N-alkenyl substituted amine-N-oxide stabilizers

A stabilized composition which comprises

• (a) a lubricant subject to oxidative, thermal or actinic-induced degradation, and
• (b) an effective stabilizing amount of a compound of formula I ##STR6## wherein R.sub.1 and R.sub.2 are independently hydrogen, a straight or branched chain alkyl of 1 to 36 carbon atoms, alkyl of 1 to 18 carbon atoms terminated by a group --OR.sub.8, --NR.sub.9 R.sub.10, --SR.sub.11, --COOR.sub.12 or --CONR.sub.13 R.sub.14 or interrupted by arylene of 6 to 10 carbon atoms, --O--, --S--, --SO--, --SO.sub.2 --, --COO--, --OCO--, --CONR.sub.15 --, --NR.sub.15 CO-- or --NR.sub.16 -- where R.sub.8, R.sub.9, R.sub.10, R.sub.11, R.sub.12, R.sub.13, R.sub.14, R.sub.15 and R.sub.16 are independently hydrogen, alkyl of 1 to 18 carbon atoms or alkenyl of 3 to 6 carbon atoms;
• or R.sub.1 and R.sub.2 are independently cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, said phenylalkyl substituted on the phenyl ring by alkyl of 1 to 18 carbon atoms or by .alpha.-cumyl;
• aryl of 6 to 14 carbon atoms or said aryl substituted by one or two alkyl of 1 to 24 carbon atoms,
• R.sub.3 and R.sub.4 are independently hydrogen, alkyl of 1 to 9 carbon atoms, said alkyl substituted by --OH or by acetoxy;
• alkenyl of 3 to 6 carbon atoms or aryl of 6 to 10 carbon atoms, and
• R.sub.5, R.sub.6 and R.sub.7 are independently hydrogen, alkyl of 1 to 9 carbon atoms, said alkyl substituted by --OH or by acetoxy;
• alkenyl of 3 to 6 carbon atoms, aryl of 6 to 10 carbon atoms, or a group of formula II ##STR7## or R.sub.3 and R.sub.4, or R.sub.3 and R.sub.5, or R.sub.3 and R.sub.7, or R.sub.4 and R.sub.5, or R.sub.4 and R.sub.7, or R.sub.5 and R.sub.6, or R.sub.6 and R.sub.7 together are a straight or branched chain alkylene of 2 to 8 carbon atoms to form a cycloalkyl or cycloalkenyl ring with 5 or 6 ring atoms.