DE1518418C2 - Process for the reductive alkylation of an organic compound having an amino or nitro group as a substituent - Google Patents

Description

The invention relates to a process for the reductive alkylation of an organic compound having an amino or nitro group as substituent, by reaction with an aldehyde or ketone and hydrogen at a temperature of 10 to 26O ⁰ C and under a pressure from 6.8 to 204 in the presence of at a catalyst which was produced by impregnating alumina carrier particles with an aqueous solution of a platinum compound and treating the subsequently dried particles at 38 to 816 ° C. with hydrogen.

The method is characterized in that a catalyst is used that had been treated according to the treatment with hydrogen so long as at 38 to ⁰ 816 C with a vaporous sulfiding, the catalyst contained up to 0.5 mole percent sulfur 0.05.

Such processes are known per se, but the catalysts used here contain platinum sulfide as an active catalyst component. For example, according to Belgian patent specification 6 43 911 and the German Auslegeschrift 15 18 394 from chloroplatinic acid solution through hydrogen sulfide black platinum sulfide precipitated and the precipitate used as such after drying or platinum on it Carbon is converted to sulfide with hydrogen sulfide and then flushed with hydrogen then for the production of N-alkylated amines by reductive alkylation of amino or nitro compounds to be used with aldehydes or ketones. Also with the one in the Belgian patent specification 6 51667 described process for the reductive alkylation of a chlorinated or brominated primary aromatic amine with aldehyde or ketone is the platinum sulfide in powder form or on a carrier z. B. as Alumina-containing catalyst used. Platinum metal sulfides are also used as heterogeneous hydrogenation catalysts in Journ. At the. Chem. Soc. 1965, pp. 2767 and 2768.

ίο Based on German patent specification 11 76 620 is it is also known to activate metal sulfide catalysts by optionally reacting the catalysts after a hydrogen treatment with an aqueous solution of the metal sulfate corresponding to the metal sulfide treated and subjected to renewed hydrotreatment after drying.

According to the older proposal of the German patent specification 12 60 444, the production of a finally takes place sulfided platinum on carbon containing catalyst by the fact that carbon particles with a mixed aqueous platinum solution, the platinum compound hydrolyzed with alkali, the deposited on the carrier Platinum oxide is reduced and then with a sulfiding agent in one over to convert to platinum sulfide required amount treated in an aqueous slurry.

The invention has the object, the reductive alkylation of an organic compound with a Amino or nitro group as substituents by reaction with an aldehyde or ketone and To improve hydrogen by using a specially prepared platinum supported catalyst and the To reduce the formation of undesired by-products during the alkylation.

In contrast to the previously known catalysts, the catalyst used according to the invention contains for reductive alkylation, the platinum is not used as a sulfide, but as a vapor as a result of the use The sulfiding agent and its application after the hydrogen treatment contains sulfur in different valence levels, combined with the carrier, as well as free sulfur, but by no means Platinum sulfide as detected by X-ray diffraction analysis.

The catalyst used according to the invention preferably contains fluorine or chlorine and platinum in an amount in the range from 0.01 to 25 percent by weight of the composition, preferably being that Platinum concentration in the range of 0.2 to 5 percent by weight and the halogen concentration in the range of 0.1 to 8 percent by weight of the finished catalyst. It is also appropriate that the hydrogen treatment takes place under a pressure of air pressure to 340 atm for half an hour to 12 hours.

The sulfidation treatment is expediently carried out at an elevated temperature of 38 to 816 ° C., preferably from 204 to 649 ° C, under overpressure up to 340 at or more. The sulfidation time is expediently one half an hour to 12 hours. In addition to hydrogen sulfide, aliphatic and aliphatic agents are used as sulfidating agents aromatic mercaptans, carbon disulfide or sulfur vapors into consideration.

The method according to the invention is particularly applicable to the reductive alkylation of p-nitroaniline, p-phenylenediamine, p-nitrophenol, or p-aminophenol with a ketone to produce one Ν, Ν'-di-sec-alkyl-p-phenylenediamine or an N-sec-alkyl-p-aminophenol, both of which are particularly advantageous

Oxidation inhibitor in unstable organic compounds, especially in cracked gasoline are.

However, it is also used for the reductive alkylation of other aromatic amino and / or nitro compounds, including those with one or more hydroxyl groups, such as nitrophenol, aminophenol or nitroaminophenol. Furthermore, the process can be applied to appropriately substituted Naphthalenes or afithracenes are used. The aldehydes or ketones used as alkylating agents can be aliphatic, cycloaliphatic or aromatic in nature and one or more amino groups contain. For the preparation of phenylenediamines substituted by alkyl on the nitrogen, one uses z. B. formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde or valeraldehyde.

As a result of the use of the sulfided platinum catalyst, higher levels are achieved according to the invention Yields, for example of Ν, Ν'-di-sec-alkyl-p-phenylenediamine, while, on the other hand, considerably smaller amounts of monoalkylates and alcohol are formed. This simplifies the separation of the product and eliminates the loss of ketone.

