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I am looking to attempt an extraction of an organic compound that had just been prepared using a Friedel-Crafts acylation. The compound was prepared in MDC (~20 mL in total). After the reaction, the organic compound was poured into ~20 mL of ice-cold distilled water. The protocol I am referring to states

"The reaction mass was cooled and water was added slowly under stirring condition. Product was extracted in MDC (12 X 2) and washed with water followed by treating with saturated sodium chloride solution (20 mL) ... "

I don't want to make any inferences as to what this means since I am new to synthetic lab work, but my guess is that it means 2 portions of 12 mL of MDC were used to separate the compound from the aqueous phase. I am not sure why they follow this by washing with water unless I am interpreting what "Extracted in MDC (12 X 2)" means. Similar sections in the paper include a little more detail that confirms my original speculations regarding what is meant by (12 X 2), but it still does not make sense to me why this would be followed by washing with water and not skip immediately to washing with a saturated NaCl solution. Here is the DOI to the paper: https://doi.org/10.1016/j.bmc.2018.05.016. The section I am looking at is 2.1.4.

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  • $\begingroup$ Sorry for this seemingly trivial question. I am just looking to gain a more complete understanding of reading experimental sections, as I have not had much experience with this. $\endgroup$ – Eli Jones Dec 31 '19 at 15:56
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    $\begingroup$ You are reasoning as if DCM and MDC are the same substance ? I am not sure. DCM may be dichloromethane. But MDC ? $\endgroup$ – Maurice Dec 31 '19 at 15:59
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    $\begingroup$ Sorry for the confusion, I did not realize that I used two different acronyms until I had posted the question. I will change it to be more clear. $\endgroup$ – Eli Jones Dec 31 '19 at 16:29
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    $\begingroup$ The backwash with water is to remove any inorganics that may have been carried through into the DCM product solution. It is a good idea to keep all your aq wash fractions until you have isolated your product. If your yield is low that is where the rest of your product is. $\endgroup$ – Waylander Dec 31 '19 at 16:48
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    $\begingroup$ The amount of DCM doesn't really matter as it will be removed under reduced pressure. I rather doubt they precisely added 12ml each time. 20ml washes would be perfectly OK $\endgroup$ – Waylander Dec 31 '19 at 17:28

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