Fernández-Stefanuto, VerónicaCorchero Morais, RaquelRodríguez Escontrela, IriaSoto Campos, Ana MaríaTojo Sierra, Rafael2020-09-302020-09-302018V. Fernández-Stefanuto, R. Corchero, I. Rodríguez-Escontrela, A. Soto, E. Tojo, ChemPhysChem 2018, 19, 2885http://hdl.handle.net/10347/23327This is the peer reviewed version of the following article: V. Fernández-Stefanuto, R. Corchero, I. Rodríguez-Escontrela, A. Soto, E. Tojo, ChemPhysChem 2018, 19, 2885, which has been published in final form at https://doi.org/10.1002/cphc.201800735. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsIonic liquids derived from prolinium esters, previously described as fully green and stable, were found to decompose in the presence of water by ester hydrolysis. To avoid this problem, a new family of these biodegradable salts incorporating an alcohol instead of the ester group is proposed. From this family, two novel ionic liquids that incorporate the prolinolium cation [HOPro] and the [DS] or [DBS] anion were selected (DS=dodecylsulfate; DBS=dodecylbenzenesulfonate). Both salts are liquid at room temperature, a property not usually found in ionic surfactants, and are also chemically and thermally stable. Moreover, they are more effective in reducing the surface tension of water than the corresponding traditional surfactants in the form of sodium salts, being useful for applications related to their aggregation capacity. They were tested for surfactant enhanced oil recovery and an optimal formulation for reservoirs at high salinity and temperature, able to produce ultra‐low interfacial tension, was found with [HOPro][DBS]eng© 2018 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsAmino acidsEnhanced oil recoveryIonic liquidsProliniumSurfactantsjournal article10.1002/cphc.2018007351439-7641open access