Components Of Binary Mixture Research Articles

Experimental utilization of displacement effect for the optimization of the separation of a two-component mixture

Using a mixture of two substituted cyclohexanone epimers, sample loading, binary mixture composition and column efficiency were investigated for their influence on the displacement effect observed between the first and the second eluted components (“sample self-displacement effect”). This effect occurs and can enhance production for loads as high as 1 g on a 250 × 21.4 mm I.D. column. Separations over a broad range of epimer mixture compositions, from 10:90 to 75:25, show a displacement effect on the first-eluting component by the second. In loading and composition studies, interference between the tailing portion of the first component and the front of the second component is the predominant factor influencing recovery loss for both components. A high column efficiency is essential for sharpening band zone boundaries and maximizing yields. There is a very good correlation between experimental results and reported computer simulations of the band profiles of binary mixture components.

Evaluation of computer-assisted second-derivative ultraviolet spectrophotometry for analysis of binary mixtures

Three second-derivative spectra identification (DESPI) programs have been developed. The DESPI-1 program is used for the computerized recognition of the spectral components in known binary mixtures. The DESPI-2 and DESPI-3 programs are applied to the automatic identification of unknown binary mixtures. The performances of these computer-assisted procedures are evaluated and compared for nineteen single compounds (purines and pyrimidines) and twelve binary mixtures.

Condensation of nonazeotropic binary mixtures in a horizontal tube. (R113+R11).

Complete condensation of nonazeotropic binary mixtures of R11-R113 refrigerants is experimentally studied. The test apparatus consists of two concentric horizontal tubes, with the vapor mixture flowing in the inner tube and the cooling water in the annular space in the countercurrent direction. The composition and the mass flow rate of the binary-component mixture are systematically varied. Through the measurement of the local temperature of the wall, the cooling water and the vapor along the tube axis, the axial distribution of the local heat transfer coefficients are obtained. An empirical equation is derived to correlate condensation heat transfer performance.

High-resolution/higher-order derivative spectrophotometry for identification and estimation of synthetic organic pigments in artists' paints

Twenty-two pigments commonly used in artists' paints were investigated by recording the fourth-derivative (d 4) ultraviolet-visible spectra. Dimethyl sulphoxide was used as a universal solvent. It was possible to distinguish pigments which were chemically very similar and of the same colour, and to quantify the components of binary mixtures without separation by using side-peak-side ratio computations. Acrylic or oil media had no influence on the derivative spectra. For mixtures of more than two components, the pigments were separated by thin-layer chromatography and the d 4-spectra were recorded directly from the developed spots; 10 ng of each pigment in 5 μl of solvent was enough for the analysis.

Theory and simulation of associating liquid mixtures

We present a theory for mixtures in which molecular association occurs, and apply it to binary mixtures of components A and B in which AB dimers are formed, but there is no AA or BB dimerization. The theory, which is an extension to mixtures of one recently proposed by Wertheim, is based on a resummed cluster expansion. The attractive sites within the molecules are modeled by off-center point charges in a dipolar symmetry. The effect of these attractive sites on the concentration of dimers and thermodynamic excess functions is studied. Monte Carlo computer simulations are carried out for the model fluid, and the results are compared with the theory. Excellent agreement is found. The theory describes the main physical effects present in a prototype mixture of this type, chloroform-acetone.

Surface Energy Analysis of the Detergency Process — Surface Tension Components of Binary Mixtures of Organic Liquids and Aqueous Solutions of Surfactants

The applicability of the surface energy analysis method to the detergency system is discussed. This method involves multicomponent washing liquids, such as binary mixtures of organic liquids and aqueous solutions of surfactants. The surface tension and its components of these mixtures and surfactant solutions, which were calculated from contact angle measurements, were not linearly proportional to the molar ratio or concentration. Oily dirt/washing liquid interfacial tensions were estimated from surface tension components. The interfacial tension tended to be overestimated compared with that observed in the systems using surface active materials. The results of a rolling-up test of oil drops suggest a correlation between the work of adhesion and washability.

