CS217455B1 - Process for the preparation of anilines substituted with aralkyls on the nucleus - Google Patents

Abstract

The invention solves the simplification of the preparation of anilines of the general formula I or II where R1 and R2 mean hydrogen, a straight or branched hydrocarbon chain with 1 to 4 carbon atoms, R3 hydrogen or methyl, the alkyl group being either in position 2 or 4, as well as increasing the yield and selectivity of the reaction. This purpose is achieved by reacting aromatic amines of the general formula III KHR1 III where R1 and R2 mean hydrogen, a straight or branched hydrocarbon chain with 1 to 4 carbon atoms, R2 being either in position 2 or 4 with styrene or α-methylstyrene at a temperature of 100-140 °C under normal pressure and in the presence of aluminosilicate as a catalyst. The resulting reaction product can serve as an intermediate in the preparation of rubber vulcanization accelerators.

Description

The invention relates to a process for the preparation of aralkyl-substituted anilines on the nucleus by reacting aromatic amines with styrene or α-methylstyrene in the presence of a catalyst.

Until now known aralkylations of anilines on the nucleus are carried out by reacting an aromatic amine with styrene or α-methylstyrene at high temperatures (about 200 ° C) and pressures in the presence or absence of a catalyst.

These procedures may have many disadvantages. When operating at high temperatures and under pressure, polymerization in the reaction mixture of styrene present occurs. On the one hand, the absence of Catalyst Isa results in the fact that not only one product is formed, but the mixture of individual isomers and yields are relatively low. When the reaction is carried out in the presence of a catalyst, higher selectivity of alkylation is achieved as well as higher yields.

A disadvantage of the catalyst used so far, aluminum anilide. is that, prior to alkylation, a catalyst needs to be prepared from aniline and aluminum in the presence of mercury chloride, which is a relatively inconvenient process.

These disadvantages are eliminated according to the invention by a process for the preparation of anilines substituted with aralkyls on the nucleus of formula I or II

wherein R ¹ and R ² are hydrogen, straight or branched (C 1 -C 4) alkyl, R ³ is hydrogen or methyl, wherein the aralkyl group is either in the 2 or 4 position by reaction (aromatic amine of formula III)

MHR ¹

Wherein R ¹ and R ² are as defined above, wherein R ² is in the 2 or 4 position with styrene or α-methylstyrene in the presence of a catalyst.

The reaction is carried out at 10-40 ° C under normal pressure and in the presence of an aluminosilicate catalyst.

The process according to the invention has many advantages over the prior art processes. The reaction runs at relatively low temperatures, it is a non-pressure reaction, i. j. it does not require the use of an autoclave, which has other advantages. No catalyst needed prior to reaction. High selectivity and recovery are achieved.

The following are examples of possible practical embodiments of the method of the invention.

Example # 1

2- (α-methylbenzyl) aniline

In a 100 ml four-necked flask equipped with a magnetic stirrer, a thermometer, (18.63 g (0.2 mol)) of freshly distilled (aniline, 41.76 g (0.4 mol) styrene) and 6 g (10 wt. Under vigorous stirring, the reaction mixture was driven to 120-430 ° C. After all of the reactions (aniline (the progress of the reaction was checked by TLC) were reacted, the reaction mixture was cooled to 70 ° C, unreacted styrene was distilled off under reduced pressure. filtered.

The crude product 2- (α-methylbenzyl) aniline e was crystallized from n-heptane.

