JPS58146534A - Preparation of n-alkylaniline - Google Patents

Abstract

PURPOSE:To prepare the titled compound, in high yield and selectivity, by reacting an aniline compound with a lower alcohol, etc. in a vapor phase using a solid acid composition composed of a sulfate ion, a titanium compound and a zirconium compound as a long-acting catalyst. CONSTITUTION:The objective compound of formula II (at least one of R<1> and R<2> is lower alkyl and the other is H) is prepared by reacting the aniline compound of formulaI(X is halogen or lower alkyl; n is 1-5) with a lower alcohol and/or di(lower alkyl) ether in the presence of a solid acid composition catalyst composed of sulfate ion, a titanium compound and a zirconium compound, in the vapor phase at 200-300 deg.C under atmospheric pressure. The solid acid composition is a hydrogel mixture of titanium and zirconium containing sulfate ion and obtained by the coprecipitation of a raw material mixture having an atomic ratio Ti/Zr of 0.05-20 and S/(Ti+Zr) of 0.02-4 in the presence of sulfate ion keeping the pH of the mother liquor at 3-10.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing N-alkylanilines from anilines. WlK for details.

Applying a solid acid catalyst prepared from a titanium compound and a zirconium compound in the presence of sulfate ions, anilines are reacted with alcohol-μ and/or ether in the gas phase to produce N-alkylanilines. Regarding how to.

Conventionally, production of ON-alkylanilines from anilines has been carried out in a liquid phase using a homogeneous catalyst such as sulfuric acid or phosphoric acid. Since this method requires the use of a pressure- and corrosion-resistant reactor and a neutralization step, gas phase methods have long been studied and various catalysts have been investigated. Among these, r-alumina is considered to be relatively good.

Regarding nickel sulfate, r-alumina requires a two-step reaction to increase the reaction rate of anilines, while nickel sulfate requires high temperature for reaction and also collapses due to moisture absorption when left in the air. Therefore, it has the disadvantage of being difficult to handle.

The present inventors were able to obtain N-alkylanilines from anilines in good yield in the gas phase.

As a result of our efforts to develop a solid acid catalyst that is readily available, we have completed the present invention. That is, the present invention provides the following method: in the presence of a solid acid catalyst prepared from a titanium compound and a zirconium compound in the coexistence of sulfate ions, (1m is 1 to 5)) and a lower AμCOμ and/or a V lower AμETEμ are reacted in the gas phase (where X has the same meaning as above, and n is 1 to 5. R1 and lp represent a hydrogen atom or a lower alkyl group, and at least one of them is a lower alkyl group. This is a turtle on how to do it.

The anilines used in the present invention are represented by the general formula (1), and specific examples include aniline, 2-chloroaniline, 3-90roaniline, 4-chloroaniline, 2-methylaniline, '3-methylaniline. , 4-ethylaniline, 2-ethylaniline, 3-ethylaniline, 4-ethylaniline, 2-prohylaniline, 3-prohylaniline, 4-prohylaniline, 2.4-diethylaniline, 2-methyaniline Examples include l/-4-propylaniline.

Specific examples of lower alcohol μ used in the present invention include:
Examples include methyl alcohol, ethyl alcohol, propyl alcohol, and butyl alcohol.

Specific examples of di-lower ethers used in the present invention include dimethyl ether, diethyl ether, diderobil ether, and diptyle ether.

The catalyst used in the present invention is obtained by co-precipitating hydrogen of titanium and zirconium by adding alkali from a mixed aqueous solution of a soluble salt of titanium and a soluble salt of zirconium in the presence of sulfate ions. Composition, composition in which sulfate ions are added to a hydrogel co-precipitate of titanium and zirconium, composition in which titanium hydrogel and zirconium hydrogen μ are homogeneously and thoroughly mixed in the presence of sulfate ions, in the presence of sulfate ions A composition in which zirconium hydrogen μ is deposited on titanium oxide, a composition in which titanium hydrogen μ is deposited on zirconium oxide in the presence of sulfate ions, or titania-zirconia is impregnated in an aqueous solution containing sulfate ions. It can be obtained by drying and baking from the composition.

The titanium compound as the catalyst raw material used in the present invention is as follows:
Examples include soluble salts of titanium tetrachloride, titanium sulfate, titanium oxysulfate, titanium nitrate, titanium hydroxide, and titanium dioxide. Further, as the zirconium compound, soluble salts such as zirconium chloride, oxidized V-filled zirconium, zirconium sulfate, zirconium oxysulfate, zirconium nitrate, zirconium oxynitrate, zirconium acetate, zirconium oxyacetate, zirconium hydroxide, zirconium oxide, etc. are used. It will be done. As the sulfate ion raw material, sulfates such as sulfuric acid, ammonium sulfate, sodium sulfate, titanium sulfate, titanium oxysulfate, and zirconium sulfate are used. Furthermore, hydrogen μ can be added to these salt aqueous solutions.
Examples of alkaline substances that cause precipitation are caustic alkali and ammonia.

Alternatively, there are urea and the like which produce ammonia by thermal decomposition.

