Solubility of the quaternary system RbCl-EuCl3-HCl(13.44, 22.75%)-H2O at 298.15 K was determined and corresponding equilibrium diagrams were constructed. The quaternary system is simple, and consists of two equilibrium solid phases RbCl and EuCl3 · 6H2O. The composition of double saturation point (average) is 13.29% HCl, 16.18% RbCl, and 18.72% EuCl3 for the RbCl-EuCl3-HCl(13.44%)-H2O quaternary system, and 22.44% HCl, 15.59% RbCl, and 6.26% EuCl3 for the RbCl-EuCl3-HCl (22.75%)-H2O quaternary system.

Phase equilibrium in the system RbCl-EuCl3-HCl(13.44, 22.75%)-H2O at 298.15 K

The solubility of the quaternary system RbCl−NdCl3−HCl(13.26 %)−H2O at 298.15 K was determined, and the corresponding equilibrium diagram was constructed. The quaternary system consists of three equilibrium solid phases, RbCl, RbNdCl4·4H2O (1:1 type), and NdCl3·6H2O. The new solid phase compound RbNdCl4·4H2O was found to be congruently soluble in the system. The compound RbNdCl4·4H2O was characterized by X-ray diffraction, X-ray diffraction single crystal structure analysis, thermogravimetry, and differential thermogravimetry. It belongs to an orthorhombic system, with space group P21212, a = 0.6986(6) nm, b = 1.1319(1) nm, c = 0.6665(6) nm, Dc = 2.795 g·cm−3, and Z = 2. The compound loses its crystal water by one step at (370 to 474) K. The standard molar enthalpy of solution of RbNdCl4·4H2O in deionized water was measured to be −(26.97 ± 0.24) kJ·mol−1 by heat conduction microcalorimetry. Its standard molar enthalpy of formation was calculated to be −(2732.3 ± 1.0) kJ·mol−1.

Phase Equilibrium in the System RbCl−NdCl3−HCl(13.26 %)−H2O at 298.15 K and Standard Molar Enthalpy of Formation of New Solid Phase Compound

Green solvent production of ethyl lactate via process intensification

The solubility in the RbCl–TmCl3–HCl–H2O and RbCl–LuCl3–HCl–H2O quaternary water–salt systems was studied along the ∼22 % hydrochloric acid section by the isothermal solubility method at 298.15 K, and corresponding equilibrium diagrams were constructed. The compositions of solid phases were established by the Schkreinemakers’ wet residue method. The quaternary system RbCl–TmCl3–HCl–H2O is a simple eutonic type, but the quaternary system RbCl–LuCl3–HCl–H2O is complicated, and one incongruently saturating complex phase is formed in this system: Rb2LuCl5·7H2O. The compound Rb2LuCl5·7H2O was identified and characterized by the methods of powder X-ray diffraction, thermogravimetric, and differential thermal analysis. The crystal water was lost at (308 to 499) K. The standard molar enthalpy of solution of Rb2LuCl5·7H2O in water was measured to be (6.04 ± 0.17) kJ·mol–1 by heat conduction microcalorimetry, and its standard molar enthalpy of formation was calculated to be −(4009.9 ± 1.3) kJ·mol–1.

Phase Equilibria in the Systems RbCl–TmCl3–HCl(22.12 %)–H2O and RbCl–LuCl3–HCl(21.37 %)–H2O at 298.15 K and Standard Molar Enthalpy of Formation of Rb2LuCl5·7H2O

Influence of imidazolium based ionic liquids with different anions on liquid-liquid phase behavior for separation of azeotropic mixture isopropyl alcohol + diisopropyl ether

An azeotropic mixture of acetone and n-heptane is commonly found in many pharmaceutical wastewaters. In this work, the separation of acetone / n-heptane was studied using intermediate- and high-boiling-point entrainers (benzene and p-xylene, respectively). To maximize the economic benefits and mitigate the economic and environmental impact of the separation process, traditional extractive distillation and side-stream extractive distillation processes were developed for different entrainers. The sequential iteration method was employed to optimize the extractive distillation process, with the total annual cost as the constraint objective. The results show that p-xylene can facilitate the separation of acetone / n-heptane, with high efficiency and low energy consumption, when using a double distillation column. Among the four separation processes developed, the p-xylene side-stream extractive distillation process delivers the best economic and environmental performance, with a total annual cost of 6.04 × 105 $/y and CO2 emissions of 1114.66 kg/y. Compared to the case of traditional p-xylene extractive distillation and benzene side-stream extractive distillation processes, the total annual cost of the p-xylene side-stream extractive distillation process was reduced by 9.56% and 49.22%, respectively, while the corresponding CO2 emissions were reduced by 15.71% and 48.85%. 