17O, 15N and 13C NMR chemical shifts of N,N‐dimethylmethanesulphinamide in various solvents

AbstractThe 17O, 15N and 13C NMR chemical shifts have been determined for N,N‐dimethylmethanesulphinamide (1), both as the neat liquid and in dimethyl sulphoxide, acetone, chloroform and various alcohols. The 17O and 15N nuclei of 1 resonate at a lower frequency than those of the corresponding sulphonamide, and depend on the solvent and concentration of the components in binary solution mixtures. Hydrogen bond‐forming solvents shift the signals to lower frequency than those of the neat amide. On changing the solvent, the change in the 17O NMR chemical shift of the sulphinamide is smaller than that of carboxamides, but the difference in the 15N NMR chemical shifts between these two systems with a solvent change is much lower and opposite in direction, reflecting the differences in the resonance structures of carboxamides and sulphinamides.

Solid-surface derivative room-temperature luminescence spectrometry of mixtures

Derivative solid-surface room-temperature fluorescence and phosphorescence were combined for the identification of components in binary and ternary mixtures of nanogram amounts of nitrogen heterocycles. Direct, and first and second derivative room-temperature phosphorescence excitation, room-temperature fluorescence and room-temperature phosphorescence spectra were used in the identification of the components in the mixtures by matching spectral wavelengths from mixtures with spectral wavelengths from standards. The criteria for matching wavelengths, subtracting background signals and obtaining derivative spectra at the 0.5-ng level are discussed.

Convective Filmwise Condensation of Nonazeotropic Binary Mixtures in a Vertical Tube

Complete condensation of binary mixtures of R11-R114 refrigerants is experimentally and theoretically studied. The test apparatus consists of two concentric tubes, with the vapor mixture flowing downward in the inner tube and the cooling water in the annular space in countercurrent direction. The composition of the binary-component mixtures is varied. An empirical equation is derived to correlate condensation heat transfer performance. A semitheoretical model is developed to predict laminar- and turbulent-film condensation on a vertical surface. Theory compares well with experiments. The vapor-coolant temperature difference remains practically constant throughout the entire flow passage, thus reducing the exergy loss to a minimum. The device is particularly attractive in extracting the available energy from geothermal and ocean thermal energy sources.

Separation of a Two-Component Particulate Material Mixture by a Vibro-Impacting Separator

Abstract The vibro-impacting separator, the so-called Paddy table, is widely used for the separation of the components of binary mixtures of particulate materials. This paper presents an improved mathematical model of vibro-impacting separation and experimental results aimed at the further investigation of vibro-impacting motion, the adequacy of the model, and the improvement of the efficiency of vibro-impacting separation, with special attention to friction between the particles and the operational element of the separator. It is concluded that friction decreases the instability of the periodic symmetric motion of the particles and that the model adequately represents the physical system in the range of the operational variables tested. Also, it is found that the formulas obtained are suitable for design purposes and that friction decreases the separation efficiency. In conclusion, we believe that vibro-impacting separation is a promising candidate for many fields of industry.

Perception of components in binary odour mixtures

Changes in perceived intensity and odour quality of mixtures of trans -2-hexenal and trans -2-decenal, common products of fat oxidation, were measured using category scales and a profiling technique, respectively. Twenty three quality terms appropriate to these odours were derived from a list of 152 descriptors and used to obtain profiles of the mixtures. Qualities perceived in mixtures appeared to depend on the relative intensities of the odorants; however, only a small intensity difference between odorants was necessary for the qualities of the higher intensity component to predominate, or for only that odorant to be perceived. When odorants were of approximately equal intensity, most of the qualities of both odorants were perceived. Scores for intensities of mixtures agreed well with those predicted by the vector model of intensity summation and a value of 109° for α was obtained for the two odorants. Although there was some evidence of intensity enhancement and suppression, the general effect resulting from mixing the two odorants confirmed the earlier finding of Jones and Woskow (1964), that the total intensity of a mixture is always less than the sum of the intensities of the two components.

On some properties of high an low density polyethylene mixtures filled with carbon black

AbstractMechanical properties (yield strain, ultimate strength and elongation at break) as well as some melting parameters of mixtures consisting of high density polyethylene with average melting index (PE‐HD) and low density polyethylene with low and high melting indexes (PE‐LD‐I and PE‐LD‐II) in the presence or absence of carbon black have been investigated. It has been established that there are ranges of concentration in which the influence of one of the components of binary polyethylene mixtures prevails. Further the decrease of PE‐LD melting index and the filling with carbon black affect the parameters of mixtures melting in the same way.