The raw material composition of the catalyst is Ti/Zr in atomic ratio of 0.05 to 20.
, S/(Ti+Zr) is preferably 002 to 4. If the raw material composition is within the range, a catalyst with good activity and selectivity can be obtained.

The catalyst used in the present invention can be prepared from the above-mentioned raw materials by the coprecipitation cogelation method, crosstalk method, or deposition method, but the coprecipitation cogelation method is preferred.

In preparing the catalyst used in the present invention, H is preferred. If the pH is 10 or more, the catalytic activity of the obtained solid acid is low, and if the pH is 3 or less, hydrogen production is incomplete.

The hydrogel obtained by the previous method is separated, washed with water, and dried in a conventional manner to become a solid acid, and the firing temperature is 700°C or less, preferably 200 to 600°C. Outside this range, the catalytic activity of the obtained solid acid is low.

The catalyst obtained as described above is stable even when left in the air without decomposing due to moisture absorption.

The catalyst used in the present invention further contains ferrous oxide, ferric oxide, amiumina, and molybdenum oxide.

In the present invention, the use of □, lower alcohol, di-lower alkyl ether, etc. contains a small amount of one or more selected from tungsten oxide, silica, boria, phosphorus pentoxide, etc., without affecting the catalyst performance. The appropriate amount is usually 1 to 10 mo of the aniline compound.

The lower alcohols and di-lower alcohols may be used alone or in combination.

The reaction of the present invention is carried out in the gas phase, and the reaction temperature is 20
0 to 300°C is preferred. 200 tl: At much lower temperatures, the yield of N-alkylanilines decreases, and 300 tl
At temperatures even higher than ℃, nuclear alkylation may occur and high boiling point products may be produced.

In carrying out the present invention, a mixed gas of aniline and lower alcohol μ or di-lower alkyl ether, which has been heated and vaporized at 200 to 300°C, is usually used in a reaction tube K filled with a catalyst. It is diluted with an inert gas such as nitrogen, helium, or argon and then supplied for reaction. In addition, before contacting with the catalyst, anilines and lower alcohols, °
It is preferable to preheat the di-lower alkyl ether to around the reaction temperature.

There is no particular restriction on the ratio of anilines and catalyst used, but when using a fixed bed flow reactor, anilines t-LH
It is preferable to supply 8V0.01 to 1.00h-''.

The reaction pressure may be normal pressure, but may also be pressurized.
1], such as N-lower alkylaniline,
N, N-di-lower alkyl-aniline, N-lower alkyl-
Examples include halogenated aniline and N-lower 7μ-lower alkylaniline. The N-7μ anilines obtained by the method of the present invention can be separated and purified by known methods.

According to the present invention, the catalyst does not disintegrate due to moisture absorption even when left in the air, does not corrode the reaction equipment, and can produce N-alkylanilines from anilines at a high yield.

It can be obtained with high selectivity, and has little tar adhesion during the reaction, and its activity lasts for a long period of time.

Hereinafter, the features of the present invention will be described in detail in catalyst preparation examples and examples.

Catalyst Preparation Example 1 500 grams of titanium tetrachloride was dropped little by little into 11 grams of distilled water cooled to 0°C, and after one drop had been added.

Dilute to 21 by adding distilled water. To 90 ji (0.12 mo/l/) of this titanium tetrachloride aqueous solution was added 8 ji of water of zirconium oxychloride! 2ooP (o, szmo~) and ammonium sulfate 38F (0.29 mol) were mixed, and distilled water was added to make 1 t of a homogeneous solution. Add 28W to this solution while stirring.
tl of ammonia water was added dropwise until the pH reached approximately 7 to obtain a coprecipitate of titanium and zirconium hydrogen containing sulfate ions. The required amount of ammonia water is 100 F (1
, 35 moμ). This hydrogel was separated in a furnace, washed with water until the amount of chlorine ions was reduced to a trace, dried at 90 to 120°C for 5 hours, and fired at 500 tons in an air atmosphere for 3 hours.
Solid acid composition 93F was obtained.

Catalyst Preparation Examples 2 to 4 Solid acid compositions having different composition ratios were obtained in the same manner as in Catalyst Preparation Example 1 except that the weight composition of the raw materials was changed. Table 1 shows the atomic ratios of the raw material compositions.

