HK1079763B - Molecular tags for organic solvent systems - Google Patents

Description

Molecular markers for organic solvent systems

The present application is a divisional application of an invention patent application having an application date of 28/8/2001, an application number of 018235816, and an invention name of "molecular marker for organic solvent system".

Background

In the present invention, the use of novel chromogenic chemicals as molecular markers for organic solvent solutions, particularly petroleum products, is disclosed. Also disclosed is a method for synthesizing, detecting and quantifying these novel substances. These detection methods provide a new and improved process for the detection and quantification of certain known marker substances. With the present invention, color or fluorescence can be exhibited in a single phase system containing petroleum products without the need for a separate extraction step.

Proton-accepting chemicals that impart little or no noticeable color to organic solvents at solution concentrations of less than about 20 micrograms/liter have been used as markers or markers in many instances, particularly for petroleum-derived fuels. The label is dissolved in the liquid to be identified and then detected by simple physical or chemical assay of the labeled liquid. Markers are sometimes used by government agencies to ensure that appropriate taxes are paid for a particular grade of fuel. Oil companies also mark their products to help identify those who dilute or alter their products. These companies often pay a significant price to ensure that the petroleum products to which they are branded meet certain specifications, such as volatility and octane number, as well as to provide their petroleum products with an effective combination of additives including detergents and other components. Consumers rely on the names and quality specifications of these products to ensure that the purchased products are of the desired quality.

The presence of acidic substances (the accuracy of which varies with the nature of the marker) is generally detected and optionally quantified by extracting the petroleum product with an immiscible aqueous or bulk water-containing solution of these substances. The acid reacts with the basic compound to produce easily visible, more or less dark cations, which are dissolved in the aqueous acid phase. This process is described in US patent US 5,145,573.

The amount of the marker substance in the extract can also be determined, for example by visible light absorption spectroscopy, and the results compared to a reference standard to determine the initial concentration of the basic marker in the fuel. For complete quantification, it is sometimes necessary to repeat (typically 2 or 3 times) the extraction of the fuel to recover all the marker originally present. Thus, it is also relatively simple to remove the marker from the labeled fuel by this reaction. This is a shorthand for these prior art basic labeling substances; dishonest personnel who want to defraud the tax department or individual consumers can remove them from the fuel more easily. For example, the tag in tagged low octane gasoline may be removed via washing for resale as untagged, higher priced premium fuel. Alternatively, the tag in #2 fuel oil, which is a tag for duty free sales of home heating oil or railroad or agricultural diesel, is removed to be resold as road, diesel fuel at a higher post-tax price. Legitimate tax agencies therefore lose their revenue. In the united states, these taxes have increased by approximately $ 20 billion due to the implementation of the marking program in 1993.

In addition, the separated phase of the extraction is a hazardous waste and presents safety and legal disposal problems, especially when testing is performed "in the field". Moreover, the fuel with which it comes into contact may be water-wet, making it difficult to return to its original source, and thus presenting additional waste disposal problems.

By using the colour developer according to the invention, in particular a hydrocarbon or alcohol solution of an organic phosphoric or sulphonic acid, the marker colour or fluorescence can be made clearly and immediately visible without extraction from the petroleum product and can be quantified.

A fast and deterministic determination step is very important for practical detection, which can minimize the occurrence of delayed delivery and false car-bonuses of the vehicle. Isotopic labeling can also be used as an auxiliary analytical step to independently confirm results that have been obtained by chromogenic analysis.

Summary of The Invention

The present invention provides compositions comprising an organic phase forming petroleum product, a marking substance dissolved in the petroleum product, and an anhydrous acid associated with the marking substance in the organic phase to exhibit a detectable color. It also includes compositions comprising an organic phase forming petroleum product, a labeling substance dissolved in the petroleum product, and an acid which binds to the labeling substance and petroleum product to exhibit a detectable color or fluorescence in the organic phase.

