| abstract |
The invention relates to the use of benzaldehydes of the formula (I), in which ring A can be benzo-anellated and R<1>, R<2> and R<3> are hydrogen, hydroxy, C1-C15 alkyl, C1-C15 alkoxy, cyano, nitro or a radical of the formula NR<4>R<5> or COOR<6>, in which R<4> is hydrogen or possibly substituted C1-C15 alkyl, R<5> is possibly substituted C1-C15 alkyl or a radical of the formula L-NX<1>X<2>, in which L is C2-C8 alkylene and X<1> and X<2> are mutually independently C1-C6 alkyl or, together with the nitrogen atom bonding them, a heterocyclic radical, and R<6> is hydrogen, possibly substituted C1-C15 alkyl or a radical of the formula L-NX<1>X<2>, in which L, X<1> and X<2> have the above meanings, as marking agents for hydrocarbons, a process for detecting these benzaldehydes in hydrocarbons and hydrocarbons containing the above benzaldehydes. |