Ternary (liquid + liquid) equilibria for mixtures of (methanol + aniline + n-octane or n-dodecane) at T = 298.15 K

(Liquid + liquid) equilibrium (LLE) data for the ternary mixtures of (methanol + aniline + n-octane) and (methanol + aniline + n-dodecane) at T = 298.15 K and ambient pressure are reported. The compositions of liquid phases at equilibrium were determined and the results were correlated with the UNIQUAC and NRTL activity coefficient models. The partition coefficients and the selectivity factor of methanol for the extraction of aniline from the (aniline + n-octane or n-dodecane) mixtures are calculated and compared. Based on these comparisons, the efficiency of methanol for the extraction of aniline from (aniline + n-dodecane) mixtures is higher than that for the extraction of aniline from (aniline + n-octane) mixtures. The phase diagrams for the ternary mixtures including both the experimental and correlated tie lines are presented. From the phase diagrams and the selectivity factors, it is concluded that methanol may be used as a suitable solvent in extraction of aniline from (aniline + n-octane or n-dodecane) mixtures.     

Partition behaviour of benzoic acid in (water + n-dodecane) solutions at T = (293.15 and 298.15) K

The partition coefficients of benzoic acid in solutions of two immiscible solvents, water and n-dodecane, were measured at temperatures of (293.15 and 298.15) K. The experimental results indicated that at both temperatures the partition coefficients were not constant, but showed linear dependences on the concentration of benzoic acid in water. Dimerization of benzoic acid in n-dodecane and ionization in water were assumed based on the chemical theory and the experimental results verified this assumption quite well. Accordingly the association equilibrium constants of benzoic acid in n-dodecane were obtained by a linear regression. The regression results also showed that there was a very strong dimerization of benzoic acid in n-dodecane over the temperatures and concentration range investigated.     

Organocatalytic chemoselective monoacylation of 1,n-linear disulfonamides

Predominant monoacylation of 1,n-linear disulfonamides took place in the presence of pyrrolidinopyridine-type organocatalysts when the chain length of the linear disulfonamides was n = 3, 4, or 5 (monoacylate/diacylate = up to 44). The chemoselectivity of the competitive acylation between N,N′-ditosyl-1,5-pentanediamine (n = 5) and N,N′-ditosyl-1,3-propanediamine (n = 3) was found to be 36, favoring the former substrate. Different chain length by only one carbon atom was discriminated in the competitive acylation between N,N′-ditosyl-1,5-pentanediamine (n = 5) and of N,N′-ditosyl-1,4-butanediamine (n = 4) with the relative acylation rate of 16 in the presence of the organocatalyst.     

(Liquid + liquid) equilibria for ternary mixtures of (methanol or ethanol + toluene or m-xylene + n-dodecane)

(Liquid + liquid) equilibrium (LLE) results for the ternary mixtures of (methanol or ethanol + toluene or m-xylene + n-dodecane) at three temperatures (298.15, 303.15 and 313.15) K are reported. The compositions of liquid phases at equilibrium were determined by g.l.c. measurements and the results were correlated with the UNIQUAC and NRTL activity coefficient models. The partition coefficients and the selectivity factor of methanol and ethanol are calculated and compared to suggest which alcohol is more suitable for extracting the aromatic hydrocarbons (toluene or m-xylene) from n-dodecane. The phase diagrams for the ternary mixtures including both the experimental and correlated tie lines are presented. From the phase diagrams and the selectivity factors it is concluded that methanol has a higher efficiency as a solvent in extraction of aromatic hydrocarbon from alkane mixtures.     

Excess molar enthalpies of binary mixtures containing 2-decanone or dipentyl ether with long-chain n-alkanes at T = 298.15 K

Excess molar enthalpies (H^E) of binary mixtures of 2-decanone or dipentyl ether with n-alkanes, including n-dodecane, n-tetradecane, and n-hexadecane, were measured with an isothermal titration calorimeter (ITC) at T = 298.15 K under atmospheric pressure. All the measured H^E values are positive over the entire range of composition, indicating that all these mixing processes are endothermic. The H^E values varying with composition are found to be nearly symmetric for each binary system. It was also shown that the H^E values follow the order of n-hexadecane > n-tetradecane > n-dodecane at a given composition in either the 2-decanone or dipentyl ether binary systems. An empirical Redlich–Kister equation correlated quantitatively these new H^E data. The Peng–Robinson and the Patel–Teja equations of state, and the NRTL model were also applied to fit the H^E results. Among these tested correlative models, the Patel–Teja equation of state with two adjustable binary interaction parameters generally yielded the best representation.     

