Sciencemadness Discussion Board

precipitation question

andre178 - 28-4-2010 at 10:57


a paper calls for precipitation from methylene chloride/pentane. Is this a typical chemistry procedure? any references? I have not found anything on google regarding this combination of chemicals, and how this would come about. Screenshot below:

Picture 13.png - 20kB

matei - 28-4-2010 at 11:26

This simply means you have to dissolve your compound in dichloromethane and than add pentane (or petroleum ether b.p. 40-60 degC) until the compound precipitates. This assumes that your substance is polar, so it will be soluble in dichloromethane but insoluble in an nonpolar solvent like an alkane. This kind of purification is often used for polymers, for which the usual purification methods in organic chemistry (recrystallization, distillation, sublimation, etc.) can't be used.

andre178 - 28-4-2010 at 11:59

excellent explanation!