CH655093A5 - METHOD FOR PRODUCING ORTHO-PHENYLENE DIAMINE. - Google Patents

Description

The invention relates to a process for the preparation of the o-phenylenediamine which can be used as an intermediate in the production of medicinal and crop protection active ingredients. According to the invention, this compound is made up of compounds of the general formula (I)

"NO,

(I)

- wherein X is hydrogen or chlorine - prepared by hydrogenating the compound of general formula (I) in an aqueous, ammoniacal medium in the presence of an active hydrogenation catalyst with hydrogen or a hydrogen-containing gas according to claim 1.

The known processes for the preparation of o-phenylene-diamine are based primarily on the reduction of the o-nitroaniline. In the known methods of reduction, iron, zinc or tin are used as reducing agents (Winnak-5 ker-Küchler: Kémiai technológia I., pp. 742-748, Müszaki Kö-nyvkiadó, Budapest 1962) or sodium sulfide in an aqueous medium (FIAT Final Report No. 1313) is used.

Recently the reduction of o-nitroaniline has been carried out as a catalytic reduction. The catalytic hydrie-10 rank can 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 a carrier (Monsanto Chemicals, British Patent No. 1 077 920/1967 /) be made. In hydrogenation in the liquid phase, Raney nickel (Chem. Zvesti 2,114 / 1948 /) or supported palladium or platinum catalysts (du Pont de Nemours, DE-AS No. 2 461 615 / 1975 /); U.S. Patent No. 3,230,259).

20 The o-phenylenediamine can also be produced by the reduction of o-dinitrobenzene, but this compound is practically not accessible on an industrial scale.

The preparation of the o-phenylenediamine by ammono-2s lysis of o-dichlorobenzene is known from some Japanese patents (Japanese patents 95 615-95 617, Toyo Soda Mfg. Co. Ltd / 1977 /). The ammonolysis is carried out at 200 ° C. in the presence of a copper oxide catalyst and takes 16 hours.

30 The amination of the aniline to o-phenylenediamine can be carried out with a nickel catalyst containing Mg, Sr and Zn oxide at 350 ° C. and a pressure of 300-400 bar and gives moderate yields (du Pont de Nemours, DE-AS No. 2 114 170/1970 /).

35 The main disadvantage of the non-catalytic reductions in o-nitroaniline is that large quantities of by-products and wastewater have to be rendered harmless. The catalytic reduction taking place in the vapor phase takes place at temperatures above 250 ° C, and 4o due to the pressure used to increase the hydrogenation rate, the temperature must be increased even more so that the gas phase is retained.

The processes in the liquid phase with suspended catalysts were implemented almost without exception as 45 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 application of this process on a large industrial scale requires the regeneration of large amounts of organic solvents.

The o-nitroaniline is itself an intermediate produced in several reaction documents, and therefore the multi-stage processes which are based on benzene or intermediates of a lower degree of processing (chlorobenzene, nitrobenzene) are really of interest for the preparation of o-phenylenediamine. These syntheses, which proceed via the o-nitroaniline, generally have the disadvantage that in the production of the o-bifunctional compound (o-chloro-nitrobenzene, o-nitroacetanilide) as a by-product, twice the amount of p-isomer can be obtained.

A separate process (Hungarian Patent No. 65 175 397), which proceeds via the nitration of p-dichlorobenzene with subsequent amination and catalytic hydrogenation, eliminates this disadvantage; no isomeric by-products are formed in this process.

The syntheses that do not run via the o-nitroaniline have not found their way into practice because, despite the inaccessibility of the starting materials and the intensive reaction conditions, the yields which can be achieved are too low.

The most widespread use on an industrial scale is the amination of o-chloronitrobenzene and the reduction of the o-nitroaniline obtained. However, the o-chloronitro-benzene always occurs together with the isomeric p-chloronitrobenzene; the use of the former must therefore also include the utilization of the latter; In this case, the production of o-phenylenediamine from o-chloronitrobenzene is advantageous.

Of the known processes, the most advantageous are those in which the o-nitroaniline suitably obtained from o-chloro-15 nitrobenzene and the 2-nitro-4-chloroaniline prepared from p-dichlorobenzene are catalytically hydrogenated to o-phenylenediamine.

