Detection of marked mineral oils and novel azo dyes

Abstract

Method for detecting marked mineral oils by treating the marked mineral oil with an extractant comprising water, a solvent and a base comprises using as marker an azo dye of the formula ##STR1## where ring A may be benzofused,m is from 1 to 4,X.sup.1 is hydrogen, C.sub.1 -C.sub.4 -alkyl, cyano or nitro,X.sup.2 is hydrogen, C.sub.1 -C.sub.4 -alkyl, cyano, nitro, C.sub.1 -C.sub.4 -alkoxy or C.sub.1 -C.sub.16 -alkoxycarbonyl,X.sup.3 is hydrogen, C.sub.1 -C.sub.4 -alkyl, cyano or C.sub.1 -C.sub.16 -alkoxycarbonyl, andX.sup.4 is hydrogen, hydroxyl, substituted or unsubstituted C.sub.1 -C.sub.8 -alkyl, C.sub.1 -C.sub.4 -alkoxy, amino, C.sub.1 -C.sub.4 -dialkylamino or substituted or unsubstituted C.sub.1 -C.sub.16 -monoalkylamino,as solvent a partially or completely water-miscible organic solvent, and as base an alkali or alkaline earth metal hydroxide, an alkali metal carbonate or a quaternary ammonium hydroxide, the use of azo dyes as markers for mineral oils, and novel azo dyes.

Description

The present invention relates to a novel method for detecting azo dye marked mineral oils, the use of monoazo or disazo dyes as markers for mineral oils, and novel azo dyes.

U.S. Pat. No. 5,156,653 discloses the use of phenylazophenols for marking mineral oils. The markers are detected there by shaking the marked mineral oil with a mixture of water, diethylene glycol and methoxyethoxypropylamine to form a mineral oil phase and an aqueous phase containing the azo dye. However, it has been found that the method of detection described there is not satisfactory. It does not have universal utility and frequently produces only an extremely weak coloring of the aqueous phase, since some of the dye used remains in the oil phase.

U.S. Pat. No. 3,764,273 describes the extraction of quinizarin derivatives and of specific azo dyes, inter alia with aqueous alkali and dimethyl sulfoxide.

Finally, U.S. Pat. No. 5,252,106 discloses the use of 4-(4'-phenylazophenylazo)phenols for marking mineral oils.

It is an object of the present invention to provide a novel method for detecting azo dye marked mineral oils which is simple to carry out and by means of which the markers, even in low concentrations, can be visibilized by strong color reaction.

We have found that this object is achieved by a method for detecting azo dye marked mineral oils by treating the marked mineral oil with an extractant comprising water, a solvent and a base, the azo dye transferring from the mineral oil into the aqueous phase, which comprises using as marker an azo dye of the formula I ##STR2## where ring A may be benzofused,

m is from 1 to 4, X.sup.1 is hydrogen, C.sub.1 -C.sub.4 -alkyl, cyano or nitro, X.sup.2 is hydrogen, C.sub.1 -C.sub.4 -alkyl, cyano, nitro, C.sub.1 -C.sub.4 -alkoxy or C.sub.1 -C.sub.16 -alkoxycarbonyl, X.sup.3 is hydrogen, C.sub.1 -C.sub.4 -alkyl, cyano or C.sub.1 -C.sub.16 -alkoxycarbonyl, and X.sup.4 is hydrogen, hydroxyl, C.sub.1 -C.sub.8 -alkyl, which may be phenyl-substituted, C.sub.1 -C.sub.4 -alkoxy, amino, C.sub.1 -C.sub.4 -dialkylamino or C.sub.1 -C.sub.16 -monoalkylamino whose alkyl chain may be interrupted by from 1 to 3 oxygen atoms in the ether function, as solvent a partially or completely water-miscible organic solvent, and as base an alkali or alkaline earth metal hydroxide, an alkali metal carbonate or an ammonium compound of the formula ##STR3## where R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each independently of the others C.sub.1 -C.sub.16 -alkyl or benzyl.

Any alkyl appearing in the abovementioned formulae may be straight-chain or branched.

Unless otherwise stated, substituents in substituted phenyl or naphthyl appearing in the abovementioned formula need not all be the same.

X.sup.1, X.sup.2, X.sup.3, X.sup.4, R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each for example methyl, ethyl, propyl, isopropyl, butyl, isobutyl or sec-butyl.

X.sup.4, R.sup.1, R.sup.2, R.sup.3 and R.sup.4 may each also be for example pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, 2-methylpentyl, heptyl, octyl, 2-ethylhexyl or isooctyl.

R.sup.1, R.sup.2, R.sup.3 and R.sup.4 may each also be for example nonyl, isononyl, decyl, isodecyl, undecyl, dodecyl, tridecyl, 3,5,5,7-tetramethylnonyl, isotridecyl, tetradecyl, pentadecyl or hexadecyl (the above designations isooctyl, isononyl, isodecyl and isotridecyl are trivial names derived from the oxo process alcohols - cf. Ullmanns Encyclopadie der technischen Chemie, 4th edition, Volume 7, pages 215 to 217, and Volume 11, pages 435 and 436).

