Process for producing triazine toluylene liquid fluorescent whitening agents

Abstract

The invention discloses a preparation method for triazine-stilbene liquid fluorescent brightener. The prior preparation method has the following problems: secondary reactions are numerous, the yield of the product is low and the quality of the product is poor. The preparation method comprises the following steps: a) cyanuric chloride, sulfanilic acid and metanilic acid undergo the first step condensation to obtain a mixture containing two components, namely 4-(4, 6-dichlorotriazine-2-amino) benzene sulfonic acid and 3-(4, 6-dichlorotriazine-2-amino) benzene sulfonic acid; and b) the mixture obtained in step a) and 4,4-diaminostilbene-2,2-disulfonic acid firstly undergo the second step condensation, the obtained product and diethanolameine undergo the third step condensation, and finally symmetrical and unsymmetrical triazine-stilbene liquid fluorescent brightener compositions are obtained. When whitening paper, the triazine-stilbene liquid fluorescent brightener has better whitening effect than single component, and has the function of compounding enhanced effect, and simultaneously the triazine-stilbene liquid fluorescent brightener has the advantages of good water-solubility, high whiteness and small use amount.

Description

technical field [0001] The invention relates to a special auxiliary agent for papermaking, in particular to a preparation method of a triazine stilbene liquid fluorescent whitening agent. Background technique [0002] With the improvement of people's living standards, people's requirements for color are getting stronger. Since the stilbene fluorescent whitening agent has the effects of whitening, brightening and brightening, it meets people's visual needs. Therefore, stilbene-based optical brighteners are widely used in industries such as papermaking, textiles, coatings, and washing. Traditional fluorescent whitening agents, such as VBL, CXT, etc., have the following problems: First, the synthesis process is that cyanuric chloride is first condensed with DSD acid, and the problem is that the reaction product has a relatively large molecular weight, but only 2 sulfonic acids group, low solubility, making the material viscous during the condensation reaction, which is not co...

AI Technical Summary

Problems solved by technology

Traditional fluorescent whitening agents, such as VBL, CXT, etc., have the following problems: First, the synthesis process is that cyanuric chloride is first condensed with DSD acid, and the problem is that the reaction product has a relatively large molecular weight, but only 2 sulfonic acids group, low solubility, making the material viscous during the condensation reaction, which is not conducive to mass transfer, uneven distribution of pH value, resulting in increased side reactions, low product yield, and poor quality; , drying, crushing and other processes, the operation is cumbersome and pollutes the environment

[0003] Chinese patent CN130342A discloses a water-soluble complex of fluorescent whitening agent and quaternary ammonium compound that basically does not contain impurity salts in the reaction process, but the purification techniques used include extraction, separation, high-pressure ultrafiltration, etc., and the methods are relatively complicated , which is not conducive to expanding production, but also affects production costs

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