FA13+CHEM+225+Exp8+Column+Chromatography_001

When all of the white solid has eluted from the

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Unformatted text preview: leum ether to rinse residual white solid from the tip of the column into your collection flask. When all of the white solid has eluted from the column, change the collection flask to another small clean beaker. Allow about 5 mL of petroleum ether to elute from the column (stop if the yellow band starts to elute from the column), and then change the eluent to dichloromethane. Watch the progress of the yellow band as it will proceed more quickly down the column. When the yellow band just reaches the bottom of the column bed, rinse any solid from the tip of the column, then change the collection flask to a third clean small beaker. Continue eluting with dichloromethane until all of the yellow band has been removed from the column (usually ~10 mL CH2Cl2 will be required). Analysis and Isolation. Before evaporation of the solvents, perform TLC analysis of the column fractions, using 15% dichloromethane in petroleum ether as the eluent (Remember, be as accurate as possible and prepare this solution <10 min before you use it), and the following sample loading on the TLC plate: Lane 1: Fraction 1 Lane 2: Fraction 2 Lane 3: Fraction 3 Lane 4: Original mixture (dilute 1 drop in 2 mL before depositing on the TLC plate) Isolate the fluorene and 9-fluorenone by evaporating the solvent using the steam cone (do not use a hot plate, as the solvent is highly flammable). When the fluorene and 9-fluorenone are completely dry, determine the melting points and weight of each compound. Submit your TLC plate and samples to your section instructor. Label samples with (1) your full name, (2) section #, (3) date, (4) compound name. Laboratory Report. You will write a laboratory report for this experiment. 2...
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This document was uploaded on 01/16/2014.

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