Results For Binary Mixtures Research Articles

Sustainable environment-friendly quantitative determination of three anti-hyperlipidemic statin drugs and ezetimibe in binary mixtures by first derivative Fourier transform infrared (FTIR) spectroscopy.

FTIR spectrometry is considered a sustainable green analytical chemistry procedure. Its use in quantitative analysis of pharmaceutical compounds in their raw resources and in their dosage forms is growing currently. The current research offers an environment-friendly, speedy, cost-effective, reliable and easy method for the simultaneous estimation of anti-hyperlipidemic drugs. No sample preparation was required except for grinding and mixing with KBr for making pellets used for acquisition of the FT-IR spectra. First-derivative FTIR spectroscopy is used to assess quantitatively atorvastatin (ATR), rosuvastatin (RSV) and simvastatin (SMV) in their binary mixtures with ezetimibe (EZT). For the first mixture, EZT and ATR were determined at 1733.18cm-1 and 1647.74cm-1, respectively. In the second mixture, the zero-crossing wave numbers selected for the determination of EZT and RSV were 1733.18cm-1 and 955.69cm-1, correspondingly. Whereas, the third mixture was quantified at the wavenumbers of 1520.93 and 3569.68cm-1 for EZT and SMV, respectively. Validation of the procedure has been performed complying with recommendations of the International Conference of Harmonization (ICH) presenting linearity, accuracy, precision, robustness and selectivity. The linear range for all drugs was 2-30mg/g. It was found that the LOD was 0.607, 0.311, 0.491 and 0.395mg/g and the LOQ was found to be 1.839, 0.942, 1.490 and 1.190mg/g for EZT, ATR, RSV, and SMV, correspondingly. The proposed technique was found to be accurate and precise in terms of percentage error and percentage relative standard deviation among intraday and interday measurements. It was also found selective through comparison of the results of standard drugs with results of binary mixtures and of pharmaceutical tablets. It was found robust through making slight variations in the working conditions and the results obtained remained statistically equivalent. The technique was applied effectively for the estimation of the binary mixtures under study in their tablets. Comparing the found outcomes to those of reference derivative UV spectrophotometric methods gave no significant difference between them. Analytical eco-scale and the scale of Green Analytical Procedure Index (GAPI) are the two scales utilized for evaluation of the greenness of the technique and it was found to be excellent green.

Liquid Phase Density, Sound Speed, and Vapor Pressure of Linear Alkanes Using the Mattedi–Tavares–Castier Equation of State

This work assesses the ability of the Mattedi–Tavares–Castier (MTC) equation of state (EOS) in representing the liquid phase density, sound speed, and vapor pressure of linear alkanes (C6–C20). It is found that its deviations from experimental data for liquid phase density, liquid phase sound speed, and vapor pressure are similar to, yet slightly higher than, those of the PC-SAFT EOS for the same compounds. Using only experimental data points at reduced pressures smaller than 20 for parameter fitting, a condition observed in most commercial chemical processes, leads to smaller deviations from the experimental values. Adopting for the lattice cell volume the value of 15 cm3/mol, which is the molar volume of the methylene group in the lattice-based UNIQUAC model, all the adjustable MTC EOS parameters follow regular trends with respect to the number of carbon atoms in the linear alkane chains. These parameters could be fitted to empirical expressions. When used, they produce deviations in pure-component liquid phase density, liquid phase sound speed, and vapor pressure equal to 0.6, 2.8, and 9.8%, respectively. The results for binary mixtures are generally in good agreement with the experimental data.

Isotropic-nematic phase equilibria of hard-sphere chain fluids-Pure components and binary mixtures.

The isotropic-nematic phase equilibria of linear hard-sphere chains and binary mixtures of them are obtained from Monte Carlo simulations. In addition, the infinite dilution solubility of hard spheres in the coexisting isotropic and nematic phases is determined. Phase equilibria calculations are performed in an expanded formulation of the Gibbs ensemble. This method allows us to carry out an extensive simulation study on the phase equilibria of pure linear chains with a length of 7 to 20 beads (7-mer to 20-mer), and binary mixtures of an 8-mer with a 14-, a 16-, and a 19-mer. The effect of molecular flexibility on the isotropic-nematic phase equilibria is assessed on the 8-mer+19-mer mixture by allowing one and two fully flexible beads at the end of the longest molecule. Results for binary mixtures are compared with the theoretical predictions of van Westen et al. [J. Chem. Phys. 140, 034504 (2014)]. Excellent agreement between theory and simulations is observed. The infinite dilution solubility of hard spheres in the hard-sphere fluids is obtained by the Widom test-particle insertion method. As in our previous work, on pure linear hard-sphere chains [B. Oyarzún, T. van Westen, and T. J. H. Vlugt, J. Chem. Phys. 138, 204905 (2013)], a linear relationship between relative infinite dilution solubility (relative to that of hard spheres in a hard-sphere fluid) and packing fraction is found. It is observed that binary mixtures greatly increase the solubility difference between coexisting isotropic and nematic phases compared to pure components.

