DD270208A3 - METHOD FOR THE PRODUCTION OF ORTHO-PHENYLENDIAMINE - Google Patents

Abstract

The invention relates to a process for the preparation of o-phenylenediamine. The o-phenylenediamine is prepared from compounds of general formula (I) wherein X is hydrogen or chlorine, by reduction with hydrogen or hydrogen-containing gas in the presence of an active hydrogenation catalyst. The hydrogenation is conveniently carried out continuously in the presence of 30 to 70% ammonia and 10 to 15% water, then the ammonia is removed from the solution, the catalyst is filtered off, then the product is separated by extraction with a solvent and / or crystallization. Formula.

Description

The invention relates to a process for the preparation of o-phenylenediamine which can be used as an intermediate in the preparation of pharmaceutical and pesticide active ingredients. According to the invention, this compound is prepared from o-nitroaniline and / or 2-nitro-4-chloroaniline of general formula (I)

(D

- wherein X is hydrogen or chlorine - prepared by the compound of general formula (I) is hydrogenated in aqueous ammoniacal medium in the presence of an active hydrogenation catalyst with hydrogen or a hydrogen-containing gas.

The known processes for the preparation of o-phenylenediamine are based primarily on the reduction of o-nitroaniline. Iron, zinc or zinc (Winnacker-Kuchler: Komiai Technologia I, p.742-748, Müszaki Könyvkiado, Budapest 1962) or sodium sulfide in aqueous medium are used as reducing agents in the known methods of reduction (FIAT Final Report No. 1313 ) used.

Recently, the reduction of o-nitroaniline is carried out as a catalytic reduction. The catalytic hydrogenation can be carried out in the gas phase with a copper catalyst (Brown, Carrick: J. Am. Chem. Soc., 41, 439) or a palladium catalyst with Fuller's earth as carrier (Monsanto Chemicals, British Patent Specification No. 1077920 [1967]). In hydrogenation in the liquid phase, Raney nickel (Chem. Zvesti 2,114 [1948]) or palladium-supported platinum-supported platinum catalysts are generally used in a solvent as catalyst (du Pont de Nemours, DE-AS No. 2461615 [1975]; U.S. Patent No. 3,230,259 [1966]).

The o-phenylenediamine can also be prepared by the reduction of o-dinitrobenzene, but this compound is practically inaccessible on an industrial scale.

The production of o-phenylenediamine by ammonolysis of o-dichlorobenzene is known from some Japanese patents (Japanese Patent Publication Nos. 95615-95617, Toyo Soda Mfg. Co. Ud [1977]). DieAmmonoi ¹ -ε is carried out at 200 ⁰ C in the presence of a copper catalyst and lasts 16 hours.

The amination of the aniline to o-phenylenediamine can vorgenommer with a nickel catalyst containing Mg, Sr and Zn-oxide at 350 ⁰ C and a pressure of 300-400 bar and gives moderate yields (du Pont de Nemours, DE-ASNr .2114170 [1970]).

The main disadvantage of the non-catalytic reductions of o-nitroaniline is that neber products and wastewater must be made harmless in large quantities. The vapor phase catalytic reduction proceeds at temperatures above 250 ° C, and the pressure applied to increase the rate of hydrogenation must increase the temperature even further to maintain the gas phase.

The liquid-phase: suspended catalyst processes were realized almost without exception as discontinuous processes. The o-nitroaniline is dissolved in suitable organic solvents (aromatic hydrocarbons, esters or alcohols), the catalyst is suspended in the solution and the hydrogenation is carried out with vigorous stirring. The use of these processes on an industrial scale requires the regeneration of large quantities of organic solvents.

The o-nitroaniline itself is an intermediary prepared in several reaction steps, and therefore those for the production of o-phenylenediamine are those of very interest in the lower stages of benzene or intermediates of lower workup grade (chlorobenzene, nitrobenzene). These above-the o-nitroaniline syntheses generally have the disadvantage that in the preparation of the o-bifunctional compound 'o-chloronitrobenzene, o-nitroacetanilide) may be obtained as a by-product, twice the amount of p-isomer.

