| abstract |
Fuels for internal combustion engines or lubricants contain small amounts of compounds of the formulae Ia and/or Ib <IMAGE> Ia <IMAGE> Ib where R is an aliphatic hydrocarbon radical having a number average molecular weight of from 250 to 5,000 and X is <IMAGE> where the radicals R1 may be identical or different and are each hydrogen, C1-C10-alkyl, C1-C8-hydroxyalkyl or C1-C8-aminoalkyl, or where the two radicals R1 may form a nonaromatic ring. |