Thermodynamic Properties of Binary Mixture of Tributylphosphate and n-Alkanols

The excess molar enthalpies for binary systems of tributylphosphate(TBP) +methanol/ethanol/1-propanol/1-butanol were measured by calorimetry at 298.15 K as well as a little mixtures at 293.15 K and 303.15 K. The experimental results were in the range of -0.3 - 0.3 kJ·mol-1 and were invariant with the change of temperature. The excess molar entropies, excess molar Gibbs free energies, and activity coefficients for the binary mixtures had been obtained according to the athermal solution model. The thermodynamic analysis showed that the model provided reliable results for binary mixtures of TBP+methanol/ethanol/propan-1-ol, but did not for TBP+butan-1-ol.

냉매 이성분 혼합물의 포화 풀핵비등 특성에 관한 연구

Saturated nucleate pool boiling experiments for binary mixtures, which are consisted of refrigerant R11 and R113, were performed with constant wall temperature condition. Results for binary mixtures were also compared with pure fluids. A microscale heater array and Wheatstone bridge circuits were used to maintain the constant temperature of the heating surface and to obtain heat flow rate measurements with high temporal and spatial resolutions. Bubble growth images were captured using a high speed CCD camera synchronized with the heat flow rate measurements. The departure time for binary mixtures was longer than that for pure fluids, and binary mixtures had a higher onset of nucleate boiling (ONB) temperature than pure fluids. In the asymptotic growth region, the bubble growth rate was proportional to a value between and . The bubble growth behavior was analyzed to permit comparisons with binary mixtures and pure fluids at the same scale using dimensionless parameters. There was no discernable difference in the bubble growth behavior between binary mixtures and pure fluids for a given ONB temperature. And the departure radius and time were well predicted within a error. The minimum heat transfer coefficient of binary mixtures occurred near the maximum value, and the average required heat flux during bubble growth did not depend on the mass fraction of R11 as more volatile component in binary mixtures. Finally, the results showed that for binary mixtures, a higher ONB temperature had the greatest effect on reducing the heat transfer coefficient.

Single bubble growth in saturated pool boiling of binary mixtures

Nucleate pool boiling experiments for binary mixtures, which are consisted of R11 and R113, were performed with constant wall temperature condition. Results for binary mixtures were also compared with pure fluids. A microscale heater array and Wheatstone bridge circuits were used to maintain the constant temperature of the heating surface and to obtain heat flow rate measurements with high temporal and spatial resolutions. Bubble growth images were captured using a high-speed CCD camera synchronized with the heat flow rate measurements. The departure time for binary mixtures was longer than that for pure fluids, and binary mixtures had a higher onset of nucleate boiling (ONB) temperature than pure fluids. In the asymptotic growth region, the bubble growth rate was proportional to a value between t 1/6 and t 1/4. The bubble growth behavior was analyzed to permit comparisons with binary mixtures and pure fluids at the same scale using dimensionless parameters. There was no discernible difference in the bubble growth behavior between binary mixtures and pure fluids for a given ONB temperature. And the departure radius and time were well predicted within a ±30% error. The minimum heat transfer coefficient of binary mixtures occurred near the maximum | y− x| value, and the average required heat flux during bubble growth did not depend on the mass fraction of R11 as more volatile component in binary mixtures. Finally, the results showed that for binary mixtures, a higher ONB temperature had the greatest effect on reducing the heat transfer coefficient.

Densities, viscosities, and refractive indexes for {C 2H 5CO 2(CH 2) 2CH 3+C 6H 13OH+C 6H 6} at T=308.15 K

In this work we present densities, kinematic viscosities, and refractive indexes of the ternary system {C 2H 5CO 2(CH 2) 2CH 3+C 6H 13OH+C 6H 6} and the corresponding binary mixtures {C 2H 5CO 2(CH 2) 2CH 3+C 6H 6}, {C 2H 5CO 2(CH 2) 2CH 3+C 6H 13OH}, and {C 6H 13OH+C 6H 6}. All data have been measured at T=308.15 K and atmospheric pressure over the whole composition range. The excess molar volumes, dynamic viscosity deviations, and changes of the refractive index on mixing were calculated from experimental measurements. The results for binary mixtures were fitted to a polynomial relationship to estimate the coefficients and standard deviations. The Cibulka equation has been used to correlate the experimental values of ternary mixtures. Also, the experimental values obtained for the ternary mixture were used to test the empirical methods of Kohler, Jacob and Fitzner, Colinet, Tsao and Smith, Toop, Scatchard et al., and Hillert. These methods predict excess properties of the ternary mixtures from those of the involved binary mixtures. The results obtained for dynamic viscosities of the binary mixtures were used to test the semi-empirical relations of Grunberg–Nissan, McAllister, Ausländer, and Teja–Rice. Finally, the experimental refractive indexes were compared with the predicted results for the Lorentz–Lorenz, Gladstone–Dale, Wiener, Heller, and Arago–Biot equations. In all cases, we give the standard deviation between the experimental data and that calculated with the above named relations.