A separate process (Hungarian Patent No. 175397), which proceeds via the Nli'ierung of p-dichlorobenzene with subsequent Aminimierung and catalytic hydrogenation, eliminates this disadvantage; In this process, no isomeric by-products are formed.

The syntheses that do not involve the o-nitroaniline have not been put into practice since, despite the inaccessibility of the starting material and the intense reaction conditions, the achievable yields are too low. On an industrial scale, the most widely used is the amination of o-chloronitrobenzene and the reduction of the resulting o-nitroaniline. However, the o-chloronitrobenzene always accumulates together with the isomeric p-chloronitrobenzene, and the use of the former must therefore necessarily include a cognition of the latter; in this case, the production of o-phenylenediamine from o-chloronitrobenzene is advantageous.

Accordingly, the most advantageous of the known processes are those in which it is expedient to obtain from o-chloronitrobenzene. o-i \ itroaniline and the 2-nitro-4-chloroaniline prepared from p-dichlorobenzene be catalytically hydrogenated to o-phenylenediamine.

In the investigation of the production possibilities for o-phenylenediamine has now been found that the hydrogenation in 40 to 90%, advantageously 50-60% ammonia-containing aqueous medium can be made more advantageous than in organic solvents. Own measurements have shown that more than 40% ammonia-containing aqueous ammonia solutions form a homogeneous reaction mixture, especially at temperatures above 100 ⁰ C with the various organic compounds. This also applies to the o-nitroaniline and / or 2-nitro-4-chloroaniline of the general formula (I) in which X is H or Cl. Bet 100 ⁰ C forms the mixture of 60% ammonia, 30% water and about 20% of 2-nitro-4-chloroaniline a single liquid phase. Due to the presence of the ammonia, a favorable and constant pH is given in the reaction medium, which has a favorable effect on the activity of the palladium catalyst applied to activated carbon. When the hydrogenation proceeds concurrently with the hydrogenolysis of the halogen, the large excess of ammonia will bind the resulting hydrochloric acid while at the same time keeping the byproduct ammonium chloride in solution. If organic solvents are used, the precipitation of the salt must be expected, which causes difficulties especially in pressurized, continuously operating devices. The excess of the ammonia can be simply blown off from the hydrogenation mixture above 100 ° C. The o-phenylonediamine precipitates in crystal form from the residual aqueous solution on cooling, while the ammonium chloride remains in solution The efficiency of the separation of the target product o-phenylenediamine extraction of the two products by extraction may be carried out without prior crystallization, in which case the o-phenylenediamine solution and the ammonium chloride solution are separated and worked up individually The o-nitroaniline or 2-nitro-4-chloroaniline of the general formula (I) are industrially almost exclusively obtained by ammonolysis of o-chloronitrobenzene or 2,5-dichlorobenzene of the general formula (II)

(II)

- wherein the meaning of X, H or Cl is - made. This ammonolysis must in any case be carried out with an excess of ammonia. The isolation of the compounds of general formula (I) occurs in the usual way, by boiling the ammonia and removing the ammonium chloride. If now the production of o-phenylenediamine by hydrogenation with the preparation of the compounds of general formula (I) by ammonolysis, it is not necessary to isolate the compounds of general formula (I). The mixture leaving the aminating reactor, which contains ammonia, water, the intermediary of the general formula (I) and ammonium chloride, can be passed directly into the hydrogenation reactor. There, the aqueous suspension of the hydrogenation catalyst is slowly added and introduced hydrogen and hydrogenated in the still homogeneous reaction mixture, the compound of general formula (I) to o-phenylenediamine. Since the o-phenylenediamine can be prepared most advantageously via these steps of aminimization and hydrogenation, the direct coupling of the two reaction steps ensures significant technical advantages.

