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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: skunny on December 12, 2018, 04:37:30 AM

Title: Seperation of two substances by column chromatography
Post by: skunny on December 12, 2018, 04:37:30 AM

Hey

I was really hoping somebody could help me out here, because i have no clue anymore what Else to try...

I am trying to seperate Ethyl-4-hydroxybenzoat and ethylvanillin....i Just don't find the right Solvent mixture....I have a good seperation between those substances, but only If i use ammonia and evaporating ammonia by a rotary evapirator doesnt work Out so Well...does anyone have an idea how i might successful:/? Thx!!!

Title: Re: Seperation of two substances by column chromatography
Post by: Babcock_Hall on December 12, 2018, 11:30:43 AM

I have used rotary evaporation to remove aqueous ammonia on many occasions.  If it is not completely removed on the first pass, sometimes redissolving in a solvent and rotovapping again is necessary.  Triethylamine is an alternative, I suppose.

Sometimes removal of one solvent is aided by adding a second solvent to strip away the first.  I don't have any specific suggestions regarding ammonia in that regard, however.

Title: Re: Seperation of two substances by column chromatography
Post by: wildfyr on December 12, 2018, 12:32:55 PM

Running the column with triethylamine or ammonia then doing an aqueous acid extraction at the end seems reasonable.