When examining the production possibilities for o-phenylenediamine, it has now been found that the hydrogenation 20 in 30-70% by weight, expediently 40-50% by weight ammonia-containing aqueous medium can be carried out more advantageously than in organic solvents. Our own measurements have shown that the aqueous ammonia solutions containing more than 40% ammonia form a homogeneous reaction mixture with the various organic compounds, especially at temperatures above 100 ° C. This also applies to the compounds of the general formula (I). At 100 ° C, the mixture of 30% ammonia, 30% water and about 20% 2-nitro-4-chloroani- 30 lin forms a single liquid phase. The presence of ammonia results in a favorable and constant pH in the reaction medium, which has a favorable influence on the activity of the palladium catalyst applied to activated carbon. If the hydrogenation takes place simultaneously with the hydrogenolysis of the halogen, the large excess of ammonia binds the hydrochloric acid formed and at the same time keeps the ammonium chloride obtained as a by-product in solution. If organic solvents are used, the salt must be expected to precipitate, which in particular poses difficulties for pressurized, continuously operating devices. The excess ammonia can simply be blown off from the hydrogenation mixture, which is heated to over 100 ° C. When cooling, the o-pheny-45-lendiamine separates from the remaining aqueous solution in crystal form, while the ammonium chloride remains in solution. The efficiency of the separation of the target product o-phenylenediamine from the by-product ammonium chloride can be increased by extraction.

The separation of the two products by extraction 50 can also be carried out without prior crystallization; in this case, the o-phenylenediamine solution and the ammonium chloride solution are separated from one another and worked up individually.

The use of aqueous ammonia as the reaction medium has another important advantage. The compounds of the general formula (I) are industrially produced almost exclusively by ammonolysis of compounds of the general formula (II)

60

(II)

65

655 093

- wherein the meaning of X is the same as above - made. In any case, this ammonolysis must be carried out with an excess of ammonia. The compounds of the general formula (I) are isolated in the customary manner, by boiling out the ammonia and removing the ammonium chloride. If the preparation of the o-phenylenediamine by hydrogenation is now combined with the preparation of the compounds of the general formula (I) by ammonolysis, it is not necessary to isolate the compounds of the general formula (I). The mixture emerging from the amination reactor, which contains ammonia, water, the compound 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 hydrogen is introduced, and the compound of the general formula (I) is hydrogenated to o-phenylenediamine in the reaction mixture which remains homogeneous. Since the o-phenylenediamine can be produced most advantageously via these steps of amine rank and hydrogenation, the direct coupling of the two reaction steps ensures significant technical advantages.

According to the invention, the o-phenylenediamine is prepared by stirring the compound of the general formula (I) in a pressurized stirred tank at 100 ° C. with water which preferably contains 50-60% ammonia to form a homogeneous mixture, 5-10% palladium-activated carbon catalyst an amount of 0.05-2% in the form of a 1-10% aqueous suspension and hydrogenated at 100-160 ° C and 60-200 bar pressure while passing hydrogen or hydrogen-containing gas. Under these conditions, the conversion is more than 98% within 20-60 minutes. The excess of the ammonia is blown off warm from the hydrogenated reaction mixture and the catalyst is filtered off. At least 80% of the o-phenylenediamine can be isolated from the aqueous solution by cooling, crystallizing and filtering. The o-phenylenediamine is removed from the remaining mother liquor by extraction with an organic solvent. The ammonium chloride remains in the aqueous solution and can be obtained from it by evaporation. Ammonium chloride is an industrially usable product, so separating it has an economic advantage, on the other hand it is advantageous from an environmental point of view that the salt does not get into the water with the waste water.

For the extraction, the extraction agent used is, 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 the ammonia has been blown off without prior crystallization of the o-phenylenediamine, the total amount of o-phenylenediamine is obtained in the organic phase and is isolated from it by crystallization or evaporation.

A discontinuously operating stirred reactor or a cascade reactor constructed by connecting such reactors in series or else a continuously operating column or tube reactor can be used for the hydrogenation. The catalyst is kept in suspension in the reactor by mechanical stirring or by introducing the gas. The ammonia is recovered from the gas emerging from the reactor by washing with water under pressure. The hydrogen gas is either blown off or kept in circulation. Instead of hydrogen, hydrogen-containing gas from ammonia synthesis can also be used.

655 093 4

If the hydrogenation is to be carried out directly with the amination carbon catalyst, it is suspended in 10 g of water. To couple the susaction, proceed as follows. The pension is placed in a hydrogenation reactor of 0.2 dm3 volume. The compound of the general formula (II) is added, which is provided with a heating medium and a perforated plate which serves for the aqueous ammonia solution containing 70-90% ammonia. The catalyst is stirred into a homogeneous mixture and is kept in suspension at 180-5 g by introducing gas. Aminated at 220 ° C. The temperature of the reactor is raised to 130 ° C. and its pressure to. The amination can be controlled batchwise or continuously at 100 bar. Now the o-nitroaniline, ammonia loan will be made. After 20-40 minutes of reaction and water-containing mixture using nitrogen, the reaction mixture is cooled to 100-160 ° C. and the hydrogenation reactor is pressed. After a reaction time of 40 minutes, it is passed into the hydrogenation reactor where, after the addition of the catalyst, the supply of hydrogen is shut off and the hydrogenation is blown off by opening the blow-off valve of the ammonia by torsus suspension. Then takes place. the contents of the reactor are discharged, the catalyst