According to the invention, the o-phenylenediamine. prepared by stirring o-nitroaniline and / or 2-nitro-4-chloroaniline in a pressurized stirred tank at 100 ⁰ C with 50-60% ammonia-containing water to a homogeneous mixture, 5-1C% palladium activated carbon catalyst in an amount of 0.05-2% in the form of a 1-10% aqueous suspension and hydrogenated at 100-1 P ^ ⁰ C and 60-200 bar pressure while passing hydrogen or hydrogen-containing gas. Under these conditions, the reaction is more than 98% within 20-60 minutes. From the hydrogenated reaction mixture, the excess of ammonia is blown warm, the catalyst is filtered off. From the aqueous solution, at least 80% of the o-phenylenediamine can be isolated by cooling, crystallizing and filtering. From the remaining mother liquor, the o-phenylenediamine is removed by extraction with an organic solvent. The ammonium chloride remains in the aqueous solution and can be recovered from it by evaporation in crystal form. The ammonium chloride is an industrially utilizable product, its separation therefore has an economic advantage, for the a -! It is advantageous from the aspect of environmental protection that the salt does not get together with the waste water in the waters.

For extraction, the extractants used are, for example, chlorinated hydrocarbons such as chloroform, 1,2-dichloroethane, trichlorethylene, perchlorethylene, 1,1,2-trichloroethane, or benzene, toluene, ether or ester. If the extraction is carried out after blowing off the ammonia without prior crystallization of the o-phenylenediamine, then the entire amount of o-phenylenediamine accumulates in the organic phase and is isolated from this by crystallization or evaporation.

For hydrogenation, a discontinuous; Rührroaktor or built by in-series Sohalten such reactors cascade reactor or a kontini. Permitting working column or tube reactor can be used. The catalyst is kept in suspension in the reactor by mechanical stirring or by introducing the gas. From the gas leaving the reactor, the ammonia is recovered by washing with water under pressure. The hydrogen gas is either blown off or kept in circulation. Hydrogen-containing gas from ammonia synthesis can also be used instead of hydrogen.

If the hydrogenation is to be coupled directly with the amination reaction, the procedure is as follows: The o-chloronitrobenzene and / or 2,5-dichloro-nitrobenzene is stirred with 70-90% ammonia-containing aqueous ammonia solution to a homogeneous mixture and at 18u-220 ° C aminated The amination can be carried out batchwise or continuously. After 20-40 minutes reaction time, the reaction mixture is cooled to 100-160 ⁰ C and passed into the hydrogenation reactor, where after addition of the catalyst suspension hydrogenation takes place in the manner described. For the continuous, coupled implementation of the amination and hydrogenation steps, a pilot plant was built, the function of which will be explained in the accompanying figure.

The o-chloronitrobenzene or 2,5-dichloronitrobenzene is metered from the metering container 2 by means of the metering pump 6, the concentrated aqueous ammonia solution from the metering container 3 by means of the metering pump 7. After mixing, the homogeneous liquid phase reaches a forming reaction mixture in the tubular reactor 9 where at 220-22O ⁰ C runs out the amination. The reaction mixture containing ammonia, water, ammonium chloride and o-nitroaniline or 2-nitro-4-chloroaniline is cooled in a heat exchanger to 100-16O ⁰ C and then introduced at the bottom of the hydrogenation 11. There is also fed from the metering 4 by means of dosing pump 8, the aqueous suspension of Palladiumaktivkuhlekatalysators. The hydrogenation gas under 60-200 bar pressure is also introduced at the bottom in the reactor. The reaction mixture passes through the hydrogenation reactor 11 and from there into the separator 12, where the saturated with P mmoniak gas is separated from the liquid phase. The gas is passed into the pressurized absorber 13, where the ammonia is washed out with water. The thereby resolving solution of the recovered ammonia can be used orneutly after the addition of some fresh ammonia. From the separator 12, the liquid phase is continuously passed into the heater 14. The ammonia liberated by boiling in the heater 14 is conducted into the adsorber 13 and absorbed there. The liquid phase exiting the heater passes to the filter 17, on which the catalyst is filtered off. The o-phenylenediamine and ammonium chloride containing, warm saturated solution is fed into the countercurrent extractor 15, in which by the au. the container 1 by means of the metering pump 5 metered solvent, the o-phenvlenediamine is extracted from the liquid. The aqueous solution, which now only contains the ammonium chloride, is passed into the storage tank 19. From the extractor 15, the solution of the solvent, saturated with o-phenylenediamine, exits and enters the crystallizing container 16 where it is cooled and finally fed to the filter 18, on which the o-phenylenediamine is separated off. The final product collects in the container 21. The mother liquor leaving the filter 18, which still contains 2-5% o-phenylenediamine, is collected in the storage container 20 and can be fed again to the extraction. The invention will be explained in more detail with reference to the following embodiments.