X.sup.4 may also be for example dimethylamino, diethylamino, dipropylamino, diisopropylamino, dibutylamino, methylamino, ethylamino, propylamino, isopropylamino, butylamino, isobutylamino, sec-butylamino, pentylamino, isopentylamino, neopentylamino, tert-pentylamino, hexylamino, 2-methylpentylamino, heptylamino, octylamino, 2-ethylhexylamino, isooctylamino, nonylamino, isononylamino, decylamino, isodecylamino, undecylamino, dodecylamino, tridecylamino, 3,5,5,7-tetramethylnonylamino, isotridecylamino, tetradecylamino, pentadecylamino, hexadecylamino, 2-methoxyethylamino, 2-ethoxyethylamino, 2-methoxypropylamino, 3,6-dioxaheptylamino, 3,6-dioxaoctylamino, 3,6,9-trioxadecylamino, 3,6,9-trioxaundecylamino, benzyl or 1- or 2-phenylethyl.

X.sup.2 and X.sup.4 may each also be for example methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy or sec-butoxy.

X.sup.2 and X.sup.3 may each also be for example methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, pentyloxycarbonyl, isopentyloxycarbonyl, neopentyloxycarbonyl, tert-pentyloxycarbonyl, hexyloxycarbonyl 2-methylpentyloxycarbonyl, heptyloxycarbonyl, octyloxycarbonyl, 2-ethylhexyloxycarbonyl, isooctyloxycarbonyl, nonyloxycarbonyl, isononyloxycarbonyl, decyloxycarbonyl, isodecyloxycarbonyl, undecyloxycarbonyl, dodecyloxycarbonyl, tridecyloxycarbonyl, isotridecyloxycarbonyl, tetradecyloxycarbonyl, pentadecyloxycarbonyl or hexadecyloxycarbonyl.

Attention is drawn in particular to a method of detection using azo dyes of the formula I where

X.sup.1 is hydrogen or C.sub.1 -C.sub.4 -alkyl, X.sup.2 is hydrogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy or C.sub.1 -C.sub.16 -alkoxycarbonyl, X.sup.3 is hydrogen, C.sub.1 -C.sub.4 -alkyl, or C.sub.1 -.sub.16 -alkoxycarbonyl, and m, Y and X.sup.4 are each as defined above.

Particular preference is given to using in the method of the invention azo dyes of the formula Ia ##STR4## where m is from 1 to 4,

X.sup.1 is hydrogen, cyano or nitro, X.sup.2 is hydrogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy or C.sub.1 -C.sub.13 -alkoxycarbonyl, X.sup.3 is hydrogen or C.sub.1 -C.sub.4 -alkyl, and X.sup.4 is hydrogen or C.sub.1 -C.sub.4 -alkyl, which may be phenyl-substituted.

Particular preference is further given to using in the method of the invention azo dyes of the formula Ib ##STR5## where X.sup.1 is hydrogen,

X.sup.2 is hydrogen, X.sup.3 is hydrogen or C.sub.1 -C.sub.4 -alkyl, X.sup.4 is hydrogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -dialkylamino or C.sub.1 -C.sub.16 -monoalkylamino, X.sup.5 is hydrogen or C.sub.1 -C.sub.4 -alkyl, and X.sup.6 is hydrogen, C.sub.1 -C.sub.4 -alkyl or C.sub.1 -C.sub.4 -alkoxy, with the proviso that a) at least one of the three radicals X.sup.1, X.sup.2 and X.sup.3 is different from hydrogen, b) X.sup.2 may also be cyano when X.sup.4 is C.sub.1 -C.sub.4 -dialkylamino, c) X.sup.2 may also be C.sub.1 -C.sub.4 -alkoxycarbonyl when all the radicals X.sup.4, X.sup.5 and X.sup.6 are different from hydrogen, and d) one of the radicals X.sup.1, X.sup.2 or X.sup.3 may also be nitro when X.sup.4 is C.sub.1 -C.sub.16 -monoalkylamino and X.sup.6 is C.sub.1 -C.sub.4 -alkyl.

Very particular preference is given to using in the method of the invention azo dyes of the formula Ia where X.sup.4 is hydrogen or 1-phenylethyl.

Very particular preference is further given to using in the method of the invention azo dyes of the formula Ia where X.sup.1 is hydrogen, X.sup.2 is methyl or C.sub.1 -C.sub.13 -alkoxycarbonyl, and X.sup.3 is hydrogen or methyl.

Suitable alkali or alkaline earth metal hydroxides or alkali metal carbonates for use in the method of the invention include for example lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, lithium carbonate, sodium carbonate and potassium carbonate.

Suitable ammonium compounds include for example tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide and benzyltributylammonium hydroxide.

The use of alkali or alkaline earth metal hydroxides as base is preferred with particular attention being drawn to alkali metal hydroxides.

Particular preference is given to the use of lithium hydroxide, sodium hydroxide or potassium hydroxide as base, sodium hydroxide being of particular importance.

Since the extractant includes water, the alkali or alkaline earth metal hydroxides, alkali metal carbonates or ammonium compounds are preferably used directly in the form of an aqueous solution, this aqueous solution generally having an alkali or alkaline earth metal hydroxide, alkali metal carbonate or ammonium compound content from 0.1 to 10% by weight, preferably from 1 to 10% by weight, each percentage being based on the weight of the aqueous solution.