Using enantioselective dispersive liquid–liquid microextraction for the microseparation of trans-cyclohexane-1,2-diamine enantiomers

A new chiral separation system effective for the enantioselective extraction of racemic trans-cyclohexane-1,2-diamine is presented. Enantioselective dispersive liquid–liquid microextraction has been used for the chiral microseparation of trans-cyclohexane-1,2-diamine, with a chiral azophenolic crown ether being identified as a versatile chiral selector. The influence of various process conditions on the extraction performance was studied experimentally. It was found that the operational selectivity in one extraction step is mainly related to the type and volume of the solvents, chiral selector concentration, extraction time, temperature of sample solution, and pH. At optimum conditions (300 μL of diethyl ether as the extraction solvent 1 mL of methanol as the disperser solvent, with 5 mmol L^?1 chiral selector concentration, pH of the sample equal to 4.5, 30 min extraction time and a temperature of 10 °C), the distribution ratio of (R,R)- and (S,S)-trans-cyclohexane-1,2-diamine was 18.3 and 1.8, respectively, while the enantioselectivity value of 10.2 was found at the optimum condition.     

Measurement and prediction of (solid + liquid) equilibrium for sulfur compounds with aliphatic hydrocarbons

(Solid + liquid) equilibrium (SLE) of thiophene or diethylsulfide with n-heptane, n-octane or n-dodecane mixtures was measured by a static method. All the systems under study are simple eutectic systems. The DISQUAC group contribution model is fairly successful in predicting SLE.     

Quaternary liquid–liquid equilibria for systems of {(water + methanol or ethanol) + m-xylene + n-dodecane}

Liquid–liquid equilibrium (LLE) data were determined for the quaternary systems of {(water + methanol or ethanol) + m-xylene + n-dodecane} at three temperatures 298.15, 303.15 and 313.15 K and atmospheric pressure. The composition of liquid phases at equilibrium was determined by gas–liquid chromatography and the results were correlated with the UNIQUAC and NRTL activity coefficient models. The partition coefficients and the selectivity factor of the solvent are calculated and compared. The phase diagrams for the quaternary systems including both the experimental and correlated tie lines are presented.     

Rapid determination of illegal additives chrysoidin and malachite green by surface-enhanced Raman scattering with silanized support based substrate

Silanized support based SERS substrate is applied to detect chrysoidin in Sprite at 0.01 mg/L and malachite green in fish pond water at 0.0001 mg/L. The SERS method is sensitive, cost-effective and convenient, which has great potential in detection of illegal additives and harmful substances.     

Synthesis of a reduction-sensitive Bletilla striata polysaccharide amphiphilic copolymer

A reduction-sensitive stearic acid modified-Bletilla striata polysaccharide amphiphilic copolymer is synthesized. The copolymer enabled to spontaneously form micelles which display faster docetaxel release rates under reduction condition and enhanced anticancer activity in vitro after incorporating docetaxel into micelles.     

Novel dual inhibitors against FP-2 and PfDHFR as potential antimalarial agents: Design,synthesis and biological evaluation

A series of novel 2,4-diaminopyrimidine-modified compounds was designed and synthesized. Compound 14 showed micromolar dual inhibitory effect on both FP-2 and PfDHFR, and potential inhibition to the proliferation of P. falciparum 3D7 strain and chloroquine-resistant P. falciparum Dd2 strain.     

Synthesis and antiviral bioactivity of novel chalcone derivatives containing purine moiety

A series of novel chalcone derivatives containing purine group was synthesized and evaluated for their antiviral activities against cucumber mosaic virus and tobacco mosaic virus. Compound 3o exhibited remarkable antiviral activities and strong combining capacity to tobacco mosaic virus coat protein.     

In-line Raman spectroscopy and advanced process control for the extraction of anethole and fenchone from fennel (Foeniculum vulgare L. MILL.)

Plants are a desirable source for molecules of all kinds and for every purpose. Besides traditional techniques for extraction, plants are challenging for modern process engineering due to great variations because of their natural origin. One way to ensure high quality and low costs, as well as highly resource-efficient extraction, is in-line monitoring and process control. This study demonstrates the use of in-line Raman spectroscopy for monitoring the extraction of anethole and fenchone from fennel seed as a typical example. A partial least square calibration model with high accuracy was created. (Anethole: R² = 0.99, root mean square error of calibration (RMSEC) = 0.01256 g/L, root mean square error of validation (RMSEV) = 0.02608 g/L, and calibration range up to 2 g/L. Fenchone: R² = 0.98, RMSEC = 0.01188 g/L, RMSEV = 0.01945 g/L, and calibration up to 0.75 g/L.) These data are directly linked to a physicochemical process model to control the extraction process in real time and to perform predictive simulations while processing. The added value of this approach for modern phytoextraction is highlighted and exemplified as a major step toward sustainable Green Extraction processes.     

Anionic polymerization initiated by lithium amides for preparing high molecular weight polyacrylonitrile

Lithium amides have been proved to be effective anionic initiators for the anionic polymerization of acrylonitrile to get high molecular weight polyacrylonitrile in this study. Polyacrylonitrile with weightaverage molecular weight ranging from 1.02 × 10~6 g/mol to 1.23 ×10~6 g/mol (M_w/M_n= 1.9-2.2) could be prepared utilizing lithium amides derived from diisopropylamine, diethylamine, hexamethyldisilazane,dicyclohexylamine, and 2,2,6,6-tetramethylpiperidine as initiators. The polymerization of acrylonitrile proceeded in a homogeneous manner in N,N-di methyl for mamide and insignificant contribution of side reactions was confirmed.     

