Method for synthesizing 3,5-diamido benzoic acid by industrial continuous hydrogenation

A technology of diaminobenzoic acid and dinitrobenzoic acid, which is applied in the fields of chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of not disclosing substantive content, affecting the number of times of application, and being unable to apply. Significant economic and social benefits, reducing the use of metals, and ensuring product quality

Active Publication Date: 2013-10-30
济宁市金泰利华化工科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although it is recorded in the description that the product purity is as high as 95%, and the yield is as high as more than 96%, there is no sufficient record in the examples of this patent on the use of activated carbon catalysts to prepare the relevant data of m-diaminobenzoic acid, and the description does not disclose this technology. The detailed substantive content of the scheme, and the method recorded in this patent is only in the small test stage and is not suitable for industrialized large-scale production
In addition, this patent also has the following deficiencies: 1. The batch production process is adopted, and the operation procedure is cumbersome, and the operator must be on site at all times, so there are human safety hazards, and the batch production needs to be replaced every time, and the replacement needs to consume a certain amount of nitrogen and hydrogen. , and part of the solvent will be brought into the air, resulting in pollution; 2. The use of organic solvents such as methanol or ethanol, which are extremely volatile, flammable and explosive solvents, have certain pollution to the air or surface water, and the product purity and yield relatively low
The compatibility of this material with organic solvents (methanol or ethanol) is not good, and it cannot be completely dissolved, and this material is acidic, with a pH of about 1-3, which affects the activity of nickel-based catalysts. Realize industrial production
If the pH is adjusted to make the material into a salt, it will be almost insoluble with organic solvents, and the reaction situation cannot be verified.

Method used

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  • Method for synthesizing 3,5-diamido benzoic acid by industrial continuous hydrogenation
  • Method for synthesizing 3,5-diamido benzoic acid by industrial continuous hydrogenation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Take 100 kilograms of m-dinitrobenzoic acid to produce 3,5-diaminobenzoic acid as example, the catalyst used is the palladium / carbon of loading 3wt%, and the total amount of catalyst used in the production process is 3% (3 kilograms) of raw material, The total amount of water is 8.5 times (850 kg) of the raw material. During continuous production, dinitrobenzoic acid, water and catalyst are added according to the flow rate. The specific process is as follows:

[0033] 1. Start the feeding pump, adjust the flow rate to 540 L / h, and pass it into the primary reduction kettle at this flow rate, and at the same time, pass the catalyst (3wt% of the raw material) and water (8.5 times the mass of the raw material) into the primary reduction kettle In the process, adjust the stirring speed of the first-stage tank to about 200 rpm, and then introduce hydrogen to carry out the reduction reaction. The hydrogen reaction starts at 0.1Mpa. In this embodiment, the hydrogen pressure is k...

Embodiment 2

[0040] Production of 3,5-diaminobenzoic acid with 100 kilograms of m-dinitrobenzoic acid is an example, the catalyst used in the production process is the palladium / carbon of loading 3wt%, and consumption is 3% (3 kilograms) of m-dinitrobenzoic acid ), the total amount of water is 8.5 times (850 kilograms) of raw material, and during continuous production, dinitrobenzoic acid, water and catalyzer are added according to flow velocity flow, react according to the continuous production process of embodiment 1, in order to investigate The stability of technology, carry out ten experiments continuously according to above-mentioned method, and its result is as follows:

[0041]

[0042] As can be seen from the above table, the conversion rate of 3,5-diaminobenzoic acid reaches 100%, the selectivity of diamino is more than 98%, and the average can reach more than 99%, and the average content of the final product GPLC external standard method can be It can reach 95% (including 5% s...

Embodiment 3

[0044] Taking 100 kilograms of m-dinitrobenzoic acid to produce 3,5-diaminobenzoic acid as an example, the catalyst used in the production process is palladium / carbon with a load of 3wt%, and the dosage is 3% (3 kg) of m-dinitrobenzoic acid , the total amount of water is 8.5 times (850 kilograms) of raw material, and during continuous production, dinitrobenzoic acid, water and catalyst are added according to flow rate flow, react according to the continuous production process of embodiment 1, difference is The catalyst is recycled, which is embodied in step 4: the reaction liquid flowing out from the three-stage tank overflows into the settler, and the reducing liquid entrained with the catalyst is separated from the solid and liquid after settling. When the liquid level of the settler reaches 83% , open the discharge valve of the settler, open the self-regulating valve, the liquid layer with a low solid content in the settler enters the filter, and the reducing solution that f...

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Abstract

The invention discloses an industrial continuous hydrogenation method for synthesizing 3,5-diaminobenzoic acid. Using m-dinitrobenzoic acid and hydrogen as raw materials and water as a reaction solvent, water and a catalyst are added to a reduction kettle. In addition, the raw materials m-dinitrobenzoic acid and hydrogen are respectively added to carry out the reduction reaction; the reaction solution continues to react in the second and third reduction kettles until the conversion rate reaches 100%, and then the reaction solution is crystallized to obtain the product. The present invention uses three successively connected reduction kettles to complete the reduction reaction. The contact time of the raw materials is long, and the conversion rate of the raw materials can reach 100%. More than 97%.

Description

Technical field [0001] The present invention involves a method of preparing a 3,5-dilatelybenzoic acid, which specifically involves a method of industrialized continuous hydrogen hydrogenation of 3,5-dilate phenyl acid, which is a technical field of organic synthetic chemistry. Background technique [0002] 3,5-dihydonzolic acid is an important type of dye. Medicine intermediates, with it as raw materials, can develop many high value-added downstream products.A series of yellow -active dyes derived from it can be used as a dark yellow dye, or it can also be used as a yellow component in black dyes. The current market demand is large.3,5-diodes are generally obtained by the reaction of 3,5-diitrocytybenzoic acid as the raw material.The literature involves 3,5-di-nitrate phenolic acid reduction and preparing 3,5-dilate phenyl acid:: Iron powder restoration, pupae restore and hydrogenation reduction three routes.The use of iron powder reduction method to produce 3,5-dilate phenyl ac...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C229/60C07C227/04
Inventor 刘爱兵赵勇张红艳
Owner 济宁市金泰利华化工科技有限公司
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