KR820000052B1 - Dinitroaniline purification with inorganic acid halides - Google Patents

Abstract

Nitrosamines were removed from dinitroanilines, eg., trifluoralin, isopropalin, benefin, butralin, tendimethalin, fluchloralin, profluralin, dinitramine by treating with Ti-Cl4, PCl3, PCl5, PBr3, POCl3, SCl2, SOCl2, SO2Cl2, or SOBr2. Thus, the nitrosamine content of 30g trifluraline treated with 0.1 mL TiCl4 for 2 hr at 90≰C decreased from 68 to 3.8 ppm.

Description

Method for Purifying Dinitroaniline with Inorganic Acid Halides

The present invention relates to a process for purifying dinitroaniline by reducing the nitrosamine concentration in dinitroaniline.

Aliphatic N-nitrosamines are described in Russ. Chem. Rev. 40 (1) 34-50 (1971) Eng. Denitrosation of six nitrosamines (not included in the scope of this method) using thionyl chloride has also been reported in the literature (Analy. Lett. 6 (4) 369-72 ( 1973) (Chem. Abst. 79132916b).

German Patent No. 2,035,796 (recorded in Chem. Abst 76: 126964e) is a method for substituting the residue of an activated halogenated organic compound with a nitroso group on a heterocycle compound and in German Patent No. 482,795 (Chem. Abst. 24: 378). Recording) relates to denitrification with Ticl ₃ .

Compounds of dinitroanilines include various commercially available manufacturers. Recently a new analyzer, known as a thermal energy analyzer (TEA), has been developed. See J. Chromatogr. 107 (1975), 351 and reberence therecited; and "N-Nitroso compounds in the Environment", IARC Scientific publication # 9 (International Agency for Research on concer, cyon, 1947), P40]

O) Used for group analysis, it is possible to detect even lower concentrations of 0.02 ppm than in the analytical method of the prior art. Accordingly, several dinitroanilines by TEA have shown that dinitroaniline contains a very small amount of nitrosamines. Nitrosamines have been shown to confer carcinogenicity to animals. Therefore, it is desirable to reduce the concentration of nitrosamines in dinitroaniline.

In this way, the amount of nitrosamines present in dinitroaniline can be reduced and the adverse effects on humans or animals can be weakened.

The present invention relates to 1) trituralin, isopropalin, benepine, etafluralin, butyralline, tendimethalin, fluchlorine, propluraline, dinitramine, 4-trifluoromethyl-2, 6 Nitrosamines selected from -dinitro-3-chloro-N, N-diethylaniline, 4-methyl-2, 6-dinitro-N, N-bis (2-chloroethyl) aniline, oryzaline and nitraline Containing dinitroaniline (a) in a liquid phase and (b) a reagent selected from (b) pcl ₃ , pcl ₅ , p _B r ₃ , pocl ₃ , scl ₂ , socl ₂ , so ₂ cl ₂ , soBr ₂ or Ticl ₄ A method of recovering (c) dinitroaniline after reacting until the concentration is reduced is provided.

Dinitro aniline that can be used in the present invention is as follows. (The parenthesis is normal)

(1) 4-trifluoromethyl-2,6-dinitro-N, N-di-n-propyl aniline (tripulalurine),

(2) 4-isopropyl-2,6-dinitro-N, N-di-n-propyl aniline (isopropelin),

(3) 4-trifluoromethyl-2,6-dinitro-N-n-butyl-N-ethylaniline (benephine),

(4) 4-trifluoromethyl-2,6-dinitro-N-ethyl-N-metall aniline (ethalfluranine),

(5) 4-tert-butyl-2,6-dinitro-N-secondary-butyl aniline (butraline),

(6) 3,4-dimethyl-2,6-dinitro-N- (1-ethylpropyl) -aniline (tendimethalin),

(7) 4-trifluoromethyl-2,6-dinitro-N-propyl-N- (2-chloroethyl) aniline (fluchlorine),

(8) 4-trifluoromethyl-2,6-dinitro-N-propyl-N- (cyclopropyl ethyl) aniline pro (fluralin),

(9) 4-trifluoromomethyl-2,6-dinitro-3-amino-N, N-diethylaniline (dinitramine),

(10) 4-trifluoromomethyl-2,6-dinitro-3-chloro-N, -diethylaniline

(Intermediates of dinitramine),

(11) 4-methyl-2,6-dinitro-N, N-bis (2-chloroethyl) -aniline,

(12) 4-sulfamoyl-2,6-dinitro-N, N-di-n-propyl aniline (orizaline) and

(13) 4- (methylsulfonyl) -2,6-dinitro-N and N-di-n-propyl aniline (nitraline).