Belsp'911

13, Gg o-nitroaniline are placed in a provided with stirrer, heatable pressure vessel. After '/ λ. At the rate of 18g of water, the baht is closed. From a pressure-stabbing dosing 28 g of liquid A.imoniak were added to the reactor and then its contents heated to 100 ⁰ C with stirring. 40mg of 10% Palladiumaktiv .. hle K atalyzer are suspended in 10g of water. The suspen sion is placed in a hydrogenation reactor of 0.2Dm ³ volume provided with a heating mantle and a gas distribution perforated plate. The catalyst is kept in suspension by introducing gas. The temperature of the reactor is controlled to 130 ° C, its pressure to 100bar. Now, the mixture containing o-nitroaniline, ammonia and water is forced into the hydrogenation reactor by means of nitrogen. After a reaction time of 40 minutes, the supply of hydrogen is shut off and the ammonia is blown off by opening the blow-off valve. Then the contents of the reactor are drained, the catalyst is removed by filtration. By cooling you warm saturated solution 8g o-Phenylenoiamin are separated, which melts after drying at 101 ⁰ C. By evaporation of the mother liquor, a further 2.6 g of Proo'ikt are obtained with a melting point of 98 ⁰ C.

Example 2

To 17.2 g of 2-nitro-4-chloroaniline 18 g of water and 28 g of liquid ammonia are added in the manner described in Example 1. In the hydrogenation reactor according to Example 1, the suspension of 100 mg of 10% palladium activated carbon in 10 g of water. Hydrogenation is carried out in the manner described in Example 1 for 60 minutes. After releasing the pressure, boiling the ammonia and filtering the catalyst, o-phenylenediarine is obtained by crystallization from the solution in an amount of 8.5 g. The mother liquor is extracted three times with 20 ml of chloroform each time. Evaporation of the organic phase gives a further 2 g of o-phenyl-diamine. 5 g of crystalline ammonium chloride are separated by evaporation from the aqueous phase.

Example 3

15.8 g of o-chloronitrobenzene are added to a 120 ml autoclave made of acid-resistant steel in a volume of 30 g of liquid ammonia and 8 g of water. The autoclave is heated with shaking to 220 ° C. In the hydrogenation reactor according to Example 1, the suspension of 80 mg 5% palladium activated carbon catalyst is introduced into 20 g of water. The hydrogen gas is turned on, the temperature adjusted to 140 ⁰ C and the pressure to 100 bar and pressed the reaction mixture of Aminimierung in the hydrogenation reactor. After a reaction time of 40 minutes, the hydrogen supply is switched off, the ammonia is boiled off, the catalyst is filtered off warm from the reaction mixture and the filtrate is extracted 5 times with 20 ml of benzene each time. Evaporation of the organic phase 10.2 g o-phenylenediamine are obtained, which melts at 99 ⁰ C.

