Chainsaw Posted April 13, 2016 Just curious whether anyone knows what the other 2% consists of in 98% caustic soda...and if it was used for an acid base extraction would it contaminate final product? Share this post Link to post Share on other sites
botanicalSEEKER Posted April 13, 2016 https://en.wikipedia.org/wiki/Chloralkali_process Think about solubility of salts. 1 Share this post Link to post Share on other sites
rahli Posted April 13, 2016 If extracting bases be sure to do a final wash with a sodium carbonate solution to draw out the sodium hydroxide or it will contaminate your extract. 1 Share this post Link to post Share on other sites
Alchemica Posted April 13, 2016 Go to page 3 of this pdf for a typical analysis of caustic soda. See the "Regular technical flake" column 1 Share this post Link to post Share on other sites
botanicalSEEKER Posted April 14, 2016 (edited) @rahli, whats the concept behind a carbonate wash ? I may be confused but aren't they are both bases. If an immiscible solvent was use wouldn't successive H2O achieve the same effect. Edited April 14, 2016 by botanicalSEEKER Share this post Link to post Share on other sites
Strontium Dawg Posted April 14, 2016 If the h2o is even slightly less than pH 7, it might salt out an alkaline extract. 1 Share this post Link to post Share on other sites
rahli Posted April 14, 2016 (edited) The basic sodium carbonate polar solution attracts the sodium hydroxide out of the non polar solvent. Failure to remove the sodium hydroxide from the extract results in it taking on the hyroscopic properties of sodium hydroxide. This is no longer an issue after the sodium carbonate wash. Maybe someone with more of a chem theoretical background can chime in with why this is the case. Edited April 14, 2016 by rahli Share this post Link to post Share on other sites
Chainsaw Posted April 15, 2016 Thanks everyone for your input... much appreciated My question actually relates to an amine which I understand is basic so the sodium carb wash would be appropriate yeah? The procedure I read mentioned only an acetone wash...would you wash with sodium carb first then acetone or other way round? And if I understand the list of contaminants correctly, most are salts which would be soluble in water and discarded when separated from the solvent layer before adding acid? Apart from some heavy metals which hopefully aren't too dangerous at low concentration? Share this post Link to post Share on other sites
rahli Posted April 15, 2016 (edited) You wash the nonpolar solvent containing the base extract first, then wash the base extract with acetone. Edited April 15, 2016 by rahli Share this post Link to post Share on other sites
