Acetone-chloroform Mixture Research Articles

Tuning the Regioselectivity of Topochemical Polymerization through Cocrystallization of the Monomer with an Inert Isostere.

Regiochemistry of topochemical reactions depends on the crystal packing and biasing the regiochemistry necessitates precise crystal engineering. The pristine crystals of monomer 1 upon topochemical azide-alkyne cycloaddition (TAAC) reaction give a 1 : 1 blend of 1,4- and 1,5-triazole-linked polymers due to the presence of two self-sorted reactive conformers in the crystal. We designed a binary isomorphous cocrystal of monomer 1 and a structurally similar dummy molecule 2 to limit the number of reactive conformers of 1 to one and thus to get one type of polymer. Equimolar solution of 1 and 2 in chloroform-acetone mixture gave two 1 : 1 cocrystals Co-I and Co-II. The Co-II, a chloroform adduct, on heating undergoes desolvation and polymorphic transition to Co-I. Co-I is isomorphic to 1 and 2 and possess self-sorted arrays of 1 and 2. Heating Co-I results in the TAAC polymerization giving 1,4-triazolyl-linked polymer of 1 selectively, showing the power of crystal engineering in regiocontrol.

Экспериментальные и расчетные значения температуры вспышки смесей растворителей, применяемых в промышленности

The experimental verification of the calculated flash point temperatures of solvent mixtures used in industry is presented, and the evaluation of the adequacy of the methods for calculating the rate of its evaporation is given. To verify these methods, acetone-benzene and acetone-chloroform mixtures were experimentally studied, for which a deviation from Raoult's law could be assumed. The dependences of the evaporated substance on time at room temperature are obtained. An increase in the saturated vapor pressure and an increase in the evaporation rate are observed in the first mixture, and a decrease in the second. In the first case, the amount of substance that is taking part in the explosion increases and must be taken into account when calculating the room pressure increase during explosion, and the second can be used to reduce the potential explosive hazard of solvent mixtures. The problem of predicting fire and explosion hazard of solvents is associated with the identification of the fact of the formation of explosive concentrations of their vapors and change of flash point temperatures of the mixed liquids. By the example of a number of binary mixtures of flammable liquids, the influence of the interaction of their components on the flash point is shown, the calculated and experimental (reference) data in a closed crucible are compared for the ratio of components in the range from 0 to 100 % in benzene-toluene and benzene-ethanol mixtures. It is noted that for mixtures with a similar molecular structure, the results of calculating the flash point are in good agreement with the experiment, otherwise, the calculation gives overestimated values for liquids of various classes. Therefore, for mixtures of solvents used in industry, the number of components of which is three or more, it is required to check the flash point experimentally in order to more accurately predict their fire and explosion hazard.

Self-Diffusion and Heteroassociation in an Acetone–Chloroform Mixture at 298 K

The self-diffusion coefficients of acetone and chloroform in a binary acetone–chloroform mixture at 298 K are determined via pulsed field gradient NMR spectroscopy. It is estimated that the hydrodynamic radii of the mixture’s components, calculated using the Stokes–Einstein equation, grow as the concentrations of the components fall. It is shown that such behavior of hydrodynamic radii is due to acetone–chloroform heteroassociation. The hydrodynamic radii of monomers and heteroassociates in a 1: 1 ratio are determined along with the constant of heteroassociation, using the proposed model of an associated solution.

ИСПОЛЬЗОВАНИЕ УФ СПЕКТРОФОТОМЕТРИИ ДЛЯ ВЫЯВЛЕНИЯ УСЛОВИЙ ЭКСТРАКЦИИ МЕТАПРОТА ИЗ ВОДНЫХ РАСТВОРОВ

We have studied conditions for metaprote extraction from water solutions with pH indices 1 – 12.45. We have also established that metaprote is maximally extracted with chloroform with pH index 6.86 – 9.19, with chloroform-acetone mixture 9:1 with pH index 4.01 – 12.45. We have determined the probability of UV spectrophotometry application for detection and identification of metaprote in extracts. The results received are recommended for use in development of method of metaprote isolation from biological liquids and its detection and identification with UV spectrophotometry for chemical and toxicological analysis

ОЛИГОЛИГНАНЫ ДРЕВЕСИНЫ PICEA OBOVATA LEDEB.

