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Green nitrification treatment method of m-toluic acid

A technology of toluic acid and treatment method, which is applied in the field of green nitration treatment of m-toluic acid, can solve the problems that waste dilute nitric acid is difficult to be effectively recovered and applied mechanically, and achieves avoiding the enrichment of organic solid impurities, reducing the content, avoiding The effect of safety, environmental protection and cost issues

Active Publication Date: 2020-10-23
山东友道化学有限公司
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  • Claims
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Problems solved by technology

[0005] The main purpose of the present invention is to provide a kind of green nitration treatment method of m-toluic acid, to solve the problem that the waste dilute nitric acid existing in the nitration treatment process of m-toluic acid in the prior art is difficult to obtain effective recovery and apply mechanically

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  • Green nitrification treatment method of m-toluic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0068] m-toluic acid and nitric acid with a mass fraction of 80% from the concentrated nitric acid storage tank are added to the reactor according to the mass ratio of 1:5 to mix and nitration reaction occurs. The reaction temperature is controlled at 10 ° C. After the addition, The material was kept warm in the reactor for 100 minutes, and the conversion rate of m-toluic acid was detected to be 98% by sampling, and the reaction was stopped to obtain the nitration reaction liquid and produce the first smoke tail gas.

[0069] Add the nitration reaction solution into a centrifuge for solid-liquid separation, wash and replace the nitric acid in the separated solid with fresh water until the nitric acid mass content is 0.2%, and then obtain the nitration product 2-nitro-3-methylbenzoic acid, and the filtrate The separated mother liquor obtained by merging with the washing liquid is transferred to the dilution tank, and the recovered waste water and fresh water are added to the dil...

Embodiment 2

[0077] m-Toluic acid and nitric acid with a mass fraction of 98% from the concentrated nitric acid storage tank are added to the continuous nitration reactor according to the ratio of 1:2 by mass, and the nitration reaction takes place. The reaction temperature is controlled at -30°C. The residence time in the continuous nitration reactor is 25min, and the nitration reaction liquid is obtained, and the first smoke tail gas is produced, and the obtained nitration reaction liquid will account for 45% of the dilute phase liquid in the mass fraction of the nitration reaction liquid after being thickened by the thickener Applying it to the nitration reaction, the conversion rate of m-toluic acid is 99.5% by sampling the obtained dense phase slurry.

[0078] adding the dense phase nitration reaction solution into a centrifuge for solid-liquid separation, washing with fresh water to replace the nitric acid in the separated solid until the mass content of nitric acid is 1%, and then ob...

Embodiment 3

[0086] m-Toluic acid and nitric acid with a mass fraction of 90% from the concentrated nitric acid storage tank are added to the reactor according to the ratio of 1:4 by mass and mixed for nitration reaction. The reaction temperature is controlled at -10°C. , the material was kept in the reactor for 60 minutes, and the conversion rate of m-toluic acid was detected to be 98.9% by sampling, and the reaction was stopped to obtain the nitration reaction liquid and produce the first smoke tail gas.

[0087] Add the nitration reaction solution into a centrifuge for solid-liquid separation, wash and replace the nitric acid in the separated solid with fresh water until the nitric acid mass content is 0.4%, and then obtain the nitration product 2-nitro-3-methylbenzoic acid, and the filtrate The separated mother liquor obtained by merging with the washing liquid is transferred to the dilution tank, and the recovered waste water is added to the dilution tank for stirring and dilution. The...

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Abstract

The invention provides a green nitration treatment method of m-toluic acid. The green nitrification treatment method comprises the following steps: S1, carrying out nitrification reaction on m-toluicacid and concentrated nitric acid to obtain a nitrification reaction solution, S2 and S3, carrying out solid-liquid separation on the nitration reaction liquid to obtain a nitration product and wastedilute nitric acid, S4, carrying out pre-concentration treatment on the waste dilute nitric acid so that recycled wastewater and recycled dilute nitric acid are obtained, so that the concentration ofnitric acid in the recycled wastewater is lower than that of nitric acid in the recycled dilute nitric acid, S5, concentrating the recovered dilute nitric acid by adopting a sulfuric acid method to obtain recovered concentrated nitric acid and a sulfuric acid aqueous solution, and returning the recovered concentrated nitric acid to the step S1 to be used as at least part of concentrated nitric acid for nitration reaction, S6, concentrating the sulfuric acid aqueous solution to obtain crude concentrated sulfuric acid, and S7, refining the crude concentrated sulfuric acid to obtain recovered concentrated sulfuric acid, and returning the recovered concentrated sulfuric acid to the step S5 to be used as sulfuric acid for concentrating and recovering dilute nitric acid by a sulfuric acid method. The nitric acid waste liquid is effectively recycled and reused.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a green nitration treatment method of m-toluic acid. Background technique [0002] For the nitration of m-toluic acid, a mixture of urea nitric acid and sulfuric acid, dinitrogen pentoxide, fuming nitric acid, etc. can be used as nitrating reagents, and concentrated nitric acid is the most commonly used. When m-toluic acid is nitrated with nitric acid, in order to ensure the conversion rate of m-toluic acid, nitric acid is generally excessive, resulting in a large amount of waste nitric acid in the production process, because the nitration product of m-toluic acid has a certain Solubility, so the waste nitric acid produced by the nitration of m-toluic acid generally contains more organic matter, which makes it difficult to directly recycle and apply. If it is used as the three wastes for neutralization treatment, the three wastes will have a large amount of treatment a...

Claims

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Application Information

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IPC IPC(8): C07C201/08C07C201/16C07C205/57
CPCC07C201/08C07C201/16C07C205/57
Inventor 孙美玲邹珊珊张海波王勤波任苗苗熊振华张本松
Owner 山东友道化学有限公司
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