Title of Invention

"AN IMPROVED PROCESS FOR THE PREPARATION OF 4-AMINO-4-ACETYLAMINO-2-SULPHONIC ACID"

Abstract

"An improved process for the preparation of 4-amino-4-acetylamino-2-sulphonic acid" This invention relates to an improved process for the preparation of 4-amino-4-acetylamino-2-sulphonic acid comprising in the steps of reducing nitroacetanalide in the presence of hydrazine hydrate and nickel as a catalyst at room temperature for 20-60 minutes to produce amino acetylanalide, condensation of amino acetylanalide in the presence of 4-chloro-nitro benzene-3-sulphonic acid a catalyst selected from platinum, rhodium and rhodenium at a temperature of 90-110°C for 3 to 5 hours, subjecting the aforesaid acid to the step of reduction in the presence of hydrazine hydrate and nickel as a catalyst to produce 4-amino-4-acetylamino-2-sulphonic acid.

Full Text

This invention relates to an improved process for preparation of 4-amino-4-acetylamino-2-sulphonic acid. It has generally known that 4-amino-4-acetylamino-2-sulphonic acid a dye intermediate. However, the conventional processes for the synthesis of 4-amino-4-acetylamino-2-sulphonic acid are attended with the distinct disadvantage of being highly pollutant. Such known processes are expensive in that it envisages the use of effluent treatment equipments for removal of the pollutants. The known process for the preparation of 4-amino-4-acetylamino-2-sulphonic acid consists in subjecting nitroaniline to the step of acetylation and subsequent reduction in the presence of hydrochloric acid and iron to produce amino acetanilide. Amino acetanilide is reacted with chlorobenzene nitro sulphonic acid at 103'C in an acidic media. The reacted product is refluxed for 60 hours and then calcium hydroxide is added to provide a precipitate consisting of 4-nitro-4-acetylamino-2-sulphonic acid. Such a compound is subjected to the step of reduction in the presence of hydrochloric acid and iron for a period of 15 to 16 hours to obtain 4—amino-4—acety1amino—2-sulphonic acid . Several distinct disadvantages are associated with such a known process. Once such disadvantage is that in each step of reduction there is a discharge containing hydrochloric acid. Yet another disadvantage is that the process requires an approximate period of 60 hours for completion. Yet another disadvantage is that the process is not exothermic in nature, and consequentially requires a considerable amount of energy. A further disadvantage is that the effluent contains iron chloride as a pollutant. A still further disadvantage is that of low purity. An object of this invention is to propose an improved process for the preparation of 4—amino-4-acetylamino—2-sulphonic acid . A further object of this invention is to propose a process for the preparation of 4—amino-4-acetylamino-2-sulphonic acid which obviates the disadvantages referred to hereinabove. A still further object of this invention is to propose a process for the preparation of 4—amino-4— acetylamino-2-sulphonic acid which no longer contains a pollutant in the discharge. Yet a further object of this invention is to propose an improved process for the preparation of 4-arnino-4-acetylamino-2-sulphonic acid which requires a lesser period of time for completion. Still another object of this invention is to propose an improved process for the preparation of 4-amino-4-acetylamino-2-sulphonic acid which has a high purity. According to this invention there is provided an improved process for the preparation of 4-amino-4-acetylamino-2-sulphonic acid comprising in the steps of: i) reducing nitroacetanalide in the presence of hydrazine hydrate and nickel as a catalyst at room temperature for 20-60 minutes to produce amino acetylanalide, ii) condensation of amino acetylanalide in the presence of 4-chloro-nitro benzene-3-sulphonic acid a catalyst selected from platinum, rhodium and rhodenium at a temperature of 90-110°C for 3 to 5 hours, iii) subjecting the aforesaid acid to the step of reduction in the presence of hydrazine hydrate and nickel as a catalyst to produce 4-amino-4-acetylamino-2-sulphonic acid. The process of the present invention comprises in subjecting nitro acetanalide to the step of reduction in the presence of a solvent and hydrazine hydrate. The solvent may be selected from butyl alcohol or mixtures of alcohol, though butyl alcohol is preferred. The step of reduction is carried out in the presence of a catalyst such as mickel and present in trace amounts of .01 to 0.1% to produce amino acety lanal ide . The reaction is carried out at room temperature for 20—60 minutes. The reaction is represented as follows: (FigureRemoved) ' The next steps in the process consists in subjecting amino acety lanal ide to the step of condensation in the presence of 4-chloro— nitro— benzene— 3-sulphonic acid. The step of condensation is carried out in the presence of the same medium present in the vessel and a catalyst selected from platinum, rhodium and rhodenium and present in trace amounts of .01 to 0.1%. The reduction is carried out at 90-110*C for a period of 3 to 5 hours. The reaction temperature is maintained at 90 to 110.C, as higher temperatures would decompose the product and, consequentially, would affect the yield. The reaction is represented as follows: (Figure Removed) The final step in the process consists in subjecting 4-amino-4-acetylamino-2-sulphonic acid obtained from the step of condensation to the step of reduction in the presence of hydrazine hydrate and nickel as a catalyst. i -'i.I'll IF Witro acetanilide (1 mol) was dissolved in butyl alcohol (2 mol) and reduced with hydrazine hydrate using the presence of metal catalyst such as nickel (0.05%). The time period is 40 min. This produced 4— aminoacetani1ide. In the same mass 4—chlorobenzene sulphonic acid was added. The reaction was carried out in alcoholic medium in presence of platinum catalyst. The reaction period is 6 hrs. After this reaction the, 4-nitro - acetanilide-4-amino-benzene—2-sulphonic acid obtained was subjected to further reduction in the presence of trace amount of metal catalyst (0.05% nickel) and hydrazine hydrate. The final product 4-amino—4-acetylamino -2-sulphonic acid with 90% yield and 95% purity. Claims 1. f\ process for the preparation of 4-amino-4- acetylamino-2-sulphonic acid comprising in the steps of i) subjecting nitroacetanalide to the step of reduction in the presence of hydrazine hydrate and nickel as a catalyst to produce amino acetylanali.de; ii) subjecting amino acetylanalide to the step of condensation in the presence of 4—chloro-nitro—benzene— 3—sulphonic acid and a catalyst selected from platinum, rhodium and/or rhodenium to produce t-nitra-4— acetylamino-2-sulphonic acid; iii) subjecting the aforesaid acid to the step of reduction in the presence of hydrazine hydrate and nickel as a catalyst to produce 4-amino-4-acetylamino—2-sulphonic acid. 2. A process as claimed in claim 1 wherein the first step of reduction is carried out for a period of 20-60 minutes. 3. A process as claimed in claim 2 wherein said step of reduction is carried out at room temperature, 4. A process a-s claimed in claim 1 wherein the step of condensation is carried out at a temperature of 90-110'C. 5. A prosess as claimed in claim 4 wherein said step of condensation is carried out for a period of 3 to 5 hours . 6. A process for the preparation of 4-amino-4- acetylafflina-2-sulphonic acid substantially as herein described and .illustrated in the example.

Documents:

2224-del-1997-abstract.pdf

2224-del-1997-claims.pdf

2224-del-1997-correspondence-others.pdf

2224-del-1997-correspondence-po.pdf

2224-del-1997-description (complete).pdf

2224-del-1997-form-1.pdf

2224-del-1997-form-19.pdf

2224-del-1997-form-2.pdf

2224-del-1997-form-26.pdf