Azo Dye Lab Report

The purpose of this lab was to synthesize indigo and an azo dye and to determine how effective each dye was to dye different types of fabrics. 0.168g of 2-nitrobenzaldehyde was dissolved into acetone along with 25 drops of distilled water and NaOH to synthesize indigo. The solution was filtered, and the solid indigo was placed into the filter flask to reduce indigo to leucoindigo with 10mL of 3M NaOH. The flask was heated along with sodium dithionite and distilled water added to the flask. Afiber strip was added and heated for 10 minutes. The strip was removed and rinsed with water. A3 was the azo dye that was assigned, and 0.499g sulfanilic acid was added to the test tube with 5 mL of sodium carbonate. The tube was placed in a hot water bath, and
Nylon 66 was the brightest blue teal, and bleached cotton was blue gray. The name of the azo dye that was synthesized is 2-hydroxy-5-[(4-sulfophenyl)diazenyl]benzoic acid. Worsted wool and silk were the fabrics that were able to absorb the most amount of dye, and therefore resulted in the deepest colors for both dyes. Disperse polyester and polyacrylic were the ones that absorbed the least amount of dyes, which resulted in the lightest colors for both dyes. The amount of dye the fabrics were able to absorb had to do with the hydrogen bonding between the fabric and the dye. The more polar the fabric was, the more hydrogen bonds the fabric was able to make with the dye, which resulted in a darker color. The azo dye that had the strongest colors was B1 because worsted wool and able to be dyed into a deep red color. The other dyes dyed the fabrics into a red orange color. A source of error would be that when dying the strips in the azo dye, there was not a lot of dye to cover the fabric completely. This error was minimized by occasionally pressing down on the fabric so that it was soaked in the