利福霉素S的固液相平衡和溶解热力学

在288.15—323.15 K温度范围内,采用静态法测定了利福霉素S在5种纯有机溶剂(乙醇、异丙醇、正丁醇、乙酸乙酯和乙酸丁酯)中的溶解度,结果显示:利福霉素S在5种溶剂中的溶解度均随温度的升高而增大。使用修正Apelblat方程对溶解度的实验值进行了关联,并采用X射线衍射仪测定利福霉素S的晶型。在范特霍夫方程的基础上,对溶解过程中相关的热力学参数进行了估算,所得的溶解焓和吉布斯自由能均为正值,从而说明该过程是吸热的,而当溶液饱和后继续溶解是需要吸收能量的;并且分析了溶解过程中不同溶剂条件下焓与熵的贡献率。为制得纯度更高的利福霉素S,整体优化利福平合成工艺提供了理论指导。     

对苯二甲酸在醋酸水溶液中的固液相平衡研究

在自制高温高压固液平衡装置中对苯二甲酸(TA)在醋酸水溶液中达到了固液相平衡,用一个特殊的取样装置取出饱和液相样品并冷却至常温。加入内标物异丙苯于样品中,采用液相色谱法定量了样品中的TA浓度。利用此法测定了1.4 MPa下423.15—493.15 K对TA在质量分数为60%、70%、80%、90%和100%的醋酸水溶液中的溶解度数据。用Apelb lat方程对所测数据进行关联,得到了相应的模型参数。用该模型对本体系进行了计算,计算值与实验值的平均偏差较小,结果令人满意。     

沙芬酰胺在不同溶剂中的溶解度测定及热力学关联研究

溶解度数据是设计和优化结晶过程的重要依据。沙芬酰胺（SAF）是一种新型的单胺氧化酶（MAO-B）抑制剂,在临床上主要用于治疗帕金森病。利用重量法测定了沙芬酰胺在6种纯溶剂（包括甲醇、乙醇、异丙醇、丙酮、乙腈和乙酸乙酯）中的溶解度,测定温度范围为293.15～328.15K,测试压力为常压。沙芬酰胺在6种溶剂中的摩尔溶解度均随温度的升高而增大。在一定温度下,溶解度的由大到小依次为丙酮、甲醇、乙醇、乙酸乙酯、异丙醇、乙腈。用修正的Apelblat方程模型对摩尔溶解度和温度进行数学关联。结果表明：Apelblat方程与沙芬酰胺的摩尔溶解度具有较好的相关性。     

λh方程在混合溶剂中的应用

推导了固体在混合溶剂中的溶解度模型（λｈ方程）。对８９个三元体系和４个五元体系的两参数回归计算表明,该模型具有较好的精度。进而本文提出了一个与混合溶剂组成有关的基于纯溶剂参数的混合规则。根据该规则仅用于个参数回归三元体系就能获得较好的精度,利用三元体系的回归参数预测五元体系的溶解度也获得了令人满意的结果。     

双季戊四醇在3种混合溶剂中的固-液相平衡

采用动态平衡法,在293.15～332.80 K、常压下,测定了双季戊四醇（DPE）在水+（甲醇、乙醇、异丙醇）三种混合溶剂中的溶解度数据。结果表明:DPE在不同质量分数的水+（甲醇、乙醇、异丙醇）混合溶剂中的溶解度随体系温度升高而增大;同一温度下,其在所选取溶剂体系中的溶解度随着甲醇、乙醇或异丙醇质量分数的增大而先增大后减小。λh方程、两参数方程与Apelblat方程均能够对所测定的溶解度数据进行较好的关联;通过修正的van’t Hoff方程计算得到DPE在所选取溶剂体系中Δ_solH⁰、Δ_solS⁰和Δ_solG⁰均大于零,表明DPE在所选取溶剂体系中的溶解过程为吸热、熵增的非自发过程。     

固液相平衡模型研究进展

固液相平衡研究对反应混合物的溶剂选择、药物结晶过程及工厂安全评估等方面具有重要的意义,是分离及提纯工艺的设计基础。介绍了活度系数模型、状态方程模型、经验模型、溶剂物性关联模型及人工神经网络法5类固液相平衡模型。重点综述了活度系数模型、状态方程模型及经验模型模型,并对模型的适用性进行了分析。基于目前相平衡模型研究进展,对未来的发展方向进行了展望。     

