Purple color Essay Example for Free

Purple color Essay Purple color of tetraphenylcyclopentadienone was isolated by aldol condensation between dibenzylketone and benzil. Water was also produced, but it was eliminated by polar protic solvent, triethylene, and heat. Thus, the mixture was heated until the temperature of the mixture reached to 100 ? C so as to eliminate the water present and also to increase the rate of reaction due to increase in entropy. Benzyltrimethylamonium hydroxide was used as a base catalyst. Since catalyst increases the reaction rate much faster at higher temperature, it was added to the mixture at 100 ? C. Once the catalyst was added to the mixture, it turned to dark muddy like and the temperature went up to 120 ? C. Dark purple, muddy like mixture indicated the completion of the reaction. Increase in the temperature indicated that the reaction was exothermic reaction. The completion of the reaction was also confirmed by the color of the filtrate. Methanol washed the impurities and the catalyst on the filter and thus color of the filtrate changed from brown to purple. The product, tetraphenylcyclopentadienone, was purple even though the two reagents benzil and dibenzylketone were yellow and colorless respectively. Tetraphenylcyclopentadienone has extended conjugation between five carbon rings and four phenyl groups that increase stability and thereby lowers overall energy of the molecule. Thus, it absorbs light at lower energy and longer wavelength that is in visible spectrum. Thin layer chromatography (TLC) was used to test purity of the product, i. e. , tetraphenylcyclopentadienone. Only one spot in the product lane in the TLC plate was observed under UV light which indicated that the product was relatively pure. The percentage of recovery was 76%. Some of the product was possibly lost when the mixture was heated. The mixture was heated quickly, so some of undesired product was also formed. Also, some of the product was possibly washed by methanol because solubility is not absolute.