Method of preparing 3-aminophthalic acid from 3-nitrophthalic acid

Abstract

The invention discloses a making method of 3-amino phthalic acid through 3-nitro phthalic acid, which is characterized by the following: making sodium salt solution through dissolving 3-nitro phthalic acid in the sodium hydroxide solution; reducing nitro group into amino group through hydrazine hydrate; improving receiving rate to 95% and purity not less than 96%.

Description

technical field

[0001] The invention relates to a method for preparing 3-aminophthalic acid by using 3-nitrophthalic acid as a starting material and reducing it with hydrazine hydrate under the action of a catalyst. Background technique

[0002] 3-Aminophthalic acid is widely used and is an important intermediate in pharmaceutical, pesticide, pigment, dyestuff and other industries. The preparation method of this product is rarely reported in the literature, and Pd / C has been used as a catalyst for hydrogenation reduction. However, due to the high cost, high risk, and high equipment requirements of this method, it has not been able to enter large-scale industrial production. Can only reach 90%. In addition, 3-aminophthalic acid is prepared by using iron powder reduction method, which has great environmental pollution and lower yield, and the yield only reaches 50-60%. Contents of the invention

[0003] The present invention provides a kind of preparation method of 3-amino...

Examples

Embodiment 1

[0014] (1) Add 260g of water to a 500ml three-neck flask, start stirring, then add 16g (96%) of sodium hydroxide, and then add 40g (0.19mol) of 3-nitrophthalic acid after dissolving, and stir to dissolve into a transparent solution ;

[0015] (2) Add catalyst (FeCl 3 / C): ferric chloride (FeCl 3 .6H 2 (2) 2.5g and activated carbon (for decolorization) 14g;

[0016] (3) Heat the catalyst-added solution to 95° C. (close to reflux), start to add 25 g of 80% hydrazine hydrate solution dropwise, continue heating to reflux reaction for 3.5 hours, after the reaction is completed, filter while it is hot, and collect the filtrate for later use;

[0017] (4) Add concentrated hydrochloric acid to the filtrate to acidify to PH3.5, cool and crystallize and filter, and dry at 80°C for 3 hours to obtain 31.9g of 3-aminophthalic acid finished product, the appearance is light yellow crystalline powder, purity: 96.42% (HPLC ), yield: 93%.

Embodiment 2

[0019] (1) Add 260g of water to a 500ml three-neck flask, start stirring, then add 18.5g (96%) of sodium hydroxide, and then add 40g (0.19mol) of 3-nitrophthalic acid after dissolving, stir and dissolve to become transparent solution;

[0020] (2) Add catalyst (FeCl 3 / C): ferric chloride (FeCl 3 .6H 2 (2) 3.5g and activated carbon (for decolorization) 16g;

[0021] (3) Heat the catalyst-added solution to 95° C. (close to reflux), start to add 29 g of 80% hydrazine hydrate solution dropwise, continue heating to reflux reaction for 4.5 hours, after the reaction is completed, filter while it is hot, and collect the filtrate for later use;

[0022] (4) Add concentrated hydrochloric acid to the filtrate to acidify to pH 3.5, cool and crystallize and filter, and dry at 80°C for 3 hours to obtain 32.8g of 3-aminophthalic acid finished product, which is light yellow crystalline powder with a purity of 96.5% ( HPLC), yield: 95%.

Embodiment 3

[0024] (1) Add 260g of water to a 500ml three-neck flask, start stirring, then add 22g (96%) of sodium hydroxide, and then add 40g (0.19mol) of 3-nitrophthalic acid after dissolving, and stir to dissolve into a transparent solution ;

[0025] (2) Add catalyst (FeCl 3 / C): ferric chloride (FeCl 3 .6H 2 (2) 4.2g and activated carbon (for decolorization) 19g;

[0026] (3) Heat the catalyst-added solution to 95° C. (close to reflux), start to drop 34 g of 80% hydrazine hydrate solution, continue heating to reflux reaction for 5 hours, after the reaction is completed, filter while it is hot, and collect the filtrate for later use;

