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I was reading about purification of organic compounds and I came across this.

I quote below, a line from the excerpt that caused my confusion.

The organic solvent is later removed by distillation or by evaporation to get back the compound.


My question: Why can't we just seperate the organic compound from the water by distillation/evaporation directly?


My approach:
The aim of the procedure is to - seperate out from water, the required organic compound that is presented to us in an aqueous solution form.
If the organic compound has relatively higher boiling point, use evaporation. If the organic compound has relatively lower boiling point, use distillation. If more than two compounds are to be recovered, use fractional distillation.


I felt like it was 'unnecessary' to mix it with an organic solvent and then proceed with evaporation/distillation of the new organic solution without water content. We could just proceed with evaporation/distillation of the aqueous solution directly and recover the organic compound - I've stated how in the 'My approach' section.


Self-evaluation:

  1. I might not be aware of the various reasons because of my lack of knowledge and hence consider it unnecessary.
  2. Distillation might cause reactions/decomposition because it is being heated in an aqueous medium while it might not react in an inert organic solvent.
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    $\begingroup$ Typically there are other components in the mixture that are left behind in the water. Hence the “purification” aspect $\endgroup$
    – Andrew
    Feb 13 '21 at 14:33
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    $\begingroup$ Water can, of course, be removed by evaporation (or freeze-drying), but if you used mains water then be aware there is a mineral content that will be left in your organic product. $\endgroup$
    – Waylander
    Feb 13 '21 at 14:43
  • $\begingroup$ That's highly dependant on context this question lacks. $\endgroup$
    – Mithoron
    Feb 13 '21 at 21:55

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