Synthesis Of Color Surfactants And Studies Of Their Properties

Surfactants are used widely as auxiliary agents in textile and dyeing industries. They are treated as effluents after used, and make some environment pollution. Although there are many researches about surfactants and dyestuffs respectively, the reports of combining these two functions together are very few. This article are concerned about whether the compounds are both have color and good surfactivity, and still have good surfactivity after the change and complication of the color parts of molecular structures.We started with the simple molecular structure. 3'-fatty amido-4'-hydroxy azobenzene-4-sulfonic acids(AAS) contained long chains and azo structures were synthesized. They show good surfactivities through detection of surfactive performances, but weak water solubility. In order to improve their water solubility, 4'-fatty amido-3'-sodium carboxylate azobenzene-4-sodium sulfonates(AFAS) were synthesized. They are azo compounds with two hydrophilic groups of carboxyl and sulfonyl. They decrease the surface tension in dilute solution slowly, and show some surfactivity, but are not surfactants. The probable reason is their relative strong hydrophile. Furthermore, their colors are not fresh and far from our destination. In order to make the azo part structure close to the structure of commodity dyestuffs, 3'-fatty amido-41- hydroxy azobenzene-2-(4-sulfonic benzene-l-azo)-4-sulfonic acids(BAS) contained long chains and bisazo structures were synthesized. They show better water solubility than AAS, and good surfactivities. The dyeing effects of AAS and BAS are worse than commodity dyestuffs. The ratios of dyeing are low, and the colors are tint. The probable reason is these compounds are lack of some affinitive groups with textile. Both AAS and BAS have some hindrance to the adsorption of oil with cloth by the experiments of absorption and desorption.Through these pilot studies, the design of azo compounds with surfactivities can work by combining the long chain alkyls and azo structures together. It is possible to show some functions of surfactant when they are dyed on the textile.