Melting point: 55—56 ° C Yield: 85.1%

Elemental analysis:% N calculated - 7.1 found - 6.85

IC spectrum (cm &^lt; ^{4 >} ): [delta] (NH) = 3475;

υ sym (NH) = 3390

1 H NMR spectrum (σ): 6.30-7.02 benzene nucleus with NH ₂ ), corresponding to the 1,2-substituent. Example # 2

2? (? -Methylbenzyl) -N-ethylianiline Following the procedure outlined in Example 1 of the following batches:

24.2 g (0.2 mol) of N-ethylaniline

41.76 g (0.4 mol) styrene

6.6 g (10% by weight) of aluminosilicate

Melting point: 46-47 ° C

Yield: 82%

Elemental analysis:% N calculated - 6.22 found - 6.05

IR (cm ^-1 ): ν (NH) = 3420;

1 H NMR spectrum (σ): 6.32-7.05 (benzene nucleus with NH ₂ ) corresponds to 1,2-substitution.

Example # 3

2- (α-methylbenzyl) -6-methyl aniline Following the procedure in Example 1, from the following batches:

21.4 g (0.2 mol) o-toluidine

41.76 g (0.4 mol) styrene

6.3 g (10% by weight) aluminosilicate

Melting point: 37 ° C

Yield: 80%

Elemental analysis:% ’N calculated - 6.63 found - 6.58

IR spectrum (cm * ¹ ): at as (NH) = 3490 at sym (NH) = 3405

H NMR (σ) = 6.43 to 7.05 (benzene ring with the NH ₂₎ corresponding 1,2,3 - substitution.

Example # 4

4- ^(ad, and ^{the methyl,} benzyl) -6-metylanilíin

Using the procedure given in Example 1 of the following weighings:

21.4 g (0.2 mol) o-toluidine

47.7 g (0.4 mol) α-methylstyrene 6.91 g (10% by weight) of aluminosilicates

Melting point; 51-53 ° C

Yield: 85%

Elemental analysis:% N calculated - 6.22 found - 5.11

IC spectrum (cm ^-1 ):? As (NH) = 3490? Sym (NH) = 34-05

1 H NMR spectrum (σ) = 6.27-6.94 (benzene nucleus with NH ₂ ) corresponds to 1.2.4, substitution. Example # 5

4- (α-dimethylbenzyl) aniline Following the procedure in Example 1, the following batches were weighed:

18.63 (0.2 mol) aniline

47.7 g (0.4 mol) α-methylstyrene

6.63 g of 1 (10% by weight) aluminosilicate

Melting point: 194-197 ° C / 3.99 kPa Yield: 80%

Elemental analysis:% N calculated - 6.63 found - 6.58

IR (au ⁴ ): [delta] (NH) = 3420;

1 H NMR spectrum (σ) = 6.27-6.56 (benzene nucleus with NH ₂ ) corresponds to 1.4 substitutions. Example # 6

24 (.alpha.-methylbenzyl) -4-methyl aniline Following the procedure of Example 1, the following weights are as follows:

21.4 g (0.2 mol) p-toluidine

41.76 g (0.4 mol) styrene

6.3 g (10% by weight) of alumosilicate

Melting point: 38-39 ° C

Yield: 89%

Elemental analysis:% N calculated - 6.63 found - 6.57

IR spectrum (cm ^-1 ): at as (NH) = 3485 υ sym (NH) = 3400

1 H NMR spectrum (σ) = 6.27-6.94 (benzene core with NH ₂ ) corresponds to 1.2.4 substitution.

The substances themselves deflate an anfcioxidative effect and can optionally be used as intermediates for the synthesis of sulfenamide accelerators of rubber vulcanization.

Claims (1)

OBJECT OF THE INVENTION A process for the preparation of ariline-substituted amilines on a core of formula I or II wherein R ¹ and R ² are hydrogen, branched or unbranched alkyl of 1 to 4 carbon atoms, R ³ is hydrogen or methyl, wherein the aralkyl group is either in the 2-position or 4 by reacting an aromatic amine of formula III NHR ¹ Wherein R ¹ and R ² are as defined above, wherein R ² is either in the 2 or 4 position with styrene or α-methylstyrene in the presence of a catalyst characterized in that the reaction is carried out at a temperature of 100-140 ° C under normal pressure and in the presence aluminosilicate catalyst.