Excess molar enthalpies and volumes of binary mixtures of nonafluorobutylmethylether with ethylene glycol ethers at T = 298.15 K

Abstract

Excess molar enthalpies, H m E and volumes, V m E were reported for binary mixtures of {nonafluorobutylmethylether, (NFBME, C 4F 9–O–CH 3)} + [five ethylene glycol ethers, EGE n, m-R, {C m H 2 m + 1 -(OCH 2CH 2) n -R, n = 1 and 2, m = 1 to 4, R = OH and OCH 3}] at 298.15 K. Results of excess molar enthalpies and volumes were positive over whole range of concentrations for all the mixtures. The magnitude was in order: EGE1,4-OH > EGE1,3-OH > EGE1,2-OH > EGE1,1-OH > EGE2,1-OH > EGE2,1-OCH 3 for H m E and EGE2,1-OCH 3 > EGE1,4-OH > EGE1,3-OH > EGE1,2-OH > EGE1,1-OH > EGE2,1-OH for V m E at the maximum point. The curves of H m E and V m E for the EGE2,1-OH system were depressed in the middle mole fraction of NFBME, x 1 suggesting a quasi-stable state in the solution. We observed occurrences of the stable emulsification state in solutions in concentrations range of 0.35 < x 1 < 0.55. From these results, excess partial molar enthalpies, H m , 2 E , ∞ , and volumes, V m , 2 E , ∞ , of EGE n, m-R at infinite dilution, apparent molar enthalpies of solvation, Δ solv H 2, of the EGE n, m-R in NFBME were evaluated. The dependence of these thermodynamic quantities on the number of carbon atoms in the alkyl group, m, the number of the ethylene oxide group, n, and the difference of R group were discussed in consideration of various kinds of intermolecular interactions in pure component liquids and solutions.