Synthesis,bioactivity, action mode and 3D-QSAR of novel anthranilic diamide derivatives

Several newly synthesized anthranilic diamide derivatives were found to exhibit excellent bioactivity. The action mode test and 3D-QSAR analysis provided valuable information for evaluation and future design of anthranilic diamide insecticides.     

Super-resolution morphological dissemination of intercalating dye in single DNA molecules via binding activated localization microscopy

Super-localization of intercalating dye YOYO-1 in single λ-DNA at super-resolution by binding activation localization microscopy (BALM).     

Nearcritical and supercritical ethanol as a benign solvent: polarity and hydrogen-bonding

Nearcritical (NC) and supercritical (SC) ethanol may offer novel media for both chemical reactions and separations as a replacement for environmentally undesirable organic solvents. We investigated the dipolarity/polarizability, hydrogen-bond donating acidity and accepting basicity in terms of Kamlet–Taft solvatochromism parameters π¹, α and β in saturated liquid ethanol from 25 to 225 °C and in gaseous and SC ethanol at 250 °C as a function of pressure. Reichardt’s E_T(30) scale was determined for ethanol under the same conditions. NC and SC ethanol has a wide range of solvent strength, which can be readily and continuously tuned by temperature and pressure. Liquid ethanol becomes nearly nonpolar as the temperature increases towards its critical point. The dipolarity/polarizability for SC ethanol ranges from gas-like to nonpolar liquid-like with increasing pressure. On the other hand, ethanol maintains significant hydrogen-bond donating acidity even under the supercritical conditions at 250 °C and at pressures up to 18.7 MPa. The hydrogen-bond accepting basicity, however, is considerably weakened at elevated temperatures. These well-established solvent parameters greatly improve our understanding of hot compressible ethanol, and allow us to explore the feasibility of using it in a variety of benign processes.     

Diterpenoids from the aerial parts of Leonurus macranthus

One cis clerodane-type (1) and three highly oxygenated labdane-type diterpenes (2-4) were isolated from the aerial parts of Leonurus macranthus. Compound 1 represents the first example of cis clerodane-type diterpene in the plants of Leonurus genus.     

Thermochemical data for n-alkylmonoamines functionalization into lamellar silicate Al-kanemite

Al-kanemite was synthesized by using inorganic salts as a source for silicon and aluminum in the hydrothermal synthesis of the material. The resulting solid was used as hosts for functionalization of polar n-alkylamine molecules of the general formula H₃C(CH₂)_n?NH₂ (n = 1 to 5) in aqueous solution. The compound was calorimetrically titrated with amine in 1,2-dichloroethane, requiring three independent operations: (i) titration of matrix with amine, (ii) matrix salvation, and (iii) dilution of the amine solution. From those thermal effects the variation in enthalpy was calculated as: (?6.81, ?7.76, ?8.97, ?9.94, and ?11.83) kJ · mol^?1, for n = 1 to 5, respectively. The exothermic enthalpy values reflected a favorable energetic process of amine-host functionalization in 1,2-dichloroethane. The original and modified Al-kanemite samples were characterized by elemental analysis, scanning electron microscopic (SEM), and nuclear magnetic nuclei of silicon-29 and carbon-13. The negative Gibbs free energy results supported the spontaneity of all these functionalization reactions. The positive favorable entropic values, as carbon chain size increased, are in agreement with the free solvent molecules in the solution, as the amines are progressively bonded to the crystalline inorganic matrix at the solid/liquid interface.     

Enthalpies of solvation of ethylene oxide oligomers CH3O(CH2CH2O)nCH3 (n = 1 to 4) in different H-bonding solvents: Methanol,chloroform, and water. Group contribution method as applied to the polar oligomers

The enthalpies of solution and solvation of ethylene oxide oligomers CH₃O(CH₂CH₂O)_nCH₃ (n = 1 to 4) in methanol and chloroform have been determined from calorimetric measurements at T = 298.15 K. The enthalpic coefficients of pairwise solute–solute interaction for methanol solutions have been calculated. The enthalpic characteristics of the oligomers in methanol, chloroform, water and tetrachloromethane have been compared. The hydrogen bonding of the oligomers with chloroform and water molecules is exhibited in the values of solvation enthalpy and coefficient of solute–solute interaction. This effect is not observed for methanol solvent. The thermochemical data evidence an existence of multi-centred hydrogen bonds in associates of polyethers with the solvent molecules. Enthalpies of hydrogen bonding of the oligomers with chloroform and water have been estimated. The additivity scheme has been developed to describe the enthalpies of solvation of ethylene oxide oligomers, unbranched monoethers and n-alkanes in chloroform, methanol, water, and tetrachloromethane. The correction parameters for contribution of repeated polar groups and correction term for methoxy-compounds have been introduced. The obtained group contributions permit to describe the enthalpies of solvation of unbranched monoethers and ethylene oxide oligomers in the solvents with standard deviation up to 0.6 kJ · mol⁻¹. The values of group contributions and corrections are strongly influenced by solvent properties.