Production system and process for 3,5-diaminobenzoic acid

Abstract

The invention discloses a production system for 3,5-diaminobenzoic acid. The system comprises a nitro material tank, a water storage tank, a slurry preparing pot, a slurry metering tank, a reduction pot, a filter press, an acid metering tank, an acid precipitation pot, a centrifugal machine and a drying machine. The invention also discloses a production process for the 3,5-diaminobenzoic acid. Theproduction process comprises the following steps: step 1, preparing slurry; step 2, performing reduction; and step 3, performing acid precipitation. The production system and process provided by theinvention shorten feeding time, reduce working intensity of feeding, reduce manual investment, reduce production costs, increase the yield of the product, improve a stability degree of the reaction and the output of the product, solve the problem of pollution to the environment due to overflow of waste gas, better distinguish a degree of the reduction reaction, and reduce difficulty of reduction operation; and the production system and process can reduce the reaction time, save a large amount of water, and reduce a generation amount of partial wastewater.

Description

[0001] Technical field: [0002] The invention relates to a production system and process, in particular to a 3,5-diaminobenzoic acid production system and process. [0003] Background technique: [0004] The existing production process of 3,5-diaminobenzoic acid with 3,5-dinitrobenzoic acid as raw material is divided into: reduction, reduction pressure filtration, material analysis, flash drying process; in the reduction process, [0005] The raw material 3,5-dinitrobenzoic acid and reducing agent iron powder are added to the reduction kettle, and the reaction temperature is strictly controlled at 95-100°C to obtain the reduced material, and then the reduced material is press-filtered to obtain the reduced press filtrate and iron sludge , the reduction press filtrate passes through material precipitation, flashes and dries, obtains the finished product, and the reaction involved is [0006] [0007] During the reduction reaction, it is necessary to carry out the detection ...

AI Technical Summary

Problems solved by technology

[0009] 1. The product 3,5-diaminobenzoic acid has poor water solubility. After the reduction reaction, a large amount of 3,5-diaminobenzoic acid is not in the solution and enters the iron sludge during press filtration, which affects the yield of the product

[0010] 2. The raw material 3,5-dinitrobenzoic acid powder is fed manually. The 3,5-dinitrobenzoic acid powder is slowly added to the reduction pot with a shovel. Evenly, every shovel of 3,5-dinitrobenzoic acid powder added to the reduction kettle will lead to local severe reduction reaction, instantaneous and severe heat release, and local temperature rise to produce by-products dinitrobenzene, p-phenylenediamine, Or 3-amino-5-nitrobenzoic acid, etc., because the by-products are soluble in water, on the one hand, it affects the yield and purity of the product. judgment;

[0011] 3. The reduction pot is exposed during manual feeding, and exhaust gas overflows and cannot be recycled. On the one hand, it causes waste of resources, and on the other hand, it pollutes the atmospheric environment

[0012] 4. The iron powder for reduction is 60-80 mesh iron powder of uniform specification, and it is added to the reduction pot at one time. Because the reaction time of feeding 3,5-dinitrobenzoic acid powder is long, the consumption of iron powder is large in the early stage, and it is reflected in the later stage. Insufficient iron powder, the reaction rate is obviously reduced, and the reaction time is long; due to insufficient iron powder, the reducibility is not strong, and the amino group is easily oxidized to nitro, showing that the ring is not normal;

[0013] 5. In order to prevent the product 3,5-diaminobenzoic acid obtained from the reduction reaction from being oxidized, it is necessary to add a strong reducing agent sodium bisulfite for protection. However, the current input method of sodium bisulfite is in the 3,5-dinitro After adding the benzoic acid powder, add it at one time. However, the amino group has been oxidized during the feeding process in the early stage, and a by-product with a molecular weight less than 3,5-diaminobenzoic acid will be obtained, which will cause the material to appear brown or purple. At the end of the reaction, it is necessary to add activated carbon to adsorb small molecular weight by-products. On the one hand, it increases the production cost and prolongs the process time. On the other hand, part of the product 3,5-diaminobenzoic acid will also be adsorbed, reducing the product yield.

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