Preparation of para red and related azo dyes

Non azo dyes

Control the rate of addition so that the temperature of the solution does not rise above 20 0C. However, this experiment may still be improved by careful division of the solutions prior to mixing both solutions because the experiment is skewed if too much of one carbonyl compound is added to the other. Its absorption value is about 4. Place the flask in an ice bath to cool C. A variety of azo dyes with sulphonamide group were found have potential anti microbial properties. Result and Discussion a Table : The reported and obtained melting points of the products obtained in each synthetic step. It was discovered in by von Gallois and Ullrich, and was the first azo dye. After all the nitric acid solution has been added let the reaction mixture stands at room temperature for 20 minutes. Cool the solution to C by adding crushed ice. The second reaction with p-anisidine and 1-naphthol yielded a darker red colored azo dye solution. The resulting precipitate is p-nitroaniline. References 1. Continue to keep the ice-water bath under C so that the diazonium salt does not decompose. The difference in colors of both azo dye was because of the difference in the attachment of the hydroxyl group to the compound.

Collect the red precipitate by vacuum filtration. Ghanadzadeh, M. H2SO4 into this mixture while stirring it constantly. However, this experiment may still be improved by careful division of the solutions prior to mixing both solutions because the experiment is skewed if too much of one carbonyl compound is added to the other.

Acknowledgements The author extends the thanks to all the members of department of chemistry, St. Then cool the reaction mixture and pour the contents into a mixture of 50g of ice in 75ml of water.

Preparation of para red and related azo dyes

H2SO4 in 25ml of water in aml flask. During the addition of the NaOH, the mixture will get hot and should be well stirred. It dyes cellulose fabrics to red. Continue to keep the ice-water bath under C so that the diazonium salt does not decompose. Related Papers. P C 2. Cool the solution to C by adding crushed ice. Since Para Red is Red coloured dye, its visible absorption was measured using a uv-visible Spectrophotometer. Then cool the reaction mixture and pour the contents into a mixture of 50g of ice in 75ml of water. Continue to swirl the mixture vigorously for a few minutes. Posted by. When the hydrolysis is complete, a 1ml proportion of the reaction mixture will be soluble in 5ml of water. The difference in colors of both azo dye was because of the difference in the attachment of the hydroxyl group to the compound. Discussion : The first synthesis using the ketone, 2-napthol, and aldehyde,nitroaniline, produced a red colored para red solution while the other reaction with p-anisidine and 1-naphthol produced a darker red colored solution. Collect the red precipitate by vacuum filtration.

Moghadam, Chem Sci Trans. Para dye is a chemical dye used in printing.

Organic chemistry labs.

Download