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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: mordoh on June 21, 2004, 08:07:56 AM

Title: another question - ethanol , hot or cold?
Post by: mordoh on June 21, 2004, 08:07:56 AM

hey ,

i wanted to know, can i do extraction of plant/herb with 70% ethanol (hot) for 3-4 hours and it will be exactly the same to extraction with cold ethanol for 2 weeks?

if not , whats the diffrence?

thanks

Title: Re:another question - ethanol , hot or cold?
Post by: Mitch on June 22, 2004, 06:19:06 PM

The difference is solubillity. Solubility is a function of temperature. Typically the higher the temperature the more soluable a substance is in that medium.

Title: Re:another question - ethanol , hot or cold?
Post by: Doxorubicin on June 30, 2004, 11:30:19 PM

It depends on what you are extracting.  

Title: Re:another question - ethanol , hot or cold?
Post by: cfthb on July 14, 2004, 04:58:42 PM

Assuming that the cold extraction is also done with 70% EtOH, the quantity of solute that will dissolve should be the same, regardless of temperature; it's just much faster to do it with the hot solvent.  The nature of the solute won't matter.  BUT - the difference in solubility btwn hot/cold solvents is huge, and two weeks cold may not approach what you can do at reflux for several hrs.