Method of marking hydrocarbon liquids

Abstract

Method of marking a hydrocarbon liquid includes adding to the liquid, a tracer compound of Formula I or II: wherein at least one of R1-R6 in Formula I and at least one of R7-R14 in Formula II is selected from: i. a bromine or fluorine atom; ii. a partially or fully halogenated alkyl group; iii. a branched or cyclic C4-C20 alkyl group; iv. an aliphatic substituent linking two positions selected from R1-R6 in Formula I to one another or two positions selected from R7-R14 in Formula II to one another; or v. a phenyl group substituted with a halogen atom, an aliphatic group or halogenated aliphatic group and none of R1-R6 and none of R7-R14 being a sulphonate group or COOR15, where R15 represents H, C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C3-C15 cycloalkyl or aryl.

Dependencies are inferred from the claim text.