| abstract |
The present invention relates to the use of metal salts of formula (I) in which M + is the equivalent of a cobalt or iron ion, Q is C¿4?-C22-alkyl, C4-C22-alkenyl, aryl or hetaryl, L is carbonyl or sulphonyl, X?-¿ is a monovalent inorganic anion, m is 1, 2 or 3, y is 0, 1 or 2, and n is the sum of m and y and may be 2 or 3, for marking combustible bitumen, and relates also to such substances containing one or more of the aforementioned metal salts. |