SU46645A1 - The method of obtaining black sulfur dye - Google Patents

Description

German Patent No. 218517 describes a method for producing black sulfur dye from dinitrophenol, with 2 sulphurous sulphurus with 10% excess and 6 sulfur atoms being taken for 1 molecule of the latter. The duration of the interaction of these reagents to obtain the dye is significant. The author of this proposal has found that, with the same relative amounts of raw materials, the same result can be achieved if the interaction time is limited to about 1 hour, when operating under normal pressure. With this method of operation, the dye drops out of the reaction mixture when it is diluted with water, but the dye can also be isolated by brief air blowing or weak acidification. Thus, the proposed method can significantly reduce the duration of the process for the preparation of the dye and simplify its separation from the reaction mixture.

To illustrate the proposed method, a detailed description of the preparation of the dye is provided below.

Example. Washed dinitrochlorobenzene in the form of sodium dinitrophenol and before the synthesis of the dye is analyzed for free alkali.

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Let there be 412 kg of dinitrophenol sodium (lOOVfl-ro), in which an analysis of 80 kg of free caustic soda is found. For 412 kg of dinitrophenol it is necessary to give 520 kg of sodium sulpha bo / o-go (from a ratio of 1 mol of dinitrophenol to 2 mol).

80 kg of free caustic soda replace 52 kg of sulfurous soda 60% by the equation:

HERE ON + 4S 2Na; S-f lagVAoz + ZNO.

Thus, in this case, instead of theoretically required 520 kg of NajS, 520-52 469 kg of NajS of 60% is necessary. To this amount, it is necessary to add another 10% (for oxidation of the KazZ during the reaction), ie, 46.8 kg. Thus, a total of 468 - {- 46.8 514.8 kg (rounded 515 kg) of the 60% mazz will be required.

Sulfur takes on average from 3 to 6 atoms per 1 mole of dinitrophenolate. In this case, to obtain the same quality of the dye, it is necessary to take into account the amount of sulfur leaving for the side reaction with free caustic soda (see above), since the amount of sulfur going directly to the sulphurization of the original organic raw material changes from a change in the amount of free caustic soda. For example, if Apply

4 sulfur atoms per 1 mole of dinitrophenol, then 256.5 kg of sulfur (100%) should go to 412 kg, but in this case 42 kg of sulfur will go to the reaction with caustic soda (according to the above equation) and, therefore, if you take Only the above amount of sulfur (256.5 kg) will result in a colorant less serum than expected. In other words, the more free caustic soda in sulfurous sodium, the less you need to take sulfurous sodium and, accordingly, more sulfur. The polysulfide is prepared, as usual, by dissolving sulfur in a hot sodium sulphide solution. For example, for the above amount of sodium sulphide, about 670 liters of water are taken in which sodium sulphide is dissolved and 298.5 kg of sulfur is added at a temperature of 90-95 with stirring until complete dissolution.

The free alkali analyzed dinitrophenol t is heated to 95-97, water is let into the jacket of the reaction boiler or the coil to be cooled, and a solution of polysulfide is added in small portions (90) with good agitation. The reaction proceeds rapidly, therefore the flow of polysulfide is carried out so that the liquid is all the time in a state of boiling (100-105); in case of strong foaming of the liquid, it is recommended to put small amounts of foaming substances into the boiler, for example, green soap.

The polysulfide is usually supplied for 1 hour (approximately), after which (when foaming of the liquid ceases) the cooling of the boiler is stopped, steam is let into the jacket or coil and, when the liquid starts to boil, take a drop of liquid on the filter paper and determine by flow, Is there an excess of polysulfide or is there an excess of non-sulphurized dinitrophenol.

If there is an excess of polysulfide or unsweetened dinitrophenolate, the missing ingredient is added at a temperature of 95-105 in small portions and the sample is taken again on filter paper (leakage) in order to avoid adding an excess of the missing reagent.

If the check has shown the absence of excess polysulfide and non-saltified

dinitrophenol, then the dye is ready and the reaction mixture is fed for further processing, depending on how you want to get the dye (paste, dry concentrate, etc.).

If pasta is obtained, instead of evaporating the contents of the boiler (as is usually done), one can precipitate the appropriate number of batches using one of the indicated methods, filter and not dried paste of the dye from the filter press to add to one of the non-precipitated batches. The number of non-precipitated batches will depend on the type of dye that is set for the brand.

It is advisable to precipitate all batches, filter out the unpainted dye paste from the filter press, and mix it with the sodium sulphide solution in the ratio that is required for dyeing. The amount of water is taken in this case in order to obtain a thick non-exfoliating paste.

This method of processing the dye gives a paste that is resistant to oxidation, without mineral salts, more concentrated and perfectly ready for dyeing.

The combination of polysulfide with dinitrophenol can be maintained in reverse order, i.e. it is possible to add not polysulfide to dinitrophenol, but, on the contrary, dinitrophenol to polysulfide.

The subject matter of the invention.

1. The method of obtaining black sulfur dye by the interaction between solutions: 1 mol. sodium dinitrophenol and polysulfides prepared from 2 mol. sodium sulphide with 3-6 sulfur atoms at the boiling point of the mixture, characterized in that said solutions heated to 90-97 are mixed together during external cooling of the reaction vessel at such a rate that the liquid is maintained at all times in the state of boiling and that the mixing continues for about 1 hour, then heated to a gentle boil for 5-10 minutes. and, in the absence of both unreacted dinitrophenol and excess polysulfide in the mixture, it is processed

the resulting dye by conventional means.

2. With the method indicated in paragraph 1, in the event that an excess of either dinitrophenolate or polysulfide is found in the reaction mixture after boiling, add 95-105 small amounts to the reaction mixture.

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ingredient to the complete absence of an excess of both.

3. Modification of the above in paragraphs. 1 and 2, characterized in that the dye is precipitated from the reaction mixture instead of the usual blowing of air by diluting the reaction product with water.