Stable forms of polyalkylaromatic sulfonates

Abstract From the Canadian patent

Polyalkyl aromatic sulfonates; and particularly dialklaromatic sulfonates, useful as surfactants in steam recovery methods for enhancing oil recovery from subterranean formations have been found to comprise, essentially mixtures of meta- and para-isomers obtaind by alkylating alkylaromatics, where the alkyl group has from 1 to 4 carbon atoms with, a C14-24 olefin. It has further been found that when the ratio of para-isomer to meta-isomer is increased in this mixture a significantly, more hydrolytically, thermally stable surfactant under steam recovery operating conditions in obtained.