Synthesis of surface active agents from natural waste phenolics

Corn cob and tea leaves waste are used as raw materials for condensed phenolic structures. In this study phenolics were extracted from these waste materials, characterized, and modified to obtain surface active materials. The phenolic structures of corn cob were HGS-type lignin with 10% by mass of initial dry weight, while of tea waste were condensed tannin with catechin-like fragments with 15% by mass. Hydroxymethylation reactions were carried out to increase the reactive sites and also the water solubility. The phenolics of the corn cob were hydroxymethylated to a higher rate than the phenolics of the tea leaves waste (85 vs. 48%). Subsequent modification with maleic anhydride was carried out at a rate of about 40% for both types. Visual determinations indicated that all the materials obtained behaved like non-ionic surfactants. However, sulfonation of tannin structure (at a rate of 40%) resulted in an anionic surfactant structure, as expected.