JPS61291551A - Production of aromatic secondary amino compound - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as an intermediate for medicines, agricultural chemicals, etc., industrially and advantageously in high yield, by reacting an aniline with an alcohol in the presence of a catalyst containing a specific metal oxide and magnesium. CONSTITUTION:An aniline expressed by formula I (X is H, halogen, lower alkyl or lower alkoxy; n is an integer 1-3) is reacted with an alcohol expressed by the formula ROH (R is alkyl or phenyl) in the presence of at least two or more metal oxides selected from zinc, cadmium, aluminum, iron, calcium, nickel, copper and titanium and magnesium oxide to afford the aimed compound expressed by formula II. MgO-Zn)-Al2O3, etc., may be cited as a combination as a preferred catalyst. The catalyst having deteriorated activity can be regener ated by feeding heated air thereto. The catalyst is readily handled without forming high polymer tarry materials and ethers.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an aromatic secondary amine compound.

That is, the present invention provides anilines represented by the general formula (I): (wherein X represents a hydrogen atom, a halogen atom, a lower alkyl group, or a lower alkoxy group, and n is an integer from 1 to S) and the general formula (■):ROH(It
) (wherein the formula represents an alkyl group or a phenyl group) Alcohols represented by zinc (Zn), cadmium (Cd), aluminum (A/), iron (Fe),
/NuA (Ca), Nickel (Ni), Steel (Cu)
, titanium (Ti) and at least two metal oxides selected from titanium (Ti) and a catalyst containing magnesium oxide.
%n and R have the same meanings as above).

It is well known that anilines and alcohols are generally reacted in the presence of various catalysts to perform N-alkylation and N-arylation.
Unit Process Inorganic Chemistry, page 850.

(1958), concentrated phosphoric acid catalyst method (U.S. Pat. No. 299,151)
No. 1), Alumina Catalyst Method (Hemitskunis-Centralplatt, p. 2579).

1953). However, all of these methods not only result in a decrease in the yield of the target product due to the production of polymeric tar-like substances, but also require the handling of the catalyst, separation and purification of the product, especially in the sulfuric acid and concentrated phosphoric acid catalyst methods. It is difficult to manufacture on an industrial scale, and the process is very complicated and equipment is expensive.Also, even in the alumina catalyst method, ethers in particular are produced as by-products, resulting in high equipment costs in the alcohol recovery and separation process. becomes even more expensive. Also, the magnesia catalyst method (U.S. Patent No. 355)
No. 8706), but in this case, the reaction temperature is high and the upper conversion rate is low, which is industrially disadvantageous.

The present inventors have demonstrated the ability to selectively N-monoalkylate anilines and N-
As a result of examining methods for monoarylation, Zn, Cd
1A/1Fe%Ca.

A method using a catalyst containing at least two metal oxides selected from Ni, Cu%Ti and magnesium oxide has excellent catalyst activity, is easy to prepare and handle, and is easy to recycle. We discovered that it is economically and industrially advantageous and excellent because it can be regenerated by firing.
The method of the present invention has been completed.

The metal oxide catalyst used in the method of the present invention is Zn, Cd
, AI%Fe, Ca%Ni, Cu%Ti, and magnesium oxide. In this case, the molar ratio of magnesium oxide to the sum of other oxides is preferably 1:101 to 1.

Among these catalysts, a preferable combination is MgO-
ZnO-Alz03 lMgO-CdOk120s -
MgO-ZnO-Fe, 0. , MgO-CdO-F
Examples include e2O3.

These catalysts are prepared according to known methods, for example, as follows. Soluble salts of component elements (e.g. MgO
When obtaining the ZnO-A1203 system, aqueous solutions of magnesium nitrate, zinc nitrate, and aluminum nitrate are mixed, and an alkali is added to obtain a precipitate. The obtained precipitate is thoroughly washed with water and dried, for example, in the air at a temperature of 500 to 800
After calcination at ℃ for 2 hours, the catalyst is prepared by crushing or tableting. In this case, the catalyst may be supported on an inert carrier, or may not be supported on a carrier.

As for the reaction mode in the method of the present invention, either the pressurized contact method or the gas phase contact method can achieve the goal, but the gas phase contact method is more preferable in that the reaction can be carried out continuously.

Further, the molar ratio of the alcohol to the aniline may be at least 11 times the mole, but is preferably α5 to 10 times the mole.

1 The reaction temperature is preferably in the range of 150 to 450°C, and the reaction is carried out in the presence or absence of hydrogen gas, carbon dioxide gas, argon gas, helium gas, or nitrogen gas.

The catalyst whose activity has decreased due to the reaction can be regenerated by supplying hot air.

After the reaction is complete, the desired product can be obtained by separating the aqueous layer produced as a by-product and fractionating the oil layer, but if necessary, it is also possible to further purify it by methods such as recrystallization or column chromatography. .

The aromatic secondary amino compound obtained in this way is
It is useful as an intermediate in the general chemical industry, especially as an intermediate for pharmaceuticals, J[, etc.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1: To a mixed aqueous solution of 82 parts by weight of magnesium nitrate, 5 parts by weight of zinc nitrate, and 13 parts by weight of aluminum nitrate, 1.05 to 1 times the theoretical amount of ammonia water was added under stirring to obtain a precipitate. The precipitate was thoroughly washed with water, dried, and calcined at 550°C for 5 hours to obtain the desired catalyst (oxide molar ratio MgO:ZnO:A/10
3 = 9 Q: 5: 5).

A glass reaction tube for vapor phase contact with an inner diameter of 5 cm was filled with 1 g of the catalyst and heated to 320°C. Next, nitrogen ′jk2 is added to the reaction tube.
A mixed solution of 1 part by weight of aniline and 1 part by weight of methanol was injected into the evaporator at a rate of &5g/hour while flowing at a rate of 0d/min.The mixed vapor generated came into contact with the catalyst in the reaction tube and reacted. Distillate while doing so. When the reaction product was collected up to 5 hours after the start of the reaction and analyzed using a gas chromatograph 2F, only N-methylaniline was detected, and the conversion rate was 94.5- on the basis of aniline.

Example 2: Using the catalyst of Example 1, a reaction was carried out under the same conditions as Example 1 except that the reaction temperature was changed.

The reaction product was collected up to 5 hours after the start of the reaction and analyzed.

The results are shown in Table 1. Reactions were conducted with other catalysts under similar conditions. The results are summarized in Table 1.

Example 5: Using the catalyst of Example 1, a reaction was carried out under the same conditions as Example 1 except that the reaction temperature was 550° C. and the anilines and alcohols were changed to those shown in Table 1. The results are shown in Table 2.

2-'/'/' Example 4: Example 1 except for using phenol as the alcohol
When the reaction was carried out in the same manner as above, N-phenylaniline was obtained in high yield.

(1 other person)

Claims (1)

[Claims] General formula (I): ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, X represents a hydrogen atom, a halogen atom, a lower alkyl group, or a lower alkoxy group, and n is 1 to Anilines represented by the general formula (II): ROH (II) (wherein R represents an alkyl group or a phenyl group) are combined with zinc (Zn), cadmium Contains at least two metal oxides selected from Cd), aluminum (Al), iron (Fe), calcium (Ca), nickel (Ni), copper (Cu), and titanium (Ti) and magnesium oxide. General formula (III) characterized by the reaction being carried out in the presence of a catalyst: ▲ There are mathematical formulas, chemical formulas, tables, etc. A method for producing an aromatic secondary amino compound.