US736403A - Indigo-blue sulfur dye and process of making same. - Google Patents

Description

Patented August 18, 1903.

A l OSKAR KALTWASSER AND MAX GAUMER, OF BERLIN, GERMANY, AS-

' 'SIGNORSH on BERLfN, GERMANY.

O ACTIEN GESELLSCHAFT FUR ANILIN FABRIKATION,

INDIGO-BLUE SULFUR DYE AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent N 0. 736,403, dated August 18, 1903. Application filed May 21. 1903. Serial No. 158,104. (No specimens.)

T aZZ whom, it may concern.-

Be it known that we, OSKAR KALTWASSER and MAX GAUMER, of Berlin, in the Kingdom of Prussia, German Empire, have invented new and useful Improvements in the Prod uction of Indigo-Blue Sulfur Dye; and we do hereby declare that 'the following is a full,

. a 'clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same.

It is known that by heating compounds of the indophenol series with sulfur and alkali sulfid coloringmatters of various shades dyeing unmordanted cotton direct may be obtained. (Compare German Patent No. 132,212.) The process indicated in the aforementioned patent consists in heating an indophenol with sulfur and alkali sulfid at first for several hours to about 140 and then raising the temperature for a short time to 160. According. to the directions given in the examples of this patent the sulfur and alkali sulfid are employed in the proportions of one part ofsulfur'to four parts of crystallized sodium sulfid.

Now we have observed that when subjecting the typical indophenol i to the action of sulfur and alkali sulfid in the aforementioned way, prescribed by the German Patent No. 132,212, a product is obtained which has but a very slight affinity for the fiber and dyes unmordanted cotton weak bluish shades which are neither fast tosoaping nor washing. According to our observations this unsatisfactory result is due to the following facts-namely, the high temperature employed, and, moreover, the relative proportions of sulfur and sulfid prescribed in the German Patent No. 132,212 by the inventor. Especially the latter point is of great importance and is in'our opinion the reason why sulfureted dyestuifs of technical interest have up to the present not been obtained from the aforementioned indophenol or its nearest homologues. We have discovered that for the preparation of a valuable dyestuff. from these indophenols it is absolutely necessary to perform the process with such quantities of sulfur and sulfid of sodium that upon one molecule of sodium sulfid at least four atoms of sulfur are employed. If the quantity of sulfur is reduced toa proportion corresponding to three or two atoms, products of no technical interest are formed-as, forinstance, according to the directions of the German Patent No. 132,212, which prescribes even less than two atoms of sulfur.

When boiling the above-mentioned indophenols in an aqueous solution with such quantities of sulfur and sodium sulfid as according to our aforestated observations are essential, a coloring-matter of high technical value is obtained which renders it possible to obtain fast indigo-like shades on cotton.

The manufacture of our dyestuif is illustrated by the following example: Thirty kilos of the sodium salt of the indophenol OHO H N =O H =O are slowly added at about 80 centigrade to one hundred and eighty liters of an aqueous solution containing one hundred and twenty kilos of crystallized sodium sulfid and sixty-six kilos of sulfur. The solution obtained is heated up to boiling in a vessel combined with a reflux condenser and is kept at the boiling temperature for about twenty-four hours. The mass is'diluted with water and from the solution obtained the dye stuff is precipitated by the introduction of a current of air. It is then filtered, pressed, and dried. The product thus obtained is a brown-black powder which is insoluble in water. It dissolves in caustic alkalies with a dull bluish, in alkali sulfide with blue, color. In warm concentrated sulfuric acid the dyestuif dissolves with a violet color.

duces on cotton direct dull greenish-blue tints, which by the action of oxidizing agents are transformed into indigo-blue shades of remarkable fastness.

The following alterations may be made in the above example without materially changing the character of the product obtained.

It pro- Instead of the typical indophenol its homologues may be employed, which result, for instance, from the conjoint oxidation of paraamidophenol and orthocresol or metacresol or in a similar manner from para-amido-orthocresol or para-amidometa-cresol or orthochlor-para-amido-phenol and phenol, oriho or meta cresol.

Having now described our invention and in what manner the same is to be performed,

What we claim as new is-- 1. The process for the production of an indigo-blue sulfur dye by heating the indophein a boiling aqueous solution with sulfur and sulfid ofalkali in such proportions that upon one molecule of crystallized sodium sulfid at least four atoms of sulfur are employed. I

2. The indigo-blue sulfur dye obtained as hereinbefore described, said dye beinginsoluble in water, dissolving in causticalkalies with a dull greenish-blue color, in alkali sulfids with blue color and in warm concentrated sulfuric acid with violet color, producing on'