Preferred dinitroanilines for use in the present invention are trituralin, isopropalin, benepine and etafluralin.

In general, dinitroaniline (e.g., trituralin) is prepared by the following typical reaction pathway.

It is considered that a small amount of nitrogen oxide remaining in the nitration reaction step reacts with a part of the amine during the amination reaction to generate a small amount of nitrosamine and mix in the final product. The mixed nitrosamines are therefore expected to be nitroso derivatives of the alkylamines used. However, it can be inferred that very small amounts of other nitrosamines may also be formed. In either case, it is desirable to remove nitrosamines, and therefore also an object of the present invention.

The mechanism of this process is not elucidated, but only "denitrosation" is known which converts nitrosamines to compounds that do not contain nitrosamine groups.

This process can actually reduce the nitrosamine concentration regardless of the initial amount of nitrosamines. In most cases, the nitrosamine concentration is reduced to 10 ppm or less.

The process of the invention is carried out in the liquid phase. In the case of dinitroaniline that melts at a low temperature such as 140 ° C. or lower, nitrosamine-containing dinitroaniline can be preferably achieved by heating the melting point of the amine or a slightly higher temperature. Trituralin melts at 54-55 ° C., benepine at 65-66 ° C., isopropalin at 30 ° C., but is generally liquid at room temperature due to small amounts of impurities. In addition, the liquid state may be carried out by dissolving nitrosamine-containing dinitroaniline in a solvent. Suitable solvents are aromatic solvents such as benzene and toluene, halogenated aliphatic hydrocarbons such as chloroform, methylene chloride and carbon tetrachloride.

The amount of reagent used is not too much of a problem as long as it is sufficient to reduce the initial amount of nitrosamine. Generally, 0.1 to 2.0 g per 100 g of dinitroaniline is sufficient.

The reaction is carried out at a wide range of temperatures, such as from room temperature to 140 ° C., and when the appropriate reaction is carried out, the reaction occurs above the melting point of each of the dinitroanilines. Good results are obtained at temperatures between 70 ° and 90 ° C. when the reaction is carried out with trituralin, isopropalin, benepine and etafluralin. The reaction can also be carried out at atmospheric or elevated pressure.

The rate of carrying out the present invention may vary depending on the concentration of nitrosamines, temperature, reagents, addition ratios and other factors, but results are not good if water is present.

Nitrogen amine removal can be confirmed by gas chromatography or TEA analysis. Denitrosization is usually completed within 1 hour.

It was shown in the process of the present invention that the amount of nitrosamines was reduced at the beginning of the reaction and sometimes the nitrosamine content slightly increased as the reaction time was extended. Further nitrosamine may be produced by further extending (1) dinitroaniline and (2) denitrositization products to the reaction conditions. Therefore, it is desirable to minimize the reaction time.

Preference is given to neutralizing and separating the purified dinitroaniline.

The following examples illustrate the invention and one of ordinary skill in the art may readily practice the invention.

Unless stated otherwise, the nitrosamine concentration in the following examples is determined by gas chromatography with a sensitivity of 0.5 ppm or less.

"Not detected" (denoted "N. D") is considered to be 0.5 ppm or less of nitrosamine. This can be accomplished by using the Hilet-Packard Model 5711A gas chromatography apparatus but using gas chromatography with a flame ionization detector. A column packed with 3% Carbowax 20M of 100/120 mesh AM DMCS Chromosolve G as a 1/8 inch inner diameter 4 foot chojacoil was operated at 100 ° C. After the nitrosamine peak elutes, the column is heated at 230 ° C. for 15 minutes. The flow rate of helium is 60 ml per minute. Standards are used at concentrations approximately equal to the expected nitrosamine concentrations in the sample, and both standard and sample are prepared with methylene chloride.

