Fluid Formulations of Oxidation Dyes for Mineral Oil Products, Fats and Waxes

The present invention relates to fluid formulations of dyes which are obtained by oxidizing a compound of the general formula I ##STR3## where R.sup.1 is unsubstituted or hydroxy-, C.sub.1 -C.sub.8 -alkoxy- or C.sub.1 -C.sub.8 -alkanoyloxy-substituted C.sub.2 -C.sub.13 -alkyl,

R.sup.2 is hydrogen or unsubstituted or hydroxy- or C.sub.1 -C.sub.8 -alkoxy-substituted C.sub.1 -C.sub.13 -alkyl and

X is hydroxyl, amino or ##STR4## in an organic solvent.

Particularly suitable organic solvents to use in preparing the fluid formulations are alcohols, hydrocarbons, halohydrocarbons, amides, ketones and nitriles. Specific examples are methanol, ethanol, propanol, isopropanol, butanol, isobutanol, methoxypropanol, acetonitrile, methyl n-propyl ketone, dipropyl ketone, toluene, xylenes, alkylbenzene mixtures (for example the solvents available under the trademark .RTM.Shellsol), chlorobenzene, dimethylformamide, N-methylpyrrolidone and paraffin oil, and, preferably, .beta.-ethylhexanol.

Preferred oxidizing agents are oxygen and especially air, and they are advantageously employed in the presence of a catalyst, for example one of the compounds described in German Laid-Open Applications DOS 2,333,925 and DOS 2,427,606.

Specific examples of radicals R.sup.1 are: ##STR5## and CH.sub.2 CH.sub.2 OCOC.sub.7 H.sub.15. The above formulae include both the normal and the iso-compounds.

Examples of R.sup.2 are the same radicals as above, as well as methyl. Compounds in which R.sup.1 and R.sup.2 together contain not less than 6 carbon atoms are preferred. Further preferred compounds are those in which one of the radicals R.sup.1 and R.sup.2 is hydrogen, and compounds in which X is hydroxyl or amino.

The novel fluid formulations are advantageously prepared by dissolving a compound of the formula I in an organic solvent, preferably an alcohol, adding the catalyst and then passing air through the mixture until starting material is no longer detectable by thin layer chromatography. Reaction temperatures of about 20.degree.-100.degree. C., preferably 40.degree.-60.degree. C., are advantageous. The reaction time is as a rule from 4 to 20 hours. After the oxidation, the solvent can be distilled off, preferably under reduced pressure, and be replaced by whatever solvent is most suitable for the envisaged end use. It is of course also possible to use this solvent from the start, ie. also in the oxidation reaction, if it has proved suitable in preliminary experiments.

The use of a low-boiling solvent can be advantageous, since any desired concentration can easily be obtained by distilling off solvent.

The oxidation reactions can as a rule be carried out in highly concentrated solutions, for example of from 20 to 80% strength; in some cases it even proves possible to manage without any solvent.

The fluid formulations according to the invention are suitable for dyeing mineral oil products, fats and especially waxes, for example shoe polish. Essentially, the hues obtainable are shades of brown.

Fluid formulations obtainable from starting compounds of the formula ##STR6## are of particular importance. In this formula, R.sup.1 is preferably

In the Examples which follow, parts and percentages are by weight, unless stated otherwise.

1 part of the Fe complex of dihydrodibenzotetraaza[14]-annulene is added to a solution of 22.0 parts of N-(2-ethylhexyl)-o-phenylenediamine in 100 parts of isopropanol, the reaction mixture is heated to about 50.degree. C. and a slight stream of air is passed through it, with vigorous stirring. After about 5 hours, starting material is no longer detectable by thin layer chromatography. The catalyst is then removed by filtration or decanting, and the solvent is distilled off, preferably under reduced pressure. The residue is very easily soluble in hydrocarbons and is therefore, in the form of an about 70% strength solution in toluene, exceptionally suitable for dyeing shoe polish.

The phenylenediamine derivatives mentioned in the Table below can be converted to oxidation products, having similar properties, by a method similar to that of Example 1.

29.1 parts of 3-tridecylamino-phenol are dissolved in 100 parts of isobutanol and oxidized by a method similar to Example 1. After distilling off the solvent, a solid product is obtained, which, in the form of an about 60% strength solution in Shellsol AB (aromatic mixture, boiling point 180.degree.-210.degree. C., dyes waxes and shoe polish, which give very glossy dark brown hues on leather.

The phenylenediamine derivatives and aminophenol derivatives mentioned in the Table below can be converted to oxidation products, having similar properties, by a method similar to that of Example 9.

10 parts of the dye of Example 1 and 75 parts of mineral spirit are stirred, at about 80.degree. C., into 25 parts of a wax mixture containing 8% of OP-Wachs from BASF, 2% of AL 61-Wachs from BASF, 1% of ozokerite, 13% of paraffin wax, 52.degree./54.degree. C. and 76% of mineral spirit. After cooling, a dark brown, very glossy shoe polish is obtained.