Prediction of solvents extraction-the organochlorine pesticides in soil using solubility parameter

Prediction of the optimal extraction solvent based on the solubility parameter to extract the typical organochlorine pesticides from Jiangxi red soil was reported in this paper. Hildebrand solubility parameters, including dispersion coefficient (δ_d), polarity (δ_p) and hydrogen bonding (δ_h), of extraction solvents (including hexane, dichloromethane, hexane/methanol (4:1, v/v), hexane/acetone (1:1, v/v), hexane/dichloromethane (1:1, v/v) and organochlorine pesticides were calculated using group contribution method. The solvents, such as hexane/methanol (4:1, v/v) and hexane/acetone (1:1, v/v) were selected as ideal extraction solvents to extract o,p′-DDT o,p′-DDE and o,p′-DDD with high recoveries (>82%), furthermore, these solvents can be used to extract α-endosulfan, Endrin and HCB with the reliable recoveries (>75%). The estimated finding by solubility parameters was supported by the results of soxhlet extraction.     

A facile and efficient method for the synthesis of solasodine from diosgenin

A facile and high-yielding route for the synthesis of solasodine from diosgenin is devised. Ring opening of steroidal spiroketal under mild conditions with trifluoroacetyl trifluoromethanesulfonate (TFAT) provides an applicable protocol to prepare key intermediates 4 or 3-Ac-solasodine, which can potentially serve as a platform for the selective functionalization of C(3)-OH and N-H of solasodine. The simple operations without purification by column chromatography make this method suitable to scale up.     

A simple apparatus for data solubility determination

A relatively simple apparatus has been used to determine liquid hydrocarbon solubility in water. Liquid samples were taken from the liquid phase, through a silicon septum in the basis of the saturation cell, temporally until the final saturation. The equilibrium temperature was kept by a thermostatic bath. The liquid sample was analyzed using a gas chromatograph with a flame ionization detector (FID), and so, obtaining the solutions concentrations. For each solute, we found a different saturation time. However, it was observed that it occurred between 15 and 90 min. Measurements obtained for 1,2-dichroroethane, methylene chloride, toluene and pentane showed good agreement with literature values and allowed us to validate our equipment. The experimental data were correlated by using a two-parameter equation. The values obtained confirm the validity of equation tested.     

Solubility of drug-like molecules in pure organic solvents with the CPA EoS

Solubility data in different solvents are an important issue for separation processes involving complex molecules such as natural products and pharmaceutical drugs. Nonetheless, solubility data are in general scarce and difficult to obtain, and so models are important tools to generate the necessary estimates.Different correlative, statistical and thermodynamic models have been proposed to evaluate solubilities. From these, the more theoretically sound thermodynamic models allow to generate estimates at broader temperature, pressure and composition conditions while using a smaller amount of experimental information. Among these, the cubic-plus-association equation of state that combines the simplicity and robustness of a cubic equation of state with the Wertheim's association contribution has been under attention. In this work, this EoS is for the first time proposed to model organic phase solubilities of drug-like molecules in a wide range of temperatures.Solubilities of acetanilide, acetylsalicylic acid, adipic acid, ascorbic acid, hydroquinone, ibuprofen, paracetamol and stearic acid were estimated in alcohols, ketones, alkanes, esters, acids, aromatics, chlorinated solvents, as well as in other common solvents. The hydrogen bonding behaviour was explicitly accounted for with each associating group being treated individually, as well as multiple group substitutions.Accurate correlations were obtained using a single binary interaction parameter (global AAD of 24.2%), while considering the complexity of the studied systems predictions were generally also satisfactory.     

分光光度法测定薯蓣皂苷元

采用高氯酸反应使薯蓣皂苷元显色 ,对影响显色反应的主要因素进行了考察 ,于 41 0nm波长处对穿山龙中薯蓣皂苷元的含量进行测定 ,测定结果与高效液相色谱法相近。方法的线性范围为 3.1 2～2 1 .84μg mL ,适用于薯蓣皂苷元提取过程中的常规检测     

Solubility of Ferrocene in Organic Nonelectrolyte Solvents. Comparison of Observed Versus Predicted Values Based Upon Mobile Order Theory

Abstract

Experimental solubilities are reported at 25.0°C for ferrocene dissolved in 46 different organic nonelectrolyte solvents containing ether-, chloro-, hydroxy-, ester, methyl-and t-butyl-functional groups. Results of these measurements, combined with previously reported ferrocene solubilities taken from the chemical literature, are used to test the applications and limitations of expressions derived from mobile order theory. For the 42 solvents for which predictions could be made computations show that mobile order theory does provide fairly reasonable estimates of the saturation mole fraction solubilities. Average absolute deviation between predicted and observed values is 107.8%. In comparison, the average absolute deviation is 627% when ideal solution behavior is assumed.     

