JPS5846500B2 - Method for producing N-alkyl aromatic amine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an N-alkyl aromatic amine by reacting a primary or secondary aromatic amine with an alcohol by gas phase catalytic reaction.

Conventionally, the production of N-alkyl aromatic amines, for example, the synthesis of N,N-dimethylaniline from aniline and methanol, has been carried out in a liquid phase using a sulfuric acid method.

According to this method, the reaction is carried out at high temperature and high pressure (200°C, 30 atm), and 0.00% is required to react 1 mole of aniline.
05 to 0.3 moles of sulfuric acid and also 2.8 to 3.2 moles of methanol are required.

Since the sulfuric acid used here is a quaternary ammonium salt in the product, it is necessary to use a strong alkali, and treatment of by-products such as sodium sulfate also becomes a problem.

A method using trichlorophosphine as a catalyst is also known, but in this case as well, the reaction needs to be carried out at high temperature and high pressure.

(Houben-Weyl, Methodend d
er organ ChemieXI/I (1957)
,Page 136 ,J ,Chem, 5oc19
44,4) Since the liquid phase method has disadvantages as mentioned above, research on the gas phase method has been carried out for a long time, and methods using various catalysts have been proposed.

Among them, the most superior method is to use dimethyl ether and aniline as raw materials and aluminum oxide as a catalyst, which conducts the reaction in two stages and produces 97.6% N.

N-dimethylaniline is obtained.

However, with this catalyst, it is necessary to carry out the reaction in two stages, and the results are poor if methanol and aniline are used as raw materials.

(HoubenWeyl, Methoden, der
Organ XI/I (1957) Page 122
, Ind, Eng, Chem43.1579 (19
51)) The present inventors completed the present invention as a result of intensive studies to eliminate these conventional drawbacks.

The present invention uses a primary or secondary aromatic amine and an alcohol as a catalyst, and one or more selected from the group consisting of nickel sulfate, cobalt sulfate, iron sulfate, aluminum sulfate, and manganese sulfate. , relates to a method for producing an N-alkyl aromatic amine, which is characterized in that the reaction is carried out in a gas phase.

According to the method of the invention, N-alkyl aromatic amines are obtained in high yields.

Furthermore, when N-alkylation is carried out using methanol, it is possible to obtain highly pure tertiary aromatic amines in one step, making it difficult to separate primary aromatic amines and secondary aromatic amines. No operation required.

Primary or secondary aromatic amines used in the invention are 1, for example aniline, o-, m- or p-toluidine, tO-, m- or p-anidine.

o-, m- or p-aminostyrene, o-, m- or p-aminoethylbenzene, o-, m- or p-aminobenzonitrile, p-ia7'D biraniline, N-
Methylaniline, N-ethylaniline, N-butylaniline, o-, m- or p-chloroaniline, 2,3
-2, 4-12゜5-12, 6-13, 4- or 3,
5-diaminotoluene, diphenylamine, 2.3-1
2゜4-12, 5-2.6- 5-xylidine, 2, 3, 4- 2, 3, 5-
For 12, 3, 6-, 3,4.5-trimethylaniline, p-phenylenediamine, etc. can be used.

Further, as the alcohol used in the present invention, for example, methanol, ethanol, propatool, butanol, amyl alcohol, allyl alcohol, ethylene glycol, propylene glycol, etc. can be used.

In the present invention, commercially available nickel sulfate, cobalt sulfate, iron sulfate, aluminum sulfate, and manganese sulfate can be used as catalysts as they are, but commercially available products can be calcined at any temperature, preferably from 200 to 500°C, before use. You can also do that.

Although the catalyst can be used alone in the form of a mold, a carrier may also be used.

The carrier is preferably one with relatively low acidity, such as fired glass, carborundum, α-alumina, titanium aluminum oxide sponge, or titanium sponge.

The catalyst can be used in various forms, for example as a fixed bed or in fluidized form.

The reaction materials may be mixed before entering the reaction zone, or may be introduced separately into the reaction zone.

Inert gases such as nitrogen and water vapor may also be advantageously used as diluents.

The molar ratio of alcohol and aromatic amine introduced into the reaction zone is preferably 1 to 30:1, particularly preferably 2 to 10:1.

Excess alcohol can be easily recovered after the reaction.

The reaction is usually carried out at 200'C to 400C under atmospheric pressure, but if necessary, it is also possible to carry out the reaction under Calorie pressure or reduced pressure.