Evidence of the incorporation of normally nonaggregating hemoglobins into crystalline aggregates of deoxy hemoglobin S.

Changes in the solubility of both components of binary mixtures of sickle-cell deoxyhemoglobin (Hb degrees S) and some normally nonaggregating hemoglobins were determined by direct compositional analysis of the solution phage following sedimentation of crystalline aggregates generated from them. Increases in turbidity associated with the suspension of the crystals in solution were also monitored for each mixture. Correlations between changes in species solubility and "excess' turbidity levels were observed which define two distinct forms of interaction between hemoglobin additives and Hb degrees S. The R-state quaternary structures, COHbS and metHbS in the absence of organic phosphate, are excluded from the aggregate phase and act to lower the solubility of Hb degrees S through increased excluded volume contributions to the activity of the solution phase. Increases in turbidity which parallel this solubility change reflect the increased population of highly asymmetric Hb degrees C crystals in solution. Deoxyhemoglobin A and metHbS fixed in the deoxy conformation lower the solubility of Hb degrees S in a more complex manner, which may include the establishment of a minimum solubility. The solubility of these additives also decreases, as does the turbidity due to the resultant crystals, when the proportion of additive exceeds 40% of the total. Analysis of the composition of pellets isolated from both hybrid and nonhybrid mixtures with Hb degrees A confirms its incorporation into the aggregates. Such "mixed" crystals appear to have solubility and morphological properties different from those of Hb degrees S alone. Comparison of phase composition data from mixtures prepared with varying initial concentrations of Hb degrees S suggests that the degree of HbA incorporation into HbS aggregates is a function of the amount of Hb degrees S itself available for self-aggregation and the stage of crystal development at which HbA participates.

Calculation of phase diagrams of binary salt mixtures with a common anion

In order to calculate excess chemical potentials of the components in binary molten salt mixtures, a simple model is proposed which requires three physical parameters for each salt: the crystal lattice energy, the latent heat of melting and the sum of the ionic radii. The model has been used to calculate the liquidus temperature for various compositions of the binary system. Calculated and experimentally determined phase equilibria for the following systems are compared: LiF–KF, LiF–NaF, NaF–KF, LiCl–KCl, NaCl–CsCl, LiNO3–NaNO3, CaF2–MgF2, LiF–CaF2, NaF–CaF2 and NaCl–SrCl2.

Response and selectivity characteristics of alkylammonium ion-selective electrodes

A series of poly(vinyl chloride) matrix coated-wire electrodes based on dinonylnaph-thalene sulfonic acid (DNNS) selective to various alkylammonium ions was prepared and selectivity characteristics were evaluated. A set of tributylammonium electrodes was used to study the interference by a homologous series of alkylammonium ions. Selectivity coefficient ( k pot i,j) values for alkylammonium ions at a given carbon number decreased in the order primary, secondary, tertiary, quaternary. A linear increase in log k pot i,j with carbon number was observed in each series. Two additional sets of electrodes selective to dodecylammonium ion and to di- n-hexylammonium ion were evaluated for response to other C-12 amines. Electrodes for primary amines showed little or no response to secondary and tertiary amines, while electrodes for tertiary amines responded strongly to primary amines and less strongly to secondary amines. The effect of structural modifications was evaluated in a study of N-substituted cydohexylamines. The dependence of the magnitude of k pot i,j on the concentration of the interference was determined for both strongly and weakly interfering species. For strong interferences, k pot i,j was observed to increase to a maximum value of characteristic concentration. For weak interferences, the k pot i,j variation with concentration was markedly less. Guides for estimating the response to an interfering species based on its structure and molecular weight were obtained. The results are compared to analogous solvent-extraction systems. The significance of these results is discussed in terms of quantifying different components in binary mixtures using several electrodes simultaneously.

Tensammetric analysis of surfactant mixtures

The tensammetric behaviour of the less strongly adsorbed component in various binary mixtures of surfactants was investigated with the ac polarograph. Even at very low surface coverages the peak current for such a component was not independent of the concentration of the more strongly adsorbed surfactant. However, in many cases the less strongly adsorbed component can be determined if the concentration of the other component is known or the addition method is used.

