A process is provided for preparing a salt of a hydroxy-substituted di-ester of phosphoric acid, comprising: (a) reacting a phosphating agent with a monohydric alcohol and with an alkylene polyol, wherein the mole ratio of monohydric alcohol:alkylene polyol is about 0.2:0.8 to about 0.8:0.2 and wherein an excess of the phosphating agent is employed such that the product mixture formed thereby contains phosphorus acid functionality; and (b) reacting the product mixture of step (a) with an amine. The product is useful as an antiwear agent.