The contact time required for the reaction varies depending on the concentration of reactants, reaction temperature, type of catalyst, etc., but is generally 50 seconds to 0.1 seconds at room temperature and pressure.

The tertiary amines produced by the method of the present invention are useful as raw materials for dyes and the like.

Next, the reaction will be explained in detail with reference to Examples.

The reaction was carried out under atmospheric pressure using a U-tube fixed bed reactor.

The center of this reaction tube was filled with 10 rILl of catalyst.

The reaction raw material gas consisted of aromatic amine, alcohol, and nitrogen, and was previously brought into a gaseous state in a preheating layer before being introduced into the reaction layer.

An electric furnace was used for heating, and uniformity of heating was maintained with an alumina fluidized bath.

The reaction product was rapidly cooled at the outlet of the reactor, and the condensate was quantified using gas chromatography.

The reaction rate, yield, and alcohol recovery rate were calculated according to the following formula.

Example 1 Commercially available nickel sulfate was fired at 350°C for 5 hours.
- was filled into the reaction tube.

The temperature of the catalyst layer was maintained at 320° C., and the reaction was carried out for a contact time of 6.0 seconds.

The reaction feedstocks are 10.9 volφ of aniline and 43.6 vol.
The remaining volume was made of methanol and nitrogen gas was used as a carrier.

As a result of analyzing the reaction product by gas chromatography,
The reaction rate of aniline was 99.5%, the yield of N-methylaniline was 1.5%, and the yield of N,N-dimethylaniline was 98.0%.

Moreover, the recovery rate of methanol was 95.5.

Example 2 A reaction was carried out in the same manner as in Example 1 except that nickel sulfate calcined at 300° C. for 5 hours was used as a catalyst.

The reaction rate of aniline was 98.7 yen, the yield of N-methylaniline was 2.5 yen, and the yield of N,N-dimethylaniline was 96.2φ.

Moreover, the methanol recovery rate was 94.01%.

Example 3 A reaction was carried out in the same manner as in Example 1 except that nickel sulfate calcined at 450° C. for 5 hours was used as a catalyst.

The reaction rate of aniline was 83.7%, the yield of N-methylaniline was 1.6%, and the yield of N,N-dimethylaniline was 82.1%.

Moreover, the recovery rate of methanol was 95.2%.

Example 4 Methanol 32 instead of methanol 43.6 volφ
．． The reaction was carried out in the same manner as in Example 1 except that 7 volφ was used.

The reaction rate of aniline was 98.3φ, the yield of N-methylaniline was 1.1j%, and the yield of N,N-dimethylaniline was 97.2%.

Moreover, the recovery rate of methanol was 90.3'%.

Example 5 Methanol 65 instead of methanol 43.6 volφ
．． The reaction was carried out in the same manner as in Example 1 except that 4vol% was used.

The reaction rate of aniline was 99.4%, the yield of N-methylaniline was 0.s%, and N.

The yield of N-dimethylaniline was 98.61%.

Moreover, the methanol recovery rate was 96.2%.

Example 6 *N The reaction was carried out in the same manner as in Example 1 except that ethanol was used instead of methanol.

The reaction rate of aniline was 97.9%, the yield of N-ethylaniline was 45.2%, and the yield of N,N-diethylaniline was 52.7%.

The recovery rate of ethanol was 85.1 mcg.

Example 7 The reaction was carried out in the same manner as in Example 1 except that butanol was used instead of methanol.

The reaction rate of aniline was 59.71%, the yield of N-butylaniline was 21.9%, and the yield of N,N-dibutylaniline was 37.8%.

Moreover, the recovery rate of butanol was 70.4%.

Examples 8-22 The reaction was carried out in the same manner as in Example 1, except that the raw materials shown in Table 1 were used instead of aniline.

The results are shown in Table-1.

Example 23 The reaction was carried out in the same manner as in Example 1, except that 5.5 vol % of p-phenylenediamine was used instead of 10.9 vol φ of aniline.

The yield of N,N,N',N'-tetramethyl p-phenylenediamine was 58.9%, and the recovery rate of methanol was 90.2%.

Example 24 The reaction was carried out in the same manner as in Example 1 except that N-methylaniline was used instead of aniline.