Example 4

Starting from 19.3 g of 2,5-dichloronitrobonzene is aminated and hydrogenated in the manner described in Example 3. For amination, 30 g of liquid ammonia and 8 g of water are used. The amination is carried out at 200 ⁰ C and takes 20 minutes. For hydrogenation, the suspension of 200 mg of 10% palladium activated carbon catalyst in 20 g of water is used. The hydrogenation is carried out at 12O ⁰ C and 80 bar pressure and lasts 60 minutes. After removing the ammonia and filtering off the catalyst, the reaction mixture is extracted with 1,2-dichloroethane (3 × 20 ml). By evaporation of the solvent, 10.3 g of o-phenylenediamine are recovered, which melts at 100 ⁰ C. From the aqueous phase, 10.1 g of ammonium chloride are obtained by evaporation.

example

In a device corresponding to the attached flow chart, o-phenylenediamine is continuously produced. By means of the metering pump 3 per hour 1000 g of molten 2,5-dichloronitrobenzene, metered by the metering pump 7 per hour 2300g 80% aqueous solution of ammonium in the heated in an oil bath to 200 ⁰ C tube reactor of volume 2dm ³ . The mixture emerging from the reactor is cooled to 13O ⁰ C and printed in the hydrogenation reactor 11, whose temperature is maintained at 130 ° C by pressurized water in the heating mantle. By means of the metering pump 8, the suspension of 8 g of 10% palladium-activated carbon catalyst in 1100 ml of water is pressed into the reactor every hour. The pressure in the reactor is 150 bar. The liquid phase emerging from the separator 12 is freed of ammonia in the heater 14. The catalyst is separated on the filter 17 and used again. The o-phenylenediamine is extracted from the hot saturated aqueous solution in the continuous countercurrent extractor with 1500 ml of recirculated 1,2-trichloroethane per hour. Means crystallizer 16 and filter 18 are melted by air drying hourly 530g o-phenylenediamine, the BE * 100 ⁰ C, ietrennt. The aqueous solution of ammonium chloride is collected in the container 19. From 1 liter of solution are obtained by evaporation 280g of crystalline ammonium chloride.

Example β

820 g of o-chloronitrobenzene, 2 300 g of 80% strength ammonia solution, which are mixed with the apparatus in Example 5 per hour

1100ml Wauser prepared suspension of 6g of 5% palladium activated carbon and 1500ml of circulated

Extractor, 1,2-dichloroethane, fed. The temperature in the amination reactor is 22O ⁰ C, in the hydrogenation reactor

150 ° C at a pressure of 150 bar. In the manner described in Example 5, 543 g of o-phenylenediamine are produced per hour, which melts at 101 ° C.

The method has the following advantages:

1. The use of flammable solvents can be eliminated by using aqueous ammonia.

2. Dor for the hydrogenolysis of chlorine anyway necessary ammonia ensures a suitable pH and beyond the homogeneity of the reaction mixture.

3. In the presence of ammonia, the hydrogenolysis of the chlorine gives ammonium chloride, i. H. a recoverable by-product that poses no problems in terms of environmental protection.

4. In our process, it is unnecessary to use o-nitroaniline or 2-nitro-4-chloroaniline in its form, but these can be used in their preparation with ammonolysis in the resulting reaction mixture without isolation.

5. With the method according to the invention, the previously discontinuous step of hydriurization can advantageously be made continuously.

Claims (2)

1. A process for the preparation of o-phenylenediamine from o-nitroaniline and / or 2-nitro-4-chloroaniline by catalytic reduction with hydrogen or a hydrogen-containing gas, characterized in that the o-nitroaniline and / or 2-nitro 4-chloroaniline in the presence of 30 to 70%, preferably 40-50%, ammonia and 10-50%, preferably 30- + 0%, water dissolves, at 100 to 160 ⁰ C, advantageously at 120-140 ⁰ C, at 60-200bar, suitably at 100-120bar, continuously hydrogenated by gas stirring, the catalyst filtered from the solution, the ammonia blows out and the product is separated by extraction with a solvent and / or by crystallization. 2. The method according to claim 1, characterized in that the o-nitroaniline or 2-nitro-4-chloroaniline in the reaction mixture of the amination of o-nitrochlorobenzene or 2,5-Dichlornitrobenzols in aqueous ammoniacal medium, without intermediate isolation directly to Hydrogenated o-phenylenediamine.