Effect of potassium halide salts on mutual solubility of water + aromatic hydrocarbons liquid–liquid interface studied with surface and interfacial tensions

Abstract

Surface tension (γ, mN/m) of benzene, toluene and ethylbenzene (EB) aromatic hydrocarbons (AHCs, low density liquids, LDL) and interfacial tension (IFT, mN/m) both with water and aqueous 0.1, 0.5, 1.0molkg−1 KF, KCl, KBr, KI (high density liquids, HDL) separately at 303.15K are reported. Contributions of –CH3 and –CH2CH3 of toluene and EB to hydrophobic interactions are calculated from γtoluene–γbenzene and γEB–γbenzene, respectively. IFTs of water+AHCs liquid–liquid interfaces (LLI) are as toluene (34.71)>EB (32.35)>benzene (32.32mNm−1), with a ~32.32mNm−1 decrease from 71.40mNm−1 of water. AHCs with hyperconjugation (HC) and positive inductive effects (+ve IE) with toluene and EB LLI have reduced IFT by 39.08, 2.39, −1.56mNm−1, respectively. The effects of π-conjugation, –H, –CH3 and –CH2CH3 on surface tension are calculated as π-conjugation=Δ(IFTair–liquid−IFTAPHS–benzene), –CH3=Δ(IFTAPHS–toluene−IFTAPHS–benzene). The effects of halide salts on hypercongugation –H(–CH3)/3, –CH2CH3 are obtained from Δ(IFTAPHS–EB −IFTAPHS–benzene).