For the continuous, coupled implementation of the is removed by filtration. By cooling the warm sown

Steps amination and hydrogenation was a pilot plant solution, 8 g of o-phenylenediamine are separated, which is built, the function of which melts after drying at 101 ° C using the enclosed Figure 15. Is explained by evaporation. the mother liquor contains a further 2.6 g of product

Obtain the o-chloronitrobenzene or 2,5-dichloronitrobenzene melting point of 98 ° C.

the dosing tank 2 by means of the dosing pump 6, the concentrated aqueous ammonia solution from the dosing example 2

container 3 dosed by means of the metering pump 7. After mixing 20 g of 17.2 g of 2-nitro-4-chloroaniline, 18 g of water and 28 g of liquid ammonium are obtained as described in the example, forming a homogeneous liquid phase 1.

Reaction mixture in the tubular reactor 9, where given at 200-220 ° C niak. The amination is carried out in the hydrogenation reactor according to Example 1. The reaction mixture, the Ammo suspension of 100 mg 10% palladium activated carbon in niak, water, ammonium chloride and o-nitroaniline or 1 ° g water. Hydrogenation is carried out on the

Contains 2-nitro-4-chloroaniline, is in a heat-tendered manner for 60 minutes. After lowering the pressure

exchanger 10 cooled to 100-160 ° C and then at the bottom of the kes, boiling the ammonia and filtering the catalyst

Hydrogenation reactor 11 initiated. There the doctor also crystallizes from the solution o-phenylenedi-

sier container 4 by means of the metering pump 8, the aqueous suspension amine in an amount of 8.5 g. The mother liquor sion of the palladium activated carbon catalyst fed. This is extracted three times with 20 ml of chloroform each. By means of a hydrogenation gas at a pressure of 60-200 bar, a further 2 g are also added to the organic phase by evaporation

Soil introduced into the reactor. Obtain the reaction mixture o-phenylenediamine. The hydrogenation reactor 11 is passed through from the aqueous phase and from there reaches 5 g of crystalline ammonium chloride by evaporation.

Separator 12, where the ammonia-saturated gas separates from the.

liquid phase is separated. The gas is in the under

Pressurized absorber 13 passed where the ammonia with 35th

Water is washed out. The solution of the. Example 3

Recovered ammonia can, after adding a little .., '° S o-chlorotrobenzene, be

fresh ammonia can be used again. Autoclave made of permanent steel with 30 g liquid amm

parator 12, the liquid phase is continuously added to the heating monoxide and 8 g of water. The autoclave is passed under zer 14. The heated in the heater 14 by boiling 40 shakes to 220 ° C. In the hydrogenation reactor according to put ammonia is passed into the absorber 13 and there, Example 1, the suspension of 80 mg of 5% palladium

absorbed. The liquid phase of activated carbon catalyst emerging from the heater is poured into 20 g of water. This reaches the filter 17, on which the catalyst is filtered off, hydrogen gas is turned on, the temperature to 140 ° C.

becomes. The o-phenylenediamine and ammonium chloride contain u. ^ The pressure is set to 100 bar and the reaction

The warm, saturated solution is pressed into the countercurrent mixture of the amination in the hydrogenation reactor. After the tractor 15, in which the hydrogen supply is cut off by the reaction time of 1-0 minutes from the container 1

Using the dosing pump, 5 dosed solvents are used to make the o-pheny-, the ammonia is boiled out, the catalyst is extracted warm from lendiamine from the liquid. The aqueous filtered off the reaction mixture and the filtrate 5 times with

Solution, which now only contains the ammonium chloride, extracted ^ 0 ml of benzene. Evaporation of the organic is conducted into the storage container 19. From the extractor 50 ^ * se 10.2 g of o-phenylenediamine are obtained, which at

15 occurs the solution of 99 JC that is warmly saturated with o-phenylenediamine melts.