The algorithmic calculations of solubility parameter for the determination of interactions in dextran/certain polar solvent systems

The dextran/solvent system was employed for the evaluation of the parameters and various molecular contributions on the basis of solubility parameter with regard to the theoretical methods of Hoy and Van Krevelen-Hoftyzer pair. The theoretical magnitudes correlated quite well with the experimental values determined previously for the same system. The Δδ value predicted as ?5 for various systems previously, appeared to be >5 for the dextran/solvent systems obtained from the diagrams plotted using several solubility parameter components. An order with respect to the solvent has been proposed with regard to the distance of the solubility parameter components of the solvent from the center of the circle for which, water does not seem to be a good solvent for the system under study since it remains outside the circle of those diagrams.     

反相高效液相色谱法测定中药中薯蓣皂苷元

用反相高效液相色谱法分离并测定了穿山龙、粉草解、胡芦巴、七叶一枝花、山药等5种中草药中的薯蓣皂苷元，建立了中药中薯蓣苷元的液相色谱分离测定方法，色谱条件：ODS柱，甲醇－水（95＋5）为流动相，紫外检测波长209nm.     

Modification of the NRTL model for ternary and quaternary liquid-liquid equilibrium calculations

The original NRTL model is modified for the correlation of ternary liquid-liquid equilibria. The ternary expression of the modified NRTL model includes three additional ternary parameters and the ternary terms vanish when a ternary system degenerates to a binary. The ability of the modified NRTL model has been evaluated in the calculations of ternary vapor-liquid-liquid equilibria and quaternary liquid-liquid equilibria.     

Solubility of naproxen in several organic solvents at different temperatures

By using the van’t Hoff and Gibbs equations the thermodynamic functions Gibbs free energy, enthalpy, and entropy of solution, were evaluated from solubility data of naproxen (NAP) determined at several temperatures in octanol, isopropyl myristate, chloroform, and cyclohexane, as pure solvents. The water-saturated organic solvents also were studied except cyclohexane. The excess free energy and the activity coefficients of the solutes, and the mixing and solvation thermodynamic quantities were also determined. The NAP solubilities were higher in chloroform and octanol with respect to those obtained in cyclohexane. In addition, by using literature values for NAP aqueous solubility, the thermodynamic functions relative to transfer of this drug from water to organic solvents were also estimated.     

Liquid-liquid equilibrium for the ternary system ethanol/toluene/n-decane: a correction to the existing coexistence curve and NRTL parameters

A correction to the reported liquid–liquid equilibrium parameters using the non-random two liquid (NRTL) thermodynamic model for the ethanol/toluene/n-decane system at 298 K is reported. The parameters were calculated by minimising the residual between the calculated coexistence and the experimental compositions. However, to obtain a physically plausible coexistence curve, a parameter in the NRTL model had to be fixed. This highlights the importance of assessing the entire coexistence curve, as opposed to only comparing the calculated compositions to the experimental data points. This is because undertaking the regression for all the available parameters will result in a smaller residual and better fit of the calculated points to the experimental points. This leads to an apparent improved fit but the complete coexistence curve will show that the parameters are not physically plausible.     

The solubility and solvation of salts in mixed nonaqueous solvents. 1. Potassium halides in mixed aprotic solvents

The solubilities of potassium fluoride, chloride, and bromide in acetonitrile, N,N-dimethylformamide, and dimethylsulfoxide and in binary mixtures of these solvents were determined at 25°C. The standard molar Gibbs free energies of solution, _solnG°, in the neat solvents were related to the polarizabilities and basicities of the anions and the dipole moments and acidities of the solvents. The values of _solnG° in the mixtures were fitted by expressions from the quasi-lattice quasi-chemical theory. The mean number of each kind of solvent in the nearest environment of the ions was obtained from these results.     

利用溶解度参数选择有机溶剂提取土壤中多种有机氯农药

采用基团贡献法计算了提取溶剂（正己烷、二氯甲烷、正己烷—甲醇（体积比4：1)、正己烷—丙酮（体积比1：1)、正己烷—二氯甲烷(体积比1：1))和有机氯农药（o,p′—DDT,o．p′—DDE,o,p′—DDD,α—endosubn,endrin,HCB)的色散溶解度参数(δd)、极性溶解度参数(δp)和氢键溶解度参数(δh),运用溶解度参数的理论筛选有机溶剂提取江西红壤中多种有机氯农药：研究表明正己烷—甲醇（体积比4：1)和正己烷—丙酮（体积比1：1)是提取江西红壤中o,p′—DDT,o,p′—DDE,o,p′—DDD多种有机氯农药的最佳提取溶剂（回收率大于82％),对α—endosulfan,endrin,HCB的提取也能满足检测需要（回收率大于75％)。超声波提取的结果验证了溶解度参数预测的合理性。     

New polyhydroxylated metabolite derived from biotransformation of diosgenin by the white-rot fungus Coriolus versicolor

<正>Microbial transformation of diosgenin(1) was carried out with the white-rot fungus,Coriolus versicolor.A new polyhydroxyl metabolite,(25R)-spirost-5-ene-3β,7β,21-triol(2),was obtained as a result of hydroxylation.Its structure was elucidated on the basis of 1D and 2D NMR as well as HR-ESI-MS spectroscopic analysis.     

