SU1721046A1 - Method of producing mesidene - Google Patents

Abstract

The invention relates to amines, in particular the preparation of mezidine used in the synthesis of anthraquinone dyes. The goal is to increase the yield of the target product and simplify the process. It is carried out by nitrating a 25-40% excess mesitylene with a mixture of sulfuric and nitric acids in a medium of sulfuric acid in the presence of urea at room temperature, followed by reducing the nitromezitylene with hydrogen in the presence of a nickel or palladium catalyst, regenerating mesitylene and returning it to the nitration stage. In this case, the spent sulfuric acid with the latter in the amount of 50-55% is returned to the process. These conditions increase the yield of the target product from 64.5% to 92.5% (basic substance content up to 98%) while reducing solid and liquid wastes and the possibility of excluding heat exchange equipment at the nitration stage. 1 hp f-ly. .5 E

Description

The invention relates to chemical technology, in particular, to a method for producing mesidin from mesitylene, which is an organic intermediate used in the synthesis of anthraquinone dyes and in the manufacture of medical preparations.

A two-step process for the preparation of mesidine from mesitylene is known. The first stage — nitration of mesitylene — is as follows. Mesitylene is slowly added to a mixture of acetic anhydride and concentrated nitric acid cooled to 10 ° C, then an additional amount of acetic anhydride is added to the reaction mass at 25-30 ° C, the mixture is kept at room temperature for 2 hours, cooled and poured into a mixture of sodium chloride and ice, the precipitate

filtered, washed with water, dissolved in petroleum ether, the solution is mixed with an aqueous alkali solution, the organic layer is separated from the alkaline, dried, evaporated to dryness. Nitromethylene is obtained with a yield of 87.3% based on mesitylen.

In the second stage, nitromosytylene is reduced in an alcoholic solution; First, the Ni-Rene catalyst is added, then the hydrazine hydrate is slowly added. The solution is heated in a water bath and evaporated to dryness. Mezidine is obtained with a yield of 85% based on nitromezitylene, 74% based on mesitylene. This process is characterized by the use of expensive, scarce, highly toxic raw materials (acetic anhydride, hydrazine hydrate), strong aggressiveness of the reaction masses, which requires

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special equipment; the use of acetic anhydride in a mixture with nitric acid makes the process explosive; the acid waste produced at this stage, containing a mixture of acetic and sulfuric acids, is not utilized.

A known method for producing mesidine from mesitylene, also consisting of two stages.

In the first nitration stage, sulfuric acid with a concentration of 64-80% is used as the medium. For nitration, a mixture containing 17% HNOZ, 65% NAZSM, 18% H2U is taken; molar ratios of nitric acid and mesitylene are 0.8-1.2%; nitro mixture is added to the reaction mass at a rate of 0.1-1.0% / min by the weight of the entire slurry; during the nitration process, sulfamic acid or urea is added to suppress the oxidation processes in an amount of 1.5% by weight of mesitylene; during the process, the temperature is maintained at between 10 and 40 ° C. The yield of nitroproducts is 97-98% of theory per mesitylene.

In the second stage, nitromeresylen is reduced by iron for 10 hours, after which the mass is neutralized with lime and distilled with steam. The top layer of distillate is distilled under vacuum. The yield of the isolated product is 59-64.5% based on mesitylene.

The known method makes it possible to eliminate expensive and scarce raw materials - acetic anhydride, hydrazine hydrate; use of a large amount of nitric acid (17.5% excess from theory); additional labor-intensive, expensive and dangerous stages of isolation of the reaction products — dilution of the reaction mass, with a large amount of water, and subsequent extraction; use of a dangerous mixture of acetic acid (or anhydride) with HNOZ.

In addition, the known method also reduces the corrosivity of the reaction media, eliminates the problem of the release of acetic acid from wastewater, which is extremely expensive.

A disadvantage of the known method is the presence of hardly recyclable waste (iron sludge) and a large amount of liquid waste, and, in addition, it is characterized by a low yield of product.

The purpose of the invention is to create a two-step method for the production of mesidine from mesitylene by nitrating the latter in a solution of sulfuric acid and subsequent reduction to increase the yield of mezidine; simplify the process.