The assay was performed by the method described in J. Chromatogr. 109. (1975), 271. This method according to the invention can detect low concentrations of nitrosamines, such as 0.05 ppm. In the TEA analysis of the sample, no nitrosamine was detected as "N.D".

Example 1

Trituralin, Nitrosamine Removal from PCl ₃

30 g of trituralin and 0.5 g of PCl _{3 having an} average assay value of 68 ppm of nitrosamine were mixed and heated to 70 ° C., and then the reaction mixture was stirred for 1 hour while maintaining 70 ° C. Samples were taken at 30 minutes and 1 hour and analyzed for nitrosamine concentration. The reaction mixture was neutralized with 2 ml of 10% sodium carbonate solution to separate the layers, and the aqueous layer was extracted with the same amount of methylene chloride. Methylene chloride extracts are also analyzed for nitrosamine content. The test results are as follows.

Sampling time Nitrosamine concentration

1.2 ppm for 30 minutes

1 hour N. D.

-(Methylene chloride extract) N. D.

Example 2

Trituralin, Nitrosamine Removal from PCl ₃

The process was carried out in the same manner as in Example 1 except that 1) 0.2 g of PCl ₃ was used, 2) the temperature was 90 ° C., and 3) the reaction was completed in 30 minutes. As a result of analyzing the nitrosamine content of the sample, 0.9 ppm was detected.

Example 3

Trituralin, Nitrosamine Removal from PCl ₃

Reaction as in Example 2 but here 0.02 g of PCl ₃ is used. As a result of analyzing the nitrosamine content, it was not detected.

Example 4

Trituralin, Nitrosamine Removal from PCl ₃

The reaction was carried out as in Example 3, but the temperature was 120 ° C. Sample analysis showed no nitrosamines.

Example 5

Etalfluralin, Nitrosamine Removal from PCl ₃

After heating 30 g of etafluralin containing 8.6 ppm of nitrosamines to 90 ° C., 0.2 g of PCl ₃ was added and the reaction mixture was stirred at 90 ° C. for 1 hour. 5 ml of 10% sodium carbonate solution is added and the layers are separated. The etaplanin layer is taken and analyzed for nitrosamine content by TEA.

As a result, 5 ppm of nitrosamine was detected.

Example 6

Isopropaniline, nitrosamine removal from PCl ₃

Xylene solution of isopropelin (corresponds to 35 g of isopropalin with 33.5 ppm Nitros amine assay).

50 ml are removed by rotary evaporator at 90 ° C. for 20 minutes.

0.5 ml of PCl _{3 is} added and the reaction mixture is stirred at 80 ° C. for 30 minutes. After adding 20 ml of 5% sodium carbonate, the mixture was stirred for 10 minutes, removed by a rotary evaporator (evaporated at 100 ° C. for 15 minutes), and analyzed for nitrosamine content. As a result, 1.9 ppm of nitrosamines were detected.

[Example 7-9]

Trituralin Removes Nitrosamines from SOCl ₂

A series of three reactions is carried out with varying amounts of SOCl ₂ used, reaction temperature and reaction time. In each reaction, 30 g of trituraline and SOCl ₂ with an average assay value of 68 ppm of nitrosamines are mixed and heated to each reaction temperature. The reaction mixture is kept at reaction temperature for a period of time, neutralized with 2 ml of 10% sodium carbonate solution, the layers are separated and in the first reaction the organic layer is extracted with the same amount of methylene chloride. Nitros amine content analysis results of the samples are as described below.

Example 10

Etalfluraline, Nitrosamine Removal from SOCl ₂

30 g of etafluralin having a nitrosamine analysis value of 8.6 ppm are heated to 90 ° C, 0.2 g of SOCl _{2 is} added, and the reaction mixture is stirred at 90 ° C for 1 hour. 5 ml of 10% sodium carbonate solution is added and the layers are separated. As a result of analyzing the organic layer by the TEA method, 0.44 ppm of nitrosamine was detected.

EXAMPLE 11-13

Trituralin Removes Nitrosamines from PBr ₃

In the first reaction, 30 g of trituralin with an average assay of 68 ppm nitrosamine were heated to 70 ° C. and 0.5 g of PBr _{3 was} added. The reaction mixture is kept at 70 ° C. for 30 minutes, neutralized with dilute sodium carbonate solution and the layers are separated.

