Pollution-free production technology of direct fast black G

Abstract

The invention relates to a pollution-free production technology of direct fast black G, comprising the following implementation steps: firstly, primary acid coupling is carried out on nitroaniline after diazotization and H-acid; after the full reaction of the H-acid is detected, sodium carbonate is added and pH is adjusted to 8 to 8.2 to carry out secondary basic coupling; the coupling product is added into a sodium sulfide solution for reduction, and the temperature gradually raises to t of 38 DEG C to 40 DEG C in the reaction process; after the sodium carbonate is added into the reduction product after acidification to adjust the pH of a medium to 7.5 to 8, the mixture is adsorbed by activated carbon and filtered, and ternary coupling is carried out on the obtained filter liquor after diazotization and lentine; and after the reaction is detected to be end point, the materials are directly delivered to a drying tower for spray drying. In the invention, the reduced reaction solution does not need the processes of salting out, acidification and filtration, activated carbon adsorption is adopted instead. In the process, no waste liquor is generated, and environment pollution caused in the production process of dye is greatly reduced. Simultaneously, wastewater processing is not needed, and the cost is saved. The optimized technology directly transfers the reaction solution after ternary coupling into the drying tower for spray drying; and the yield and the coloring intensity of the dye are effectively increased, energy is saved, the consumption is reduced, and the effect is obvious.

Description

technical field [0001] The invention relates to a production process of a dye, in particular to a pollution-free production process of direct sunfast black G. Background technique [0002] At present, the competition in the direct dye industry is becoming increasingly fierce, and people's requirements for the color of textiles are also increasing, and the requirements for dyes are also getting higher and higher. Environmentally friendly dyes and salt-free liquid dyes with bright colors and high dye uptake are very popular. [0003] In the traditional production process of direct dyes, the process of salting out, filtration and concentration is generally carried out; the purpose is to desalt, remove unreacted raw materials, intermediates and secondary dyes, and remove water to obtain dyes with the required concentration and purity. It is then dried in an oven to make powdered dyes or directly prepared as liquid dyes. Practice has proved that the impurities and salt brought i...

AI Technical Summary

Problems solved by technology

However, a large amount of waste water is produced in the traditional production process of the dye, which will cause serious environmental pollution if discharged without treatment

And the treatment of process wastewater will increase the cost of the product

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