The goal is achieved by the fact that according to the method both stages of the process are carried out in excess of mesitylene (25-40%), used as a solvent, the reduction is carried out with hydrogen on a nickel or palladium catalyst followed by regeneration of mesitylene and

0 by returning it to the nitration stage, and at the nitration stage, 50-55% of the spent sulfuric acid can be used.

If the excess mesitylene is less than 25%,

5 then the nitromeresylen will crystallize out, which would entail the need to heat the reaction mass. The use of excess mesitylene more than 40% although does not degrade the quality of the product,

0 but impractical due to significant

drop in process performance.

Only 50-55% of the spent sulfuric acid can be returned to the process, since only such an amount ensures that at the end of the nitration process the concentration of sulfuric acid is 65-70%,

The process according to the proposed method is carried out as follows.

0 Mesitylene is nitrated with a mixture of nitric and sulfuric acids, as well as water. Under stirring and at a temperature of 20-25 ° C, the concentration of sulfuric acid used is 65-70%. After the end of the nitration process, the aqueous and organic layers are divided. In this case, part of the spent sulfuric acid (50-55%) can be returned to the process to prepare a solution of mesitylene and: sulfuric acid. Organic

The 0 layer, which is a solution of nitromosytylene in mesitylene, is directed to reduction, which is carried out with hydrogen at a temperature of 60–120 ° C and a pressure of 3–60 atm on the catalyst. Both rene nickel and promoted nickel catalysts as well as Pd catalysts used for the reduction of aromatic nitro compounds can be used as catalysts for the lysator. AT

As a result of reduction, a mixture containing mesidine, mesitylene and water is obtained, from which the reaction mass is distilled, and then mesitylene. Mezidin is subjected to rectification and get the product with the output to

5 92.5% (calculated on mesitylene) and the content of the basic substance is not less than 99%.

Example 1, Into a reactor equipped with a stirrer, which makes a 1000 rpm thermometer, 82.35 hl are introduced by a dropping funnel. (0.7892 mol) of concentrated sulfuric acid and 35 wt.h. water. To the cooled solution urea is added in the amount of 3.2 parts by weight, stirred until complete dissolution and 92.43 parts by weight, (0.769 mol) of mesitylene are charged, which corresponds to an excess of 25% by weight.

To the emulsion obtained after vigorous stirring at a temperature of 20-25 ° C from. 126.4 wt.h. nitrous mixtures containing 27.9% HNOZ (0.5596 mol), 57.5% HaSO (0.741 mol), maintaining the indicated temperature of an ice bath. Nitrosum load with a speed of not more than 1.14% by weight of the nitromix in 1 min. At the end of the addition of the nitrous mixture, the reaction mixture is stirred at 20-25 ° C for 2 hours, after which the mixture is allowed to stand, the acidic aqueous layer is separated from the organic layer, 117 ppm by weight is obtained. organic layer, containing by GLC 70.5% nitromezitylene, 25.1% mesitylene and 2.2% dinitromezitylene.

The mixture is loaded into a reactor with a capacity of 400 cm with vigorous stirring (1500 rpm), 1.0 wt.h. nickel skeleton catalyst and reduction is carried out at a pressure of 10 atm and a temperature of 80 ° C. The resulting reaction mass is filtered from the catalyst and then the reaction water is separated on a separatory funnel. After the rectification of the organic layer receive 29 wt.h. mesitylene and 66.1 wt.h. mesidin with the content of the main substance of 99.0%. Selected mesitylene after regeneration returns to the nitration stage. The yield of mesidin on the mesitylene reacted is 92.5%, the loss of mesitylene is 1%,

Example 2 (comparative). 82.35 wt.h. are introduced into the reactor equipped with a stirrer, which makes a 1000 rpm thermometer, a dropping funnel. (0.789 mol) of concentrated sulfuric acid and 35 wt.h. water.

3.2 parts by weight were added to the cooled solution. urea, stirred until complete dissolution and load 92,43 wt.h. mesitylene (100%) - 0.769 mol, which corresponds to a 20 wt.% excess. To the emulsion obtained after vigorous stirring at a temperature of 20–25 ° C, 134.88 wt.h. Nitric mixtures containing 27.9 NMO3 (0.597 mol), 57.5% H2SO4 (0.791 mol), maintaining the indicated cooling temperature of an ice bath. Nitrosum load with a speed of not more than 1.14% by weight of nitrosomea in 1 min. At the same time, a suspension is formed due to the crystallization of the formed nitromezitylene. For further implementation of the process, additional heating of the reaction mass is necessary.