Suitable solvents are partially or completely water-miscible organic solvents. This includes for example amides, especially carboxamides, such as formamide, N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, pyrrolidin-2-one, 1-methylpyrrolidin-2-one (NMP), 1,3-dimethylhexahydropyrimid-2-one or hexamethylphosphoramide, N,N,N',N'-tetramethylguanidine, acetonitrile, nitromethane, amines, such as 2-aminoethanol, 1,10-diamino-4,7-dioxadecane, 1,13-diamino-4,7,10-trioxatridecane, 2- or 3-methoxypropylamine, 1,8-bis(dimethylamino)naphthalene or an amine of the formula H.sub.2 N--CH(CH.sub.3)CH.sub.2 [--OCH(CH.sub.3)CH.sub.2 ].sub.2,6 --OCH.sub.2 CH--(CH.sub.3)--NH.sub.2, 1-methylpyrazole, dimethyl sulfoxide (DMSO) or sulfolane.

Preferred solvents are 1-methylpyrazole, pyrrolidin-2-one, 1-methylpyrrolidin-2-one, dimethyl sulfoxide and sulfolane.

In some cases it can also be of advantage for the extractant to include further admixtures, for example 4-nonylphenol, or for the mineral oil to have 4-nonylphenol added to it prior to the extraction.

Based on the weight of the extractant, the proportion of solvent typically ranges from 50 to 99% by weight, preferably from 90 to 99% by weight.

To mark mineral oil, the azo dyes of the formula I are used either without a solvent or in the form of solutions. Suitable solvents include preferably aromatic hydrocarbons, such as toluene, xylene, dodecylbenzene, diisopropylnaphthalene or a mixture of higher aromatics commercially available from Shell as Shellsol.RTM. AB. The solubility may be improved in a conventional manner by using further, co-solvents, for example alcohols, such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, pentanol, hexanol, heptanol, octanol, 2-ethylhexanol or cyclohexanol, glycols, such as butylethylene glycol or methylpropylene glycol, amines, such as triethylamine, diisooctylamine, dicyclohexylamine, aniline, N-methylaniline, N,N-dimethylaniline, toluidine or xylidine, alkanolamines, such as 3-(2-methoxyethoxy)propylamine, o-cresol, m-cresol, p-cresol, ketones, such as diethyl ketone or cyclohexanone, lactams, such as .gamma.-butyrolactam, carbonates, such as ethylene carbonate or propylene carbonate, phenols, such as t-butylphenol or nonylphenol, esters, such as methyl phthalate, ethyl phthalate, 2-ethylhexyl phthalate, ethyl acetate, butyl acetate or cyclohexyl acetate, amides, such as N,N-dimethylformamide, N,N-diethylacetamide or N-methylpyrrolidin-2-one, or mixtures thereof. To avoid the resulting solution from becoming too viscous, it is generally advisable to use a concentration of azo dye I from 1 to 50% by weight, preferably from 10 to 50% by weight, each percentage being based on the solution.

In the course of the treatment of the marked mineral oil with the extractant, for example by shaking, the azo dye of the formula I transfers into the aqueous phase, which takes on a distinctly visible color in the process.

The method of the invention provides a very simple means of detecting mineral oils marked with azo dyes of the formula I. A further advantage of the method of the invention is that it permits the extraction of dyes which have only little acidity.

The present invention further provides for the use of azo dyes of the abovementioned formulae Ia and Ib for marking mineral oils.

Preference for marking mineral oils is given to the use of azo dyes of the formula Ia where X.sup.4 is hydrogen or 1-phenylethyl.

Preference for marking mineral oils is further given to the use of azo dyes of the formula Ia where X.sup.1 is hydrogen, X.sup.2 is methyl or C.sub.1 -C.sub.13 -alkoxycarbonyl, and X.sup.3 is hydrogen or methyl.

Particular preference for marking mineral oils is further given to the use of azo dyes of the formula Ic ##STR6## where Y is C.sub.7 -C.sub.11 -alkyl.

Mineral oils for the purposes of the present invention include for example motor fuels, such as gasoline, kerosine or diesel fuel, or oils, such as fuel oil or engine oil.

The azo dyes of the formula Ia or Ib are especially suitable for marking mineral oils where a form of identification is required, for example for tax reasons. To keep the costs for this to a minimum, it is desirable to keep the amount of marker used to a minimum.

Marking for the purposes of the present invention is the addition of the azo dyes of the formula Ia or Ib to mineral oils in such a concentration that, to the human eye, the mineral oils have barely any or no visible color, although the dyes of the formulae Ia and Ib are readily and distinctly visibly detectable by the methods of detection more particularly described herein.

To mark mineral oil, the azo dyes of the formula Ia or Ib, as mentioned above, are used either without a solvent or in the form of solutions.

The azo dyes of the formula Ia or Ib to be used according to the invention have the advantage of being suitable, depending on their concentration, of conferring a clearly visible color on mineral oils and/or for use as marker substances.

The azo dyes of the formula Ia or Ib to be used according to the invention permit very simple detection of marked mineral oils, even if the marker substances are present only in a concentration of about 10 ppm or less.