Effect of entrainers with different boiling point sequences on the design and performance for side-stream extractive distillation processes

The equilibrium solubility of the quaternary system RbCl-PrCl3-HCl-H2O was determined at 298.15 K and the corresponding equilibrium diagram was constructed in this paper. The quaternary system is complicated with three equilibrium solid phases, RbCl, RbPrCl4 · 4H2O (1:1 type) and PrCl3 · 6H2O, of which the new compound RbPrCl4 · 4H2O was found to be congruently soluble in the system. The new compound obtained was identified and characterized by the methods of X-ray diffraction, thermogravimetry, and differential thermogravimetry. The compound loses its crystal water by one step at 343 K to 453 K. The standard molar enthalpy of solution of RbPrCl4 · 4H2O in deionized water was measured to be −24.53 ± 0.22 kJ mol−1 by heat conduction microcalorimetry. Its standard molar enthalpy of formation was calculated to be −2743.20 ± 1.09 kJ mol−1.

Phase equilibrium system of RbCl-PrCl3-HCl(12.86 mass %)-H2O at 298.15 K and standard molar enthalpy of formation of new solid-phase compound

Extraction performance and interaction analysis of 2-pyrrolidone-based brønsted acidic ionic liquids on removal of quinoline from coal-based products

Experimental and quantum chemical calculations investigations of morpholine-based ionic liquids as extractants for efficient extraction of nitrogen heterocyclic neutral compounds

• Three ILs [Bmim][H 2 PO 4 ], [Emim][PF 6 ] and [Bmim][PF 6 ] were used to extract IPA. • The LLE data for IPAC + IPA + ILs were determined and correlated. • The interactions between the ILs and IPA were explored. • [Bmim][H 2 PO 4 ] is a suitable extractant to recover IPA from IPAC. During the production of isopropyl acetate (IPAC), a mixture of IPAC and isopropanol (IPA) can be produced. Because IPAC and IPA can form a minimum azeotropic mixture with the azeotropic temperature of 354.08 K, it is difficult to separate such a mixture. In this work, liquid-liquid extraction is considered to separate the mixture of IPAC and IPA. Herein, the liquid-liquid equilibrium (LLE) data was determined and correlated for the separation of IPAC and IPA. For separating IPAC and IPA by extraction, three ionic liquids (ILs) 1-ethyl-3-methyl-imidazolium hexafluorophosphate, 1‑butyl‑3-methyl-imidazolium hexafluorophosphate and 1‑butyl‑3-methyl-imidazolium dihydrogen phosphate were selected as extractants. The liquid-liquid equilibrium phase behavior of ternary mixtures (IPAC + IPA + ILs) at 298.15 K was investigated. The distribution functions of charge density and interaction energy were determined by the COSMO-SAC model and Dmol 3 in Materials Studio, and the interactions between molecules were explored. The experimental data showed that the three ILs can extract IPA from the mixture of IPAC and IPA and the IL [Bmim][H 2 PO 4 ] has a better extraction ability compared to the other ILs. The measured LLE data were fitted using the NRTL model and the interaction parameters were regressed, which is a favor in separating the mixture for industrial practice. 

Liquid-liquid equilibrium and insights of intermolecular interactions for separation of isopropyl acetate + isopropanol by imidazolium-based ionic liquids

Junlin Gao

Papers

Effect of entrainers with different boiling point sequences on the design and performance for side-stream extractive distillation processes

Phase equilibrium system of RbCl-PrCl3-HCl(12.86 mass %)-H2O at 298.15 K and standard molar enthalpy of formation of new solid-phase compound

Extraction performance and interaction analysis of 2-pyrrolidone-based brønsted acidic ionic liquids on removal of quinoline from coal-based products

Experimental and quantum chemical calculations investigations of morpholine-based ionic liquids as extractants for efficient extraction of nitrogen heterocyclic neutral compounds

Liquid-liquid equilibrium and insights of intermolecular interactions for separation of isopropyl acetate + isopropanol by imidazolium-based ionic liquids