US906307A - Manufacture of indigo-white preparations suitable for fermentation-vats. - Google Patents

Description

UNITED sTAT s PATENT OFFICE.

ALBRECHT SCHMIDT, OF HOOHST-ON-THE-MAIN, GERMANY, ASSIGNOR TO FARBWERKE VORM. MEISTER LUCIUS & BRUNING, OF HOCHST-ON-THE-MAIN, GERMANY, A COR- PORATION OF GERMANY.

MANUFACTURE OF INDIGO-WHITE PREPARATIONS SUITABLE FOR FEBMEN'IATION- VATS.

Specification of Letters Patent.

Application filed March 22, 1905. Serial No. 261,447.

Patented Dec. 8, 1908.

To all whom it may concern:

Be it known that I, ALBRECHT SCHMIDT, Ph. D., chemist, a citizen of the Empire of German and residing at Htichst-on-the- Main, Germany, have invented certain new and useful Improvements in the Manufacture of Indigo-White Preparations Suitable for Vats, Especially Fermentation-vats, of which the following is a specification.

A considerable part of indi .0 is used for the fermentation-vat, es ecially in Eastern countries. The chemica vats require the indigo to be in a fine state of sub-division and capable of being readily made into a paste, a condition all the more essential for the fermentation-vat. The reason why synthetic indigo has hitherto not been able to supplant natural indigo is that the latter is readily soluble in the fermentation-vat, yielding excellent vats, whereas the conversion of synthetic indigo into a soluble vat meets with greater difiiculties. This disadvantage of the synthetic indigo is" due to the physical condition of the products in question, which may be explained by the various methods of their preparation. Natural indigo is isolated at its place of production as a fine amorphous powder from the lucosid of strongly diluted indigo-white. ts partioles are so fine as to resist only slightly the reducing action of agents in the vat and thus are readily dissolved.

Synthetic indigo is obtained from comparatively very concentrated solutions of indoxyl by oxidation and condensation; under these circumstances synthetic indigo is produced in crystalline form. As a consequence of its physical structure, the synthetic indigo greatly resists the gentle reducing agents of the vat, so that the artificial product dissolves only insufiiciently in the difierent fermentation-vats. From a commercial point an essential difference has to be made between natural and synthetic indigo. As

soon as this difference was recognized by the producers, efiorts were made to bring the synthetic indigo into such a form as to permit its being used in the fermentation-vat.

It has been tried to obtain synthetic indigo in a finely divided state by grinding indigo powder in the disintegrator, without, however, attaining the desired state of fine subdivision of natural indigo. The pastes prepared by the consumer in grinding indigo powder in a moist condition did not come near to the reducibility of natural indi o. Nor was the object attained by means of t e known process of treating indigo with sulfuric acid. Further experiments were made to treat indigo cakes similar to alizarin cakes, with starch, dextrin etc. These indigo-lumps, however, could not supersede the natural indigo in the fermentation-vats. Another method to obtain a suitable product was to mix indigo pastes with ferments and alkalies, yet with no better result. None of these methods succeeded in giving to the synthetic indigo such a form as to permit a competition with the natural indigo.

The best preparation hitherto obtained is that in form of a paste of 20%. It has supplanted natural indigo in all chemical vats,

but for the fermentation-vat, especiallyin the East, it is not that what is wanted. Apart from the little reducibility, the pasty form is rather inconvenient for transport and little suitable for the small. consumer of the East, for, as soon as the packages are opened the paste soon becomes dry and very difficult to reduce afterwards. Applicant has tried another way to overcome these difiiculties and.

succeeded in obtaining a highly concentrated indigo-preparation more suited for the fermentation-vat than natural indigo. This process consists in mixing indigo-white with molasses, syrup and similar bodies. The difiiculties to overcome were to obtain a vat preparation having the following characteristics:

1. The vat or indigo-white composition had to be highly concentrated for reasons of transport and at the same time capable of being made into a paste.

2. Stability towards the oxidizing action of the air, ermitting even the use of not quite air-tig t barrels.

3. The-composition should not be infiu enced by the warm atmosphere of the East,

' even after the barrel or like packing has been opened, that is to say, the preparation must .at any time be capable'of being made into a paste containing t e indigo in form of indigowhite ca able of reaction.