Markers for petroleum products are also provided. They have the following structure:

wherein A, B and C are independently of each other an aromatic carbocyclic moiety, N is nitrogen, and R is an alkyl group or a hydrogen atom. Further, the present invention provides a method for identifying a petroleum product containing a marker reactive with an acid, comprising first obtaining a sample of the petroleum product containing the marker reactive with an acid, and then adding a developer comprising an anhydrous acid or a solution thereof to the sample, thereby forming a single phase in which the acid and the marker combine to exhibit a detectable color.

Detailed Description

The present invention provides novel molecular markers or tags and color developers for use therewith. The developer may also be used with a pre-existing acid-reactive label. These markers are essentially invisible when present in the liquid petroleum product in effective use amounts, but exhibit a clear color and/or fluorescence when contacted with a suitable developer of the present invention. The step of the present invention for developing color or fluorescence is simple and easy in practical use, and the reagent for developing the color is easy to handle and recover.

With the present invention, for petroleum-derived compositions, the steps of detecting and quantifying the acid-reactive label can be performed directly in the petroleum product without the need to extract the aqueous phase. The reaction is preferably accomplished using an anhydrous organic acid solution that is miscible with petroleum products. This binding allows the presence of the labeling substance to be immediately visible or, if desired, to be indicated by an instrument. The concentration of the label can be accurately determined by, for example, standard chromatographic procedures, such as detection and quantification with a spectrophotometer, detection and quantification with a spectrofluorimeter when the label is a fluorescent label, and detection and quantification with an isotope assay when the label is isotopically labeled. The procedure of the present invention is faster and more convenient for producing quantitative results than extraction using aqueous acid (which takes longer to achieve complete phase separation). The new step also reduces potential environmental disposal problems as the coloured and marked product can be returned to its origin; optionally, the acid developer is neutralized, for example, with an aliphatic amine that is miscible with the petroleum product. It is also possible to use a marker substance which is reactive with acids (which are not easily extractable from petroleum products under aqueous acid conditions).

The developers of the invention are generally represented by R-OH, where the OH group is part of the acid moiety, its pK_aThe value is 3.5 or less and R is a mono-or arylsulfonic acid moiety or a mono-or dialkylphosphoric acid.

Preferably, the marker-developing acids are those that are completely miscible with petroleum products. Furthermore, for quantitative analysis, the salts formed by their reaction with the marker substance should also be completely dissolved in the fuel.

The final choice of acid can vary from system to system with varying solubility parameters. For example, high octane gasoline typically contains a large amount of aromatic hydrocarbons that have good solvency for the marking substances and developers. In contrast, kerosene fuels and lubricating oils are essentially aliphatic and/or cycloaliphatic in nature and have relatively poor solvency for many of the marking substances and their salts resulting from reaction with acids.

Although organic sulfonic acids such as methanesulfonic acid may be used, acids with more complex organic functional groups are preferred in order to achieve good mixing. Particularly preferred are higher alkylated benzenesulfonic acids, especially C₁₀-C₂₀Alkyl substituted benzene sulphonic acids, of which dodecylbenzene sulphonic acid is most conveniently used. The compounds are produced in large quantities as the basis for many laundry and other detergents. The dodecyl chain may be linear or branched, and linear compounds are preferred because they are more readily biodegradable, but both are fully effective in the present invention.

As an alternative to such sulfonic acids, mono-or di-alkyl or aryl esters of phosphoric acid may be used as color developers or detection agents. Many of these compounds are commercially available and, for organic sulfonic acids, the ultimate choice depends on the compatibility of the particular fuel with the assay system. The di (2-ethylhexyl) ester of phosphoric acid is a particularly preferred compound because of its broader compatibility.