Microbial transformation of diosgenin by Syncephalastrum racemosum (Cohn) Schroeter

<正>Microbial transformation of diosgenin(1) by Syncephalastrum racemosum yielded five new polar metabolites,which wereidentified as(25R)-spirost-5-en-3β,7α,9α-triol-12-one(2),(25R)-spirost-5-en-3β,9α,12α-triol-7-one(3),(25R)-spirost-5-en-3β,9α-diol-7,12-dione(4),(25R)-spirost-4-en-9α,12β,14α-triol-3-one(5),and(25S)-spirost-4-en-9α,14α,25β-triol-3-one(6).Compounds 1-6 exhibited moderate cytotoxicity against K562 cells and among them compounds 2,3,and 6 were more potentthan the parent compound 1.     

Estimation of solubility parameter by the modified ER equation of state

The applications of the solubility parameter in chemical, petroleum and polymer engineering industries have been cleared up along the past 50 years. In this article, the Hildebrand solubility parameter of over 250 substances were calculated by the modified ER (Esmaeilzadeh–Roshanfekr) equation of state and some others (the Peng–Robinson, Soave–Redlich–Kwong, Patel–Teja and Schmidt–Wenzel) and compared with the experimental data. Once the less average errors of the mER method predictions were satisfied in subcritical and some supercritical fluids region, a correlation based on this EOS was presented in order to calculate the total HSP (Hansen solubility parameter) of various types of organic components categorized in 13 distinct groups including paraffins, olefins, aromatics, naphthenes, alcohols, aldehydes, ketones, ethers, esters, amines, carboxylic acids and two petroleum sub-fractions (resins and asphaltenes). The optimal values of the model parameters were obtained applying the DE (differential evolution) optimization method. The absolute average deviations of the proposed correlations results from the experimental ones lied between 0.09 and 6%.     

Thermodynamic study of solubility of B6 hydrochloride in water + co-solvent systems with UNIQUAC model at different temperatures

In this study, due to the importance of the solubility of this vitamin in solvents, based on the UNIQUAC activity coefficient equation, its solubility in the presence of water, acetonitrile, n-propanol and isopropanol has been studied. To investigate the interaction behavior of components in the system, the desired thermodynamic equations were optimized based on experimental results with a combined Genetic + PSO algorithm. Based on the objective function, the value of the theoretical and experimental model was acceptable. Therefore, the optimized model can be significant for formulating and investigating solubility of B6 hydrochloride based on the design of a computer program.     

Extension of the electrolyte NRTL and Wilson models for correlation of viscosity of strong electrolyte solutions at different temperatures

The electrolyte NRTL model [C.C. Chen, L.B. Evans, AIChE J. 32 (1986) 444–454] and electrolyte Wilson model [E. Zhao, M. Yu, R.E. Sauvé, M. Khoshkbarchi, Fluid Phase Equilibr. 173 (2000) 161–175] have been extended for the representation of the dynamic viscosity of strong electrolyte solutions. The models are based on Eyring's absolute rate theory and the electrolyte NRTL and Wilson models for calculating the excess Gibbs energy of activation of the viscous flow. The utility of the models is demonstrated with a successful representation of the viscosity of several electrolyte solutions at different temperatures. The results show that, the model is valid for the whole range of salt concentration and it is reliable for correlation of the viscosity of electrolyte solutions at different temperatures by only four adjustable parameters per binary system.     

Measurement and correlation of solubility of 4-chloro-2,5-dimethoxynitrobenzene and 4-chloro-2,5-dimethoxyaniline in methanol,ethanol, xylene and toluene

The solubility of 4-chloro-2,5-dimethoxynitrobenzene (CDMB) and 4-chloro-2,5-dimethoxyaniline (CDMA) in methanol, ethanol, xylene and toluene was measured over the temperatures range from (278 to 338) K by the dynamic method using a laser monitoring observation technique. The solubility in all solvents increased with temperature and the greatest solubility of both systems was obtained in toluene. The Wilson and the NRTL models were applied to correlate the experimental results. The root-mean-square deviations for the system of (CDMB + solvent) ranged from T = (0.11 to 0.34) K and (0.08 to 0.33) K calculated by the Wilson and the NRTL models, respectively, while for the system of (CDMA + solvent) the root-mean-square deviations ranged from T = (0.11 to 0.32) K and (0.14 to 0.33) K. The melting points and enthalpies of fusion of CDMA and CDMB were determined by differential scanning calorimetry (DSC). Toluene was found to be the preferred solvent for the reduction of CDMB to CDMA from the point of view of reaction and product separation