Lubricating compositions containing an amine phosphate with a terminal imide ring

A lubricating oil containing a major proportion of lubricating oil and a minor proportion of at least one amine phosphate with a terminal imide ring consisting of a product resulting from the reaction, under conditions for the formation of an amine salt by the neutralization of at least one acid function, of at least one phosphate having the general formula (I):

• ##STR8## in which n is equal to 1 or 2, R.sup.1 is a divalent hydrocarbon group having from 1 to 32 carbon atoms, R.sup.6 represents a hydrogen atom or a hydrocarbon group having usually from 1 to 200 carbon atoms, with at least one amine having the general formula (II) or (III):
• ##STR9## in which each of R.sup.3, R.sup.4 and R.sup.5, which may be identical or different, represents a hydrogen atom or a hydrocarbon group having from 1 to 60 carbon atoms, Z is selected from the groups --O-- and --NR.sup.7 --, in which R.sup.7 represents a hydrogen atom or a hydrocarbon group having from 1 to 60 carbon atoms, R.sup.3 and R.sup.7 can combine to form, along with the nitrogen atom to which they are connected, a heterocycle, each one of the groups R.sup.2 represents independently a hydrogen atom or a hydrocarbon group having from 1 to 4 carbon atoms;
• when Z is --NR.sup.7 --, p is a whole number which is larger than or equal to 2, and m is equal to zero or to a number from 1 to 10;
• when Z is --O--, p is a whole number larger than or equal to 1, and m is a whole number from 1 to 10;
• each of D, E, F and G, which may be identical or different, represents a divalent hydrocarbon group having from 2 to 6 carbon atoms, a is a whole number from 1 to 60, b and c, which may be identical or different, are equal to zero or to a whole number from 1 to 50, and the sum a+b+c is a whole number from 1 to 60.