The amount of developer used in the detection step is at least 1 molar equivalent per mole of labeling substance, preferably 2-5 times in excess. The acid developer is preferably added as a dilute solution in a hydrocarbon, alcohol or glycol ether. The reason for this is that the concentration of the marking substance in the petroleum product is 100mg/L or less, and the molar amount of the developer acid used will be very small, and it is inconvenient to add it as an undiluted substance. For gasoline fuels, rather highly volatile solvents are recommended, such as toluene, xylene, ethanol or n-propanol. For less volatile fuels such as kerosene, 2-ethylhexanol or 1-dodecane may be preferred due to their greater compatibility with such systems. These solvents are also suitable for use with lubricating oils and greases. In the latter case, the concentration of dodecylbenzene sulphonic acid may have to be increased considerably due to the presence of other bases, in particular inorganic compounds such as lithium hydroxide, in the grease. In general, the ratio of acid to label material can be varied over a wide range of concentrations to optimize the development of the label in different systems. The concentration of acid used in the present process is generally much less than the aqueous or aqueous-alcoholic developer/extractant described in the prior art.

The active content of the acid in the present invention may be 0.05 mole or even lower. This is in contrast to the recommended 2.5-3.0 molar acid concentration used in the extraction step. Therefore, the developer of the present invention has lower corrosiveness and much lower risk than the prior art, particularly in the case of in-situ measurement.

Suitable solvents for the acid developer include aliphatic and aromatic hydrocarbons, alcohols, glycols and glycol ethers. Lower alcohols such as methanol, ethanol and propanol are preferred for this purpose, particularly when the petroleum product is gasoline, but hydrocarbons such as toluene or xylene are most preferred. For use with other petroleum products, such as in combination with tagged diesel fuel, a low volatility solvent is preferred. In general, higher aliphatic and aromatic hydrocarbons are of particular value in this regard, particularly isooctane, dodecane, and other aliphatic hydrocarbons having desirable combination properties including good solvency and miscibility with petroleum fuels, low vapor pressure at room temperature, high flash point, and no mutagenicity. This combination minimizes the risk of harm to human health and fire hazard.

The concentration of the acid in the solution of the invention may vary within a wide range. Preferably, sufficient acid is present to react with all of the marker in the fuel sample. For practical reasons, it is preferred that the solvent has dissolved therein about 0.5 to 10%, preferably about 1%, of an acid solution. The solvent therefore typically comprises about 90-99% of the anhydrous developer.

The developer of the present invention can be used, for example, with the novel labeling substance of the present invention or a prior art labeling substance such as Solvent Yellow 56 or Solvent Yellow 124.

Preferred novel labels or label materials of the present invention are aromatic carbocyclic monoazo compounds represented by the following general formula:

wherein A, B and C are aromatic carbocyclic moieties, preferably benzene or naphthalene, N represents a nitrogen atom and R is an alkyl group or a hydrogen atom. R is preferably branched or unbranched C₁-C₂₀。

The hydrogen atoms attached to structural element A, B and C may optionally be replaced by one or more other atoms or groups that do not significantly impart water solubility to the molecule. Typical substituents may be halogen atoms, nitro, alkyl, alkoxy or hydroxy, carboxylate, carboxamide or sulfonamide functional groups. Particularly useful substituents are, for example, alkyl groups, which increase the solubility of the basic labeling substance in organic solvents, especially the aliphatic hydrocarbons which make up the largest proportion of many petroleum fuels. In addition, in the case of combustion of the marking substance as part of the fuel, it is particularly preferred to limit its composition to carbon, hydrogen, nitrogen and oxygen atoms, in order to avoid the emission of atmospheric pollutants such as sulfur oxides and hydrogen halides which may be generated.

The monoazo marker compounds of the present invention may be prepared by conventional procedures which may include diazotization of a preferably carbocyclic primary aromatic amine followed by azo coupling with an N-arylaminoanilide or an N-arylnaphthylamine, the amine not being subjected to azo coupling at the 4-position of the aromatic nucleus (1-position with the N-arylamino substituent).