EXAMPLE 3 The nitration process is carried out analogously to example 1. Sulfuric acid 5 is taken in an amount of 0.75 mol, and to the emulsion of mesitylene obtained after vigorous stirring (an excess of 30% by weight) in sulfuric acid with the addition of urea nitrous mixture in the amount of 10 120.69 wt.h ,, containing 0.5344 mol HN03 and 0.71 mol H2S04. As a result of nitration, 113.131 parts by weight are obtained. product containing by GLC 66.6% nitromezitylene, 29.8% mesitylene, 2.45% dinitrome-15sitylene.

The mixture was charged to the reactor for reduction and reduced as in Example 1, but at a pressure of 3 atm and a temperature of 100 ° C. After rectification receive 33.2 wt.h.

0 mesitylene, 59.4 wt.% Mesidin with a basic substance content of 99%. The yield of mesidin on the mesitylene reacted is 89%, the loss of mesitylene is 1.5%.

5 EXAMPLE 4 The nitration process is carried out analogously to Example 1. An excess of mesitylene is 40% by weight. Sulfuric acid is taken in the amount of 0.59 mol. The amount of added nitromix is 90.34 parts by weight. She is

0 contains 0.40 mol HNO3.0.53 mol HaSO-q. As a result of nitration, 110.8 g of a troproduct are obtained. containing by GLC 56.0% nitromezitilen, 40.0% mesitylene, 1.3% dinitromesitylene. The nitroproduct is reduced as in example 1 in a reactor at a pressure of 60 atm and a temperature of 80 ° C. As a result of the reduction, 43.88 wt.h. mesitylene, 50.5 wt.h. mesidin with a mass fraction of the main substance of 99%.

0 The yield of mezidine per mesitylene reacted was 92.5%, the loss of mesitylene was 1.0%.

Example 5 (on spent sulfuric acid). To a reactor equipped with a stirrer,

5 making up to 1000 rpm, with a thermometer, dropping funnel, 118.73 wt.h. waste sulfuric acid from the previous nitration stage (example 1) - 50% of the total amount containing 67% sulfuric acid, and then the process is carried out as in example 1, while 122.9 parts by weight are added. nitro mixtures containing 0.5440 mol HNM, 0.721 mol H2SO4.

Get 115,19 wt.h. technical

5 product containing by GLC 70.4% nitromezitylene, 25.91% mesitylene, 1.68% dinitromezilena. The obtained nitro product is subjected to reduction as in Example 1 at a pressure of 60 atm and a temperature of 80 ° C.

As a result of the recovery, 29.55 mph are obtained. mesitylene, 65.77 wt.h, mezidine with mass fraction of the main substance 99%.

The yield of medisin per mesitylene reacted was 92.5%, the loss of mesitylene was 1%.

Example 6. The process is carried out analogously to example 5, with 130 wt.h. spent sulfuric acid from nitration, obtained in example 5 (55% of the total).

After separation of the layers, 115.3 wt.h. nitroproducts containing 65.91%. nitromezitylene, 29.01% mesitylene, 2.04% dinitromezilena. The reduction is carried out as in Example 1 at a pressure of 10 atm and 60 ° C. Get 32,95 wt.h. mesitomylene, 60.3 wt.h. mesidin with a mass fraction of the main substance of 99%. The yield of mesidin is 90.0%, based on the mesitylene that entered into the reaction, the mesitylene loss of 1.5%.

Example 7. The nitration process is carried out analogously to example 1 in 68% sulfuric acid, taken in an amount of 0.681 mol per 0.769 mol of mesitylene (an excess of 35 May.%) With a nitrous mixture containing 0.47 mol of HNM03, 0.623 mol of H2S04.

As a result of nitration, 110.14 wt.h. with mesitylene content of 35.03-%, nitromezilene 63.07%, dinitromezilene 1.12%. The nitroproduct is subjected to reduction on a Ni catalyst with the addition of Cr (0.6 parts by weight) at a pressure of 10 atm and a temperature of 80 ° C. After processing receive 38.2 wt.h. mesitylene, 56.29 wt.h. mesidin with the content of the main substance of 99%. The yield of mesidin per mesitylene reacted was 92%, mesitylene loss 1%.

