CS265786B1 - Process for preparing 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine - Google Patents

Abstract

The essence of the solution is the use of mother liquors remaining after separation of 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine prepared by reaction of 4,5-dichloro-1-phenyl--6-oxo-1H-pyridazine with aqueous ammonia solution in the presence of 4-phenolsulfonic acid sodium salt as catalyst; in another cycle of 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine. To said mother liquors containing ammonium chloride, ammonia and 4-phenol sulfonic acid sodium salt, a 20 to 50% aqueous sodium hydroxide solution is added in any order at a temperature of 10 to 45 ° C, an aqueous solution of 4-phenolsulfonic acid at a concentration of 40 to 50%. 80%, 4,5-dichloro-1-phenyl-6-oxo-ΙΗ-pyridazine and a lack of ammonia, with a molar ratio between 4-phenol sulfonic acid and sodium hydroxide being 1: 1 and a molar ratio between ammonium chloride and sodium hydroxide is 1: 0.1 to 1.1 and the resulting mixture is reacted in a known manner with 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine.

Description

The present invention relates to a process for the preparation of 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine by reaction

4,5-Dichloro-1-phenyl-6-oxo-1H-pyridazine with an aqueous ammonia solution in the presence of a reaction catalyst formed.

4-Amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine is an active ingredient of a herbicidal composition intended primarily for the selective control of weeds in sugar beet (Burex, Pyramine).

Several methods for producing 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine are known to date.

Podía čs. AO 120 858 is based on the reaction of 4,5-dichloro-1-phenyl-6-oxo-1H-pyridazine with ammonia gas at a temperature which keeps the reaction mixture in the form of a melt. Other methods for preparing 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine are by reacting 4,5-dichloro-1-phenyl-6-oxo-1H-pyridazine with an aqueous ammonia solution under pressure and at room temperature. elevated temperature (GB No. 871 674) optionally still in the presence of a catalyst.

Subject of MS. AO 214 843 is a process for the preparation of 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine in the presence of 4-phenolsulfonic acid as catalyst, wherein after separation of the desired product the mother liquor is added after the missing components are ammonia; 4-phenol sulfonic acid is again used in the production process.

Use of a 4-phenolsulfonic acid sodium salt in the preparation of 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine by reaction of 4,5-dichloro-1-phenyl-6-oxo-1H-pyridazine with aqueous ammonia solution is described in U.S. Pat. AO 226,250.

Preparation of 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine by reaction of 4,5-dichloro-1-phenyl-6-oxo-1H-pyridazine with aqueous ammonia in the presence of a technical acid sodium salt catalyst phenol-4-sulfonic acid containing sodium chloride and optionally ammonium chloride is the subject of AOC. 268,061th

We have now found a process for preparing 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine by reaction

4,5-Dichloro-1-phenyl-6-oxo-1H-pyridazine with aqueous ammonia in the presence of a reaction catalyst formed - 4-phenol sulfonic acid sodium salt at a molar ratio to 4,5-dichloro-1-phenyl-6-oxo -1H-pyridazine 0.1-1.5: 1 and in a ratio of 4,5-dichloro-1-phenyl-6-oxo-1H-pyridazine to ammonia 1: 2 to 50 to 100 to 200 ° C and pressure 0.1 to 5.0 MPa according to the invention.

SUMMARY OF THE INVENTION The principle of the invention is to add to the solution remaining after filtration of 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine containing ammonium chloride, ammonia and sodium 4-phenolsulfonic acid at a temperature of 10 to 45 ° C, in any order, an aqueous solution of sodium hydroxide at a concentration of 20 to 50%, an aqueous solution of 4-phenolsulfonic acid at a concentration of 40 to 80%, 4,5-dichloro-1-phenyl-6-oxo-1H-pyridazine and missing the molar ratio between 4-phenolsulfonic acid and sodium hydroxide is 1: 1 and between ammonium chloride and sodium hydroxide 1: 0.1 to 1.1, and the resulting mixture is reacted in a known manner to the desired 4-amino-1- phenyl-5-chloro-6-oxo-pyridazine.

An advantage of the process according to the invention is that the technical catalyst-sodium salt of 4-phenolsulfonic acid is prepared directly in the reaction mixture during the reaction.

Sodium hydroxide added to the reaction mixture neutralizes 4-phenolsulfonic acid to the sodium salt and decomposes the ammonium chloride, to the ammonia required in the amination, and sodium chloride together with the 4-phenolsulfonic acid sodium salt to ensure high purity and yield of the desired 4-amino. -l-phenyl-5-chloro-6-oxo-pyridazine.

Up to now, in the preparation of 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine, the 4-phenolsulfonic acid sodium salt was prepared isolated from 4-phenolsulfonic acid and subsequent filtration, resulting in losses due to its solubility in water and to waste water pollution.

The following examples illustrate but do not limit the scope of the invention.