For practical and economic reasons, the preferred primary amines are aniline and its ring alkylated derivatives, especially dodecylaniline. Esters of aminobenzoic acids are also of value, the main function of which is to increase the solubility of the marking substances in hydrocarbon solvents, in particular in aliphatic, naphthenic and cycloaliphatic hydrocarbons, which are the main components in gasoline, diesel, domestic heating and lubricating oils and kerosene.

Alternatively, preferred compounds of the present invention may also be synthesized by diazotizing 4-aminodiphenylamine followed by azo coupling with phenol or substituted phenols. Of particular interest as coupling components are the alkylphenols, whereby the appropriate choice of the alkyl group ensures good solubility of the final compound in the aforementioned aliphatic cycloalkane solvents and alicyclic hydrocarbon solvents.

The following examples are intended to illustrate but not limit the scope of the invention.

Example 1

To a 1 liter stirred glass bottle was added 50 grams of ice followed by 28.1 grams of 32% hydrochloric acid. 26.1 g of dodecylaniline dissolved in 50ml of xylene are added dropwise while the mixture is stirred at 0 ℃. Next 17.25 grams of sodium nitrite (at a concentration of 40%) was added while maintaining the temperature below 5 ℃. After a 10 minute sulfone positive test (positive sulfone test), sulfamic acid was added to remove excess sodium nitrite. 16.9 g of diphenylamine dissolved in 50ml of xylene are poured into the reaction and stirred. Sodium formate was added to adjust the pH to 3. After the coupling was completed, the reaction was neutralized with aqueous ammonia and left to stand. Water was removed and the solvent was evaporated to give 88.8% crude product. The substance dissolved in xylene at a concentration of 10mg/L turned bright purple when reacted with dodecylbenzenesulfonic acid, with an absorption maximum at 561 nanometers (nm).

Example 2

To a 1 liter stirred glass bottle was added 50 grams of ice followed by 28.1 grams of 32% hydrochloric acid. 26.1 g of dodecylaniline dissolved in 50ml of xylene are added dropwise while the mixture is stirred at 0 ℃. Next 17.25 grams of sodium nitrite (at a concentration of 40%) was added while maintaining the temperature below 5 ℃. After a 10 minute sulfone positive test, sulfamic acid was added to remove excess sodium nitrite. 18.3 g of N-methyldiphenylamine dissolved in 50ml of xylene are poured into the reaction and stirred. Sodium formate was added to adjust the pH to 3. After the coupling was completed, the reaction was neutralized with aqueous ammonia and left to stand. Water was removed and the solvent was evaporated to give 92.1% crude product. This dye is very similar to that of example 1, except that it shows a slightly reddish purple color with an absorption maximum at 559 nm.

Example 3

To a 2 liter stirred glass bottle was added 12ml of 45% sodium hydroxide and 200ml of water followed by 20.6 grams of di-sec-butylphenol. The vessel was heated to 70 ℃ and then cooled to 50 ℃. To a separate 1 liter flask, 200ml of water, 28.1 grams of 32% hydrochloric acid, and 18.4 grams of 4-aminodiphenylamine base were added, followed by heating. Once the aminodiphenylamine was converted to its hydrochloride salt, the mixture was cooled to 10 ℃ and 17.25 grams of sodium nitrite (at a concentration of 40%) was added. After a 10 minute sulfone positive test, sulfamic acid was added to remove excess sodium nitrite. The diphenylamine diazonium solution is stirred into a di-sec-butylphenol solution while maintaining the pH above 12. After the coupling was complete, the solution was acidified to pH3 by the addition of acetic acid. The pH of the multiphase solution was then adjusted to 6.5. Water was removed and the solvent was evaporated to give 93.0% crude product. A solution of the resulting product at a concentration of 10mg/L turned reddish blue upon reaction with 2-ethylhexyl-phosphoric acid, with its absorption being greatest at 588 nm.

