TmC47 wrote:Is it normal that xylene clouds up pretty strongly when FASA is added to it?
Just wanting to exclude the possibilty of unwanted precipitates later, it seemed like a good idea. Just adding acetone to the same batch of xylene produced no such fenomenon. After washing with water, a repeating of this experiment produced the same result exactly.
Yes it is pretty normal for xylene pulls to cloud strongly after FASA. Just adding acetone to xylene of course is not going to produce anything, same goes for FASA added in clear xylene. There may be some precipitation of fumaric acid in the latter case but this is minimal.
TmC47 wrote:Now, I'm sure Fumaric acid's solubility in acetone is different than in xylene's and probably lower at that. I'm also aware that an acetone wash of a hypothetical extraction should 'clean-up' the DMT-fumarate. I'm just surprised it hasn't, to my knowledge, been discussed before.
It has been discused a lot actually. Fumaric acid is pretty much insoluble in xylene to the best of SWIM's knowledge. Adding FASA to xylene for some reason does not lead to fumaric acid crashing out, but adding FASA to naphtha actually leads to fumaric acid crashing out. Why that may be, it is a matter of speculation for the moment.
Also, washing the dmt-fumarate with acetone is the pretty much standard way to clean any residual fumaric acid as well as xylene traces. So standard that is that is was an important part of the FASA tek when it was written.
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