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Extraction/purification caffeine - help

  1. Mar 5, 2005 #1
    lo all, i´m having a small prob here
    -extract the caffein of the tea leaves with CH2Cl2 + NaOH

    - after the liquid-liquid extraction the organic phase (that contains the caffeine) was evaporated. then i joined some hot "toluen" (C6H5CH3) to the caffeine to occur a cristalization by slow evaporation of the solvent..
    ok,i understand that but why the heck should i join some PETROLEUM ETHER to the cristals?

    good lord,my english is painfull,sry

    tks for any tip
  2. jcsd
  3. Mar 5, 2005 #2
    because ether is a good extraction solvent.
  4. Mar 5, 2005 #3


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    Science Advisor
    Homework Helper

    I believe it is used in this case as a transfer/rinse solvent, in which caffeine is moderately soluble. Usually the crude caffeine is dissolved in acetone, to remove the impurities and subsequently the former is used.
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