Evaluation of Long-Chain Phosphorus Compounds as Lubricity Additives

Two and 5% blends of a series of new long chain phosphates and phosphonates were examined for suitability as lubricity additives in bis(2-ethylhexyl) sebacate and mineral oil. The most effective anti-wear agents were diethyl stearoxyethyl-, dibutyl lauroxyethyl- and di (2-ethyl-hexyl) lauroxyethylphosphonate and dibutyl lauroxypropyl phosphate, the most promising extreme pressure agents were di(2-ethylhexyl) lauroxyethyl phosphonate, diethyl oleoxyethyl, diethyl oleoxybutyl, and dibutyl lauroxypropyl phosphates. Coefficient of friction measurements using steel on steel varied from that of the base fluid to 0.04. The latter was obtained with dibutyl lauroxypropyl, diethyl oleoxyethyl, and diethyl oleoxybutyl phosphates. The lubricity properties of the long chain phosphorus additives compare favorably with the values determined on presently used hypoid gear oils. The phosphorus derivatives also improved the oxidation stability of the diester but there appeared to be no improvement in rust prevention in eith...