The azo dyes of the formula Ia have the application advantage of very good solubility and also excellent dilutability. Moreover, in the detection reaction, they give distinctly more bathochromic hues than the dyes known from U.S. Pat. No. 5,156,653.

It is a further object of the present invention to provide novel azo dyes which shall be advantageous for use as marker substances for mineral oils.

We have found that this object is achieved by the azo dyes of the formula II ##STR7## where Y.sup.1 is hydrogen, or C.sub.1 -C.sub.4 -alkyl-substituted phenylazo,

Y.sup.2 is hydrogen, Y.sup.3 is hydrogen or C.sub.1 -C.sub.4 -alkyl, X.sup.4 is hydrogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -dialkylamino or C.sub.1 -C.sub.16 -monoalkylamino, X.sup.5 is hydrogen or C.sub.1 -C.sub.4 -alkyl, and X.sup.6 is hydrogen, C.sub.1 -C.sub.4 -alkyl or C.sub.1 -C.sub.4 -alkoxy, with the proviso that a) at least one of the three radicals Y.sup.1, Y.sup.2 and Y.sup.3 is different from hydrogen, b) Y.sup.2 may also be cyano when X.sup.4 is C.sub.1 -C.sub.4 -dialkylamino, c) Y.sup.2 may also be C.sub.1 -C.sub.4 -alkoxycarbonyl when all the radicals X.sup.4, X.sup.5 and X.sup.6 are different from hydrogen, and d) one of the radicals Y.sup.1, Y.sup.2 or Y.sup.3 or may also be nitro when X.sup.4 is C.sub.1 -C.sub.16 -monoalkylamino and X.sup.6 is C.sub.1 -C.sub.4 -alkyl.

Preference is given to azo dyes of the formula II where Y.sup.1 is hydrogen.

The novel azo dyes of the formula II are obtainable in a conventional manner, for example by diazotizing an aniline of the formula III ##STR8## where Y.sup.1, Y.sup.2 and Y.sup.3 are each as defined above, and coupling the resulting diazonium compound with a phenol of the formula IV ##STR9## where X.sup.4, X.sup.5 and X.sup.6 are each as defined above.

The further azo dyes of the formula I and those of the formula Ia are generally compounds known per se. They are described for example in U.S. Pat. No. 5,156,653 or U.S. Pat. No. 4,473,376 or can be obtained by the methods mentioned therein.

The Examples which follow illustrate the invention (parts are by weight).

EXAMPLE 1

Commercial diesel fuel was admixed with 10 ppm of a dye (F1) of the formula ##STR10##

9 parts of the diesel fuel thus marked red were admixed with 0.5 part of a mixture of 4 parts of distilled water, 4 parts of 1,10-diamino-4,7-dioxadecane and 2 parts of 10% strength by weight sodium hydroxide solution and vigorously shaken. After about 1 min an aqueous phase with a strong red color separated off as bottom layer. The supernatant diesel fuel phase was almost colorless. The coloring of the aqueous phase was unchanged after 24 h at room temperature.

A blank test carried out on unmarked diesel oil under similar conditions produced an aqueous phase which was almost colorless.

Performing the reaction under similar conditions with a commercial gasoline (from Aral) marked with the dye F1 produced the same color effect as was obtained in the case of marked diesel fuel.

A blank test carried out on unmarked gasoline (from Aral) under similar conditions produced an aqueous phase which was almost colorless.

Similar detection results were achieved on diesel fuel marked with the dyes listed below using various reagent solutions likewise listed below.

Dyes: ##STR11## Reagent solutions: R1 9 parts of NMP and 1 part of 1% strength by weight aqueous lithium hydroxide solution R2 9 parts of 2-pyrrolidinone and 1 part of 1% strength by weight aqueous lithium hydroxide solution R3 9 parts of DMSO and 1 part of 2% strength by weight aqueous lithium hydroxide solution R4 9.5 parts of 1-methylimidazole and 0.5 part of 5% strength by weight aqueous lithium hydroxide solution R5 9.5 parts of amine of formula H.sub.2 N--CH(CH.sub.3)CH.sub.2 [--OCH(CH.sub.3)CH.sub.2 ].sub.2,6 --OCH.sub.2 CH(CH.sub.3)--NH.sub.2 and 0.5 part of 1% strength by weight aqueous lithium hydroxide solution R6 9 parts of 1,3-dimethylhexahydropyrimid-2-one and 1 part of 1% strength by weight aqueous lithium hydroxide solution R7 9 parts of 1,13-diamino-4,7,10-trioxatridecane and 1 part of 1% strength by weight aqueous lithium hydroxide solution R8 5 parts of 3-methoxypropylamine and 1 part of 5% strength by weight aqueous potassium hydroxide solution R9 4 parts of distilled water, 4 parts of 1,10-diamino-4,7-dioxadecane and 2 parts of 10% strength by weight sodium hydroxide solution R10 9 parts of DMSO, 1 part of 2% strength by weight aqueous lithium hydroxide solution and 1 part of 4-nonylphenol

The following results were obtained:

______________________________________ Hue of Hue of Marker oily oily concen- Hue of phase phase trationEx. Re- aqueous after before in dieselNo. Dye agent phase shaking shaking fuel______________________________________ 2 F1 R1 strongly colorless strongly 10 ppm red yellow 3 F1 R2 strongly colorless strongly 10 ppm red yellow 4 F1 R3 strongly colorless strongly 10 ppm red yellow 5 F1 R4 strongly colorless strongly 10 ppm red yellow 6 F1 R8 weakly weakly strongly 10 ppm red yellow yellow 7 F1 R10 strongly almost strongly 10 ppm red colorless yellow 8 F2 R1 strongly colorless strongly 5 ppm orange orange 9 F2 R2 strongly colorless strongly 5 ppm orange orange 10 F2 R3 strongly almost strongly 5 ppm orange colorless orange 11 F2 R4 yellowish weakly strongly 5 ppm orange yellow orange 12 F2 R5 strongly colorless strongly 5 ppm orange orange 13 F2 R6 strongly slightly strongly 5 ppm orange yellow orange 14 F2 R7 strongly colorless strongly 5 ppm orange orange 15 F2 R8 strongly almost strongly 5 ppm orange colorless orange 16 F2 R9 orange slightly strongly 5 ppm yellow orange 17 F2 R10 strongly almost strongly 5 ppm orange colorless orange 18 F3 R1 strongly almost strongly 5 ppm orange colorless orange 19 F3 R2 strongly colorless strongly 5 ppm orange orange 20 F3 R3 strongly almost strongly 5 ppm orange colorless orange 21 F3 R4 strongly weakly strongly 5 ppm orange orange orange 22 F3 R5 strongly colorless strongly 5 ppm orange orange 23 F3 R6 strongly almost strongly 5 ppm orange colorless orange 24 F3 R7 strongly colorless strongly 5 ppm orange orange 25 F3 R8 orange weakly strongly 5 ppm orange orange 26 F3 R9 strongly weakly strongly 5 ppm orange orange orange 27 F3 R10 strongly almost strongly 5 ppm orange colorless orange 28 F4 R1 strongly colorless strongly 10 ppm red yellow 29 F4 R2 strongly colorless strongly 10 ppm red yellow 30 F4 R3 strongly almost strongly 10 ppm red colorless yellow 31 F4 R8 yellow weakly strongly 10 ppm yellow yellow 32 F4 R9 weakly weakly strongly 10 ppm yellow yellow yellow 33 F4 R10 strongly weakly strongly 10 ppm yellow yellow yellow 34 F5 R1 strongly slightly strongly 10 ppm orange yellow yellow 35 F5 R2 strongly slightly strongly 10 ppm orange yellow yellow 36 F5 R3 strongly almost strongly 10 ppm orange colorless yellow 37 F5 R8 yellow weakly strongly 10 ppm yellow yellow 38 F5 R9 weakly weakly strongly 10 ppm yellow yellow yellow 39 F5 R10 strongly weakly strongly 10 ppm orange orange yellow 40 F6 R1 strongly colorless strongly 10 ppm orange yellow 41 F6 R2 strongly colorless strongly 10 ppm orange yellow 42 F6 R3 strongly almost strongly 10 ppm orange colorless yellow 43 F6 R8 strongly almost strongly 10 ppm red colorless yellow 44 F6 R9 strongly weakly strongly 10 ppm red yellow yellow 45 F6 R10 strongly almost strongly 10 ppm red colorless yellow 46 F7 R1 strongly slightly strongly 5 ppm red yellow yellow 47 F7 R2 strongly almost strongly 5 ppm red colorless yellow 48 F7 R3 strongly almost strongly 5 ppm reddish colorless yellow violet 49 F7 R8 strongly almost strongly 5 ppm red colorless yellow 50 F7 R9 strongly weakly strongly 5 ppm red yellow yellow 51 F7 R10 strongly almost strongly 5 ppm red colorless yellow 52 F8 R1 strongly almost strongly 20 ppm orange colorless yellow 53 F8 R2 strongly almost strongly 20 ppm orange colorless yellow 54 F8 R3 strongly almost strongly 20 ppm orange colorless yellow 55 F8 R8 strongly weakly strongly 20 ppm orange yellow yellow 56 F8 R9 weakly weakly strongly 20 ppm yellow yellow yellow 57 F8 R10 strongly slightly strongly 20 ppm orange yellow yellow 58 F9 R1 orange weakly yellow 5 ppm yellow 59 F9 R2 strongly weakly strongly 5 ppm orange orange yellow 60 F9 R3 strongly almost strongly 5 ppm orange colorless yellow 61 F9 R4 strongly almost strongly 5 ppm red colorless yellow 62 F9 R5 strongly weakly strongly 5 ppm orange orange yellow 63 F9 R6 strongly weakly strongly 5 ppm orange orange yellow 64 F9 R7 strongly weakly strongly 5 ppm orange orange yellow 65 F9 R8 orange weakly strongly 5 ppm orange yellow 66 F9 R9 strongly weakly strongly 10 ppm bright yellow yellow red 67 F9 R10 strongly weakly strongly 10 ppm red yellow yellow 68 F10 R1 strongly almost strongly 5 ppm violet colorless yellow 69 F10 R2 strongly almost strongly 5 ppm violet colorless yellow 70 F10 R3 strongly almost strongly 5 ppm dark blue colorless yellow 71 F10 R4 strongly weakly strongly 5 ppm green green yellow 72 F10 R5 strongly weakly strongly 5 ppm violet red yellow 73 F10 R6 strongly almost strongly 5 ppm violet colorless yellow 74 F10 R7 strongly almost strongly 5 ppm bluish colorless yellow gray 75 F10 R8 strongly almost strongly 5 ppm reddish colorless yellow violet 76 F10 R9 strongly weakly strongly 5 ppm red yellow yellow 77 F10 R10 strongly almost strongly 5 ppm violet colorless yellow 78 F11 R1 strongly almost strongly 5 ppm violet colorless yellow 79 F11 R2 strongly weakly strongly 5 ppm yellowish yellow yellow orange 80 F11 R3 strongly almost strongly 5 ppm violet colorless yellow 81 F11 R4 strongly weakly strongly 5 ppm orange yellow yellow 82 F11 R5 strongly weakly strongly 5 ppm orange yellow yellow 83 F11 R6 strongly weakly strongly 5 ppm orange yellow yellow 84 F11 R7 strongly weakly strongly 5 ppm orange yellow yellow 85 F11 R8 strongly weakly strongly 5 ppm orange yellow yellow 86 F11 R9 strongly weakly strongly 5 ppm red yellow yellow 87 F11 R10 strongly weakly strongly 5 ppm dark red yellow yellow 88 F12 R1 strongly almost strongly 5 ppm reddish colorless yellow violet 89 F12 R2 strongly almost strongly 5 ppm violet colorless yellow 90 F12 R3 strongly almost strongly 5 ppm violet colorless yellow 91 F12 R4 strongly almost strongly 5 ppm green colorless yellow 92 F12 R5 strongly almost strongly 5 ppm reddish colorless yellow violet 93 F12 R6 strongly almost strongly 5 ppm dark blue colorless yellow 94 F12 R7 strongly almost strongly 5 ppm reddish colorless yellow violet 95 F12 R8 strongly almost strongly 5 ppm bright colorless yellow blue 96 F12 R9 strongly weakly strongly 5 ppm bright yellow yellow blue 97 F12 R10 strongly weakly strongly 5 ppm violet yellow yellow 98 F13 R1 strongly weakly strongly 5 ppm yellowish yellow orange brown 99 F13 R2 strongly weakly strongly 5 ppm reddish yellow orange brown100 F13 R3 strongly weakly strongly 5 ppm reddish yellow orange violet101 F13 R4 strongly weakly strongly 5 ppm yellow yellow orange102 F13 R5 strongly weakly strongly 5 ppm red yellow orange103 F13 R6 strongly weakly strongly 5 ppm yellowish yellow orange green104 F13 R7 yellowish weakly strongly 5 ppm brown yellow orange105 F13 R8 greenish weakly strongly 5 ppm gray yellow orange106 F13 R9 colorless weakly strongly 5 ppm yellowish orange orange107 F13 R10 strongly weakly strongly 5 ppm reddish yellow orange brown108 F14 R1 strongly weakly strongly 5 ppm orange yellow yellow109 F14 R2 strongly weakly strongly 5 ppm orange yellow yellow110 F14 R3 strongly weakly strongly 5 ppm orange yellow yellow111 F14 R4 strongly weakly strongly 5 ppm yellow yellow yellow112 F14 R5 strongly weakly strongly 5 ppm orange yellow yellow113 F14 R6 strongly weakly strongly 5 ppm orange yellow yellow114 F14 R7 strongly weakly strongly 5 ppm orange yellow yellow115 F14 R8 strongly weakly strongly 5 ppm orange yellow yellow116 F14 R9 strongly weakly strongly 5 ppm orange yellow yellow117 F14 R10 strongly weakly strongly 5 ppm orange yellow yellow______________________________________

