Extraction and Thin Layer Chromatography
Kaya Gaudet 6784928
January 9, 2013
Line Structure References
Extraction: A process used to separate different compounds in a mixture based on their solubility in an immiscible substance. Usually an aqueous and organic phase are used. During extraction the desired compound moves one phase and leaves the unwanted substance behind. Extraction normally has to be done a few times to leave all of the impurities behind. TLC plating can be used to mark the progress of the extraction. Thin Layer Chromatography (TLC) Plating: This is a common method that is used to monitor the progress of a reaction and determine when it is complete. In our chromatography there was a stationary phase/adsorbant of Silica gel and we used mobile phases of ethyl acetate, hexanes, and a 2:8 mix of both. During the process, the mobile phase passes over the compound spots at the bottom and drags them up the adsorbant. The resulting spots where the compounds stop can be used to measure their polarity and solubility in the mobile phase. We had a reference spot, unknown spot, and compound spot where we mixed both. Salting: In an extraction, if the compound is partially soluble in water then the process of salting out can help further separate it into the organic layer by increasing the polarity of the aqueous solution and forcing the organic compound out.
Procedure and observations:
Part A: Extraction of water soluble dyes (an introduction to extracting) added 1ml of ether and 1ml of distilled water into two test tubes, then added 0.006M of methylene blue to one test tube and 0.006M of methyl red solution to the other and shook each vigorously with a stopper in the first test tube there was blue on the bottom and clear on top, in the second test tube it was yellow on top and purple on bottom Salting out
added 5ml of distilled water, roughly 1-2 drops of 0.003M aqueous crystal violet and 0.5ml of 1-butanol to two test tubes, add a bit of NaCl to one and shake both the one without salt had a uniform purple colour throughout and the one with salt had a slight gradient after a few minutes which turned into a layer of purple on the surface after about 3 hours
Part B: Identifying components of an unknown mixture using TLC added 5ml of 2:8 ethyl acetate and 5ml of hexanes after misreading (results should still be plausible) to a reference jar and put the lid on drew a line 1cm from the bottom on 6 plates and three evenly spaced dots on each in pencil got unknown sample 1 from TA and dissolved it in 2ml of dichloromethane, spotted this on the furthest right dot and middle dot on all 6 plates by dipping it in the mixture and then lightly touching it to the paper spot benzophenone on the furthest left spot of three plates and spot biphenyl on the furthest left spot of the other three plates placed the plates one at a time in the reference jar and took them out when the liquid moved to about 1cm from the top after removing the plates shined a UV light on them and outlined the dots in pencil
Part C: Effect of solvent on TLC
emptied the jar in the organic waste and refilled it with 10ml of just ethyl acetate and put the top on put one tlc plate with biphenyl in the jar then one benzophenone visualize them again with the UV light and mark the spots in pencil repeat but with 10ml of just hexanes
Part D: Separating a mixture with reactive extraction
i made a new sample with my unknown 1 and 10ml of dichloromethane and poured it into a 50ml erlenmeyer flask and swirl it pour into seperatory funnel with the stopcock on, rinse the flask with dichloromethane and pour that into the funnel too add 10ml of 2M NaOH into the funnel and invert it with the stopper on, opening it every few seconds to let gas out place funnel on rack and wait a couple minutes for it separate then take off the stopper from the top...
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