Protecting ferrous metals from corrosion

Claim 1

METHOD FOR PROTECTING FERROUS METALS FROM CORROSION WHICH COMPRISES FORMING, IN THE PRESENCE OF WATER AND CORROSIVE MATERIAL SELECTED FROM THE GROUP CONSISTING OF HYDROGEN SULFIDE, CARBON DIOXIDE, SULFUR, INORGANIC SULFATES, AND INORGANIC SULFIDES, A PROTECTIVE FILM ON A FERROUS METAL SURFACE OF A PETROLUEM NAPHTHENIC ACID SALT OF A MATERIAL SELECTED FROM THE GROUP CONSISTING OF A COMPOUND HAVING THE FORMULA RNH( (CH2)MNH)NH WHERE R IS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN AND THE HYDROCARBON RADICAL OF A NATURALLY OCCURING FATTY ACID RCOOH, WHERE M IS AN INTEGER FROM 2 TO 5, AND WHERE N IS AN INTEGER FROM 1 TO 10, AN N-HYDROXYALKYL DERIVATIVE OF SAID COMPOUND WHEREIN THE HYDROXYALKYL GROUPS CONTAIN A TOTAL OF 2 TO 10 CARBON ATOMS, AND AN ETHANOLAMINE RESIDUE OBTAINED IN THE REACTION OF ETHYLENE OXIDE AND AMMONIA TO PRODUCE ETHANOLAMINES, AFTER DISTIALLATION OF LOWER BOILING ETHANOLAMINES FROM THE REACTION PRODUCTS, SAID RESIDUE HAVING EQUIVALENT WEIGHT WITHIN THE APPROXIMATE RANGE FROM 145 TO 165.