Example No. 2	Diazo component	Coupling component	Visual appearance after protonation	Maximum absorption nm
					4	Dodecyl aniline	1-phenylaminonaphthalene	Blue color	616
5	Dodecyl aniline	3-methyldiphenylamine	Purple color	559
					6	2-Aminobenzoic acid butyl ester	Diphenylamine	Red colour	543
7	4-Aminobenzoic acid butyl ester	Diphenylamine	Blue and red	549
					8	4-aminodiphenylamine	4-nonyl phenol	Violet blue	599

In addition to the aforementioned novel azo label substances, other basic organic compounds which have been proposed in the prior art as dye labels can also be detected and quantified by the process of the present invention, even if they have previously only been proposed for use in detection or the like using extraction with proton donating agents containing water or a large amount of water. Mention may be made of bases which are generally colourless or slightly coloured, such as triarylmethanes, xanthenes, azines and other related dyes. These bases form dark ammonium, oxonium and carbocations by protonation. Readily available materials include triarylmethane carbinols (e.g., methyl viologen), triarylmethane lactones (e.g., crystal violet lactone and rhodamine B base), and amines (e.g., victoria blue base and nile red a). These compounds, which are present in the organic solvent in a concentration of 0.1 to 200mg/L, but preferably 1 to 20mg/L, can react with anhydrous acids or substantially anhydrous acid solutions to give dark cations which absorb part of the wavelengths of light in the visible spectrum, thus giving the fuel or lubricating oil a visible yellow to brown colour. In the case of a very dark fuel or the like, the quantitative determination of the labeling substance can be improved by processing the linear absorption spectrum using differential processing (particularly, second order differential processing).

Example 9

An aliquot of a dilute solution of rhodamine B base, c.i. solvent red 49 in phenol ethylene glycol was added to water white #1 kerosene lamp oil to make a colorless 2mg/L rhodamine B base solution. 10ml of a 1% solution of technical-grade dodecylbenzene sulphonic acid in dodecane were added to 100ml of the fuel. Producing a pink fast fluorescence with maximum absorption at 545 nanometers (nm) and maximum emission at 565 nm. The unknown concentration of rhodamine B base in the fuel can be quantified by comparison to a calibration reference standard. When only very low concentrations of rhodamine are present, or the fuel has a high background color, detection and quantification is more readily achieved by spectrofluorimetry than by spectrophotometry.

Example 10

1 liter of unleaded gasoline was added to 10ml of a solution of 0.1% methyl viologen dissolved in denatured ethanol. This resulted in a fuel base concentration of 10ml/L^-1. 100ml of the labeled gasoline was thoroughly mixed with 900ml of unlabeled premium gasoline. 100ml of this mixture was then added to 10ml of a 1% solution of diethylhexylphosphoric acid in xylene. Immediately purple color appeared, which could be quantified spectrophotometrically to confirm that the concentration of marker in the diluted gasoline was 1 mg/L. If 1ml of N, N-dimethylethanolamine is added to said gasoline which assumes a purple color, the color disappears and the fuel resumes its original appearance.

Example 11

The procedure described in example 10 was repeated, except that 1% 1, 1, 1-trichloroacetic acid solution was used instead of di-2-ethylhexyl phosphoric acid. The same quantification of methyl violet-labeled substances was achieved.

Example 12

1 liter of #2 household heating oil (already used at a concentration of 26mg/L with Unisol)LiquidRed BNM, according to the US IRS chapter), labeled with Victoria blue B base at a concentration of 5 mg/L. To 100ml of the labeled heating oil was added 10ml of a 1% strength solution of dodecylbenzene sulfonic acid in 2-ethylhexanol. The appearance of the fuel immediately changed from red to purple. If a developed fuel sample is scanned in an absorption spectrophotometer, the relative concentrations of red and blue can be determined.

Example 13

Similar quantification of the red dye and label is achieved if the victoria blue B base listed in example 12 is replaced by the same concentration of the azo compound synthesized according to example 1.

