Preparation method for fluorescent whitening agent

Abstract

The present invention relates to a preparation method of fluorescence brightening agent. The present invention effectively solves the problems that the emission quantity of acid liquid is large, the dust pollution is serious, the water solubility is poor, the yellowing point is low, the solidness for solarization is poor, and the scope of application is narrow. In the preparation method, 500 to 700 kg ice water of mixed ice and water is added into a reactor, hydrochloric acid is used for adjusting the pH value, 77 to 109 kg of melamine is added when the reaction solution is stirred, 72 to 102kg of sulfanilic acid is added, sodalye solution is dropped to adjust the pH value and is stopped to be dropped when the pH value can no longer be reduced, simultaneously 2200 to 2600 kg of DSD acid aqueous solution and sodalye solution are added, the sodalye solution is stopped to be dropped when the pH value can no longer be reduced, the reaction solution is added into an acid eduction pot, hydrochloric acid is added to adjust the pH value when the reaction solution is mixed, the reaction solution is transmitted to a pressure filter to be processed through pressure filtration, the filter cake is collected, the filter cake, 100 to 140 kg of diethanolamine and 66 to 94 kg of diglycol are added when the reaction solution is stirred, the sodalye solution is used for adjusting the pH value, and then the product is packaged. The present invention has the advantages that the method is simple, the scope of application is wide, the effects of application are good, and the present invention is a large innovation in the chemical field.

Description

1. Technical field [0001] The invention relates to the field of chemical industry, in particular to a method for preparing a fluorescent whitening agent. 2. Background technology [0002] Fluorescent brighteners are widely used in industries such as papermaking, textiles, coatings, and detergents. Most of them are powder products in China. VBL is the earliest introduced technology, the widest application range, and the largest output. However, there are large acid emissions, dust Serious pollution, poor water solubility, low yellowing point, poor light fastness, narrow application range and other problems, so its improvement is imperative. 3. Contents of the invention [0003] In view of the above situation, in order to overcome the defects of the prior art, the purpose of the present invention is to provide a preparation method of fluorescent whitening agent, which can effectively solve the problem of large acid discharge, serious dust pollution, poor water solubility and...

AI Technical Summary

Problems solved by technology

[0003] In view of the above situation, in order to overcome the defects of the prior art, the purpose of the present invention is to provide a preparation method of fluorescent whitening agent, which can effectively solve the problem of large acid discharge, serious dust pollution, poor water solubility and yellowing in the preparation of fluorescent whitening agent. Low point, poor light fastness, and narrow application range. The technical solution is to add 500-700kg of ice water mixed with ice and water to the reactor, the diameter of the ice cube is about 50mm, and the mass concentration is ≥30%. Hydrochloric acid to adjust the pH value to 1.0-3.0, keep the temperature ≤ 5 ° C, add 77-109 kg of cyanuric chloride and 72-102 kg of p-aminobenzenesulfonic acid while stirring, stir for 15-25 minutes, and drop the mass concentration of 42% The caustic soda aqueous solution, adjust the pH value to 3.5-4.5, and the temperature is ≤5°C. When the pH value no longer drops, stop adding the caustic soda aqueous solution and keep stirring for 25-35 minutes. Concentration of 15% DSD acid (DSD acid full name is 4,4-diaminostilbene-disulfonic acid) aqueous solution 2200-2600kg and mass concentration are 42% caustic soda aqueous solution (caustic soda is also called caustic soda, sodium hydroxide, molecular formula NaOH, the same below), maintain the temperature at 55-65°C, pH value 3.5-4.5, add the DSD acid aqueous solution within 2.5-3.5 hours, stop when the DSD acid aqueous solution is added and the pH value remains at 3.5-4.5 and no longer drops Add caustic soda aqueous solution dropwise, keep warm for 1.5-2.5 hours, and then cool down to below 30°C to obtain the reaction solution; put the reaction solution into the acid analysis tank, add hydrochloric acid with a mass concentration of ≥30% while stirring, and adjust the pH value to 1.5 -2.0; the material (reaction liquid) in the acid analysis tank is sent to the filter press for pressure filtration through the feeding pump, and the filter cake is collected; the preparation kettle is started, and then the filter cake, diethanolamine 100-140kg, and diglycol are added sequentially while stirring. Alcohol 66-94kg, after 15-25 minutes, use caustic soda aqueous solution with a mass concentration of 42% to adjust the pH value to 7.5-8.0, and release the material after 15-25 minutes for packaging