The reaction rate of N-methylaniline was 99.8, N. The yield of N-dimethylaniline was 99.8%, and the recovery rate of methanol was 95.71%.

Example 25 The reaction was carried out in the same manner as in Case 1 except that 0-chloroaniline was used instead of aniline.

The reaction rate of 0-chloroaniline was 54.6%, the yield of N-methyl 0-chloroaniline was 10.3%, and N,N
The yield of -dimethyl O-chloroaniline was 44.3%.

In addition, the recovery rate of methanol was 92.4 yen.

Example 26 The reaction was carried out in the same manner as in Example 1 except that N-ethylaniline was used instead of aniline.

The reaction rate of N-ethylaniline is 98 slope, N. The yield of N-methylethylaniline was 93.3%, and the recovery rate of methanol was 96.2%.

Example 27 A reaction was carried out in the same manner as in Example 1, except that cobalt sulfate calcined at 350° C. for 5 hours was used as a catalyst instead of nickel sulfate.

The conversion rate of aniline is 99.1010, and the yield of N-methylaniline is 2.9.

Further, the yield of N,N-dimethylaniline was 96.21%.

The recovery rate of methanol was 94.8%.

Example 28 The reaction was carried out in the same manner as in Example 1, except that ferrous sulfate calcined at 350°C for 5 hours was used as the catalyst instead of nickel sulfate, and the temperature of the catalyst layer was maintained at 360°C. .

The reaction rate of aniline was 77.0%.

The yield of N-methylaniline was 1.2φ, and N,N-
The yield of dimethylaniline was 75.8φ.

The recovery rate of methanol was 73.6φ.

Example 29 Aluminum sulfate calcined at 350°C for 5 hours was used as a catalyst in place of nickel sulfate, and the temperature of the catalyst layer was adjusted to 3.
The reaction was carried out in the same manner as in Example 1 except that the temperature was maintained at 60°C.

The reaction rate of aniline was 63.6.

The yield of N-methylaniline was 2.5 tons, and N,N-
The yield of dimethylaniline was 61.1%.

Moreover, the recovery rate of methanol was 84.5 k.

Example 30 Manganese sulfate calcined at 350°C for 5 hours was used as a catalyst instead of nickel sulfate, and the temperature of the catalyst layer was set at 360°C.
The reaction was carried out in the same manner as in Example 1, except that the temperature was maintained at .

The reaction rate of aniline was 58.5.

The yield of N-methylaniline was 1.3%;

The yield of N-dimethylaniline was 57.2%.

Moreover, the recovery rate of methanol was 84.1%.

Example 31 A reaction tube was filled with 10 rfLl of commercially available nickel sulfate, and the temperature of the catalyst layer was raised to 330° C. over 3 hours.

Then, a reaction was carried out in the same manner as in Example 1 at 330°C.

One hour after the start of the reaction, the reaction rate of aniline was 99.1%, and the yield of N,N-dimethylaniline was 93.1%.
31%, the yield of N-methylaniline was 5.8%,
The recovery rate of methanol was 95%.

Example 32 A reaction was carried out in the same manner as in Example 1, using a catalyst consisting of 50 weight φ of nickel sulfate and 50 weight φ of cobalt sulfate calcined at 350° C. for 5 hours, and maintaining the temperature of the catalyst layer at 320° C.

The reaction rate of aniline was 98.7%, the yield of N,N-dimethylaniline was 95.9φ, the yield of N-methylaniline was 2.8%, and the recovery rate of methanol was 93.3%.

Example 33 A reaction was carried out in the same manner as in Example 1 except that allyl alcohol was used instead of methanol.

The reaction rate of aniline was 92.4φ, the yield of N,N-diallylaniline was 44.6 m, the yield of N-allylaniline was 39.9%, and the recovery rate of methanol was 51.5 mn.

Example 34 The reaction was carried out in the same manner as in Example 1 except that ethylene glycol was used instead of methanol.
The formation of hydroxyethylaniline, N1N-dihydroxyethylaniline, and N,N'diphenylpiperazine was observed.

Claims (1)

[Claims] 1. A primary or secondary aromatic amine and an alcohol are mixed in a gas phase using one or more selected from the group consisting of nickel sulfate, cobalt sulfate, iron sulfate, aluminum sulfate, and manganese sulfate as a catalyst. 1. A method for producing an N-alkyl aromatic amine, the method comprising reacting the N-alkyl aromatic amine.