2results about "Styryl-azo dyes" patented technology

Provided is a preparation method for a yellow oxidized azo and azo-stilbene dye, including the following steps: taking 4-nitrotoluene-2-sulfonic acid as a starting material, and taking water as a reaction solvent to obtain Direct Yellow 11 through a condensation reaction in the presence of choline hydroxide. A molecular structure of choline hydroxide contains both a quaternary ammonium group and a hydroxyl group. The hydroxyl group provides additional hydrophilicity, which is conducive to improving the solubility and dispersibility of the dye in aqueous media, thereby enhancing affinity of the dye with fibers. Choline hydroxide can effectively provide the alkaline environment required for the reaction, promoting the progress of dye synthesis, and controlling the selectivity and yield of the reaction better. The choline hydroxide can form hydrogen bonds with the sulfonic acid groups in the dye molecules, thereby enhancing intermolecular stability and improving light fastness and acid / alkali resistance of Direct Yellow 11.

The application provides a preparation method of quaternary ammonium base and application thereof in dye synthesis. Propylene oxide is added into trimethylamine, nucleophilic ring-opening addition reaction of trimethylamine to the epoxy group of propylene oxide is carried out, hydroxypropyltrimethylammonium hydroxide is obtained, then the hydroxypropyltrimethylammonium hydroxide is used to replace sodium hydroxide in the dye synthesis process, inorganic salt is not introduced into the reaction system, and after the reaction is completed, multiple water washing and salt removal are not needed, so that the wastewater amount and salt load can be obviously reduced.