C.I. Acid Green 28

Using 1, 4, 5, 8-tetrahydroxyanthraquinone and p-butylaniline as raw materials, firstly 1, 4, 5, 8-tetrahydroxyanthraquinone is partially reduced, then condensed with p-butylaniline, and then oxidized. Sulfonated and neutralized products. The finished product is obtained by salting out, filtering, drying and crushing. It is also possible to use 1, 4-dihydroxy-5, 8-dichloroanthraquinone and p-butylaniline as raw materials, and obtain products through condensation and sulfonation. Put 47.3g of p-butylaniline, 5g of 1, 4, 5, 8-tetrahydroxyanthraquinone cryptobarium, 2g of boric acid and 0.6g of p-nitrotoluene into a three-necked flask, stir and warm up to 130°C to react for 0.5-1h, and cool When the temperature reaches 70°C, add industrial ethanol, continue to stir for 0.5h, cool to about 35°C, the condensate precipitates, stand, filter, and dry to obtain the condensate 6-6.5g. Add 72g fuming sulfuric acid and 0.57g boric acid to a three-necked flask, stir and heat to 70°C to dissolve, cool to below 20°C in an ice bath, add the condensate in batches, and react at below 30°C for 20-30min to the end of the reaction. Pour the reactants into ice, filter, dissolve the filter cake in ice water, neutralize with 30% sodium hydroxide to pH=6-7, add salt to salt out, filter, dry, and crush to obtain 11-19g of product.

Weak acid green 5GS is used for dyeing and printing of real silk, nylon, wool fabrics, and tussah silk, with bright colors and good fastness. Also used for leather coloring.