CS218720B1 - Method of making the diphenylamine - Google Patents

Abstract

The invention relates to a process for the production of diphenylamine liquid aniline in the presence of a catalyst system which is formed from hydrogen fluoride ammonium or ammonium fluoride and acid boron or boron oxide directly in the aniline which is used for production diphenylamine.

Description

! The invention relates to a process for the preparation of diphenylamine = from aniline in the liquid phase in the presence of a catalyst system which is formed from ammonium hydrogen fluoride or ammonium fluoride and boric acid or boric oxide.

In more recent processes for the production of diphenylamine from aniline, most of the fluorine and boron-containing substances in their molecule, e.g.

Aniline or ammonia complex with iboron trifluoride (NSR Pat. No. 1,116,231). 20% conversion of aniline to diphenylamine was achieved in 8 hours at 300 ° C without removal of ammonia from the reaction system. According to a further procedure, diphenylamine is prepared from aniline by condensation in the presence of ammonium tetrafluoroborate, boron trifluoride and complexes thereof (U.S. Pat. No. 3,071,619). Another method for preparing diphenylamine from aniline uses R ₁ (OH) ₂ BF ₂ and R ₂ O (BF ₃ ) ₄ as catalysts wherein R 6 is ammonium or aniline and R ₂ is twice aniline or twice ammonium (NSR Pat. No. 2,503,660). A disadvantage of using a catalyst of the type R ₂ O (BF ₃ ) ₄ lies in the actual preparation of the compound of the formula. Substances containing boron and fluorine in their atomic ratio of 1: 2 to 1: 4 are used as catalysts for the preparation of diphenylamine from aniline (NSR Pat. No. 2,521,293). This procedure (NSR Pat. No. 2,521,293), for example, was carried out at a temperature of 330 ° C by using the aniline used _; 0.77% ammonium tetrafluoroborate and 0.38% water. The resulting ammonia was removed during the reaction and after 5 hours the diphenylamine content of the reaction mixture was 27% by weight. However, when tetrafluoroboric acid, prepared from hydrofluoric acid and boric acid, in an amount of 1% by weight, calculated on boron trifluoride, has been used, with the addition of 1% by weight of water, working with the ammonia effluent, 3 hours 20.5% diphenylamine in the reaction mixture. The latest procedure for; int diphenylamine from aniline (USSR Pat. Specification ^of 547224) using aluminum chloride as catalyst with the addition of ammonium tetrafluoroborate in quantities; it is 8 to 21% by weight. When using the mixed catalyst in the ratio indicated, higher conversions of aniline ria and diphenylamine were achieved than with the individual components of the catalyst mixture ^; in clean condition. The problem with this catalyst remains the corrosion of the production equipment caused by aluminum chloride.

The above drawbacks ¹ are eliminated in the invention describing a process for the preparation of diphenylamine from aniline in the presence of fluorine or boron-containing substances or a mixture in the presence of water, characterized in that ammonium hydrogen fluoride or ammonium fluoride and boronic acid or oxide boron such that the molar ratio of fluorine / boron is in the range of 1 to 5% the range is 0.04 to 2 or 4 to 30, and is operated without the

in the presence of water or in the presence of water db ‘<0.1% by weight, or in the range from> 5 to 7% by weight, based on aniline, at a temperature of 290 to 390 ° C.

The production of diphenylamine in this manner is carried out as a continuous or discontinuous process, respectively. semi-continuous without or preferably with removal of the resulting ammonia.

An advantage of the process according to the invention is that higher conversions of aniline to; diphenylamine in a shorter time compared to previous processes. The catalyst is prepared according to the proposed process directly in aniline, which is used for the preparation of diphenylamine, the resulting catalyst being relatively well soluble in the reaction mixture without water and very well soluble in water. The advantage is that you can 'work' even without the addition of water, which due to the presence of 'fluorine! of the compounds significantly reduces reactor corrosion. The catalyst is prepared from the available fluorine compounds.

The following examples illustrate the invention in more detail.

Example 1

The production of diphenylamine from aniline is carried out in a rotamag 100 stirred laboratory autoclave equipped with a 250 ml pressure vessel, an electric resistance heater with temperature measurement and control, pressure measurement, sampling during reaction, and a magnetic stirrer.

To 100 g of aniline (1.073 mol) were added 1.63 g of ammonium hydrogen fluoride - NH ₄ HF ₂ - and 0.88 g of boric acid (the fluorine concentration was also 1.087 g and the boron concentration was 0.154 g per aniline feed). (Mol. F / B ratio = 4.03: 1). The reaction is carried out at 340 ° C, 3.5 MPa for 4 hours. The diphenylamine content of the samples taken is determined by gas chromatography at specified time intervals. In the following j tabufke no. 1 shows the time dependence of the conversion of aniline to diphenylamine (α 1).

