Part 5: TLC #2 and Melting Points

Spotting Samples for TLC

Procedure:

Make sure to have recorded weights and visual observations for solids D, F, H and K, from the earlier sections, if not go back and do that now. In this section you will obtain the melting points of theses solids. Calculate a percent recovery for the compounds you believe to be mainly acetaminophen and aspirin. Clearly label these in your lab notebook for observation credit.

Create an acetone solution of each of the four solids D, F, H, K for TLC purposes. To make these solutions, get a small amount of solid onto the tip of a spatula and rinse the spatula with a small amount of acetone into a clean reaction tube. Do this for each of the solids, for a total of four new solutions. Spot a sample of each of the four acetone solutions on a TLC plate. In addition, spot a sample of the organic layer of mixture X (from part IV) in the fifth lane. Develop the TLC plate in 10:10:1 toluene:ethyl acetate:acetic acid and visualize using UV and iodine.

A photo of a TLC plate illuminated by UV light. Five spots are visible along the baseline, one in each lane. The lanes are labeled D, F, H, K, and X.

A photo of a TLC plate developed in 10:10:1 toluene:ethyl acetate:acetic acid illuminated by UV light with a ruler next to it. The solvent front is 4.4 cm from the baseline. The first lane, labeled D, has two spots. The first spot is very faint and is 0.6 cm from the baseline, the second spot is much darker and is 1 cm from the baseline. The second lane, labeled F, has one spot. The spot is 1.9 cm from the baseline. The third lane, labeled H, has one spot. The spot is 1 cm from the baseline. The fourth lane, labeled K, has one spot. The spot is 0.6 cm from the baseline. The fifth lane, labeled X, has three spots. The spots are 0.6 cm, 1 cm, and 1.9 cm from the baseline.

A photo of a TLC plate developed in 10:10:1 toluene:ethyl acetate:acetic acid stained with iodine with a ruler next to it. The solvent front is 4.4 cm from the baseline. The first lane, labeled D, has one spot. The spot is 1 cm from the baseline. The second lane, labeled F, has one spot. The spot is 1.9 cm from the baseline. The third lane, labeled H, has one spot. The spot is 1 cm from the baseline. The fourth lane, labeled K, has one spot. The spot is 1 cm from the baseline. The fifth lane, labeled X, has two spots. The spots are 1 cm, and 1.9 cm from the baseline.

Return to Part 4

Take melting points

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