Experiment Outline: You will receive 2 mL of an ether/pentane solution containing 1.00 g of benzy lactone contaminated with a small amount of guaiazulene Make a TLC sample, and analyze this mixture by TLC, using 10% ethyl acetate/hexanes as the solvent system-see TLC Guide Record the r values. Prepare the column in the hood, using 10% ether/pentane and 50 g(about 5")of silica gel-see Flash Column Chromatography guide Elute the column with 10 mL of pentane Apply your sample to the column, being careful not to disturb the top layer of sand. Rinse the sample flask three times with l mL pentane each, and use the rinses to wash the sides of the column Run the column-See Flash Column Chromatography Guide Monitor the fractions by tlC- See TLC Guide Concentrate the set of fractions containing pure benzylacetone Weigh the purified compound and prepare a gc sample Obtain a tLC and a gas chromatogram of the purified compound Benzalacetone To obtain your CC Rating"in Purification by Flash Column Chromatography you must collect at least 0.95 g of benzylacetone. This sample must be at least 95%o pure as demonstrated using gas chromatography. Your sample must also be submitted to the TA for possible weight and purity verificationExperiment Outline: • You will receive 2 mL of an ether/pentane solution containing 1.00 g of benzylacetone contaminated with a small amount of guaiazulene. • Make a TLC sample, and analyze this mixture by TLC, using 10% ethyl acetate/hexanes as the solvent system - see TLC Guide. • Record the Rf values. • Prepare the column in the hood, using 10% ether/pentane and 50 g (about 5’’) of silica gel - see Flash Column Chromatography Guide. • Elute the column with 10 mL of pentane. • Apply your sample to the column, being careful not to disturb the top layer of sand. Rinse the sample flask three times with 1 mL pentane each, and use the rinses to wash the sides of the column. • Run the column - See Flash Column Chromatography Guide. • Monitor the fractions by TLC - See TLC Guide. • Concentrate the set of fractions containing pure benzylacetone. • Weigh the purified compound and prepare a GC sample. • Obtain a TLC and a gas chromatogram of the purified compound. CH3 H3C O CH3 CH3 H3C Benzylacetone Guaiazulene Results: • To obtain your "CC Rating" in Purification by Flash Column Chromatography, you must collect at least 0.95 g of benzylacetone. This sample must be at least 95% pure as demonstrated using gas chromatography. Your sample must also be submitted to the TA for possible weight and purity verification. 29