统生产过程流程复杂[1],能耗高。近年已提出用不同溶剂萃取分离糠醛和水[2]。本文在前文基础上[3]选择醋酸丁酯为萃取剂测定糖醛-水-醋酸丁酯体系的LLE数据,由二组二元体系和三元体系液液平衡数据确定UNIQUAC模型中三对模型参数,并采用UNIQUAC模型模拟计算糖醛水溶液萃取分离结果,以便为错流和逆流萃取试验提供依据。1　实验部分糠醛水溶液和醋酸丁酯加入液液平衡釜[4],磁力搅拌器搅拌30分钟,待温度稳定后,静置40分钟,取上相和下相分析。平衡釜采用CS501型超级恒温水浴控温,平衡结果由SP-6800…     

二丙酮丙烯酰胺共聚物膜用于渗透汽化法分离乙醇—水混合物

为将稀薄的乙醇水溶液浓缩,传统的蒸馏方法不能避免乙醇-水的共沸,能耗也很大。渗透汽化法克服了蒸馏法的这两个缺点,有希望成为分离乙醇水溶液的较为理想的方法。 作为水优先透过膜材料,有聚乙烯醇、磺化聚苯乙烯、聚丙烯腈、醋酸纤维素、聚乙烯亚胺、阴、阳离子交换膜阴、阳离子性多糖类、聚丙烯酸等及各种共聚物和共混     

Pt/WO3/ZrO2 催化甘油选择性脱羟基制 1,3-丙二醇反应的溶剂效应

 考察了不同溶剂中 Pt/WO3/ZrO2 催化剂催化甘油加氢制 1,3-丙二醇的反应性能. 结果表明, 质子溶剂乙醇和水有利于甘油转化为 1,3-丙二醇. 含有乙醇或水的二元混合溶剂表现出明显的溶剂组分协同效应, 使用混合溶剂时 1,3-丙二醇选择性超过使用单一溶剂, 而且混合溶剂的组成对反应性能影响很大.     

反应法去除近共沸浓度乙醇-水混合物中水的宏观动力学研究

 针对乙醇汽油制备过程中乙醇原料的除水问题,提出了用反应法除去近共沸浓度乙醇中水的新技术路线,着重进行了近共沸乙醇-水混合物与异丁烯水合醚化反应的宏观反应动力学研究. 实验以β分子筛为催化剂,在2.0 MPa和313～363 K的条件下考察了搅拌速度、乙醇中初始水含量、烯水比和温度等因素对水的转化率和叔丁醇选择性的影响. 结果表明,乙醇对异丁烯水合反应有先促进后抑制的作用,而水对异丁烯醚化反应影响较小; 水的转化率随烯水比的增大而增大,随乙醇中初始水含量的增大而减小,随着温度的升高呈现先增大后减小的趋势. 叔丁醇的选择性随初始水含量的增大而增大. 基于实验结果和Langmuir-Hinshelwood-Hougen-Watson理论,充分考虑反应体系的高度非理想性,以活度代替浓度建立了宏观反应动力学模型; 采用混合进化算法对模型进行求解,结果表明模型计算值与实验值可较好地吻合.     

L-半胱氨酸衍生物配体交换手性色谱固定相

应用密闭微波萃取装置对芦荟中的有效成分芦荟甙进行了微波萃取研究,并利用透射电子显微镜对微波萃取机理进行了初步探讨,讨论了不同萃取剂、溶剂浓度、萃取时间和微波功率等对提取率的影响,在萃取剂为乙醇-水体系,溶剂（乙醇）体积分数为70％、萃取时间为4min及微波功率为340W的条件下,萃取效果最佳,与索氏提取及超声波萃取法相比,本法具有萃取速度快、提取率高及溶剂用量少等特点。     

An extension of Barker's method for reduction of VLE data

A set of P vs. x data for vapor-liquid equilibrium properly contains the pure-component vapor pressures. These values are as uncertain as the values for other measured pressures, and data reduction should yield smoothed values for these as well as for the other pressures. However, the vapor pressures also appear as constants in the reducing equation; here they must have assigned values. This paper shows how the results of data reduction are influenced by different treatments of the vapor pressure.     

Thermodynamic consistency of experimental VLE data for asymmetric binary mixtures at high pressures

A thermodynamic consistency of isothermal vapor–liquid equilibrium data for 9 non-polar and 8 polar binary asymmetric mixtures at high pressures has been evaluated. A method based on the isothermal Gibbs–Duhem equation was used for the test of thermodynamic consistency using a Φ–Φ approach. The Peng–Robinson equation of state coupled with the Wong–Sandler mixing rules were used for modeling the vapor–liquid equilibrium (VLE) within the thermodynamic consistency test. The VLE parameters calculations for asymmetric mixtures at high pressures were highly dependent on bubble pressure calculation, making more convenient to eliminate the data points yielding the highest deviations in pressure. However the results of the thermodynamic consistencies test of experimental data for many cases were found not fully consistent. As a result, the strategies for solving these problems were discussed in detailed.     

