Metatester is an important intermediate for the synthesis of KN reactive dyes, which do not contain his soluble gene on the dye molecules, so that β-hydroxyethyl sulfone sulfate can be converted into vinyl sulfone and react with cotton fibers during dyeing, and the insoluble small molecular dyes generated can also dye synthetic fibers in the form of disperse dyes.

Chemical name: M-β-hydroxyethyl sulfone aniline; 2-[(3-aminophenyl) sulfonyl] hydrogen sulfide; 3-ethylsulfone aniline;