EXAMPLE 118 (Preparation of F7)

a) 42.6 g (0.04 mol) of m-aminoazotoluene hydrochloride (24.5% strength by weight) and 0.2 g of a wetting agent were suspended in 32 ml of water and 12 ml of 30% strength by weight hydrochloric acid. The suspension was then admixed with 20 g of ice, 7 ml of toluene and 12 ml of 23% strength by weight aqueous sodium nitrite solution and stirred at from 5 to 10.degree. C. for 2 h.

b) 3..76 g (0.04 mol) of phenol and 100 ml of water were adjusted with 50% strength by weight sodium hydroxide solution to pH 6.4 and admixed at 0.degree. C. with the diazonium salt solution described under a). The pH was held between 4 and 5 with 10% strength by weight sodium hydroxide solution. After stirring overnight the pH was reduced to 1.5 with 10% strength by weight hydrochloric acid and the precipitated solid was isolated.

Yield: 10.1 g

EXAMPLE 119 (Preparation of F9)

a) 3.0 g (0.02 mol) of methyl anthranilate were dissolved at 0.degree. C. in 30 ml of water, 50 g of ice and 5 ml of concentrated hydrochloric acid and then admixed with 6 ml of 23% strength by weight aqueous sodium nitrite solution. The mixture was then stirred at from 0.degree. to 5.degree. C. for 30 minutes until a clear solution had formed.

b) 2.7 g (0.02 mol) of 2,3,6-trimethylphenol in 100 ml of water were adjusted with 50% strength by weight sodium hydroxide solution to pH 13 and admixed with the diazonium salt solution described under a). After stirring overnight the pH was reduced to 2.1 with 10% strength by weight hydrochloric acid and the precipitated solid was isolated.

