Toshihiko Hiaki

Measuring methods of infinite dilution activity coefficients and a database for systems including water

Experimental techniques for the determination of infinite dilution activity coefficients and their improvements are reviewed. Generally, the measuring techniques can be classified as the indirect and direct methods. The indirect methods include the extrapolations from vapor-liquid equilibrium data and calculations from the other thermodynamic data, such as liquid-liquid equilibrium data, gas-liquid partition coefficient data and so on. The direct methods include the gas-liquid chromatography (GLC) method, headspace GLC method, gas-stripping method, liquid-liquid chromatography method, differential ebulliometry method and differential static method. Also, the most extensively used gas-liquid chromatographic method can be divided into the stationary phase GLC, non-steady-state GLC and relative measurement GLC. A database of infinite dilution activity coefficients, which had been measured and reported by 96 literature sources of journals in the period from 1927 through 1995 for organic compounds in water and water in organic solvents, has also been presented. The database contains a total of 1469 pieces of data of infinite dilution activity coefficients ranging from 283.15 to 373.15 K. No database of infinite dilution activity coefficients for systems including water has been previously reported.

Size-controlled synthesis of metal oxide nanoparticles with a flow-through supercritical water method

Hydrothermal synthesis of metal oxide (AlOOH/Al2O3, CuO, Fe2O3, NiO, ZrO2) nanoparticles from metal nitrate aqueous solution was carried out at 673 K and pressures ranging from 25 MPa to 37.5 MPa with a flow-through supercritical water method. Size, phase and crystallinity of the obtained particles were characterized by TEM, XRD and TG, respectively. Effect of the difference of the metals in starting materials, pressures and concentrations on particle size and crystallinity was analyzed on the basis of supersaturation, which was evaluated by estimated metal oxide solubility. The result suggests that supersaturation should be set to higher than around 104 in this method to obtain particles under 10 nm in diameter. Further, crystallinity of the obtained particles was evaluated as weight loss through TG analysis. It was found that higher supersaturation decreased the crystallinity. This result can be explained that high supersaturation led to the inclusion of water molecules during the formation of particles.

Prediction of vapor-liquid equilibrium for binary systems containing HFEs by using artificial neural network

Abstract A method using artificial neural network (ANN) was applied to estimate the vapor–liquid equilibrium (VLE) for the binary systems containing hydrofluoroethers (HFEs) and polar compounds. Our new estimation method is composed of three steps. In the first step, the sign of logarithm of activity coefficient ( γ ) is estimated for each binary system using ANN, because it had been found that the binary systems containing HFEs show different thermodynamic behaviors depending on the sign for ln( γ ). In the second step, two sets of relation between liquid mole fraction and ln( γ ) are constructed: one held for the case of positive sign and the other held for that of negative sign. In the third step, vapor–liquid composition and equilibrium temperature are calculated using the estimated activity coefficient. In order to construct this new method, the isobaric VLE data of 18 binary systems including HFEs was used. As a result, our new method could estimate VLE with reasonable accuracy.

Prediction of infinite dilution activity coefficients in aqueous solutions by group contribution models. A critical evaluation

Abstract Based on an extensive database, the predictive accuracy of the ASOG and several UNIFAC-type models has been critically evaluated for infinite dilution activity coefficients in aqueous solutions. In general, all the models give rather poor results with mean relative deviations of 45–72% (except the cases where the relative deviations are higher than 100%), whereas the modified UNIFAC (Dortmund) performs well for most of higher polar compounds (e.g., ethanol, acetone, acetic acid) in water mixtures. The UNIFAC–LLE of Magnussen et al. may provide order of magnitude estimates for some lower polar compounds (e.g., aldehydes or 2-ketones with carbon number of 6–9), although it gives poor results for the higher ones. In the particular case of alkanes in water mixtures, the specially developed model of Hooper et al. provides comparatively fair results, but the predicted mean relative deviations of 36% are still large. In this work, an improved UNIFAC will be proposed by using mixture-type groups to account for the specially hydrophobic effects in systems including water, satisfactory results are obtained.

Vapor–liquid equilibria determination for a hydrofluoroether with several alcohols

Abstract A small-capacity apparatus for vapor–liquid equilibrium (VLE) measurement was developed. The overall charge of the still with a provision for vapor and liquid recirculations was about 38 cm3 of the solution. The performance of the proposed apparatus was tested by determining the VLE for the methanol+benzene system at 101.3 kPa. The results obtained were satisfactory. The isobaric VLE were measured for three binary systems, CH3OCH(CF3)2 (1)+methanol (2), CH3OCH(CF3)2 (1)+ethanol (2) and CH3OCH(CF3)2 (1)+2-propanol (2) at 101.3 kPa using the proposed apparatus. All three binary isobaric systems form a minimum boiling azeotrope. The azeotropic points are x1(AZ)=0.711 mole fraction and T(AZ)=318.36 K for CH3OCH(CF3)2 (1)+methanol(2) system, x1(AZ)=0.859 mole fraction and T(AZ)=322.21 K for CH3OCH(CF3)2 (1)+ethanol(2) system, and x1(AZ)=0.918 mole fraction and T(AZ)=323.44 K for CH3OCH(CF3)2 (1)+2-propanol(2).