碳酸铈在NaCl-H2O体系中的相平衡热力学模型

碳酸铈是生产CeO2的重要前驱体,对其性质具有决定性影响。碳酸铈的结晶特征取决于反应结晶过程中过饱和度的控制,其在NaCl-H2O体系中的相平衡数据是关键基础数据。本工作首先在298.15~363.15 K温度范围内合成了碳酸铈,XRD分析结果显示,323.15 K及以下得到的产品为八水碳酸铈[Ce2(CO3)3?8H2O],343.15 K及以上得到的产品为碱式碳酸铈[CeCO3OH]。本工作采用经典等温法测定了这两种碳酸铈化合物在NaCl-H2O体系中的相平衡数据,并利用Aspen Plus平台的ELEC-NRTL方程建立了可准确预测Ce2(CO3)3?8H2O和CeCO3OH在NaCl-H2O体系中相平衡数据的热力学模型。在无限稀释假设的基础上,通过回归Ce2(CO3)3?8H2O和CeCO3OH在水中的溶解度数据,确定了这两种化合物的溶度积。采用赋存形态分析方法,将CeCO3+, CeOH2+, CeHCO32+等组分引入热力学模型。利用实验数据获得了新的离子对(Ce3+-HCO3-和Ce3+-Cl-)参数,提高了新模型的预测能力,所建立的热力学模型预测值与实验数据吻合较好。     

21-脱氧可的松在不同溶剂中的溶解度测定与关联

采用合成法测定了21-脱氧可的松在丙酮,乙酸乙酯,甲醇,乙醇,1,4-二氧六环中的溶解度。运用Apelblat方程和λh方程对所测数据进行了关联,取得了令人满意的关联结果,且Apelblat方程优于λh方程。结果表明,21-脱氧可的松在五种溶剂中的溶解度都随温度升高而增大,且在1,4-二氧六环和乙醇中对温度比较敏感。该结果有利于为21-脱氧可的松选择合适的重结晶溶剂,并且为21-脱氧可的松的理论研究提供了重要的固液相平衡数据。     

氨磺必利在水-丙酮中的液固平衡测量与关联

采用激光透射原理与化工中动态溶解度测定相结合的方法,测定了278.15~308.15 K之间氨磺必利在水—丙酮二元溶剂体系(溶剂组成:丙酮摩尔分数为0.2~1.0)中的溶解度,为氨磺必利生产工艺的改进提供基础数据。实验数据采用二参数和Apelblat方程进行关联,拟合结果与实验数据吻合良好,平均相对误差不超过2%。     

2,4-二氯苯酚在水中溶解度的测定及关联

在pH值为6.2或9.3条件下,采用综合法测定了2,4-二氯苯酚在水中的固液平衡数据,分别用经验方程、W ilson方程、固液平衡λH方程对实验数据进行了拟合处理。结果说明,在pH值为9.3条件下,2,4-二氯苯酚的水溶解度增大;W ilson方程、λH方程模型均能很好地关联2,4-二氯苯酚的水溶解度数据,pH=9.3时平均相对误差分别为3.00%,1.17%,其中λH方程拟合效果更好。     

一种计算含盐有机溶液固液相平衡的方法

基于Pitzer模型,提出了计算含盐有机溶液体系固液相平衡的Pitzer扩展模型,把扩展模型中的模型参数表达为Pitzer模型参数和有机溶剂摩尔组成xm的函数。文中利用吉布斯自由能差获得盐在混合溶剂中的溶度积常数,并结合扩展模型计算盐在混合溶剂中的溶解度。以NaCl,KCl,NaBr,NaI 4种盐在甲醇-水混合溶剂体系中的溶解度为例,关联得到了各体系的新模型参数。结果表明:计算结果和文献数据吻合良好,最大绝对误差为0.209mol/kg,验证了该模型的可行性,成功扩展了Pitzer模型的适用范围。因此,Pitzer扩展模型是一种可用于含盐有机溶液体系固液相平衡计算的方法。     

Prediction of adsorption equilibrium using a modified D-R equation: pure organic compounds on BPL carbon

A method for predicting adsorption equilibrium using a modified Dubinin-Radushkevich (D-R) equation is presented in this paper. We focus on adsorption of pure organic compounds on BPL-activated carbon. We introduce a new variable k_v, a volume adjusting coefficient, and simply use V_b, the constant molar volume of the adsorbate at its normal boiling temperature, instead of V_m, the temperature-dependent molar volume of the adsorbate at the adsorption temperature. The model parameters in the modified D-R equation for an adsorbate are predicted from V_b. Overall, the modified D-R equation gives more accurate results than the traditional one.     

