Use of compounds which absorb and/or fluoresce in the IR region as markers for liquids

摘要

Cpds. (I) used as marking agents for liquids are (un)metallised phthalocyanines (IA), (un)metallised naphthalocyanines (IB), Ni dithiolene complexes (IC), aminium cpds. (ID) of aromatic amines, methin dyestuffs (IE) or azulene-aquaric acid dyestuffs (IF) with absorption max. in the 700-1200 nm range. (I) is e.g. of formula (IG) where R = n-C4H9. USE/ADVANTAGE - (I) are useful for distinguishing fuel oil from diesel oil. (I) have strong enough absorption in the near IR to allow detection with standard photometers.