JPS61278567A - Production of vat dye - Google Patents

Abstract

PURPOSE:To obtain an anthraquinone vat dye which has excellent fastness and a blue tint without using any harmful material such as MnO2, by chlorinating dianthraquinone-N,N'-dihydroazine in the absence of a catalyst in conc. sulfuric acid. CONSTITUTION:An alkaline condensation agent is added to 1-aminoanthraquinone in the presence of dimethyl sulfoxide or 1,3-dimethyl-2-imidazolidinone and an oxidizing agent to effect a condensation reaction, thus obtaining dianthraquinone-N,N'-dihydroazine (A) of formula I. 1pt.wt. component A is dissovled in 90-95% sulfuric acid in a quantity of 3-20 times by weight that of component A. Chlorine is made to bubble through the soln. to chlorinate component A. Water is added thereto to adjust the concn. of sulfuric acid to 83%. The soln. is filtered at room temp. The resulting filter cake is dissolved in 98% sulfuric acid and reduced with aluminum powder to obtain a vat dye of formula II (wherein n is 1-2).

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing anthraquinone vat dyes. More specifically, the present invention relates to a process for producing a vat dye represented by the general formula ([I) (where n is an integer of 1 or 2).

This vat dye is useful as a dye for cellulose fibers that exhibits a blue hue with excellent color fastness.

(Prior art and its problems) The vat dye represented by the above general formula is C, I vat blue 6, or C, I vat dye described in the color index.
It is an important dye known from ancient times as Bat Blue 14. Various methods are known for producing these dyes, including a method in which the bromine atom of dianthraquinone-Nl'-dihydroazine (or indanthrone) is replaced with a chlorine atom, -2-
Although there are methods such as condensation of chlorinated aminoanthraquinones such as aminoanthraquinone, the method widely used industrially is the method of chlorinating indanthrone.

For example, chlorination in an inert organic solvent such as indanthrone nitrobenzene (e.g. US Pat. No. 22,054)
18), or a method in which a small amount of manganese dioxide is added in sulfuric acid and then chlorine is applied to chlorinate it (for example, Yutaka Hosoda, Theoretical Manufacturing Dye Chemistry, p. 6s9).

The latter method is usually used. However, in this method, manganese dioxide must be handled in a well-controlled working environment.

An object of the present invention is to provide a method for producing a vat dye represented by the above-mentioned general formula, which is advantageous in terms of operation. In order to solve this problem, we conducted various studies and found that, unexpectedly, even in a reaction system in which there is no catalyst such as manganese dioxide, which was conventionally considered indispensable, the above formula (I
) and completed the present invention.

That is, the present invention is characterized in that dianthraquinone-N,N'-dihydroazine represented by formula α) is chlorinated in concentrated sulfuric acid without any catalyst. or an integer of 2).

In the method of the present invention, the formula CI+ used as a raw material
Dianthraquinone-N,N'-dihydroazine represented by is obtained by subjecting 1 or 2-aminoanthraquinone to a condensation reaction by the action of an alkaline condensing agent, diluting with water or an organic solvent, and then performing a separation operation such as filtration. It can be used in wet or dry form.

Dianthraquinone-N,N'-dihydroazine obtained by combining 1-aminoanthraquinone with dimethyl sulfoxide or 1,3-dimethyl-2-imidazolidinone and an oxidizing agent by the action of an alkaline condensing agent. has good yield and quality and is most suitable for the method of the present invention.

In the method of the present invention, this raw material compound is first dissolved in concentrated sulfuric acid. This dissolution treatment is carried out using the amount of dianthraquinone-N,N'-dihydroazine dissolved in sulfuric acid having a concentration of about 90 to 95%. The amount is 3 to 2 parts by weight of dianthraquinone-N, Nl-dihydroazine.
0 times by weight, preferably 6 to 12 times by weight.

Next, chlorine is blown into the sulfuric acid solution in which this dianthraquinone-N,N'-dihydroazine is dissolved to carry out chlorination.

The temperature of chlorination is 50-55°C. The chlorine content of the chlorinated product is measured to determine when the reaction is complete.

After the chlorination is completed, water is added to the chlorination reaction solution to dilute the chlorination reaction mass to adjust the sulfuric acid concentration to about 83%, and then filtered at around room temperature, and the resulting mass is completely dissolved in 98% sulfuric acid. Then, the dye of general formula (5) can be obtained by reducing with aluminum powder or the like.

(Operations and Effects) According to the method of the present invention, since hazardous substances such as manganese dioxide, which have problems in handling, are not used, there is no need for equipment such as local exhaust equipment, and work can be done in a safe environment. .

(Example) The present invention will be explained below with reference to Examples.

Example 1 Dianthraquinone-N,N-dihydroazine 100Il
was dissolved in 950 g of 98 sulfuric acid, and then 67,3 Ji of water was dissolved.
' was added dropwise in about 1 hour at 53℃ or below, and the sulfuric acid concentration was
adjusted to %. Add 50 to 50% of chlorine 100II to this adjustment solution.
The solution was chlorinated at 5° C. for 20 hours. 55 to the reaction solution
Water was added dropwise at a temperature below 0.degree. C. to bring the sulfuric acid concentration to about 83.degree. C., and the mixture was kept at the same temperature for 1 hour, then cooled to 0.degree. C. and the precipitate was filtered.

Washed with 107 g of 83-thiosulfuric acid.

The furnace mass was dissolved in 98% sulfuric acid (700.9%) at 50°C, 3.2:i of aluminum paste was added thereto, and the mixture was stirred at the same temperature for 1 hour.

Next, drain into water, filter, wash, dry and vat dye (corresponds to 2C, I Vat Blue 6 in N of Shiki Niji) 96.8
．． ! i' was obtained. (Chlorine content 13.4%, yield 9
6.896/Dianthraquinone-N,N'-dihydroazine) This was used to dye cotton according to a conventional vat dyeing method to obtain a bright blue cloth.

Claims (1)

[Claims] 1) Chlorinating dianthraquinone-N,N'-dihydroazine represented by formula (I) ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) in concentrated sulfuric acid without catalyst General formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) A method for producing a vat dye represented by the following (in the formula, n is an integer of 1 or 2).