Preferential binding to poly(α-L-lysine HBr) from polar solvent mixtures

The preferential binding behaviour of one of the components of aqueous organic solvents or organic solvent binary mixtures to poly(α-L-lysine HBr)(PLLHBr) has been studied by differential refractometry. The aqueous mixtures have dimethyl sulphoxide (DMSO), N,N-dimethylformamide (DMF), N-methylformamide (NMF), 1,2-ethanediol (EG), 1-methyl-2-pyrrolidinone (NMP) and 2-propanol (2PrOH) as their second component, while nonaqueous mixtures comprise DMF + DMSO, EG + DMSO and NMP + DMSO. Aqueous mixtures show different behaviour; large positive binding of DMSO at lower concentrations is followed by a decrease and eventually by an inversion at higher concentrations, while the binding of 2PrOH is increasingly negative with concentration. The behaviour pattern of DMSO binding from nonaqueous mixtures is the same as that of aqueous mixtures, though the extent is different. In DMF + DMSO, the helix formation of PLLHBr is observed. The data obtained is interpreted invoking an operational model of PLLHBr, in which polar and less polar portions of the polymer residue undergo solvation separately. PLLHBr is exclusively hydrated in aqueous 2PrOH, if the polymer assumes no helix. It is suggested that the helix formation in DMF + DMSO mixtures is accompanied by the release of solvent molecules from around the less polar portion of the polymer.

Estimation of mixing index and contact number by spot sampling

Most of the available definitions of the mixing index, which specifies homogeneity or distribution of the composition in a solids mixture, are based on the variance of the concentration of a certain component among spot samples. However, for a solid—solid chemical reaction or any process involving contact between different solid phases, its rate is proportional to the contact points or area among particles of the different phases. Thus a definition of a microscopic and geometric mixing index based on the number of contact points appears to be of practical significance. The contact number is the number of contact points between two different types of particles for one key particles, a particle species which is selected as a reference. In this paper, the estimation of the mean contact number from spot samples is considered. An expression for estimating the contact number from spot samples is derived. Expressions for the expected value (population mean contact number) and the variance of this mean contact number are also derived. To verify these expression, random numbers with a uniform distribution are generated to simulate a binary component mixture in the completely mixed state. Results of the simulation are in reasonably good agreement with the derived expressions. The mixing index based on the mean contact number is able to indicate the homogeneity of a mixture with regular packing arrangement. In such a mixture, particles are packed either cubically or hexagonally in each layer, and therefore it is difficult to estimate the homogeneity of the mixture from the sample variance.

Upper limit of urea-adduct formation with ethyl esters of C8?C12 normal monocarboxylic acids

1. An experimental study has been made of the relation between ULA temperature (upper limit of adduct formation) of individual ethyl esters of C8-C12 n-monocarboxylic acids and the number of carbon atoms in the molecule; a similar study has been made of the ULA of the primary component in binary and multicomponent mixtures of these esters in relation to concentrations of the second or other components of the mixtures. 2. It has been established that all these relationships can be described by the linear equations obtained previously for individual C6-C10 n-alkanes, binary mixtures of C6-C9 n-alkanes, and ternary mixtures of n-heptane, with an average absolute error of no more than 0.8‡C. 3. A new linear relationship has been obtained for the constant slope of the equation for binary mixtures of ethyl esters as a function of the difference in number of carbon atoms in the molecules of the primary and secondary components of the mixture.

Jumps in the density and temperature of one of the components of a binary gas mixture over the plane surface of a liquid

We consider a problem concerning the vaporization (or condensation) of one of the components of a binary gas mixture situated over the plane surface of a liquid. The kinetic equation in the model form of [1] is used to describe the system. As is well known, this model agrees well with experiment and is simpler than the Boltzmann equation so far as mathematical relations are concerned. This model fails to describe a number of effects because it is assumed that the collision time of the particles is independent of their velocity. This relates primarily to the phenomenon of thermal diffusion of the gases. Thus the formulas given below are applicable to gas mixtures having a small thermal-diffusion coefficient. The model equation is solved by an approximate method developed in [2]. In [3] the temperature jump of a single-component gas at a solid wall is calculated by this method, and the method is also employed in [4] in the calculation of the slipping rate of a binary gas mixture in the field of a temperature gradient. In both cases the results agree with numerical calculations by other authors within an accuracy of 1.5%.