APPLICATION OF AZO DYES FOR LABELLING HYDROCARBONS, METHOD OF FURNISHING PROOF OF THE PRESENCE OF THE AZO DYES, HYDROCARBONS CONTAINING ONE OR MORE AZO DYES AND THE USE OF AZO DYESTUFF I, II, AND III

摘要

PCT No. PCT/EP94/04091 Sec. 371 Date Jun. 6, 1996 Sec. 102(e) Date Jun. 6, 1996 PCT Filed Dec. 9, 1994 PCT Pub. No. WO95/17483 PCT Pub. Date Jun. 29, 1995Azo dyes of the formula IMAGE where the ring A may be benzofused, n is 0 or 1, and R1-R8 are as defined, as pH-dependent markers for hydrocarbons, hydrocarbons containing the above-mentioned azo dyes, and a method for detecting these azo dyes in hydrocarbons.