It is 0 car that from the outset there was little ho e to find such a preparation answering all t ese requirements. In fact, the first use for a long time, even before synthetic -ingt indigo, possess slightlyantiseptic'pro erties' indigo was known, but a concentrated indigowhite preparation has never been known on the market. Other attempts were madev to give to indigo-whitea concentrated, stable form, by producing formaldehyde-indigowhite, carbonic acid ester-indigo-white, acetic acid ester-indigo-white etc., yet all these methods were by far too expensive and useless for the fermentation-vat, as these compounds had first to undergo an isolating process. I

Now, while preparing a fermentatican-vat with indigo-white instead of indigo, in pres-- ence of molasses as organic nutrient, indigowhite press cakes stirred with water were mixed and this mixture was added to the fermentation-vat. It was observed that the dried-up parts, instead of becoming blue by the oxidation of the air, were left intact. The addition of molasses evidently had a peculiarly preserving influenceon the indigo white, as was proved afterwards by further experiments. An experiment based on this observation for obtaining a commercial product by mixing molasses and indigo-white met with no successin another direction, for it is shown, that mixtures of indigo with organic bodies, such as starch, dextrin etc. soon become moldy. Compare British patent No. 3108 04;,lines 6-13. The addition of alkali'hydrateor lime as given in this patent is only of momentary, advantage, as by allowe indigo-white roduct to stand,.the alkali disa pears an the mass begins to mold and erment. -By further tests it was found that b impregnating indigo-white sufliciently wit concentrated molasess, products maybe obtained which are not only stable towards the influence of the air, but

also towards mold and fermentation. .The' reasonfor this was found in the-fact that technical indigo-white, brominated indigowhite, tolyl-indigo white etc., contrary to and that molasses, especially when ighly concentrated, have a preservative action as a consequence of their-containing sugar and considerable proportions of salts. It is thus tam'pa'stes containing 30, 40, and more er cent. of indigps-white, which may be simply packed in'cas where they remain intact, even when parts of the conpossible to o indigo-white,

- molasses.

tents have been used. It is remarkable that these products may be readily made into pastes without becoming dry, which is due to the large roportion of hygroscopic salts and-liquefiab e substances contained therein. The contents of Water of the products may even be reduced so far as to obtain no longer pastes but solid bodies, such as lumps, powder etc. and yet these products are still capable of being made into pastes without losing their favorable propertles.

Stable indigo-white preparations may be obtained in difl'erentways, according to the I degree. of consistency of the product desired. For instance, indigo-white ress-cakes may be directly mixed with mo asses or syrup, part of the water being distilled ofi in a suitable apparatus, such as in a vacuum, until the desired product is obtained, either as a paste,

or in a semi-solid or solid form. Or the moist lpfiessed hydraulically, may be mixed in the eading machine with molasses, until a handy paste is obtained, oragain,

indigo-white ress cakes are washed out with molasses an the roduct thus obtained is stirred alone or with a further quantity of The proportions of indigo-white and molasses vary according to the product desired; though, in general, it is not of advantage to allow the quantity of water in the molasses to be too great, as in case of too strong a dilution, the roduct is more liable to become moldy. T e new products form concentrated, stable, indigo-white pre ara: tions which are soluble in dilute so al e with a yellow-green solution from whic when exposed to the air, blue flakes se 31- rate, partly soluble in water, the insolu le part being soluble in soda-lye, while the part soluble in water shows the known reaction of saccharides.

(containing about 75 per cent. of dry indigo) .obtained by means of zinc, bisulfite, h drosulfite. or electrolysis and hydraulically glossed at about 200 atmos heres in the eading machine, are stirre stance, 700 or about 400parts of thickly liquid molasses or any sugar syrup, cane sugar, invert sugar, maltose, glucose, maltose or other saccharine substance, further dehydrated if necessary. The pasty product may be used at once. Example II. The rocess isthe same as in ,Example I, only for t e hydraulically pressed indigo-white, indigo-white paste is used,-by mixing 280 kil. of press-cakes (=80 parts of indigo-white) with, for instance, 100, 80 or 50 parts of molassesor sugar syrup, cane sugar, invert sugar, ucose, or other saccharine substance, suc for instance, as milk sugar, preferably in presence of other sugars readily soluble in water, from which about 100-170 parts of water are distilled off in a vacuum, so that after evaporating, a pasty with, for in or if further distilled, a solid obtained.

The process described for digo-White from indigo may also be applied to other indigo-white derivatives (substitution products), such, for instance, as indigowhite from meth l-indigo, (tolyl-indigo), especially ortho-tolg l-indigo or as halogenproduct is finally indigo-whites, for instance, brominated', di-

brominated and chlorinated indigo.

Having now described my invention, what I claim is:

1. The process herein described of making concentrated, stable, indigo white preparations especially suitedfor fermentation-vats, which consists in incorporating indigo-whites with saccharine substances. 2. As new-products, concentrated, stable,

obtaining in-f which, when exposed to the air, blue flakes ,will-separate, artly soluble in water, Whereby the insolu 1e art is soluble in soda-lye, and the part so uble in water shows the known reaction of saccharide's.

In testimony that I claim the foregoing as my invention, I have signed my name .in

presence of two subscribing Witnesses.

; ALBRECHT SCHMIDT.

Witnesses JEAN GRUND,

CA L GRUND.