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Improved method for synthesizing p-aminonaphthalene sulfonic acid alkali metal salt

A technology of p-aminonaphthalenesulfonic acid base and aminonaphthalenesulfonic acid base is applied in the field of improved synthesis of p-aminonaphthalenesulfonic acid alkali metal salt, can solve the problems of complex recovery, low production volume, high pressure loss and the like, and achieves high separation yield. efficiency, fewer operations, and the effect of eliminating side reactions

Pending Publication Date: 2022-06-28
YASH SPECIALITY CHEM LLP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Disadvantages of the method of DE-OS 24 56308 are the addition of special diluents, high dilution of the reactants leading to low throughput, and technically complicated recovery
In the method of DE-OS2519838, the trickle phase has little advantage, since a high dilution is also performed, which means that only low throughputs can be achieved, also at the expense of method economy
Also, expect deposits on the fixed bed interface, which can lead to a loss of high pressure in the system and possibly even clogging

Method used

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  • Improved method for synthesizing p-aminonaphthalene sulfonic acid alkali metal salt
  • Improved method for synthesizing p-aminonaphthalene sulfonic acid alkali metal salt
  • Improved method for synthesizing p-aminonaphthalene sulfonic acid alkali metal salt

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0078] Example 1 : Hydrogenation of nitronaphthalene

[0079] 1000 g (5.78 moles) of nitronaphthalene were dissolved in 1300 g of dichlorobenzene and added to a 5L S.S. autoclave. To this solution was added 15 g of Raney nickel, and the autoclave was closed, then at 30 kg / cm 2 The autoclave was heated to 130°C under hydrogen pressure for 6 hours. After the hydrogen pressure absorption ceased for 6 hours, the reaction mass was cooled to 30°C and the remaining pressure was released. The reaction mass was then removed from the autoclave and filtered. The filtrate is a mixture of 1-aminonaphthalene, dichlorobenzene and water. The water was separated from the organic layer, and the 1-aminonaphthalene was separated from the solvent (2081 g) and used as such for the next reaction.

Embodiment 2

[0080] Example 2 : Preparation of sodium p-aminonaphthalene sulfonate

[0081] A solution of 2081 g of 1-aminonaphthalene containing 785 g (5.49 moles) of 1-aminonaphthalene (obtained in Example 1, not further isolated) was placed in the S.S. reactor and diluted with 2183 g of dichlorobenzene. To this solution was added 598 g (6.09 moles) of sulfuric acid, and the solution was heated to 185°C for 5 hours. The reaction mass was then cooled and then sodium carbonate solution was added (by adding 997 g of water and 499 g of Na 2 CO 3 1496 g of sodium carbonate solution prepared from powder). After the addition was complete, an additional 872 g of water was added and the reaction mass was heated to 85°C for 2 hours. After the reaction was complete, the bottom organic material was separated from the aqueous layer. The resulting reaction mass was filtered to remove undissolved material, cooled to 25°C, and filtered again to obtain pure 1558 g of sodium p-aminonaphthalenesulf...

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Abstract

The invention relates to an improved method for synthesizing p-aminonaphthalene sulfonic acid alkali metal salt. Specifically, the present invention relates to an improved process for the synthesis of alkali metal salts of p-aminonaphthalenesulfonic acids of formula I wherein M represents an alkali metal selected from sodium (Na) and potassium (K); the method comprises the following steps: converting 1-nitronaphthalene into 1-aminonaphthalene; and converting the 1-aminonaphthalene into the alkali metal salt of the aminonaphthalene sulfonic acid in situ. The present invention also relates to an improved process for the synthesis of alkali metal salts of p-aminonaphthalene sulfonic acids of formula I wherein said process is safer, harmless, environmentally friendly, cost effective, and has improved time periods, better selectivity and high yields.

Description

technical field [0001] The present invention relates to organic synthesis. In particular, the present invention relates to an improved method for synthesizing alkali metal p-aminonaphthalenesulfonic acid salts, wherein the method is safer, harmless, environmentally friendly, cost-effective, and has an improved time period, better selectivity and high yield. Background technique [0002] The background description includes information that may be helpful in understanding the present invention. It is not intended that any information presented herein is prior art or related to the presently claimed invention, nor that any publication specifically or implicitly cited is prior art. [0003] Alkali metal p-aminonaphthalenesulfonates (eg, sodium p-aminonaphthalenesulfonate and potassium p-aminonaphthalenesulfonate) are derivatives of naphthalene with amino and sulfonic acid functional groups. Sodium p-aminonaphthalene sulfonate, also known as sodium 4-aminonaphthalene-1-sulfona...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C303/06C07C309/47C07C303/32
CPCC07C303/06C07C303/32C07C209/36C07C309/47C07C211/58
Inventor P·帕特尔J·德赛
Owner YASH SPECIALITY CHEM LLP