Excess volumes of (a polar liquid + an aromatic hydrocarbon) at the temperature 298.15 K. V. (γ-Butyrolactone + an aromatic hydrocarbon)

Excess molar volumes have been measured by means of a continuous dilution dilatometer for (γ-butyrolactone + benzene, or toluene, or o-xylene, or m-xylene, or p-xylene, or ethylbenzene, or styrene) at T= 298.15 K. The V m Evalues are negative over the entire range of composition for all the binary mixtures. The ∣ V m E(minimum)∣ and ∣ V m E( x= 0.5)∣ values of this series decrease in the sequence: C 6H 5CH=CH 2> C 6H 5CH 3> C 6H 6> p-C 6H 4(CH 3) 2> C 6H 5CH 2CH 3≈ m-C 6H 4(CH 3) 2> o-C 6H 4(CH 3) 2. The results were compared with the results for binary mixtures containing other polar liquids, and showed that the interactions between γ-butyrolactone molecules and the above-noted aromatic hydrocarbon molecules are very strong.

Influence of the mixing rule on the liquid-liquid equilibrium calculation

Liquid-liquid equilibrium data were correlated with three mixing rules that incorporate excess Gibbs energy model into a equation of state: Wong-Sandler, Heidemann-Kokal and MHV2 methods. The Soave equation of state is employed to several binary mixtures, coupled with NRTL, UNIQUAC and UNIFAC models for excess Gibbs free energy. The best results for binary mixtures were obtained with NRTL and Wong-Sandler, then this combination was used to predict the ternary liquid-liquid equilibria.

Excess volumes of (a polar liquid + an aromatic hydrocarbon) at the temperature 298.15 K: III. ( N,N-dimethylacetamide + an aromatic hydrocarbon)

Excess volumes have been measured by means of a continuous-dilution dilatometer for ( N,N-dimethylacetamide + benzene or toluene or o-xylene or m-xylene or p-xylene or ethylbenzene or styrene) at the temperature 298.15 K. V E mvalues are negative over the entire range of composition for all the binary mixtures. V E m(minimum): and | V E m( x= 0.5)| values of this series decrease in the sequence: C 6H 5CH=CH 2> C 6H 5CH 3> p-C 6H 4(CH 3) 2> C 6H 6> m-C 6H 4(CH 3) 2≈ o-C 6H 4(CH 3) 2> C 6H 5CH 2CH 3. The results were compared with the results for binary mixtures containing other polar liquids, and show that there are quite strong interactions between N,N-dimethylacetamide molecules and aromatic-hydrocarbon molecules.

Fluid mixtures at high pressures

In the present survey some important trends in the high pressure thermodynamics of fluid mixtures of non-electrolytes are reviewed. First the pressure dependence of excess functions such as the excess Gibbs energy G, the excess enthalpy 5E, the excess en— tropy 5E, and the excess heat capacity CE is discussed. They can be obtained from a knowledge of the xcess volume VE as a function of pressure, temperature, and composition. Experimental results demonstrate that the variations of E as a function of pressure can be important and that even a change of the sign of VE with increasing pressure has been found in some cases. The pressure dependence of HE values thus obtained agree well with literature values determined from direct f lowcalorimetric measurements. Until now most thermodynamic information has had to be deduced from high-pressure phase equilibria and critical phenomena where our knowledge is much better. The pressure dependence and critical phenomena of liquid-gas, liquid-liquid, and gasgas equilibria will be shortly reviewed. Mainly binary systems will be treated, but phase-separation phenomena in some ternary systems will also be considered. New developments during recent years have shown that the limits between liquid-gas, liquid-liquid, and gas-gas equilibria are not well defined and that continuous transitions occur. This continuity will be demonstrated on recent results for binary mixtures of hydrocarbons with tetrafluoromethane and nitrogen. Methods for the calculation and correlation of high-pressure phase equilibria in fluid mixtures under pressure are reviewed. They start from equations of state or from theories of mixtures using sometimes rather complicated mixing rules for the mixture parameters. Some results are presented and compared with experimental data. The significance of high-pressure phase equilibria in fluid mixtures for practical applications is briefly discussed e.g. f or fluid extraction, supercritical fluid chromatography (SFC), and for some high—pressure techniques and processes.