The reductive alkylation process according to the invention can preferably be carried out continuously because the long life of the catalytic converter allows long uninterrupted runs. However, it is expedient to work at the lowest possible temperature in the range from 10 to 260 ° C for this For this purpose, coolants can be provided to dissipate the exothermic heat of reaction. The catalyst can be introduced into the reaction column as a slurry or as a suspensoid with the reactants will.

The invention is particularly for the reductive alkylation of p-nitroaniline, p-phenylenediamine, p-nitrophenol and p-aminophenol are suitable, but other organic compounds such as mono- and Polynitrocyclohexane and / or aminocyclohexane, similarly substituted five-membered cycloalkyl compounds, similarly substituted pyridine compounds, pyrrole compounds, pyrrolidine compounds, pyrazole compounds, Furan compounds and thiophene compounds are used as starting materials.

The following examples serve to further illustrate the invention.

example 1

Alumina halogen balls about 1.6 mm in diameter with fluorine and chlorine in a total concentration below 2 percent by weight were dried at 649 ° C. and then with an aqueous chloroplatinic acid solution soaked to a content of less than 1 percent by weight platinum, then dried and annealed at 649 ° C in air.

Catalyst prepared in this way is shown below referred to as catalyst A. His analysis shows only 0.005 percent by weight sulfur.

Catalyst B according to the invention was prepared as follows: 350 cm ^{3 of} the alumina-platinum halogen spheres were heated to 538 ° C. for half an hour at 3600 cm ³ / min. Hydrogen stream heated. Then 50 cm ^{3 of} hydrogen sulfide were added per minute to the hydrogen stream and the mixture was passed over at the same temperature for about half an hour. An analysis of the catalyst obtained showed a sulfur content of 0.16 percent by weight.

Each catalyst was evaluated in a series of reductive alkylation experiments carried out as follows: 100 cm ^{3 of} catalyst were placed in a jacketed reaction tube. Hydrogen and a solution of about 8 percent by weight p-nitroaniline in ethyl amyl ketone were passed down through

ίο passed the catalyst at a rate of 100 cm ³ / h under a pressure of 58 at. A series of experiments at different temperatures were carried out with each catalyst as follows: The plant was brought up to working temperature and then the experiment was run for a time at this temperature. The product was collected and analyzed during the duration of the experiment. The temperature of the plant was then raised to the next higher level and the product was collected during another test period. The procedure was repeated to encompass the desired temperature range.

p-Nitroaniline was converted into N, N'-dioctyl-p-phenylenediamine with ethyl amyl ketone reductively alkylated. Undesired side reactions can occur

1. alcohol formed by hydrogenation of the ketone,

2. monoalkylated compound (N-octyl-p-phenylenediamine),

3. other intermediate by-products, such as by cleavage of the nitrogen and benzene ring and Reaction with the ketone formed octylamine and dioctylamine and

4. Generate a higher than the desired N, N'-dioctyl-pphenylenediamine.

The products from each test period were collected and analyzed by gas-liquid chromatography, to determine the amounts of the various fractions mentioned above.

The following table contains the results of comparable tests carried out at a jacket temperature of 130 ° C were carried out. The alcohol formed by the hydrogenation of ketone is given as a percent Alcohol stated in the ketone alcohol fraction. The monoalkylated compound is as your understanding for Amount of N, N'-dioctylp-phenylenediamine produced in the test period specified. The amounts of the other intermediate by-products are as their ratio for the amount of N, N'-dioctyl-p-phenylenediamine produced. The amounts of the higher than the latter boiling material are also given on the same basis. These relationships are based on the Area percentage analysis based on gas-liquid analyzes.

According to theory, the weight percent N ₁ N'-dioctyl-p-phenylenediamine in the gas-liquid chromatography analyzes is 19.9%. The sulfided catalyst B provided 15.8% Ν, Ν'-dioctyl-p-phenylenediamine, which is more than one and a half times the amount produced by catalyst A. Also, the amount of alcohol formed with catalyst B is less than a quarter of the alcohol formed with catalyst A. It should be noted that the other intermediates using Catalyst A were about 40% of the N, N'-dioctyl-p-phenylenediamine, while those using Catalyst B were only about 2.5%.

Table 1

fraction

Catalyst A Catalyst B

Ν, Ν'-Di-octyl-p-phenylenediamine,%

Ethylamyl alcohol (octanol) in the ketone alcohol fraction,%

Ratio of mono-N-octyl-p-phenylenediamine to Ν, Ν'-dioctyl-p-phenylene-

diamine
Ratio of the other intermediate reaction products to N, N'-dioctyl-

p-phenylenediamine

Ratio of higher-boiling material to N, N'-dioctyl-p-phenylenediamine jacket temperature, ⁰ C
Maximum catalyst temperature, ° C

10.0
16.5
0.13: 1

0.4: 1

0.03: 1

130

152

15.8
3.6
0.038: 1

0.025: 1

0.013: 1

131

151

Example 2

Another series of experiments was carried out in the same manner as in Example 1, except that the Jacket temperature in the reductive alkylation about 140 ° C. The results of these experiments can be found in the following table.

