The present invention relates to wash oil for use as an antifouling agent in gas compressors, in particular in cracked gas compressors, including at least one compound according to formulae (II) with the moieties R2 and R3 are selected from a group of linear or branched C1-C20-alkyl, C3-C10-cycloalkyl and linear or branched C1-C10-alkyl substituted C3-C10-cycloalkyl and C6-C12 aryl and C1-C10-alkyl substituted C6-C12 aryl. The moieties can be interrupted by oxygen or nitrogen. The moieties can be functionalised with hydroxyl groups or amino groups. The moieties can be the same or different. The invention relates also to the use of such wash oil as anti-fouling agent.