Yield: 5.8 g

EXAMPLE 120 (Preparation of F12)

a) 7.19 g (0.05 mol) of p-nitroaniline and 0.1 g of a wetting agent were suspended in 45 ml of water and 17.5 ml of 30% strength by weight hydrochloric acid. The suspension was then admixed with 55 g of ice and 16.5 ml of 23% strength by weight aqueous sodium nitrite solution and stirred at from 0.degree. to 5.degree. C. for 1 h.

b) 7.56 g (0.05 mol) of 2-monoethylamino-4-methylphenol were added to 100 ml of water and adjusted with 50% strength by weight sodium hydroxide solution to pH 10. Then the diazonium salt solution described under a) was added at 5.degree. C. The pH was held between 7 and 8 with 10% strength by weight sodium hydroxide solution. After stirring overnight the pH dropped to 4.6 and the precipitated solid was filtered off with suction.

Yield: 14.1 g

EXAMPLE 121 (Preparation of F13)

a) 53.3 g (0.05 mol) of m-aminoazotoluene hydrochloride (24.5% strength by weight) and 0.2 g of a wetting agent were suspended in 40 ml of water and 15 ml of 30% strength by weight hydrochloric acid. The suspension was then admixed with 25 g of ice, 8.4 ml of toluene and 15 ml of 23% strength by weight aqueous sodium nitrite solution and stirred at from 5 to 10.degree. C. for 2 h.

b) 7.56 g (0.05 mol) of 2-monoethylamino-4-methylphenol were added to 100 ml of water and pH 10 was set with 50% strength by weight sodium hydroxide solution. Then the diazonium salt solution described under a) was added at 5.degree. C. The pH was held between 7 and 8 with 10% strength by weight sodium hydroxide solution. After stirring overnight the pH was adjusted with hydrochloric acid to 1.5 and the precipitated solid was filtered off with suction.

Yield: 15.9 g

EXAMPLE 122 (Preparation of F14)

a) 42.6 g (0.04 mol) of m-aminoazotoluene hydrochloride (24.5% strength by weight) and 0.2 g of a wetting agent were suspended in 32 ml of water and 12 ml of 30% strength by weight hydrochloric acid. The suspension was then admixed with 20 g of ice, 7 ml of toluene and 12 ml of 23% strength by weight aqueous sodium nitrite solution and stirred at from 5 to 10.degree. C. for 2 h.

b) 6.7 g (0.04 mol) of m-N,N-diethylaminophenol were added to 100 ml of water and pH 13.2 was set with 50% strength by weight sodium hydroxide solution. Then the diazonium salt solution described under a) was added at 5.degree. C. The pH was held between 4 and 5 with 10% strength by weight sodium hydroxide solution. After stirring overnight the pH was reduced to 1.5 with 10% strength by weight hydrochloric acid and the precipitated solid was isolated.

Yield: 16 g

The same method gives the dyes F10 and F11.

Claims

1. A method for detecting azo dye marked mineral oils by treating the marked mineral oil with an extractant comprising water, a solvent and a base, the azo dye transferring from the mineral oil into the aqueous phase, which comprises using as marker an azo dye of the formula I ##STR12## where ring A may be benzofused,

m is from 1 to 4,

X.sup.1 is hydrogen, C.sub.1 -C.sub.4 -alkyl, cyano or nitro,

X.sup.2 is hydrogen, C.sub.1 -C.sub.4 -alkyl, cyano, nitro, C.sub.1 -C.sub.4 -alkoxy or C.sub.1 -C.sub.16 -alkoxycarbonyl,

X.sup.3 is hydrogen, C.sub.1 -C.sub.4 -alkyl, cyano or C.sub.1 -C.sub.16 -alkoxycarbonyl, and

X.sup.4 is hydrogen, hydroxyl, C.sub.1 -C.sub.8 -alkyl, which may be phenyl-substituted, C.sub.1 -C.sub.4 -alkoxy, amino, C.sub.1 -C.sub.4 -dialkylamino or C.sub.1 -C.sub.16 -monoalkylamino whose alkyl chain may be interrupted by from 1 to 3 oxygen atoms in the ether function,

as solvent a partially or completely water-miscible organic solvent, and as base an alkali or alkaline earth metal hydroxide, an alkali metal carbonate or an ammonium compound of the formula ##STR13## where R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each independently of the others C.sub.1 -C.sub.16 -alkyl or benzyl.

2. A method as claimed in claim 1, wherein the azo dye used has the formula Ia ##STR14## where m is from 1 to 4,

X.sup.1 is hydrogen, cyano or nitro,

X.sup.2 is hydrogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy or C.sub.1 -C.sub.13 -alkoxycarbonyl,

X.sup.3 is hydrogen or C.sub.1 -C.sub.4 -alkyl, and

X.sup.4 is hydrogen or C.sub.1 -C.sub.8 -alkyl, which may be phenyl-substituted.