Example 14

To 100ml of home heating oil (colored with 4mg/L of c.i. solvent red 164 and 11mg/L of c.i. solvent yellow 124, according to the regulations of ontario, canada) was added 10ml of a 1% dodecylbenzene sulfonic acid solution. The appearance of the fuel immediately changed from a faint orange-red color to a darker dark red color due to the base transition of the solvent yellow 124 to magenta red cations. If a sample of the developed fuel is scanned in an absorption spectrophotometer and the results are processed using a second order differential process or multiple components, the concentration of solvent red 164 and solvent yellow 124 in the original fuel can be quantified. This detection step is much faster and more convenient than the prior art involving 2 or 3 successive extractions of a fuel sample with aqueous hydrochloric acid, where the separate extractions need to be combined and then possibly filtered to remove entrained droplets of fuel before the sample can be spectrophotometrically analyzed.

Example 15

Diazotization of dodecylaniline by azo coupling with N, N-diethyl-m-toluidine a sample of the fuel marker was synthesized according to example 6 of WO 99/67346. The detection step of the labeled substance comprises extracting the fuel containing the labeled substance with a mixture of 10N aqueous hydrochloric acid and ethanol in equal parts by volume. By reacting the same labeling substance with the anhydrous dodecylbenzene sulfonic acid solution described in example 10 above, the labeling substance can be more conveniently detected and the operational risk reduced.

Example 16

As in example 2 of U.S. Pat. No. 2, 5,737,871, a fuel marker was prepared by azo coupling of butyric acid ester of N-phenyl-N-ethylethanolamine with diazotized aniline. According to claim 6 of the same patent, the presence of the substance in the fuel is detected by extraction with an aqueous acidic solution. The substance can also be reacted directly in the fuel with the anhydrous acid of the invention, so that it can be detected and quantified immediately. This is more convenient, less time consuming and less dangerous than extraction with aqueous acid.

Applicants' invention has been described with reference to preferred embodiments. Many modifications may be made to the invention described without departing from its scope.

Example 17

A sample of 4-amino-N-2' -ethylhexylbenzenesulfonamide was diazotized and then azo-coupled with N, N-diethylaniline. The product obtained is a yellow crystalline solid, readily soluble in most hydrocarbons. A10 mg/L colorless gasoline solution of the product reacted with a dilute solution of dodecylbenzenesulfonic acid to give a clear red color.

The marker used in the present invention can also be represented by the following formula:

wherein any hydrogen atom in the above-mentioned molecule may be replaced by a deuterium atom. Ring a may contain 0-2 substituents, X and Y, which represent any group that does not significantly impart water solubility to the molecule. X and Y may be, for example (independently of one another), halogen atoms, nitro groups, more preferably esters or amides of alkyl and alkoxy groups or carboxylic acid groups. N-alkylsulfonamide groups may also be used. R₁And R₂Which may be a hydrogen or deuterium atom or a substituted hydroxyl group, the substituent on which may react with an alkyl carboxylic acid, a halide or anhydride thereof to form an ester moiety, or may react with an alkyl vinyl ether to form an acetal moiety, particularly when the alkyl vinyl ether is isobutyl vinyl ether, which is c.i. solvent yellow 124. R₃Is alkyl, alkoxy or amido.

In another embodiment, the markers of the present invention may be added to a petroleum product that also contains a dye. The marker substance can be developed with an acid in a petroleum product sample, as described above, without the need for a separate extraction step. In other words, the presence of the dye does not interfere with the development and detection of the labeling substance in the present invention. Dyes that may be used in addition to the labeling substance include 1, 4-alkyl or substituted alkylamino anthraquinone compounds, alkyl derivatives of phenylazophenylazo-2-aminonaphthalene, and c.i. solvent red 23, and cycloalkylated homologs thereof may also be used in the present invention. C.1. The ring alkylated homologues of solvent red 23 include c.i. solvent reds 24, 25, 26, 27, 164 and 164: 1. C.i. solvent yellow 124 may also be used in the present invention.