Here again it should be noted that the amount of Ν, Ν'-dioctyl-p-phenylenediamine, when using produced by Catalyst B, more than twice that using Catalyst A generated amount was. Also, the amount of the ketone hydrogenated to alcohol was nearly 35% when used of Catalyst A, while it was only about 8% when using Catalyst B. Of special Of interest is the fact that the amount of the other intermediates is about 92% of the N, N'-dioctyl-p-phenylenediamine when using catalyst A and only about 4% when using catalyst B fraud.

Table II

fraction

Catalyst A Catalyst B

Ν, Ν'-dioctyl-p-phenylenediamine,% 8.2 18.7

Ethylamyl alcohol (octanol) in the ketone alcohol fraction,% 34.9 7.8

Ratio of mono-N-octyl-p-phenylenediamine to N, N'-dioctyl-p-phenylene-0.085: 1 0.021: 1

diamine

Ratio of the other intermediate reaction products to N, N'-dioctyl-0.927: 1. 0.043: 1

p-phenylenediamine

Ratio of higher boiling material to Ν, Ν'-dioctyl-p-phenylenediamine 0.024: 1 0.021: 1

Jacket temperature, ⁰ C 139 140

Maximum catalyst ^{temperature, 0} C 163 172

Example 3

Another series of tests was carried out in the same way as in Example 1, but the reductive alkylation in this case took place at a jacket temperature of about 150 ^° C. The results of these tests are shown in the table below.

This again demonstrates the considerable improvement that can be achieved using the method achieved according to the invention. The amount of N, N'-Dioc-

Table IH

tyl-p-phenylenediamine is more than 2 '/ 2 times as high as at Use of catalyst A. The amount of alcohol present in the ketone fraction was only 9.4% Use of catalyst B, compared to 58.4% when using catalyst A. Of particular Interest is the amount of other intermediate products formed. With Catalyst B they were only too low about 6% of the Ν, Ν'-dioctyl-p-phenylenediamine, while in the case of catalyst A they were almost twice the amount of Ν, Ν'-dioctyl-p-phenylenediamine produced.

fraction

Catalyst A Catalyst B

Ν, Ν'-dioctyl-p-phenylenediamine,% 6.3 16.6

Ethylamyl alcohol (octanol) in the ketone alcohol fraction,% 58.4 9.4

Ratio of mono-N-octyl-p-phenylenediamine to N, N'-dioctyl-p-phenylene-0.079: 1 trace

diamine

Ratio of the other intermediate reaction products to N, N'-dioctyl-1.984: 1 0.060: 1

p-phenylenediamine

Ratio of higher boiling material to Ν, Ν'-dioctyl-p-phenylenediamine 0.032: 1 0.030: 1

Jacket temperature, ⁰ C 150 150

Maximum catalyst ^{temperature, 0} C 176 176

Example 4

Another series of experiments was conducted in the same manner as in Example 1 except that the reductive alkylation was performed at a jacket temperature of about 160 ⁰ C. The results showed practically the same differences at this temperature

found as obtained in Examples 1-3. The formation of Ν, Ν'-dioctyl-p-phenylenediamine was 15.0% with catalyst B and only 2.9% in catalyst A. The content of alcohol and monoalkylated products was considerably lower for Catalyst B than for Catalyst A. Von Of particular interest is the formation of other intermediates, which are only 28% of the Ν, Ν'-di-dioctyl-p-phenylenediamines, but at Use of Catalyst A was more than five times the amount of this diamine.

Example 5

Similar results were obtained when using catalysts A and B for the reductive alkylation at a jacket temperature of about 170 ⁰ C. The amount of Ν, Ν'-dioctyl-p-phenylenediamine was 11.9% with catalyst B and only 1.4% with catalyst A. The intermediate products formed with catalyst B amounted to 58% of the Ν, Ν'-dioctyl-p-phenylenediamine,

ίο on the other hand thirteen times (1357.1%) the same Use of catalyst A.

Claims (3)

Patent claims: 1. "Process for the reductive alkylation of an organic compound having an amino or nitro group as a substituent by reaction with an aldehyde or ketone and hydrogen at a temperature of 10 to 26O ⁰ C and under a pressure of 6.8 to 204 at in the presence of a Catalyst which was produced by impregnating alumina carrier particles with an aqueous solution of a platinum compound and treating the subsequently dried particles at 38 to 816 ° C with hydrogen, characterized in that a catalyst is used which, after treatment with hydrogen, remains at 38 for so long was treated to 816 ⁰ C and a gaseous sulfiding agent, the catalyst containing up to 0.05 to 0.5 mol .-% sulfur. 2. The method according to claim 1, characterized in that the method with a Performs a catalyst containing fluorine or chlorine and platinum in an amount in the range from 0.01 to 25 Contains percent by weight of the mass. 3. The method according to claim 1 or 2, characterized in that the method with a Carries out catalyst in which the hydrogen treatment under a pressure of atmospheric pressure to 340 at took place for half an hour to 12 hours.