Morton International, Inc.

Rohm and Haas Company

Haresh A Doshi

Michael J Denci

Brian A Foley

Justin J Frederico

Mike Friswell

Theodore D Pauls

Justin Frederico

Susan I Steuer

Anjali Asgaonkar

This invention provides a method for invisibly tagging, for subsequent identification purposes, various liquid petroleum hydrocarbons, such as crude oil, diesel fuel, heating oil, kerosene, lubricating oils, waxes, jet fuel, and in particular gasoline, remarkably using visible dyes by incorporating therein one or more visible dyes at minute levels such that they cannot be visually detected by the human eye. Visible dyes which have high solubility in petroleum hydrocarbons and maximum absorption in the 550-700 nm visible wavelength range are used to impart such invisible markings. The visible dyes, although employed at non-visible levels, are still capable of detection in a relatively quick and simple manner which requires minimal instrumentation, creates no waste products for disposal, and gives true quantitative results of dye concentrations in the field. This invention, therefore, further provides a method for so identifying the tagged petroleum hydrocarbons by exposing the tagged hydrocarbon to visible light having wavelengths in the portion of the spectrum utilized and detecting and quantifying the presence of the dyes in the tagged product from their characteristic absorption with available absorption detection equipment sensitive in this spectral region. This invention also provides visible dye compositions particularly appropriate for said invisible tagging.

Method for invisibly tagging petroleum products using visible dyes

A stabilized, concentrated solution of a diazo dye is prepared by coupling diazotized aniline or substituted aniline with a dialkylaniline in the presence of an aromatic solvent. After removal of the aqueous phase, the solution is stabilized by the addition of a branched chain, primary or secondary, C.sub.3 -C.sub.6 alkyl phenol.

N,N-dialkylaniline azo dye solutions

Carbonyl compounds, such as ketones, aldehydes, esters, amides, anhydrides and carboxylic acids are added to a material, particularly a liquid material as markers. Subsequently the carbonyl compound(s) are identified by measuring the absorbency peak(s) of the carbonyl compounds in the mid-IR range. Carbonyl compounds soluble in non-polar solvents and substantially insoluble in water are particularly suitable for tagging and identifying petroleum fuels. For use in petroleum fuels, the carbonyl compound(s) preferably contains no element other than carbon, hydrogen, oxygen and nitrogen. Digital carbonyl marker systems, i.e., systems containing two or more carbonyl compounds in predetermined ratios, can be determined quantitatively with instruments, such as SpecTrace.TM. which measure absorbance in the mid-IR region.

Use of carbonyl compounds as markers

Markers which are soluble in petroleum fuel and are extractable from petroleum fuel by either acidic aqueous solutions or basic solutions and develop a color in the presence of the extracting acidic or basic aqueous solution, are identified by passing a specimen putatively containing the marker through an acidic resin column or a basic resin column, as the case may be.

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Somerville, NJ, United States of America

Haresh A Doshi