Abstract: The reaction of an aminoalkanol of the formula: ##STR1## wherein R.sup.1 and R.sup.2 are C.sub.1-17 aliphatic hydrocarbon groups (the sum of the carbon atoms in R.sup.1 + R.sup.2 being from 9 to 18); R.sup.3 and R.sup.4 represent the same or different C.sub.1-6 alkyl or alkylol groups; x represents a integer from 2 to 4; and y represents 0 or 1, with a water-soluble halocarboxylic acid provides quaternary ammonium compounds. The compounds are amphoteric surface-active agents which are soluble in water containing high concentrations of NaCl, and are useful in the recovery of underground petroleum by the flooding method.