Solubility and adsorption of high pressure carbon dioxide to poly(styrene)

Abstract Solubility and adsorption of high pressure carbon dioxide (CO2) to poly(styrene) (PS) were measured at 313.2 K and pressures up to 17 MPa using a quartz crystal microbalance (QCM) as a detector. Two kinds of PS film, made by dip coating (d-PS) and plasma polymerization (p-PS), were used as samples. The amount of adsorption onto both films was almost the same within the experimental range. The solubility to both films increased almost linearly against activity of CO2 up to unity, and that to p-PS was slightly higher than that to d-PS. Above unity, the solubility to p-PS film increased with the increase in activity. In contrast, solubility to d-PS sharply decreased near the unity and became a constant value.

Measurement of vapor-liquid equilibria and determination of azeotropic point

Abstract Hiaki, T., Tochigi, K. and Kojima, K., 1986. Measurement of vapor—liquid equilibria and determination of azeotropic point. Fluid Phase Equilibria , 26: 83–102. To measure the azeotropic point, a liquid-vapor ebullition type equilibrium still is developed. Vapor-liquid equilibria at 101.325 kPa are measured for the ternary azeotropic system benzene - cyclohexane - n-propanol, and the three constituted binary azeotropic systems. A method is introduced for graphical determination of the binary azeotropic point on the basis of experimental binary vapor-liquid equilibrium data. Also, a method is evolved for determination of the binary and ternary azeotropic points by using the extended Redlich-Kister equation applicable to the condition of constant pressure, and the azeotropic points are determined for three binary and one ternary systems.

Isothermal vapor-liquid equilibria of octane with 1-butanol, 2-butanol, or 2-methyl-2-propanol

Abstract Isothermal vapor–liquid equilibria were measured for three binary systems of 1-butanol+octane at 373.15 K, 2-butanol+octane at 358.15 K, and 2-methyl-2-propanol+octane at 343.15 K. The measurements were made in a Rogalski–Malanowski type equilibrium still with circulation of both the vapor and liquid phases. Three binary isothermal systems form a maximum pressure azeotrope. The azeotropic data are x 1 (AZ)=0.519 mole fraction and P (AZ)=75.71 kPa for 1-butanol (1)+octane (2), x 1 (AZ)=0.750 mole fraction and P (AZ)=63.58 kPa for 2-butanol (1)+octane (2), and x 1 (AZ)=0.968 mole fraction and P (AZ)=61.18 kPa for 2-methyl-2-propanol (1)+octane (2). The activity coefficients of three binary systems were correlated with the Wilson, modified Wilson, nonrandom two-liquid (NRTL), and UNIQUAC equations.

One‐Pot Synthesis of 1,3,5‐Tribenzoylbenzenes by Three Consecutive Michael Addition Reactions of 1‐Phenyl‐2‐propyn‐1‐ones in Pressurized Hot Water in the Absence of Added Catalysts

Cyclotrimerization of 1-phenyl-2-propyn-1-one in pressurized hot water gave 1,3,5-tribenzoylbenzene in one pot in 65 % yield after 7 min at 200 °C, or in 74 % yield after 60 min at 150 °C. The reaction did not take place in the absence of water, and added base promoted the reaction at 250 °C, suggesting a mechanism of three-consecutive Michael addition reactions. The reaction rates increased with temperature, but the yield of 1,3,5-tribenzoylbenzene decreased at the expense of formation of acetophenone as a side product at higher temperatures. p-Methyl and p-chloro-substituents on the phenyl ring retarded and enhanced the reaction, respectively. A mechanism involving the enol of benzoylacetaldehyde at a branching point of the pathway leading to 1,3,5-tribenzoylbenzene and acetophenone was suggested.

Vapor–liquid equilibria for 1,1,2,2-tetrafluoroethyl, 2,2,2-trifluoroethyl ether with several organic compounds containing oxygen

Isobaric vapor-liquid equilibria for 1,1,2,2-tetrafluoroethyl, 2,2,2-trifluoroethyl ether (CHF 2 CF 2 OCH 2 CF 3 ) + alcohols, ketones, or esters systems were measured at 101.3 kPa. The alcohols used were ethanol and 1-propanol. The ketone and ester components were 2-butanone and ethyl acetate, respectively. The measurements were made in an equilibrium still with circulation of both the vapor and liquid phase. The two binary isobaric systems composing of CHF 2 CF 2 OCH 2 CF 3 and the alcohols exhibit minimum boiling azeotropes. The azeotropic points are found at x 1 (az) = 0.800 mole fraction and T(az) = 326.67 K for CHF 2 CF 2 OCH 2 CF 3 (1) + ethanol (2) and x 1 (az) = 0.965 mole fraction and T(az) = 329.23 K for CHF 2 CF 2 OCH 2 CF 3 (1) + 1-propanol (2), respectively. The two binary systems of CHF 2 CF 2 OCH 2 CF 3 (1) + 2-butanone (2) and CHF 2 CF 2 OCH 2 CF 3 (1) + ethyl acetate (2) are both non-azeotropic. The experimental data for the binary systems investigated were correlated with activity coefficient equations. The nonrandom two-liquid (NRTL) equation yielded a good correlation of activity coefficients for the two systems of CHF 2 CF 2 OCH 2 CF 3 with alcohols. The CHF 2 CF 2 OCH 2 CF 3 (1) + 2-butanone (2) system is best correlated with the van Laar equation and CHF 2 CF 2 OCH 2 CF 3 (1) + ethyl acetate (2) system best with the three-suffix Margules equation. The thermodynamic consistency of data was good according to the Van Ness and the Herington test.