Swelling of lignites in organic solvents

Data on the swelling of Turkish lignites can be summarized using linear multiparameter equations that take into account various properties of solvents. Factors responsible for the amounts of absorbed solvents are the basicity and cohesion energy density of the solvents.     

纯溶剂在线性低密度聚乙烯膜中的渗透汽化

用渗透汽化实验装置测定了5种常用化工溶剂在线性低密度聚乙烯材料中的渗透性能,考察不同温度对于5种溶剂的渗透通量的影响。通过渗透通量与温度的Arrhenius关系,回归拟合得到各种溶剂的渗透活化能;并采用吸附溶胀实验测定了5种纯溶剂在该膜材料中的平衡吸附量,以此推算出25℃条件下5种溶剂在膜材料内部的扩散系数。结果表明,5种溶剂的渗透通量的顺序为正己烷正庚烷环己烷丙酮甲基吡咯烷酮,吸附量大小顺序为甲基吡咯烷酮环己烷正己烷正庚烷丙酮。     

Thermodynamic equilibrium of organic-electrolyte mixtures in aerosol particles

This thermodynamic model describes the phase equilibria of mixtures of electrolytes and organic species in aqueous solutions existing as aerosol particles. The activity coefficient of each species in solution is explicitly related to the chemical composition by treating the (inorganic) ion–water, organic–water and ion-organic interactions with a combined Pitzer–UNIFAC thermodynamic approach. It was parameterized with a new type of multifunctional “meta-group” to better represent measured properties of long-chain monofunctional compounds and short-chain multifunctional compounds. Interactions between dissolved electrolytes and organic species are modeled using the “salting-out” effect of NaCl with organic compounds to predict the hygroscopic growth of particles composed of a salt and diacid. The predicted growth agrees well with laboratory measurements. The presence of 50% malonic acid decreases the growth of pure (NH₄)₂SO₄ by 20% at high relative humidities, while mixtures with 50% succinic acid and 50% glutaric acid cause decreases of 35% and 38%, respectively. The mixing of organic compounds with solubility higher than 4 mol·L⁻¹ with salt can decrease the observed DRH. The mixture of malonic acid and (NH₄)₂SO₄ is predicted to start taking up water at 58%, much lower than the DRH of pure (NH₄)₂SO₄ (80%). Insoluble compounds do not change the observed DRH, while reducing the amount of water taken up. The predicted water contents for internal and external mixtures are largely similar, with small differences predicted for mixtures of soluble organic species. The largest deviation of 10% between the water contents of internal and external mixtures occurs for 50% malonic acid with 50% (NH₄)₂SO₄. For less soluble compounds such as succinic acid and glutaric acid, the two types of growth generally agree within 3%.     

Synthesis of cobalt ferrite in organic solvents

The possibility of synthesizing the nanosized CoFe₂O₄ particles in organic solvents, such as glycerol and diphenyl oxide, at 250°C and atmospheric pressure under conditions of distillation of the formed water was studied. In the case of glycerol, we obtained the adduct of the latter with cobalt ferrite. The reaction in diphenyl oxide resulted in the formation of ferrite particles sized 8–10 nm.     

Charging of unfunctionalized graphene in organic solvents

Unfunctionalized graphene is positively or negatively charged when it is dispersed in organic solvents. The charging is negative in solvents with high electron donor numbers and positive in those with low donor numbers. We suggest that the charging originates from electron transfer between graphene surfaces and solvent molecules, and the stable dispersion of unfunctionalized graphene in organic solvents is mainly controlled by electrostatic repulsion between the charged graphene surfaces.     

Diffusion of organic solvents in isobutylene-based polymers

Diffusion behavior of several organic solvents in polyisobutylene (PIB) and in poly(p-methylstyrene-co-iso-butylene) (PMS-BR) with different monomer ratios has been studied. The experiments have been conducted over a temperature range of 50 to 100°C using a conventional gravimetric Sorption technique. The PMS-BR copolymers contained 2, 7, and 15 weight percent p-methylstyrene, respectively. Although employing temperatures were far above the glass transition temperatures of polymers, the diffusion coefficients are correlated well with the Vrentas-Duda free-volume theory. For all the solvents, the PIB shows the highest diffusivity while the copolymer with the 15% p-methylstyrene gives the lowest value. This behavior can be explained by the amount of fractional free-volume present in a system.