The chemical composition of phenolic complex of Siberian Spruce (Picea obovata Ledeb.) wood and the compositions of its oligomeric lignan compounds have been investigated.The Siberian spruce wood was sampled close to Irkutsk city. The extractives were isolated from grinded wood (particle sizes is 10–15 mm, humidity is 5,9%) by threefold extraction with acetone. The yield of extractives was 1,5% of absolutely dry wood weight (in a.d.w.). The extract was separated by the consecutive extract treatment with the solvents ranged by increasing polarity - hexane, ethyl acetate, n-butanol. The main amount of phenolic compounds (lignans) – was concentrated in ethyl acetate fraction and it was 0,7% in a.d.w..Ethyl acetate fraction of spruce wood extract was separated by silica gel column using chloroform-acetone mixture as the eluent (with the increase of the latter content in mixture from 0 to 100%). Monomeric lignans (~60–65% of ethyl acetate fraction of spruce wood extract), oligomeric lignans (~20–25%), and polymer lignans (~12–15%) were isolated.The 13C NMR spectra for the main monomeric, oligomeric and polymeric lignan compounds of phenolic complexes have been recorded. It is found, that the structure of oligomeric and polymeric fractions includes monomeric lignan units with butyrolactone cycle, primarily, the fragments with oxymatairesinol structure. It has been shown, that the fragments with pinoresinol and lariciresinol are presented in oligomeric structures. It is noticed, that all of the monomeric structural units are characterized by guaiacyl substitution type of the aromatic cycles.A preliminary study of antiviral and antioxidant activity of the ethyl acetate fraction of acetone extract of Siberian spruce wood have been carried out. It is shown, that lignan complex exhibits the activity against Coxsackie B4 virus in cell culture and in pancreatitis model in white mice, reducing the activity of enteroviruses about in 100 times in cell culture. The magnitude of antioxidant activity of polyphenol spruce complex is comparable to those of a known antioxidant dihydroquercetin.

Study of Complexation in Acetone-Chloroform Mixtures by Infrared Spectroscopy

FTIR spectra of acetone-chloroform system with various component ratios were investigated within the spectral range 3950–4550 cm−1. Methods of multivariate curve resolution were applied to decompose the FTIR spectra into specific components of different composition. A method of decomposition based on structural model of solution which contains acetone, chloroform, and complex acetone/chloroform (1 : 1) was proposed. Results of both approaches are in good agreement within the range of measuring error.

Synergetic effect of binary separating agents in extractive rectification of homogeneous mixtures

Possibility of the use of dimethylsulfoxide-ethylene glycol binary separating agent for extractive rectification of ethanol-water and acetone-chloroform azeotropic mixtures has been considered. In both cases, the synergetic effect of binary separating agent has been detected. Upon the extractive rectification of the acetone-chloroform mixture, the assumption of a synergetic effect provides lower energy consumption upon separation compared to individual separating agents.

Prediction of the mutual diffusivity in acetone–chloroform liquid mixtures from the tracer diffusion coefficients

In recent publications (D'Agostino et al., 2011; Moggridge, 2012a), we have proposed an equation to relate the mutual diffusion coefficient in a binary liquid mixture to the tracer diffusivities in the same mixture. The equation proved satisfactory for mixtures close to their consolute point as well as the general case of non-ideal mixtures; most of the available data relates to positive deviations from Raoult's law. In only one case, mixtures of acetone and chloroform, was the proposed equation not found to be consistent with the available experimental data.However, the tracer diffusivity data on which this assessment was based is old (1959 and 1967), of low accuracy and with few measurements to cover the range of compositions. For this reason we have re-measured the tracer diffusivities in acetone–chloroform mixtures at 25°C with greater accuracy, by PFG-NMR, and used these measurements to re-examine the applicability of our equation to this system.We conclude that the proposed equation does in fact provide a good description of acetone–chloroform mixtures at 25°C. This is of particular interest because acetone–chloroform shows a negative deviation from Raoult's law. The equation also gives a satisfactory fit for diethyl ether–chloroform and water-N-methylpyrrolidone (Moggridge, 2012a), both systems showing negative deviations from Raoult's law.