Example 8. The process is carried out analogously to example 2. As a result of nitration, 116.41 parts by weight are obtained. a product with a mesitylene content of 26.77%, nitromezitylene 69.18%, dinitromezilene 1.91%, which is then subjected to reduction on a Ni catalyst with addition of Ti (0.6%) at a pressure of 10 atm and a temperature of 80 ° C. After isolation and rectification, 30.86 parts by weight are obtained. mesitylene, 64,39 wt.h. mesidin with a mass fraction of the main substance of 99%. The yield of mesidin is 92.5%, the loss of mesitylene is 1%.

PRI me R 9. The process is carried out analogously to example 2. Nitroprodukt in the amount of 114.63 wt.h. (nitromezitilen 67.99%, mesitylene 28.3%, dinitromezitilen 2.43%) restore on the catalyst 2% Pd / C (0.2 parts by weight) at a pressure of 10

temperature 80 ° C for example 1. Get 32,12 wt.h. mesitylene, 62,36 wt.h. mesidin with a mass fraction of the main substance of 99%. The yield of mezidine is 91.5% in

in terms of mesitylene reacted, mesitylene loss is 1%.

Example 10. The nitration process is carried out analogously to example 5 (on spent sulfuric acid). Take 1.2 wt.h. the catalyst is nickel on the carrier (45% NI on the SO2) and the resulting nitro product is reduced according to example 1 at a temperature of 90 ° C and a pressure of 15 atm. After isolation, mezidine is obtained with a yield of 92.1%; mesitylene loss 1%; mass fraction of the main substance of 99%.

Example 11. The process is carried out analogously to example 1. To recover the nitromezitylene, take 2.0 pfw. catalyst (30% Ni on AlOz). Hydrogenation is carried out at a temperature of 120 ° C and a pressure of 20 atm.

Mezidine is obtained with a yield of 92.0% and a mass fraction of the basic substance of 99%.

Mesitylene losses 1%.

Example 12. The nitration process is carried out analogously to example 5.

The obtained nitromezitene restore in example 1. Take 0.6 wt.h.

(3% Pd) and nitrimezitylene is hydrogenated at a temperature of 65 ° C and a pressure of 10 atm. The yield of mezidine is 92.3%. Mesitylene losses 1%; mass fraction of the main substance in the resulting product is 99%.

Example 13. The nitration process is carried out analogously to example 5.

The obtained nitromezitene restore in example 1. Take 0.2 wt.h. Pd

blacks and hydrogenation of nitromezitylene is carried out at a temperature of 60 ° C and pressure of 8 atm. The yield of mezidine is 92.1%; mass fraction of the main substance is 99.0%. Mesitylene losses 1%.

Thus, the proposed method for producing mesitylene provides, as compared with the known, an increase in the yield of mezidine up to 92.5% (known up to 64.5%) while at the same time obtaining a high-quality product (with a basic substance content of 99%); simplifying the process by eliminating the use of heat exchange equipment at the nitration stage, since it is possible to carry out this stage at room temperature (20-25 ° C); the elimination of hardly utilizable solid waste — iron sludge; reducing the amount of waste water by using spent sulfuric acid in the herds.

The formulas of the invention 1. A method of producing mezidine by nitrating mesitylene with a mixture consisting of sulfuric and nitric acid in a medium of sulfuric acid in the presence of urea, followed by reduction of the nitromesitylene produced, which in order to increase the yield of the target product and simplify the process carried out with a 25-40% excess mesitylene, and the reduction is carried out with hydrogen in the presence of nickel or

palladium catalyst followed by regeneration of mesitylene and its return to the nitration stage,

2. A method according to claim 1, characterized in that 50-55% of the spent sulfuric acid from the nitration stage is returned to the process.

Claims (2)

Claim 1. The method of producing mesidine by nitration of mesitylene with a mixture consisting of sulfuric and nitric acid in sulfuric acid in the presence of urea, followed by reduction of the obtained nitromesitylene, characterized in that, in order to increase the yield of the target product and simplify the process, the latter is carried out at 25-40 % excess of mesitylene, and the reduction is carried out with hydrogen in the presence of a nickel or palladium catalyst, followed by regeneration of mesitylene and its return to the nitration stage. 2. The method of pop. 1, characterized in that the spent sulfuric acid in an amount of 50-55% from the nitration stage is returned to the process.