CS237942B1 - Process for preparing stilbene azo dyes - Google Patents

Abstract

A method for preparing stilbene azo dyes from 4,4'-dinitrostilbene-2,2'-disulfonic acid and aromatic amino compounds or amino azole compounds in the presence of reducing sugars, whereby a mixture containing monosaccharides and oligosaccharides with a total reducing sugar concentration of 30 to 800 g/l, expressed in glucose equivalent per 1 mol of 4,4'-dinitrostilbene-2,2'-disulfonic acid used, is dosed into the reaction mixture during or after condensation, with the reduction taking place in an aqueous alkaline environment at a pH above 9. It involves the use of a mixture of reducing sugars from food production as a reducing agent in the preparation of the aforementioned azo dyes.

Description

237342

BACKGROUND OF THE INVENTION The present invention relates to a process for the preparation of stilbium azo-dyes resulting from the condensation of 4,4'-dinitro-trostilbene-2,2'-disulfonic acid with aromatic amino or amino-azole compounds.

Stilbene azoibairviva is prepared by condensation of 4,4'-dinitroistilbene-2,2'-disulfonic acid usually with amino isolates or with aromatic aminates. They are yellow and orange to red colorant dyes, whose structure is not well known, since it is a more complex mixture of azo dyes. The condensation is carried out by means of an aqueous-alkaline medium, and moderately reducing agents are added during or after condensation, affecting both the structure and the hue of the dye. The addition of crystalline glucose was used as the reducing agent, and the use of inverted sucrose was described. The use of inverted saccharose in the chemical industry is limited by the fact that it is a food and the price of crystalline glucose is relatively high.

It has now been found that in the manufacture of stillab azo dyes, it is possible to use, with very good yield and economically advantageous, various reducing agents mixtures. These can be obtained either as waste from some foodstuffs or from chemical production, or they can be prepared for reduction purposes from natural materials containing polysaccharides.

According to the invention, the process for the preparation of stilbene azo-dye-condensations of .alpha.-dinitroistilb .beta.-diisulfonic acid and aromatic amino compounds or amino azoles in the presence of reducing sugars, in the course of condensation, optionally after condensation, feeds a mixture of monosaccharides and oligosaccharides with the total concentration of reducing sugars of 30 to 800 giram / l, expressed as glucose equivalent, per mole of 4,4'-dinitrostilbene-2,2'-disulfonic acid, with the reduction being carried out in an aqueous alkaline environment. the invention can be seen both in their ease of access and in the more economical process management. Among the chemical wastes that can be used, there may be mentioned distillation residues from the production of pentaerythritol, which contain a mixture of pentos and hexos and a reaction of harmless content of pentaerythritol and calcium formate, or waste from processing beech wood into viscose. Again, this waste contains a mixture of pentos and hexoses, and for reducing the amount of furfural, acetic acid, formic acid, and lignin. Similarly, thickened distillers can be used, which is the remainder of the production of fermented ethanol from molasses. Of the food production wastes, it is preferable to use as the reducing agent the particulate filtrates after glucose 4 crystallization produced by the acid hydrolysis of starch. Tytofiltrates contain glucose as the main constituent as well as other reducing monosaccharides such as levoglucosan, xylose and araibinosu, further reducing disaccharides such as maltose, isomaltose and celobiosis and minor amounts of oligosaccharides.

Similarly, molasses containing mainly glucose and sadharose can be used, and the reducing effect of molasses can be further enhanced by inverting the sucrose present. Other uses of the food industry include thickened, liquid isocipectin waste from fruit, which contains a mixture of inorganic sugar reducing agents and possibly other substances such as acid-citric acid. Similarly, thickened wastewater from yeast production can be used.

The mixture of reducing monosaccharides, disaccharides and other oligosaccharides may also be prepared by acidic or enzymatic hydrolysis of starch or starch-containing substances, such as, for example, various types of flour, whereby flour may not be suitable for food or feed purposes. Acid hydrolysis of isolated starch, or starch contained in flour, produces a mixture of monosaccharides, disaccharides and other oligosaccharides containing predominantly glucose, malitosis, isomaltose, minor amounts of xylose and arahinosis, and other substances such as glycosides formed under the reaction of monosaccharide reaction or dehydrogenation. and glucose breakdown products such as 5-hydroxymethylfurfural, levulinic acid and formic acid. These by-products are not a defect in re-ducting. When starch degraded to reducing sugars by enzymatic amylase, the resulting reducing sugar solution is more glucose-rich. In the case where acid hydrolyzate is used after the reduction, it is necessary to remove the insoluble protein from the suspension after hydrolysis.

The reducing ability of the reductive sugar mixture solutions is preferably expressed by the so-called glucose equivalent, which is determined in a conventional manner, for example by the Luff-Schoorleh method.