Structural, single-particle and pair dynamical properties of acetone–chloroform mixtures with dissolved solutes

Structural, energetics and dynamical properties of acetone–chloroform mixtures containing an ionic or a neutral solute are investigated using molecular dynamics simulations. The primary goal has been to look at the nonideality in dynamical properties on changes of composition. Our calculations reveal the nature of selective solvation that plays a role in determining the nonideal dynamical characteristics of these solutes. The free energies of solvation of the ionic solutes are also calculated and the results are discussed in the context of their dynamical behavior. The nonideality in the dynamics of solvent molecules is also investigated. We have also calculated a pair dynamical property, namely the hydrogen bond lifetimes of acetone–chloroform pairs in these mixtures. The distribution of hydrogen bonds in these mixtures and their average energies are also calculated. The present simulation results are compared with those of experiments wherever available.

Cr3O(CH3COO)6(H2O)3]NO3⋅HNO3⋅H2O, Triaqua-Hexakis(Μ- Acetato)-Μ3-Oxo-Trichromium(III) Nitrate Nitric Acid Solvate Monohydrate

Reaction in methanol solution of the trinuclear ‘basic’ chromium(III) acetate with Pr(NO3)3⋅5H2O and further extraction by chloroform-acetone mixture led to the formation of novel unusual [Cr3O(CH3COO)6(H2O)3]NO3⋅HNO3⋅H2O (1) cluster with one “free” molecule of nitric acid. Complex 1 crystallizes in the monoclinic space group P21/c with, at room temperature, a = 13.624(2), b = 15.032(2), c = 15.180(2) Å, β = 112.98(3) °, Z = 4, and V = 2862.09 Å3. The obtained crystalline compound has been synthesized and characterized by IR and UV/Vis methods.

<b>Lindane and propuxur residues in the top soils of some cocoa growing areas in five districts of the Central Region of Ghana</b>

Lindane and propoxur residues in some topsoil samples from five cocoa growing districts in the Central Region of Ghana have been determined. Ten soil samples were taken randomly at a depth of 0-10 cm from pre-selected farms in each district. Some physical and chemical properties of the soils were determined. The pesticide residues were extracted from 50 g of topsoil by continuous Soxhlet extraction using a (1:1 v/v) acetone-chloroform mixture for six hours. Clean up of the extract was done by liquid-liquid partitioning and column chromatography using alumina and silica gel adsorbents. The pesticide residues were finally analysed by gas- chromatography using 63 Ni electron capture detector (ECD) and flame ionization detector (FID) for lindane and propoxur, respectively. Lindane and propoxur pesticide residues were found to be present in all the soils to which these pesticides had already been applied. Generally, lindane residues occurred in greater amounts than propoxur. The concentrations of lindane ranged from 2.1 to 15.4 mg kg -1 and propoxur from 1.71 to 7.95 mg kg -1 . Both the extracted lindane and propoxur residues correlated negatively with pH, cation exchange capacity, moisture content, and organic carbon. Propoxur correlated positively with the amount of clay but there was no significant correlation between the amount of clay and the extracted lindane concentration. KEY WORDS : Lindane, Propoxur, Soil, Pesticide monitoring Bull. Chem. Soc. Ethiop. 2006 , 20(2), 193-199.