3. A method as claimed in claim 1, wherein the azo dye used has the formula Ib ##STR15## where X.sup.1 is hydrogen,

X.sup.2 is hydrogen,

X.sup.3 is hydrogen or C.sub.1 -C.sub.4 -alkyl,

X.sup.4 is hydrogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -dialkylamino or C.sub.1 -C.sub.16 -monoalkylamino,

X.sup.5 is hydrogen or C.sub.1 -C.sub.4 -alkyl, and

X.sup.6 is hydrogen, C.sub.1 -C.sub.4 -alkyl or C.sub.1 -C.sub.4 -alkoxy,

with the proviso that a) at least one of the three radicals X.sup.1, X.sup.2 and X.sup.3 is different from hydrogen, b) X.sup.2 may also be cyano when X.sup.4 is C.sub.1 -C.sub.4 -dialkylamino, c) X.sup.2 may also be C.sub.1 -C.sub.4 -alkoxycarbonyl when all the radicals X.sup.4, X.sup.5 and X.sup.6 are different from hydrogen, and d) one of the radicals X.sup.1, X.sup.2 or X.sup.3 may also be nitro when X.sup.4 is C.sub.1 -C.sub.16 -monoalkylamino and X.sup.6 is C.sub.1 -C.sub.4 -alkyl.

4. A method as claimed in claim 1, wherein the base used is an alkali or alkaline earth metal hydroxide.

5. A method of marking a mineral oil, comprising adding to said mineral oil an effective amount therefor consisting of an azo dye of the formula Ia ##STR16## where m is from 1 to 4,

X.sup.1 is hydrogen, cyano or nitro,

X.sup.2 is hydrogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy or C.sub.1 -C.sub.13 -alkoxycarbonyl,

X.sup.3 is hydrogen or C.sub.1 -C.sub.4 -alkyl, and

X.sup.4 is hydrogen or C.sub.1 -C.sub.4 -alkyl, which may be phenyl-substituted.

6. A method as claimed in claim 5 where X.sup.4 is hydrogen or 1-phenylethyl.

7. A method as claimed in claim 5 where X.sup.1 is hydrogen, X.sup.2 is methyl or C.sub.1 -C.sub.13 -alkoxycarbonyl, and X.sup.3 is hydrogen or methyl.

8. A method as claimed in claim 5 of azo dyes conforming to the formula Ic ##STR17## where Y is C.sub.7 -C.sub.11 -alkyl.

9. A method of marking a mineral oil, comprising adding to said mineral oil an effective amount therefor of an azo dye of the formula Ib ##STR18## where X.sup.1 is hydrogen,

X.sup.2 is hydrogen,

X.sup.3 is hydrogen or C.sub.1 -C.sub.4 -alkyl,

X.sup.4 is hydrogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -dialkylamino or C.sub.1 -C.sub.16 -monoalkylamino,

X.sup.5 is hydrogen or C.sub.1 -C.sub.4 -alkyl, and

X.sup.6 is hydrogen, C.sub.1 -C.sub.4 -alkyl or C.sub.1 -C.sub.4 -alkoxy,

with the proviso that a) at least one of the three radicals X.sup.1, X.sup.2 and X.sup.3 is different from hydrogen, b) X.sup.2 may also be cyano when X.sup.4 is C.sub.1 -C.sub.4 -dialkylamino, c) X.sup.2 may also be C.sub.1 -C.sub.4 -alkoxycarbonyl when all the radicals X.sup.4, X.sup.5 and X.sup.6 are different from hydrogen, and d) one of the radicals X.sup.1, X.sup.2 or X.sup.3 may also be nitro when X.sup.4 is C.sub.1 -C.sub.16 -monoalkylamino and X.sup.6 is C.sub.1 -C.sub.4 -alkyl.

10. Azo dyes of the formula II ##STR19## where Y.sup.1 is hydrogen, or C.sub.1 -C.sub.4 -alkyl-substituted phenylazo,

Y.sup.2 is hydrogen,

Y.sup.3 is hydrogen or C.sub.1 -C.sub.4 -alkyl,

X.sup.4 is hydrogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -dialkylamino or C.sub.11 -C.sub.16 -monoalkylamino,

X.sup.5 is hydrogen or C.sub.1 -C.sub.4 -alkyl, and

X.sup.6 is hydrogen, C.sup.1 -C.sub.4 -alkyl or C.sub.1 -C.sub.4 -alkoxy,

with the proviso that a) at least one of the three radicals Y.sup.1, Y.sup.2 and Y.sup.3 is different from hydrogen, b) Y.sup.2 may also be cyano when X.sup.4 is C.sub.1 -C.sub.4 -dialkylamino, c) Y.sup.2 may also be C.sub.1 -C.sub.4 -alkoxycarbonyl when all the radicals X.sup.4, X.sup.5 and X.sup.6 are different from hydrogen, and d) one of the radicals Y.sup.1, Y.sup.2 or Y.sup.3 may also be nitro when X.sup.4 is C.sub.1 -C.sub.16 -monoalkylamino and X.sup.6 is C.sub.1 -C.sub.4 -alkyl.