3
$\begingroup$

I've learend that in processing liquid-liquid extractions, emulsions can appear between two immiscible solvents.

For exmaple, to extract caffeine from green tea leaves;

The caffeine in water can be moved to ethyl acetate with liquid-liquid extraction. There were precautions for not making emulsions by gently shaking the two solvents together in the sepearatory funnel. Why is this important? Don't we re-extract from the extracted water again several times to maximize the extraction of a substance(in this case, caffeine)?

If the emulsions were in the water part while extracting, it doesn't matter because we can re-extract the water again with the seperatory funnel.

Improve this question
$\endgroup$
2
  • $\begingroup$ You may need much more solvent to achive the same extraction degree, when the solvent "competes" not only with water, but also with the emulgated solvent. $\endgroup$
    – Poutnik
    Commented Oct 5, 2022 at 11:50
  • $\begingroup$ Emulsions are a problem because they make separation of the two imiscible liquids difficult. Imagine doing the extraction in a separatory funnel: you can't remove one layer cleanly if you have an emulsion. $\endgroup$
    – matt_black
    Commented Oct 6, 2022 at 12:54

0

Reset to default

Browse other questions tagged or ask your own question.