甲基是一种供电子取代基,使偶氮基的电子密度增加,这使试剂的特性得到改善。布杰申斯基等人将两个甲基引入磺酰基偶氮Ⅲ分子中,大大改善了作为滴定硫酸根的指示剂的试剂性质。同样也曾指出,钡与二甲基磺酰基偶氮Ⅲ反应的灵敏度和对比度要比其与磺酰基偶氮Ⅲ反应的高。如果两个甲基排列在偶氮基的 Methyl is an electron-donating substituent that increases the electron density of the azo group, which improves the properties of the reagents. Bujushenski et al. Introduced two methyl groups into the sulfonyl azo III molecule, greatly improving the reagent properties as an indicator of titration of sulfate. It has also been pointed out that the sensitivity and contrast of the reaction of barium with dimethylsulfonyl azo III are higher than those of the reaction with sulfonyl azo III. If two methyl arranged in azo