Method for preparing direct yellow G

Abstract

The invention discloses a method for preparing direct yellow G. DSD acid is taken as an initial raw material, and the method comprises the following steps of: reacting with sodium nitrite, phenol and chloroethane in turn, and respectively performing diazotization, coupling and chloroethane etherification to obtain the direct yellow G, wherein a solvent in diazotization, coupling and chloroethane etherification is ethanol. The DSD acid is taken as the initial raw material and is subjected to diazotization, coupling and chloroethane etherification respectively to form a dye of the direct yellow G, the ethanol is adopted as a reaction solvent in the diazotization, coupling and chloroethane etherification and can be recycled after reaction, a large amount of water is prevented from serving as the reaction solvent, the problem that a large amount of industrial wastewater is difficult to treat is radically solved and the zero emission of the industrial wastewater is achieved.

Description

Technical field [0001] The present invention involves a water -free preparation method that is directly frozen yellow G, which belongs to the field of chemical synthesis technology. Background technique [0002] Direct frozen yellow G belongs to a direct dye that can be directly dissolved in water. It has high directability to cellulose fiber. It does not need to use the relevant chemical methods to make fiber and other materials coloring.In the solution, the protein fiber (such as wool and silk) color is also used in cotton, hemp, human silk, and human cotton staining.The chromatography is complete, the price is low, and the operation is convenient. [0003] At present, the process of the usual preparation method of direct frozen yellow G is shown below: [0004] 1. DSD acid nitrogen deodorization: [0005] Add water to the heavy nitrogen tank, add dsd acid to the DSD acid to heat up to 60 ° C to match the pure alkali to make it all dissolved (pH = 8), reduce the temperature to ...

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Problems solved by technology

[0013] Adopt said method to have following shortcoming: 1, every ton of directly frozen yellow G will produce 15 tons of industrial waste water, these industrial waste waters are difficult to manage, and can take away a part of direct frozen yellow G finished product, thereby increased the cost of production; 2. The dissolution, salting-out and acid-out of DSD acid in the process will use a large amount of auxiliary materials such as industrial salt and sulfuric acid. These auxiliary materials will not only increase the cost of production, but also increase the difficulty of industrial wastewater treatment; 3. The final direct production Frozen yellow G has high salt content, low color strength, low color brightness, low solubility, low color fastness and color rate, and the product lacks competitiveness in the market

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