Molecular Modeling of Phase Behavior and Microstructure of Acetone−Chloroform−Methanol Binary Mixtures

Force fields based on a Lennard-Jones (LJ) 12-6 plus point charge functional form are developed for acetone and chloroform specifically to reproduce the minimum pressure azeotropy found experimentally in this system. Point charges are determined from a CHELPG population analysis performed on an acetone-chloroform dimer. The required electrostatic surface for this dimer is determined from ab initio calculations performed with MP2 theory and the 6-31g++(3df,3pd) basis set. LJ parameters are then optimized such that the liquid-vapor coexistence curve, critical parameters, and vapor pressures are well reproduced by simulation. Histogram-reweighting Monte Carlo simulations in the grand canonical ensemble are used to determine the phase diagrams for the binary mixtures acetone-chloroform, acetone-methanol, and chloroform-methanol. The force fields developed in this work reproduce the minimum pressure azeotrope in the acetone-chloroform mixture found in experiment. The predicted azeotropic composition of x(CHCl3) = 0.77 is in fair agreement with the experimental value of x(CHCl3)expt = 0.64. The new force fields were also found to provide improved predictions of the pressure-composition behavior of acetone-methanol and chloroform-methanol when compared to other force fields commonly used for vapor-liquid equilibria calculations. NPT simulations were conducted at 300 K and 1 bar for equimolar mixtures of acetone-chloroform, acetone-methanol, and methanol-chloroform. Analysis of the microstructure reveals significant hydrogen bonding occurring between acetone and chloroform. Limited interspecies hydrogen bonding was found in the acetone-methanol or chloroform-methanol mixtures.

Adsorption of N 2, Ar, acetone, chloroform and acetone–chloroform mixture on carbon black in the framework of molecular layer structure theory (MLST)

Adsorption of pure nitrogen, argon, acetone, chloroform and acetone–chloroform mixture on graphitized thermal carbon black is considered at sub-critical conditions by means of molecular layer structure theory (MLST). In the present version of the MLST an adsorbed fluid is considered as a sequence of 2D molecular layers, whose Helmholtz free energies are obtained directly from the analysis of experimental adsorption isotherm of pure components. The interaction of the nearest layers is accounted for in the framework of mean field approximation. This approach allows quantitative correlating of experimental nitrogen and argon adsorption isotherm both in the monolayer region and in the range of multi-layer coverage up to 10 molecular layers. In the case of acetone and chloroform the approach also leads to excellent quantitative correlation of adsorption isotherms, while molecular approaches such as the non-local density functional theory (NLDFT) fail to describe those isotherms. We extend our new method to calculate the Helmholtz free energy of an adsorbed mixture using a simple mixing rule, and this allows us to predict mixture adsorption isotherms from pure component adsorption isotherms. The approach, which accounts for the difference in composition in different molecular layers, is tested against the experimental data of acetone–chloroform mixture (non-ideal mixture) adsorption on graphitized thermal carbon black at 50 °C.

Evaluation of Allergic Potential of Rubber Products: Comparison of Sample Preparation Methods for the Testing of Polymeric Medical Devices

A round-robin study was organized in the international standardization working group, ISO/TC194/WG8, with the purpose to compare the efficacy of different sample preparation procedures for determining the sensitization potency of polymeric medical devices. Three custom-made rubber samples were supplied to the participating laboratories and tested according to predetermined extraction and test protocols: A, formulated with a high level of mercaptobenzothiazole (MBT); B, formulated with a low level of MBT; and C, formulated with zinc dibutyldithiocarbamate. Extraction protocols included the so-called ISO method that applies physiological saline and/or vegetable oil extraction media without concentration (designated here “simple extraction”) and the so-called Japanese method that applies organic solvent extract (in this study chloroform–acetone mixture) after concentration to the test systems (designated here “exhaustive extraction”). Tests included human patch test, guinea pig maximization test (GPMT), adju...

Extraction-separation of mercury with 1-nephthylthiocarbamide

The extraction of mercury(II) has been studied from mineral acid solution using 1-nephthylthiocarbamide (ANTU) in chloroform-acetone mixture (9:1). The variables such as the concentration of acid and extractant have been optimized. The extractability of some other elements at the optimum conditions for mercury is also studied in order to establish the separation procedure. The probable composition of the extracted species has been deduced from log data. Effect of a number of foreign metal ions and anions has also been studied.