Example 1

80 g of the filtrate from the previous experiment were charged to a pressure vessel after filtering 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine containing 3.1 g of ammonium chloride, 3.8 g of sodium 4- phenolsulfonic acid and 7 g of ammonia to which were added 8.6 g of a 40% aqueous sodium hydroxide solution at a filtrate temperature of 20 ° C, 6.6 g of a 75% aqueous 4-phenolsulfonic acid solution, 18 g of 4,5-dichloro 1-phenyl-6-oxo-1H-pyridazine and 20 g of 27% aqueous ammonia. The reaction mixture was heated to 160 ° C for 4 hours, at a pressure of 0.7 MPa in the reaction vessel. After cooling the reaction mixture, the product was filtered off. 16.3 g of 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine having a purity of 99.1% were obtained. The yield was 97.5% of theory.

Example 2

700 kg of the filtrate were charged to the reservoir after filtering out 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine from a previous experiment containing 34 kg of ammonium chloride and 51 kg of 4-phenol sulfonic acid sodium salt. 250 kg of a 4,5-dichloro-1-phenyl-6-oxo-1H-pyridazine wet cake of 60% dry weight were added to the filtrate with stirring. 92.2 kg of a 40% aqueous sodium hydroxide solution and 71.5 kg of a 70% aqueous 4-phenolsulfonic acid solution were then added to the mixture. The mixture was then saturated with 150 kg of ammonia gas at a temperature of 30-35 ° C. The reaction mixture was then fed continuously into a tubular reactor heated to 150 ° C at a rate of 10 kg / hr. The pressure in the reaction zone was maintained at 20 bar using a pressure reducing valve, and the reaction mixture was held in the reactor for 8 minutes. After expansion, the reaction mixture was cooled and technical 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine was isolated by filtration. After 1 hour, 10.7 kg of 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine was obtained with a purity of 98.9%. The yield was 97% of theory.

Claims (1)

The following examples illustrate, but do not limit the invention. EXAMPLE 1 80 g of the filtrate from the previous experiment were introduced into a pressure vessel after filtering off the 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine containing 3.1 g of ammonium chloride, 3.8 g of sodium 4- phenolsulfonic acid and 7 g ammonia to which 8.6 g of a 40% aqueous solution of sodium hydroxide were added at a filtrate temperature of 20 ° C, 6.6 g of a 75% aqueous solution of 4-phenolsulfonic acid, 18 g of 4,5-dichloro-1 -phenyl-6-oxo-1H-pyridazine and 20 g of 27% non-aqueous ammonia. The reaction mixture was heated to 160 ° C for 4 hours, achieving a pressure in the reaction vessel of 0.7 MPa. After cooling the reaction mixture, the product was filtered off. Obtained 16.3 g of 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine with a purity of 99.1%. Yield: 97.5% of theory. EXAMPLE 2 700 kg of the filtrate were introduced into the container after filtering off the 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine from the previous experiment containing 34 kg of ammonium chloride and 51 kg of 4-phenolsulfonic acid sodium salt. To the filtrate under stirring was added 250 kg of wet cake of 4,5-dichloro-1-phenyl-6-oxo-1H-pyridazine with a dry weight of 60%. Then, 92.2 kg of a 40% aqueous solution of sodium hydroxide and 71.5 kg of a 70% aqueous solution of 4-phenolsulfonic acid were added to the mixture. The mixture was then charged with 150 kg of ammonia gas at 30-35 ° C. The reaction mixture was then fed continuously into a tubular reactor heated to 150 ° C at a rate of 10 Kg / hr. By means of a reducing valve, the pressure of the reaction zone was maintained at 2.0 MPa while the reaction mixture was retained for 8 minutes in the reactor. The reaction mixture was cooled after cooling and 4-amino-1-phenyl-5-chloro-6-oxo-1H was added. -pyridazine was isolated by filtration. After 1 hour, 10.7 kg of 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine was obtained with a purity of 98.9%. Yield 97%. OBJECT OF THE INVENTION The process for producing 4-amino-1-phenyl-5-chloro-6-oxo-1H-pyridazine by reacting 4,5-dichloro-1-phenyl-6-oxo-1H-pyridazine with an aqueous ammonia solution in the presence of the reaction formed technical catalyst of 4-phenolsulfonic acid sodium salt at a molar ratio to 4,5-dichloro-1-phenyl-6-oxo-1H-pyridazine of 0.1 to 1.5: 1 and at a molar ratio of 4.5- dichloro-1-phenyl-6-oxo-1H-pyridazine and ammonia 1: 2 to 50 at a temperature of 100 to 200 ° C and a pressure of 0.1 to 5.0 MPa indicating that 4-amino is added to the solution remaining after filtering off 1-Phenyl-5-chloro-6-oxo-β-pyridazine, which contains ammonium chloride, ammonia and 4-phenolsulfonic acid sodium salt is added at 10 to 45 ° C in any order of aqueous sodium hydroxide solution. with a concentration of 20 to 50%, an aqueous solution of 4-phenolsulfonic acid at 40-80%, 4,5-dichloro-1-phenyl-6-oxo-1H-pyridazine and bending ammonia scavenging, wherein the molar ratio between the 4-bit The sulfonic acid and sodium hydroxide are 1: 1 and 1: 0.1 to 1.1 between ammonium chloride and sodium hydroxide, and the resulting mixture is reacted to the desired 4-amino-1-phenyl-5-chloro-6-oxo- 1H-pyridazine.