Solvent and enters the crystallization tank 16, is cooled there and finally fed to the filter 18,

on which the o-phenylenediamine is separated off. The end pro example 4

product collects in the container 21. Starting from the filter 18 55, starting from 19.3 g of 2,5-dichloronitrobenzene, the mother liquor which emerges is aminated and hydrogenated in the manner described in Example 3 and contains 2-5% o-phenylenediamine,

contains, is collected in the storage container 20 and can be fed to amination 30 g of liquid ammonia and 8 g of extraction again. Water used. The amination is carried out at 200 ° C

The invention is carried out on the basis of the following embodiment and lasts 20 minutes. The examples for hydrogenation are explained in more detail. 60 suspension of 200 mg 10% palladium activated carbon ca

Talysator used in 20 g of water. The hydrogenation is at

Example 1 120 ° C and 80 bar pressure and takes 60 minutes

13.8 g of o-nitroaniline are mixed in a stirrer. After removing the ammonia and filtering

submitted to the heatable pressure vessel. After adding the catalyst, the reaction mixture is mixed with

The container is sealed with 18 g of water. Extracted from one under 651,2-dichloroethane (3 x 20 ml). By evaporation

28 g of liquid amine and 10.3 g of o-phenylenediamine are obtained.

moniak added to the reactor and then its contents under NEN, which melts at 100 ° C. The aqueous phase becomes

Stirring heated to 100 °. 40 mg of 10% palladium active - 10.1 g of ammonium chloride obtained by evaporation.

Example 5

In a device corresponding to the enclosed flow diagram, o-phenylenediamine is continuously produced. 1000 g of molten 2,5-dichloronitrobenzene are metered per hour by means of the metering pump 6, and 2300 g of 80% strength aqueous ammonium solution per hour are metered into the tube reactor of volume 2 dm3 heated to 200 ° C. in an oil bath by means of the metering pump 7. The mixture emerging from the reactor is cooled to 130 ° C. and pressed into the hydrogenation reactor 11, the temperature of which is kept at 130 ° C. by pressurized water in the heating jacket. The suspension of 8 g of 10% palladium activated carbon catalyst in 1100 ml of water is pressed into the reactor every hour by means of the metering pump 8. 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 warm, saturated aqueous solution in the continuous countercurrent extractor with 100 ml of recirculated 1,2-trichloroethane per hour. The product crystallizes, is separated on the filter 18 and air-dried. The device produces 530 g of o-phenylenediamine per hour, which melts at 100 ° C. The aqueous solution of the ammonium chloride is collected in the container 19. 280 g of crystalline ammonium chloride are obtained by evaporation from 1 liter of solution.

5 655 093

Example 6

In the device according to Example 5, 820 g of o-chloronitrobenzene, 2300 g of 80% ammonia solution, the suspension of 6 g of 5% 5% palladium-activated carbon and 1500 ml of the circulating extractant 1,2-dichloroethane prepared with 1100 ml of water are mixed per hour fed. The temperature in the amination reactor is 220 ° C, in the hydrogenation reactor 150 ° C at a pressure of 150 bar. In the manner described in Example 5, 543 g of o-io phenylenediamine are produced per hour, which melts at 101 ° C.

The process has the following advantages:

- Instead of flammable solvents, aqueous ammonia is used as the reaction medium.

- The 15 ammonia required for the hydrogenolysis of the chlorine ensures a suitable pH value and, moreover, the homogeneity of the reaction mixture.

- In the presence of ammonia, hydrogenolysis of the chlorine gives ammonium chloride, i.e. a usable by-product that has no environmental impact

2o posing bleme.

- When working according to the coupled process, it is unnecessary to isolate the starting compound of general formula (I) from the reaction mixture of its preparation and to dissolve it again later.

25 - With the method according to the invention, the step of hydrogenation which was previously carried out discontinuously can advantageously be designed continuously.

C.

1 sheet of drawings

Claims (5)

655 093 PATENT CLAIMS 1. Process for the preparation of o-phenylenediamine from compounds of the general formula (I) NILE NO, (I) wherein X is hydrogen or chlorine, by catalytic reduction with hydrogen or a hydrogen-containing gas, characterized in that the hydrogenation is carried out in the presence of 30-70% by weight of ammonia and 10-50% by weight of water, the sum of ammonia, water and the compound of the formula is 1100% by weight, the solution is freed from ammonia, the catalyst is filtered off and the product is separated off by extraction with a solvent and / or by crystallization. 2. The method according to claim 1, characterized in that one works in the presence of 40-50 wt .-% ammonia. 3. The method according to claim 1 or 2, characterized in that one works in the presence of 30-40 wt .-% water. 4. The method according to any one of claims 1 to 3, characterized in that one works continuously. 5. Application of the process according to one of claims 1 to 4 to compounds of the general formula (I) which are obtained by ammonolysis from compounds of the general formula (II) Cr (Ii) wherein the meaning of X is the same as in claim 1, prepared and used in the form of the resulting reaction mixture, without intermediate isolation.