[0027] (4) Add concentrated hydrochloric acid to the filtrate to acidify to PH3.5, cool and crystallize and filter, and dry at 80°C for 3 hours to obtain 33g of 3-aminophthalic acid finished product, which is light yellow crystalline powder in appearance, purity: 96.7% (HPLC ), yield: 96%.

technical field

[0001] The invention relates to a method for preparing 3-aminophthalic acid by using 3-nitrophthalic acid as a starting material and reducing it with hydrazine hydrate under the action of a catalyst. Background technique

[0002] 3-Aminophthalic acid is widely used and is an important intermediate in pharmaceutical, pesticide, pigment, dyestuff and other industries. The preparation method of this product is rarely reported in the literature, and Pd / C has been used as a catalyst for hydrogenation reduction. However, due to the high cost, high risk, and high equipment requirements of this method, it has not been able to enter large-scale industrial production. Can only reach 90%. In addition, 3-aminophthalic acid is prepared by using iron powder reduction method, which has great environmental pollution and lower yield, and the yield only reaches 50-60%. Contents of the invention

[0003] The present invention provides a kind of preparation method of 3-amino...

Examples

Embodiment 1

[0014] (1) Add 260g of water to a 500ml three-neck flask, start stirring, then add 16g (96%) of sodium hydroxide, and then add 40g (0.19mol) of 3-nitrophthalic acid after dissolving, and stir to dissolve into a transparent solution ;

[0015] (2) Add catalyst (FeCl 3 / C): ferric chloride (FeCl 3 .6H 2 (2) 2.5g and activated carbon (for decolorization) 14g;

[0016] (3) Heat the catalyst-added solution to 95° C. (close to reflux), start to add 25 g of 80% hydrazine hydrate solution dropwise, continue heating to reflux reaction for 3.5 hours, after the reaction is completed, filter while it is hot, and collect the filtrate for later use;

[0017] (4) Add concentrated hydrochloric acid to the filtrate to acidify to PH3.5, cool and crystallize and filter, and dry at 80°C for 3 hours to obtain 31.9g of 3-aminophthalic acid finished product, the appearance is light yellow crystalline powder, purity: 96.42% (HPLC ), yield: 93%.

Embodiment 2

[0019] (1) Add 260g of water to a 500ml three-neck flask, start stirring, then add 18.5g (96%) of sodium hydroxide, and then add 40g (0.19mol) of 3-nitrophthalic acid after dissolving, stir and dissolve to become transparent solution;

[0020] (2) Add catalyst (FeCl 3 / C): ferric chloride (FeCl 3 .6H 2 (2) 3.5g and activated carbon (for decolorization) 16g;

[0021] (3) Heat the catalyst-added solution to 95° C. (close to reflux), start to add 29 g of 80% hydrazine hydrate solution dropwise, continue heating to reflux reaction for 4.5 hours, after the reaction is completed, filter while it is hot, and collect the filtrate for later use;

[0022] (4) Add concentrated hydrochloric acid to the filtrate to acidify to pH 3.5, cool and crystallize and filter, and dry at 80°C for 3 hours to obtain 32.8g of 3-aminophthalic acid finished product, which is light yellow crystalline powder with a purity of 96.5% ( HPLC), yield: 95%.

Embodiment 3

[0024] (1) Add 260g of water to a 500ml three-neck flask, start stirring, then add 22g (96%) of sodium hydroxide, and then add 40g (0.19mol) of 3-nitrophthalic acid after dissolving, and stir to dissolve into a transparent solution ;

[0025] (2) Add catalyst (FeCl 3 / C): ferric chloride (FeCl 3 .6H 2 (2) 4.2g and activated carbon (for decolorization) 19g;

[0026] (3) Heat the catalyst-added solution to 95° C. (close to reflux), start to drop 34 g of 80% hydrazine hydrate solution, continue heating to reflux reaction for 5 hours, after the reaction is completed, filter while it is hot, and collect the filtrate for later use;

[0027] (4) Add concentrated hydrochloric acid to the filtrate to acidify to PH3.5, cool and crystallize and filter, and dry at 80°C for 3 hours to obtain 33g of 3-aminophthalic acid finished product, which is light yellow crystalline powder in appearance, purity: 96.7% (HPLC ), yield: 96%.

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