Table 1゜Catalyst Preparation Example 5 The titanium tetrachloride aqueous solution 40II/- used in Catalyst Preparation Example 1 and a solution of zirconium oxychloride octahydrate 305V dissolved in 400-distilled water were mixed to form ammonium sulfate 32F! was added, and further distilled water was added to make a homogeneous aqueous solution of 31. Add urea 20 (1') to this solution, stir for 3 hours while heating to 100°C until the pH of the mother liquor becomes about 8,
Co-precipitated hydrogen of titanium and zirconium containing sulfate ions. The following operations were carried out in the same manner as in Catalyst Preparation Example 1. (However, calcination was performed at 200°C for 6 hours) Catalyst Preparation Example 6゜Titanium tetrachloride aqueous solution used in Catalyst Preparation Example 1 2 s Om
8 liters of zirconium oxychloride 119F and sodium sulfate 1059 were mixed in 1 l, and distilled water was added to make a homogeneous solution of 1 l. A 20 wt % aqueous sodium hydroxide solution was added dropwise to this solution while stirring until the pH reached approximately 7, to obtain a coprecipitate of titanium and zirconium hydrogel containing sulfate ions. The required amount of zowtl aqueous sodium hydroxide solution was 440 tons. The following operations were carried out in the same manner as in Catalyst Preparation Example 1. (However, calcination was performed at 400°C for 3 hours) Catalyst Preparation Example 7 30% titanium sulfate aqueous solution 4802 and zirconium chloride 9
A solution prepared by dissolving 72 in 100 g/distilled water was mixed, and distilled water was added to form a homogeneous solution of 11. While stirring, 28 wt % ammonia water was added dropwise to this solution until the pH reached approximately 7 to obtain a coprecipitate of titanium and zirconium hydrogel containing sulfate ions. The required amount of zswtl ammonia water was 170F. The following operations were carried out in the same manner as in Catalyst Preparation Example 1. (However, the calcination was at 600°C for 3 hours) Example 1 The 20-100 mesh portion 30F obtained by sieving the catalyst of Preparation Example 1 was packed into a one-layer IQ51 glass tube with a diameter of 2.1 cm and fixed. Bed gas phase reactor at 240℃
7 to 1:4 ratio of aniline and methano-μ under normal pressure.
The mixture was charged with LH8Vα2h-1. After 10 hours had elapsed, the reaction solution was collected and analyzed by gas chromatography. The conversion rate of aniline was 100%, and the composition of the reaction solution was 0.4% N-methylaniline and 0.4% N,N-dimethyl. Aniline was 99.6ch. This catalyst dloo
The initial activity 1 selectivity was maintained even after Oh had passed.

Examples 2 to 7 The same procedures as in Example 1 were carried out except that the catalysts of Catalyst Preparation Examples 2 to 7 were used as catalysts.

Table 2 shows the analysis results of the reaction solution after 10 hours.

All of these catalysts maintained their initial activity and selectivity after 1000 hours.

Table 2゜Example 8 Same as Example 1 except that the molar ratio of aniline and methanol was 1:1.5! Alms nine. The conversion rate of aniline is 9144, and the yield of N-)f-IW aniline is 95.
It was gI.

Examples 9 to 11 1 ethanol, n-
Everything was carried out as in Example 1, except for using butanol, diethyl-ether, changing the molar ratio of aniline and alkylating agent, and changing the reaction temperature. 1
Progress table 3゜Example 12 4-Chloroaniline and methi-Aμcovtotmoμ ratio 1:
The same procedure as in Example 1 was carried out except that 6% LH8Vo, xoh-' was supplied, the catalyst of Catalyst Preparation Example 3 was used, and the reaction temperature was 270°C. The reaction solution after 10 hours was analyzed by gas chromatography.

Its composition is 4-chloroaniline 3%, N-methyl 1k-4
-riqa7niline was 74%, and N,N-dimethyl-4-chloroaniline was 96%.

Example 13 Same as Example 1 except that the molar ratio of 4-methylaniline and methyl 7μcoμ was 120, the catalyst of Catalyst Preparation Example 5 was used, and the reaction temperature was 260°C. carried out. After 10 hours had elapsed, the reaction solution was analyzed using Gas Chroma F Goofy, and the composition was found to be N-methyl-
4-Methylaniline 1, N, N-dimethy7A/-4-
It was Methy μ aniline 994.

Example 14 The same procedure as in Example 13 was carried out except that 2,4-dimethylaniline was used instead of 4-methylaniline. When the reaction solution after 10 hours was analyzed by gas chromatography, its composition was tt, N-methy/L/-2
,4-dimethy~aniline 1.5, N,N-dimethy/
I/-2,4-dimethylaniline was 98.5%.

Claims (1)

[Claims] (1) The atomic ratio of the raw materials is Ti/Zr from 0.05 to 20.
VCT i +Zr ) is a sulfate ion from 0.02 to 4. A solid acid composition obtained by drying a mixture consisting of a titanium compound and a zirconium compound and calcining it at 700°C or lower is used as a catalyst, (wherein X represents a hydrogen atom, a halogen atom, or a lower alkyl group, A general formula (where X is the same as above, n is 1 to 5) characterized by reacting an aniline represented by R1, il! represent a hydrogen atom or a lower 7μ group, at least one of which is a lower alkyl group). (2) The solid acid composition is in the presence of sulfate ions. It is obtained by coprecipitation under conditions where the pH of the mother liquor is 3 to 10. The method according to claim 1, wherein the hydrogen mixture is titanium and zirconium containing sulfate ions. (2) The method according to claim 1, wherein the mixture is a mixture of titanium and zirconium human W; Ge μ coprecipitates and sulfate ions. G41 The above-mentioned mixture is obtained by depositing hydrogen μ of either a titanium compound or a zirconium compound on the other compound in the presence of sulfate ions and under conditions where the pH of the mother liquor is 3 to 100. The method described in Section 1. (5) The method according to claim 1, wherein the mixture is a mixture of sulfate ions and titania/ziconia prepared by a coprecipitation method.