Extended Surfactants Including an Alkoxylated Central Part Intermediate Producing a Gradual Polarity Transition—A Review of the Properties Used in Applications Such as Enhanced Oil Recovery and Polar Oil Solubilization in Microemulsions

Abstract

Abstract The research published in the past half century indicates that surfactant interfacial performance in producing low tension or high solubilization with polar oils is not generally attained with pure conventional species exhibiting well‐defined polar and nonpolar parts. The improvement trends reached with surfactant mixtures as well as the introduction of additives like cosurfactants and linkers lead to the introduction of the so‐called extended surfactants, whose structure includes an intermediate polarity spacer between the hydrophilic head and the lipophilic tail. Recent investigations on different kinds of surfactants in a variety of applications—such as detergency, cosmetics, enhanced oil recovery or crude demulsifying, and vegetable oil extraction—indicate that these extended surfactants are likely to be particularly performing with oils containing polar groups, such as triacylglycerols and asphaltenic crudes. Possible applications of extended surfactants in enhanced oil recovery, crude emulsion breaking, detergency and cleaning, medicine and cosmetics vehicles, and natural oil extraction as well as some other cases are quickly reviewed.