Table no. 1 ^! '

Reaction time (h) ^and AD (%) 0 6.8 0.5 ^: 15,8 1 21.7 1.5 24.4 2 26.4 3 30.4 4 32.9

Example 2

To 100 g of aniline are added 2,1 g of ammonium fluoride and 0,9 g of boric acid corresponding to the concentration of

1.08 g of fluorine and 0.157 g of boron per 100 g of aniline (ratio F: B = 4.03: 1) The aniline formation reaction is carried out at 340 ° C, at a pressure of 2.0 MPa in a 14 apparatus as in Example 1. The reaction during the first 4 hours is shown in Table 2 below as a function of the conversion of aniline to diphenylamine from reaction time.

Table no. 2

Reaction time (h) & AD (%) 0 7.1 0.5 14.0 1 17.2 1.5 22.9 2.0 23.4 3.0 26.6 4 28.6

Example 3

The diphenylamine formation reaction from aniline is carried out at a temperature of 360 ° C, a pressure of 2.8 MPa in the apparatus shown in Example 1.

To 100 g of aniline are added 3.27 g of ammonium hydrogen fluoride (0.057 mol) and 0.99 g of boric acid (0.014 mol), which corresponds to a fluorine concentration of 2.18 g and boron 0.3 g per 100 g of aniline (mol ratio F: B = 4.12: 1). Samples of the crude reaction product were analyzed for diphenylamine content by gas chromatography and are shown in Table 2. Third

Table no. 3

Reaction time (h) & AD (%) 0 8.0 0.5 17.2 1 23.4 1.5 25.6 2.0 28.4 3.0 31.7 4 35.4

Example 4

3.27 g of ammonium hydrogen fluoride and 0.88 g of boric acid, m.p. j. per 100 g of starting aniline, 2.18 g of fluorine and 0.154 g of boron (mol ratio F: B = 8.08: 1) were added.

The reaction is carried out at a temperature of 388 ° C, a pressure of 3.2 MPa in the same apparatus as in Example 1, the results are shown in Table 1. 4th

Table no. 4

Reaction time (h) & AD (%) 0 4 0.5 10.2 1 13.8 1.5 16.8 2 18.5 3 24.0 4 25.0

Example 5 2Τβ720

To 100 g of aniline is added 0.45 g of ammonium hydrogen fluoride and 0.24 g of boric acid, corresponding to a fluorine concentration of 0.3 g and boron 0.042 g per 100 g of aniline (mol ratio F: B = 4, 05: 1). The preparation of diphenylamine was carried out at 370 ° C, 3.5 MPa. The aniline and diphenylamine contents were determined by gas chromatography in the samples of the reaction mixture. The time dependence of the conversion of aniline to diphenylamine is shown in Table no. 5

Table no. 5

Reaction time (h) & AD (%) 0 2 0.5 7 1 12 1.5 15 2 18 3 20 4 24 5 26

Example 6

To 100 g of aniline are added 6 g of ammonium hydrogen fluoride (NH ₄ HF ₂ ), 0.1 g of boric acid and 6 g of water (molar ratio F / B = 12: 1). The preparation of diphenylamine is carried out at 310 ° C for 4 hours. The aniline and diphenylamine content of the reaction mixture was determined by gas chromatography. The time dependence of the conversion of aniline to diphenylamine is shown in Table no. 6th

Table no. 6

Reaction time (h) AD (%) 0 3 1 11 2 20 3 22 4 26

Example 7

To 100 g of aniline was added 6 g of ammonium hydrogen fluoride 0.05 g of boric acid (molar ratio _: F / B = 22.2: 1). The reaction was carried out without addition of water. The results in the form of time dependence and formation of diphenylamine are shown in Tab. 8th

Table no. 8

Reaction time (h) & AD (%) 0 5 1 15 2 23 3 27 4 29

Example 8

Κ 100 g of aniline were added 1.5 g of boric acid and 0.5 g of ammonium fluoride (molar ratio F / B = - 1.13: 1). The reaction was carried out at 350 ° C for 4 hours. The results of diphenylamine formation as a function of time are shown in Tab. no. 9. Table no. 9

According to the process of the present invention, diphenylamine, one of the group of amines most commonly used as an intermediate for the manufacture of rubber chemicals, can be prepared.

Reaction time (h) ^and AD (%) 0 3 1 12 2 17- 3 23 4 25

SUBJECT

Claims (1)

SUBJECT Process for producing diphenylamine from aniline in the presence of substances or mixtures thereof containing fluorine and boron and optionally in the presence of water at elevated temperature, characterized in that ammonium hydrogen fluoride or ammonium fluoride and boric acid are added to the aniline entering the reaction; OF THE INVENTION boron trioxide such that the molar ratio of fluorine / boron is in the range of 0.04 to 2 or 4 to 30, operating in the absence of water or in the presence of water up to <0.1% by weight or in the range of> 5 to 7% % by weight of pa aniline, at a temperature of 290 to 390 ° C. ¹