The invention concerns a method of marking a hydrocarbon liquid comprising the ##STR00001##
step of adding to said liquid, as a tracer compound, a compound of Formula I or Formula II:
wherein at least one of R.sup.1-R.sup.6 in Formula I and at least one of R.sup.7-R.sup.14 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 C.sub.4-C.sub.20 alkyl group; iv. an aliphatic substituent linking two positions selected from R.sup.1-R.sup.6 in Formula I to one another or two positions selected from R.sup.7-R.sup.14 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 R.sup.1-R.sup.6 in Formula I and none of R.sup.7-R.sup.14 in Formula II being a sulphonate group or COOR.sup.15, where R.sup.15 represents H, C.sub.1-C.sub.20 alkyl, C.sub.2-C.sub.20 alkenyl, C.sub.2-C.sub.20 alkynyl, C.sub.3-C.sub.15 cycloalkyl or aryl.

A marking method which is a method of marking a product having a distillation range is disclosed. The method comprises the step of adding to said product a first marker, a second marker and optionally one or more further markers. Each marker has a distillation range including a minimum boiling point (Min BP), a maximum boiling point (Max BP) and a maximum distillation boiling point (Max DBP) which is the temperature at which the maximum volume of the marker distils. Each marker has a different distillation range from each other marker and at least one marker has a Max DBP which is within the distillation range of the product. The first marker has a distillation range in the marked product which extends over the whole of the product distillation range.

A Liquid, comprising an hydrophobic flavonoid derivative electrochemically non-active, that is capable of restoring its electrochemical activity, the concentration of the flavonoid derivative being 10 ppm by weight or less, and an organic substance in an amount of 90% by weight or more.

A method for detecting mentholated tobacco, comprising irradiating tobacco containing menthol and a fluorescent taggant with radiation and observing the tobacco for fluorescence from the taggant. A system and method for detecting and separating mentholated tobacco from non-mentholated tobacco within a product stream is also provided.

The disclosure provides dyes for marking hydrocarbon compositions. More particularly, the disclosure relates to non-mutagenic dyes for marking hydrocarbon compositions.

A method for detecting mentholated tobacco, comprising irradiating tobacco containing menthol and a fluorescent taggant with radiation and observing the tobacco for fluorescence from the taggant. A system and method for detecting and separating mentholated tobacco from non-mentholated tobacco within a product stream is also provided.

A diamondoid fuel comprising a cage structure including 10, 14, 18, or 22 carbons. The diamondoid fuel also includes one of one to four cyclopropyl groups bonded to the cage structure or two to four functional groups bonded to the cage structure where the functional groups are an alkyl group, an allyl group, a cyclopropyl group, or combinations thereof. Additionally, at least one functional group is an allyl group and at least one functional group is a cyclopropyl group.

A process for the desulphurization of a gasoline cut containing sulphur-containing compounds, olefins and diolefins, involving (a) fractionating the gasoline in order to recover a light gasoline cut LCN and a first heavy gasoline cut HCN; (b) desulphurization of the first heavy gasoline cut HCN; (c) partially condensing desulphurization effluent obtained from b) in a manner such as to produce a gaseous phase of hydrogen and H.sub.2S and a liquid hydrocarbon phase HCN of dissolved H.sub.2S; (d) separating the liquid hydrocarbon phase HCN into an intermediate gasoline cut MCN and a second heavy gasoline cut HHCN; (e) carrying out a second desulphurization of the second heavy gasoline cut HHCN.

A process for the desulphurization of a gasoline cut containing sulphur-containing compounds, olefins and diolefins, involving (a) fractionating the gasoline in order to recover a light gasoline cut LCN and a first heavy gasoline cut HCN; (b) desulphurization of the first heavy gasoline cut HCN; (c) partially condensing desulphurization effluent obtained from b) in a manner such as to produce a gaseous phase of hydrogen and H.sub.2S and a liquid hydrocarbon phase HCN of dissolved H.sub.2S; (d) separating the liquid hydrocarbon phase HCN into an intermediate gasoline cut MCN and a second heavy gasoline cut HHCN; (e) carrying out a second desulphurization of the second heavy gasoline cut HHCN.

A method of fuel analysis comprising subjecting a fuel sample comprising a fuel marker and a fuel matrix to fluorescence spectroscopy to generate a measured emission spectrum comprising a first spectral component (type and amount of marker in sample), a second spectral component (spectral perturbation), and a third spectral component (matrix fluorescence); deconvoluting the measured emission spectrum to yield a deconvoluted measured emission spectrum (first and second spectral components) via removal of third spectral component; decoupling the deconvoluted measured emission spectrum to yield a corrected emission spectrum (first spectral component) via a projection function which orthogonally projects the deconvoluted measured emission spectrum onto a subspace devoid of the second spectral component; and determining the amount of fuel marker in the fuel sample from the corrected emission spectrum. The method of fuel analysis comprises temperature corrections.