Synthesis and Physico-Chemical Studies of Azo Dyes from Anacardic Acid, An Inexpensive Renewable Resource

Abstract

(3AP) and 4-aminophenol (4AP) with both unsaturated (UA) and saturated (SA) anacardic acids and the calcium salt (CA) of the unsaturated acid. The six prepared dyes are, thus, given the acronyms 3APSA, 3APUA, 3APCA, 4APSA, 4APUA, and 4APCA depending on the source of the diazonium salt and the form of anacardic acid used. The dyes were characterized using UV-Vis and FT-IR spectroscopic techniques. The UV-Vis absorption spectra of the dyes were found to have maximum peaks at 520 nm for the dyes of 3AP origin and at 295 nm for the dyes of 4AP origin. The FT-IR spectra for the dyes indicated presence of the azo group around 1450 to 1520 cm-1. The dyes showed moderate performance on textile fabrics used. The total extent of fixation was 39% for 3APSA on the fabric with 100% cotton and 31% for fabric with 35:65% cotton/polyester content. On the other hand, the total extent of fixation was 33% for 4APSA on the fabrics with 100% cotton and 29% on fabric with 35:65% cotton/polyester content. The fastness test showed that the change in shade for one of the dye was 2/5 implying fair fastness to washing.

Keywords: Anacardic acid; azo dyes; 3-aminophenol; 4-aminophenol; cashew nut shell liquid;