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Ria Armunanto
Austrian Indonesian Centre for Computational Chemistry, Universitas Gadjah Mada, Sekip Utara, Yogyakarta 55281
Chemical Engineering, Chemistry & Bioengineering Chemistry

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Theoretical Study on the Extraction of Alkaline Earth Salts by 18-Crown-6: Roles of Counterions, Solvent Types and Extraction Temperatures Saprizal Hadisaputra; Lorenz R Canaval; Harno Dwi Pranowo; Ria Armunanto
Indonesian Journal of Chemistry Vol 14, No 2 (2014)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (576.723 KB) | DOI: 10.22146/ijc.21259

Abstract

The roles of counterions, solvent types and extraction temperatures on the selectivity of 18-crown-6 (L) toward alkaline earth salts MX2 (M = Ca, Sr, Ba; X = Cl-, NO3-) have been studied by density functional method at B3LYP level of theory in gas and solvent phase. In gas phase, the chloride anion Cl- is the preference counterion than nitrate anion NO3-. This result is confirmed by the interaction energies, the second order interaction energies, charge transfers, energy difference between HOMO-LUMO and electrostatic potential maps. The presence of solvent reversed the gas phase trend. It is found that NO3- is the preference counterion in solvent phase. The calculated free energies demonstrate that the solvent types strongly change the strength of the complex formation. The free energies are exothermic in polar solvent while for the non polar solvent the free energies are endothermic. As the temperature changes the free energies also vary where the higher the temperatures the lower the free energy values. The calculated free energies are correlated well with the experimental stability constants. This theoretical study would have a strong contribution in planning the experimental conditions in terms of the preference counterions, solvent types and optimum extraction temperatures.
EXTRACTION OF STRONTIUM(II) BY CROWN ETHER: INSIGHTS FROM DENSITY FUNCTIONAL CALCULATION Saprizal Hadisaputra; Harno Dwi Pranowo; Ria Armunanto
Indonesian Journal of Chemistry Vol 12, No 3 (2012)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (740.602 KB) | DOI: 10.22146/ijc.21332

Abstract

The structures, energetic and thermodynamic parameters of crown ethers with different cavity size, electron donating/withdrawing substituent groups and donor atoms have been determined with density functional method at B3LYP level of theory in gas and solvent phase. Small core quasi-relativistic effective core potentials was used together with the accompanying SDD basis set for Sr2+ and DZP basis set was used for crown ether atoms. Natural bond orbital (NBO) analysis was evaluated to characterize the distribution of electrons on the complexes. The interaction energy is well correlated with the values of Strontium charge after complexation, the second order interaction energies (E2) and HOMO-LUMO energy gab (∆Egab). The interaction energy and thermodynamics parameters in gas phase are reduced in solvent phase as the solvent molecules weaken the metal-crown ether interaction. The thermodynamic parameters indicated that less feasibility to extract Sr2+ ion directly from pure water without presence of organic solvent. The theoretical values of extraction energy for Sr(NO3)2 salt from aqueous solution in different organic solvent is validated by the experimental trend. This study would have strong contribution in planning the experiments to the design of specific host ligand and screening of solvent for extraction of metal ion.
Co-Authors Harno Dwi Pranowo Lorenz R Canaval Saprizal Hadisaputra Saprizal Hadisaputra