The organic layer was analyzed for nitrosamine and found to be 1.1 ppm.

When the reaction temperature was set to 90 ° C. and the reaction was repeated using 0.1 g of PBr _{3, the} concentration of nitrosamine was reduced to 2.3 ppm.

Nitrosamine was not detected when the reaction temperature was set to 120 ° C. and analyzed using PBr ₃ 0.1 g as described above.

Example 14

Removal of nitrosamines from tripurine, TiCl ₄

30 g of trituralin, with an average assay value of 68 ppm of nitrosamines, are heated to 90 ° C and 0.1 ml of TiCl ₄ is added.

After maintaining the reaction mixture at 90 ℃ and periodically taking a sample to analyze the nitrosamine content.

The result is as follows.

Example 15

Trituralin, Nitrosamine Removal from SCl ₂

After dissolving 100 g of trituralin, 0.2 g of SCl ₂ is added and the reaction mixture is stirred at 90 ° C. for 1 hour.

Samples were taken and analyzed for nitrosamines.

Sampling time Nitrosamine concentration

0 50ppm

30 minutes 7.4 ppm

1 hour 7.3 ppm

[Example 16-18]

Trituralin Removes Nitrosamines from POCl ₃

Three reactions are carried out by addition of POCl ₃ .

In each reaction, 30 g of trituralin containing 68 ppm of nitrosamine average assay was heated to each reaction temperature, then POCl ₃ was added and the reaction mixture was held at each reaction temperature for 30 minutes. The reaction mixture is neutralized with sodium carbonate and the organic layer is analyzed to detect nitrosamine content. Each reaction condition and analysis result are as follows.

POCl ₃ Reaction Temperature Nitrogen Amine Concentration

0.3g 70 ℃ 5ppm

0.1g 90 ℃ 10ppm

0.1g 120 ℃ 14ppm

Example 19

Trituralin, Nitrosamine Removal from PCl ₃

30 g of trituralin with 68 ppm of nitrosamine analysis are mixed with 0.2 g of Pcl ₃ and 0.05 g of sodium carbonate. The reaction mixture is heated to 90 ° C. and maintained at this temperature for 30 minutes, then neutralized by adding 2 ml of 10% sodium carbonate solution and separating the layers. The analysis of the trituralin layer showed no nitrosamines.

Example 20

Trituralin, Nitroamine Removal from PCl ₃

30 g of trituralin with an average assay of 68 ppm of nitrosamines are heated to 90 ° C. and 30.03 ml of Pcl _{3 are} added.

The reaction mixture was maintained at 90 ° C. for 2 hours, and then the samples were periodically taken and analyzed.

Example 21

Trituralin Removes Nitrosamines from SO ₂ Cl ₂

30 g of trituraline having a nitrosamine analysis value of 36 ppm was heated to 120 ° C., and 0.5 ml of SO ₂ Cl ₂ was added thereto. The reaction mixture is kept at 120 ° C. for 1 hour and then samples are taken at 30 minutes and 1 hour. Each sample was washed with 10 ml of water, dried on a rotary evaporator at 60 ° C. for 15 minutes, and analyzed for nitrosamine content.

Sampling time Nitrosamine concentration

30 minutes 4ppm

1 hour 2 ppm

Example 22

Trituralin Removes Nitrosamines from PCl ₅

Reaction and analysis as in Example 21 using 0.5 g of PCl ₅ instead of SO ₂ Cl ₂ were as follows.

Sampling time Nitrosamine concentration

30 minutes 8ppm

4-ppm 1-

Claims (1)

Trituralin, isoprophalin, benepine, etaflularine, butyralline, tendimethalin, fluchlorine, profluralin, dinitramine, 4-trifluoromethyl-2, 6-dinitro-3- Nitrosamine-containing dinitroaniline selected from chloro-N, N-diethylaniline, 4-methyl-2, 6-dinitro-N, N-bis (2-chloroethyl) aniline, oryzaline and nitraline in recovering the _{PCl 3, PCl 5, PBr 3} , POCl 3, SCl 2, SOCl 2, SO 2 Cl 2, SOBr 2 or TiCl selected from ₄ reagent and knit was reacted until the reduced loss amine concentration dinitro aniline Method for purifying dinitro aniline, characterized in that.