Investigation of liquid–liquid equilibrium of the ternary system(water +1,6-diaminohexane + 2-methyl-1-propanol or 3-methyl-1-butanol) at different temperatures

In this study, the LLE data of ternary system (water+1,6-diaminohexane+2-methyl-1-propanol) and (water+1,6-diaminohexane+3-methyl-1-butanol) were measured at 293.15, 303.15 and 313.15 K under atmospheric pressure. Reliability of the experimental tie-line data was checked by empirical Hand, Othmer-Tobias and Bachman equations. Distribution coefficient (D) and selectivity (S) were calculated in order to investigate capability of the studied organic solvents for 1,6-diaminohexane extraction. The high values of separation factors demonstrated that 2-methyl-1-propanol and 3-methyl-1-butanol were applicable for this purpose. The experimental data were correlated by nonrandom two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) models. The percent-root-mean-square deviation (RMSD) values for NRTL and UNIQUAC models were less than 0.15, which indicated that the experimental data have been sufficiently correlated.     

Liquid-liquid equilibrium for the quaternary system of o-xylene(1)+water(2) +propionic acid(3)+1-butanol(4) at 298.15 K and atmospheric pressure

The liquid-liquid equilibrium for the quaternary system of o-xylene(1)+water(2)+propionic acid(3)+1-butanol(4) was measured at 298.15 K and atmospheric pressure. Binodal curves, tie-lines, a distribution curve, and a selectivity curve for the quaternary system have been determined in order to investigate the effect of binary solvents, oxylene and 1-butanol, on extracting propionic acid from aqueous solution. In addition, these experimental tie line data were also compared with the values predicted by the UNIFAC model. In this study, the UNIFAC model was capable of predicting the compositions of this quaternary system within an average RMSD of 1.13 mol%. This paper was prepared at the 2004 Korea/Japan/Taiwan Chemical Engineering Conference held at Busan, Korea between November 3 and 4, 2004.     

Effect of Sr2+ on phase structure and properties for 0.6(Na0.5Bi0.5)TiO3-0.4(Bi1-ySry)TiO3 relaxor ferroelectrics

0.6(Na_0.5Bi_0.5)TiO₃-0.4(Bi_1-ySr_y)TiO₃ ceramics (abbreviated BNT-BS_yT, y = 0.2, 0.3, 0.5, 0.7, and 0.9 mol) were fabricated using a traditional solid-state processing route, and the effects of Sr²⁺ on phase structure, di- and ferroelectric properties, and electrostrictive properties were systematically investigated. The values of γ for BNT-BS_yT ceramics are greater than 1.8, revealing that these materials exhibit relaxor ferroelectric properties derived from the co-occupation of Bi³⁺, Na⁺, and Sr²⁺ in the A-site and inhomogeneous polarization states (i.e., coexistence of rhombohedral and tetragonal states). In addition, T_d decreases with increasing Sr²⁺ content along with a stable and increased tetragonal phase. BNT-BS_0.9T ceramic has a slightly large maximum polarization P_max = 16.15 μC/cm², a small remanent polarization P_r = 1.6 μC/cm², and a relatively good energy storage property (density W₁ = 0.220 J/cm³ and efficiency η = 72.13%), indicating that Sr²⁺ substitution helps to promote energy storage characteristics. Moreover, there is a superior electrostrictive coefficient (Q₃₃ = 0.0385 m⁴/C²) for BNT-BS_0.3T ceramic. Therefore, we propose that this lead-free electrostrictor is a good candidate for practical applications.     

Comparative study of lithium ion conductors in the system Li1+xAlxA2−x (PO4)3 with A=Ti or Ge and 0≤x≤0·7 for use as Li sensitive membranes

Preparations and physico-chemical characterizations of NASICON-type compounds in the system Li_1+xAl_xA_2−x^IV(PO₄)₃ (A^IV=Ti or Ge) are described. Ceramics have been fabricated by sol-gel and co-grinding processes for use as ionosensitive membrane for Li⁺ selective electrodes. The structural and electrical characteristics of the pellets have been examined. Solid solutions are obtained with Al/Ti and Al/Ge substitutions in the range 0≤x≤0·6. A minimum of the rhombohedral c parameter appears for x about 0·1 for both solutions. The grain ionic conductivity has been characterized only in the case of Ge-based compounds. It is related to the carrier concentration and the structural properties of the NASICON covalent skeleton. The results confirm that the Ti-based framework is more calibrated to Li⁺ migration than the Ge-based one. A grain conductivity of 10⁻³ S cm⁻¹ is obtained at 25°C in the case of Li_1·3Al_0·3Ti_1·7(PO₄)₃. A total conductivity of about 6×10⁻⁵ S cm⁻¹ is measured on sintered pellets because of grain boundary effects. The use of such ceramics in ISE devices has shown that the most confined unit cell (i.e. in Ge-based materials) is more appropriate for selectivity effect, although it is less conductive.©