If the sugar reducing solutions are not sufficiently resistant to ethanolic fermentation, they can be preserved during storage, for example by the addition of potassium pyrosulphite, sodium sulphite, formic acid, or biocidal agents such as bisftributyltin oxide.

Of the stilbene azo dyes which can be used in the above-mentioned reducing sugar solutions, the condensation products of 4,4'-dinitroatilbene-2,2'-disulfonic acid with the following amine or amino isolates are the following: 4-aminoazoibenzene-4'-carboxylic acid4 -aminoazo-benzene-4'-sulphamic acid4-aminoazobeinzem-3'-sulphonic acid

Claims (1)

2 3 7 9 4 2 S 4-amino-2-methyl-laizobenizene-4'-sulfonic acid 4-amino-2-methyl-5-methoxyazobenzene-4'-sulfonic acid 4-amino-3-meitoxya 4-amino-2,5-dimethylazobenzene-4, -sulfonate acid 4-amino-2,5-dimethyl-4-amino-2,5-di-methylazobenzene-3'-sulfonic acid 4-amino-2,5-dimethylazobenzene 4-amino-2-methyl-4 ', 5-dimethoxyazobenzene-3'-sulfonic acid 4'-methoxyazo-3'-sulfonic acid 1- (4-sulfonylene) -4-aminonaphthaleniline 4-aminophenol dehydroithio -p-toluidine The condensation of these components occurs by heating them in water with an alkaline medium, with the solution of reducing sugars being added either during condensation, or more often after, usually from 0.3 to 1.0mol of glucose equivalent, calculated on 1mol of 4,4'-dinitroistilbene-2,2'-disulphonic acid, P, upon dissolution, the solubilizing salt of the dye is reduced by the addition of hydrochloride and, if necessary, neutralization of the acid suspension. The hydrochloric acid is isolated by filtration, and the stilen azo colorants of yellow, orange and red are particularly suitable for coloring cotton. The following examples illustrate the process according to the invention, said parts being parts by weight of solid and bulk substances in kappa. EXAMPLE 1 88 parts of 4-amino-2-methyl-4 ', 5-dimethoxyazo-benzene-3 ' -sulfonic acid are dissolved in the sodium salt in water, 97 parts of 4,4 ' 2'-disulfonic acid, 103 parts of sodium hydroxide 40%, and the mixture was heated at 100 ° C for 20 hours. After cooling to 90 ° C, 60 parts of the mother filtrates FRED M T are added. A process for the preparation of stilbea azo dyes by condensing 4,4'-dinitrostilbene-2,2'-diisulfonic acid and aromatic amino acids or aminoazoles in the presence of reducing sugars, characterized by that in the course of condensation, optionally after condensation, a dose B of glucose crystallization, with a reducing sugar content corresponding to 24 parts of glucose equivalent, is continued and the heating is continued for 30 minutes. After addition of sodium bicarbonate and sodium chloride and cooling, the dye is isolated and dried. 145 parts of a dye are obtained which stains the wool in a scarlet shade. EXAMPLE 2 103 parts of 4,4'-dinitrostilbene-2,2'-disulfoic acid are dissolved in water to disodium salt by the addition of sodium hydroxide. To the solution was added 58 parts of 4-aminobenzein-4'-carboxylic acid, 114 parts of sodium hydroxide 40% and a solution of reducing sugars obtained by concentrating the pectin waste with a sugar content of 39 parts of glucose equivalent. The mixture was then heated at 100 to 102 ° C for 5 h. After completion of the reaction, dilute with water and at 90 ° C with sodium chloride dye. After bleaching the alkali with the addition of hydrochloric acid at pH 7-8, the dye is isolated by filtration and the filter cake is dried. 270 parts of orange-colored azo dye are obtained. EXAMPLE 3 75 parts of water and 1.4 parts of hydrochloric acid (38%) are heated to a gentle boil and 48 parts of flour are added over 1 hour. The slurry is then heated to a gentle boiling for a further 8 hours. After the addition of a filter additive, such as wood flour, the insoluble proteins are filtered off and a filtrate containing 24 parts of glucose equivalent is obtained. 4'-dinitro-2,2'-di-sulfonic acid with 36 parts of 4-amino-2-methyl-azobenzene-4,4'-dinitro-2,2'-disuiphonic acid in an alkaline medium. To reduce the azo dye mixture, it is heated to 60-65 ° C for 1 hour, whereupon the dye is isolated by filtration. BACKGROUND OF THE INVENTION Into the reaction mixture, a mixture of monosacbarides and oligosaccharides with a total concentration of reducing sugars of 30 to 800 g / l, expressed as glucose equivalent, per mole of 4, 4'-dmltrostillbene-2,2'-disulfonate, is used; over 9.