Molecular structure and physicochemical properties of acetone–chloroform mixtures

The molecular structure of acetone–chloroform mixtures has been studied. Thermodynamic mixing functions, permittivity, and Rayleigh ratios of isotropic and anisotropic light scattering are considered. A molecular model including the formation of the 1 : 1 and 1 : 2 molecular complexes is substantiated. A set of thermodynamic and structural parameters of the complex formation was obtained. The thermodynamic parameters of complex formation defined by the minimisation procedure for excess Gibbs energy of mixture was applied for calculation of excess enthalpy and entropy as well as dielectric and optical properties of mixtures. For the first time the unified representation and analysis of the thermodynamic, dielectric and optical properties of acetone–chloroform mixtures in terms of generalized quasichemical models on the molecular-structural level was realised.

Solvatochromism and solvation of water-soluble molybdenum(O)-tetracarbonyl diimine-complexes

Solvatochromic behaviour is described for the water-soluble molybdenum(0)-carbonyl-diimine complexes [Mo(CO) 4(LL)] n− , where LL=fz (ferrozine;3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine-p,p′-disulphonate) and n = 2 or LL = sb (Schiff base from 2-acetyl pyridine plus β-alanine) and n = 0, in water and in a range of non-aqueous solvents, and in water-isopropanol solvent mixtures. The possibility of using solvatochromic compounds of this type to probe selective solvation in solvent mixtures is assessed, with particular reference to water-isopropanol and acetone-chloroform mixtures, and to microemulsions.

高速液体クロマトグラフィーによる血しょう中クロナゼパム定量法

A simple, sensitive and specific method of high-performance liquid chromatography (HPLC) was developed for the determination of clonazepam in plasma. Clonazepam in plasma adjusted to the pH range of 8.0-9.0 was extracted with acetone-chloroform mixture (2: 3). The organic layer was evaporated to dryness in vacuo. The residue was dissolved in methanol containing 1-naphthol as internal standard, and a part of the solution was injected into the HPLC system. For the stationary phase, a reversed phase column maintained at 30°C was used. The flow rate of the mobile phase consisted of 0.1 M acetic acid-methanol (65: 35, pH 5.0) was 0.8 ml/min, and the elutes were detected by UV monitoring at 306 nm. In this condition, the peak of clonazepam was excellently separated from that of carbamazepine, and other anticonvulsants which were often administered with clonazepam at the same time did not affect the determination of clonazepam. The calibration curve from peak height ratio was linear and a coefficient of variation was 3.5%(10ng/ml, n=5). The recovery of clonazepam from plasma sample containing 20ng/ml was 99.9±4.6%(mean±S.D., n=5). The limit of detectability for quantitation was 5 ng/ml plasma when 1.0ml of plasma was used.

Morphology and ionic conductivity of some lithium ion complexes with poly(ethylene oxide)

Deposition of LiBF 4-PEO crystalline complexes from methanol gives a material (phase II) melting at ∼340K while deposition from acetone-chloroform mixtures gives a material with a melting point of ∼433K (phase I). Both materials have the same 1:4 stoichiometry (Li +:ethylene oxide) and each gives the same wide-angle X-ray scattering pattern though phase II has the broader reflections. The observations are interpreted in terms of a double helical model with long sequences of the same helical sense for phase I, but with less long range order and frequent reversals of helical sense for phase II. The presence of both phases in LiCF 3SO 3 complexes is attributed to the contribution of the anion towards complex stability in methanol. The conductivities of the semicrystalline materials are compared with those of amorphous PEO gels complexed with LiBF 4. The highest ambient temperature conductivities are obtained from complexed gels.

Measurement of Solvent Shifts by Raman Difference Spectroscopy

The application of Raman difference spectroscopy for the determination of the small frequency shifts arising from solvent effects has been demonstrated. Data are presented for benzene-carbon disulfide, benzene-pyridine, and acetone-chloroform mixtures. The majority of the solvent shifts measured are less than 1.0 cm−1 and these can generally be determined with better than 10% accuracy using a rotating two-compartment liquid cell. The smallest shift measured in this work was 0.06 cm−1. While statistical analysis indicates that uncertainties as small as ±0.01 cm−1 can be obtained in many cases, artifacts may cause apparent shifts up to ±0.03 cm−1.