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US 5,525,516 AGranted
Method for tagging petroleum products
AssigneeEastman Chemical Company
InventorsJames J. Krutak, Michael R. Cushman, Max A. Weaver
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AssigneeEastman Chemical Company
InventorsJames J. Krutak, Michael R. Cushman, Max A. Weaver
Estimating the term…
This invention provides a method for imparting invisible markings for identification purposes to petroleum hydrocarbons by incorporating one or more infrared fluorescing compounds therein. Certain infrared fluorophores from the classes of squaraines (derived from squaric acid), phthalocyanines and naphthalocyanines are useful in providing invisibly marked petroleum hydrocarbons such as crude oil, lubricating oils, waxes, gas oil (furnace oil), diesel oil, kerosene and in particular gasoline. The near infrared fluorophores are added to the hydrocarbons at extremely low levels and are detected by exposing the marked hydrocarbon compositions to near infrared radiation having a wavelength in the 670-850 nm range and then detecting the emitted fluorescent light via near infrared light detection means.
A method for tagging a petroleum hydrocarbon for identification purposes, which comprises dissolving at ambient temperature in said hydrocarbon a near infrared fluorophoric compound selected from the group consisting of squaraines phthalocyanines and naphthalocyanines having at least one straight or branched chain C.sub.4 to C.sub.20 alkyl group, and croconic acid derivatives.
A method for identifying a petroleum hydrocarbon, wherein said product has one or more near infrared fluorophoric compounds dissolved therein, which comprises the steps:
A petroleum hydrocarbon having dissolved therein at least one near infrared fluorophoric compound selected from the group consisting of squaraines, phthalocyanines and naphthalocyanines having at least one straight or branched chain C.sub.4 to C.sub.20 alkyl group, and croconic acid derivatives.
Dependencies are inferred from the claim text.