The use of the NRTLmKW model for predicting VLE data of binary systems from the excess enthalpy data

A new local composition model NRTLmKW has been used for correlation of 15 binary excess enthalpy data. The data, binary systems formed by hydrocarbons and alkanols, have been selected to give a wide representation of various kinds molecular interactions in solution. Further the model, basing on the results of the correlation, has been used for prediction of excess enthalpy and VLE (vapour-liquid equilibria) in these systems. The obtained results have been discussed from the point of view of intermolecular interactions and some recommendations have been made on the use of the NRTLmKW model for such calculation.     

A thermodynamic consistency test for the binary constant-temperature VLE data using numerically optimized binary parameters

A thermodynamic consistency (TC) test for the constant-temperature VLE data was investigated by numerically optimizing the binary parameters of the activity coefficient equations to satisfy the Gibbs–Duhem (GD) equation. It was shown that the one parameter Margules equation can best satisfy the GD equation, even if significant experimental errors are involved. A thermodynamic consistency (TC) criterion was defined using the one parameter Margules equation. The TC criterion showed that, of the 37 alkane–alkane, 18 methanol–water and 44 ethanol–water binaries, 36, 16 and 1 binaries are reliable, respectively. Simple liquid mixtures meet the TC criterion.     

置换法测定气液平衡

本文工作在流通法的原理上提出一种不分析组成测定汽液平衡的新方法。它通过配置样品与汽液平衡测定仪汽相浓度区或液相浓度区的等体积置换,测定配样组成所对应的露点或泡点。置换法的基本原理双循环汽液平衡测定仪在达到操作稳态时,存在着三个浓度区间的划分以及相互之间的物料平衡关系。流通法的基本作法是,将平衡液相回流或平衡汽相回流引出,并以等流量的配制样品注入混合区。溶质量随时间的变化规律为,     

多功能汽液平衡测定仪的研究

研制了一种多功能液平衡测定仪－－CS-Ⅱ型VLE测定仪，阐述了该仪器的设计思想，该仪器兼有沸点仪和平衡釜的特点和功能，作为沸点仪，它具有泵结构搅拌器，可适用于拟静态法；作为平衡釜,它具有新型的汽液相取样结构和液相区冷却功能，可适用于安全互溶体系、部分互溶体系和高沸点差体系VLE的测定，本文给出了有关详细的实验考核结果。     

Baseline isotopic data of polyhalogenated compounds

The δ²H- and δ¹³C-values of polyhalogenated compounds were determined by EA-IRMS. Most of the compounds were related to the chloropesticides DDT and its metabolites, hexachlorocyclohexanes, and toxaphene, as well as several polybrominated compounds such as bromophenols and -anisoles. δ²H-values ranged between −235‰ and +75‰ whereas δ¹³C-values were found in the range −22‰ to −38‰. No correlation between δ²H- and δ¹³C-values could be identified. Comparative analysis clarified that bromophenols and the corresponding bromoanisoles may vary in their isotopic distribution. ²H NMR was used to quantify abundances of ²H isotopomers. Quantification of isotopomers of 2,4-dibromophenol and 2,4-dibromoanisole proved that both compounds from different suppliers do not originate from the same source. Differences in the δ²H-values of two toxaphene products were further investigated by the synthesis of products of different degree of chlorination from camphene. It was shown that the δ¹³C-values remained mostly unaltered as was expected since no carbon is lost in this procedure. However, the reaction products became enriched in ²H with increasing degree of chlorination. Different δ²H-values of the starting material will also impact the δ²H-values of the chlorination products.     

Thermodynamic data of the NZP compounds family

Summary The thermodynamic data for NZP compounds MZr₂(PO₄)₃ (M=Na, K, Rb, Cs, Zr_0.25) and Na₅D(PO₄)₃ (D=Ti, Zr) are reported. The heat capacities of the phosphates were measured between T=7 and T=640 K. The standard enthalpies entropies, and Gibbs functions of formation at T=298.15 K were derived. The obtained thermodynamic characteristics of phosphates of the NZP type structure and literature data are summarized. Thermodynamic functions of reactions of solid-state synthesis were calculated and the usability of ceramic technology for obtaining NZP compounds was proved.     

13C NMR data for organometallic compounds

The first examples of indium porphyrins containing a bi- or tri-nuclear framework are reported. Synthesis is realised by nucleophilic substitution of a metallate anion ^-MLn (MLn = Co(CO)₄, CpMo(CO)₃, CpW(CO)₃, Mn(CO)₅) or ^2-M'Ln (M'Ln = Fe(CO)₄) on a chloroindium(III) porphyrin. The structures of the products are established on the basis of ¹H NMR and IR measurements.