Abstract EXTREME PRESSURE ADDITIVES FOR LUBRICATING OILS ARE PREPARED BY FRIEDEL-CRAFTS-CATALYZED INTERPOLYMERIZATION OF A MONO- 1-ALKENE, AN OLEFINICALLYIUNSATRUATED CARBOXYLIC ACID (OR ESTER THEREOF) WHEREIN THE OLEFINIC BOND IS AT LEAST 2 CARBON ATOMS AWAY FORM THE CARBOXYL GROUP AND, OPTIONALLY, A CONJUGATED DIENE HYDROCARBON. PREFERABLY, THE MONO-1-ALKANE IS NORMAL AND HAS ABOUT 14 TO21 CARBON ATOMS, THE UNSATURATED ACID HAS ABOUT 10 TI 21 CARBON ATOMS AND, IF THE ESTER IS USED, IS ESTERIFIED WITH A LOWER ALKANOL, AND THE DIENE HAS 4 TO 5 CARBON ATOMS. DETERGENTS FOR LUBRICATING OILS ARE PREPARED BY CONDENSATION OF THESE POLYMERS WITH AN ESSENTIALLY ALIPHATIC POLYAMINE HAVING UP TO ABOUT 11 AMINO GROUP, AT LEAST ONE OF WHICH PRIMARY, E.G., PENTAETHYLENE HEXAMINE.