Claims (29)

1. A composition, comprising:

a) an organic phase forming petroleum product;

b) a marking substance dissolved in said petroleum product; and

c) an anhydrous acid that binds to the labeling substance in the organic phase to exhibit a detectable color.

2. The composition of claim 1 wherein the acid is selected from organic sulfonic acids.

3. The composition of claim 2, wherein the acid is dodecylbenzene sulfonic acid.

4. The composition of claim 1, wherein the acid is selected from the group consisting of monoalkyl and dialkyl phosphoric acids.

5. The composition of claim 1 wherein the acid is selected from carboxylic acids having a pKa value no greater than 3.5.

6. The composition of claim 1, wherein the acid is used in the form of a solution in an organic solvent.

7. The composition of claim 6, wherein the solvent is an aliphatic or aromatic hydrocarbon or alcohol.

8. The composition of claim 1, wherein the labeling substance is:

wherein A, B and C are independently of each other an aromatic carbocyclic moiety, N is nitrogen, and R is an alkyl group or a hydrogen atom.

9. The composition of claim 8, wherein A, B and C are independently selected from benzene and naphthalene.

10. The composition of claim 9, wherein R is branched or unbranched C₁-C₂₀An alkyl group.

11. The composition of claim 9 wherein the hydrogen atoms attached to ring A, B and C are replaced by one or more other atoms or groups that do not impart appreciable water solubility to the molecule.

12. The composition of claim 11, wherein ring a is substituted with a component selected from the group consisting of: halogen atoms, nitro, alkyl, alkoxy or hydroxy groups, carboxylic ester, carboxamide or sulfonamide groups.

13. The marking composition of claim 1, wherein the marker is:

wherein any hydrogen atom may be replaced by a deuterium atom; ring a contains 0-2 substituents, X and Y, where X and Y are any groups that do not impart significant water solubility to the molecule; r₁And R₂Independently of each other, hydrogen, deuterium or a substituted hydroxyl group, wherein the substituents on said substituted hydroxyl group form an ester moiety by reaction with an alkyl carboxylic acid, halide or anhydride thereof; and R is₃Is alkyl, alkoxy or amido.

14. The composition of claim 1, wherein the labeling substance is N, N-diethylaminoazobenzene.

15. The composition of claim 14, wherein the substituents on the substituted hydroxyl groups form an acetal moiety by reaction with an alkyl vinyl ether.

16. The composition of claim 15, wherein the alkyl vinyl ether is isobutyl vinyl ether and the substance is c.i. solvent yellow 124.

17. The composition of claim 13, wherein R₁And R₂Is a hydrogen atom.

18. The composition of claim 13, wherein one or more hydrogen atoms are replaced with deuterium atoms.

19. The composition of claim 1 wherein said petroleum product contains a dye in addition to said marking substance.

20. The composition of claim 19, wherein the dye is a 1, 4-alkyl or substituted alkylamino anthraquinone compound.

21. The composition of claim 19, wherein the dye is an alkyl derivative of phenylazophenylazo-2-aminonaphthalene.

22. The composition of claim 19, wherein the dye is c.i. solvent red 23 and its cycloalkylated homologs.

23. The composition of claim 1, wherein the pK of said anhydrous acid_aThe value is not more than 3.5.

24. The composition of claim 1 wherein the anhydrous acid binds to the labeling substance and petroleum product to exhibit detectable fluorescence in the organic phase.

25. Use of a composition as claimed in any one of claims 1 to 24 for the identification of petroleum products wherein a colour developer is added to the composition to form a single phase in which the anhydrous acid and marker combine to take on a detectable colour and the colour is detected.

26. The use of claim 25, wherein the label is detected and quantified with a spectrophotometer.

27. The use of claim 26, wherein the label is a fluorescent label and is detected and quantified by a spectrofluorimeter.

28. The use of claim 27, wherein the label is detected and quantified using a spectrofluorimeter.

29. The use of claim 28, wherein the label is isotopically labeled and the isotope is detected.