Solvent Question (urea and alkali carbonate)

[rvdzero]

hey, i was just reading a patent on alkali metal carbonates. US patent : 4,495,107 . (can get the link if needed) Ok so i was wondering, what are my options for a solvent that could dissolve the urea, but not the alkali carbonate? I read that an inert solvent which doesnt really dissolve the alkali carbonate but dissolves the urea can be used. Any thoughts on toluene or xylene? any other suggestions?

[Tartaglia]

I would have thought that any slightly polar aprotic solvent would do

[rvdzero]

ah thanks. i read it recommended using a sulfoxide. so something like dmso. my next question, dmso is miscible in water so would the a 80% aqueous solution still be suitable, or would the presence of h20 interfere?

[Tartaglia]

If you use DMSO I would be tempted to use it dry or dryish. I would probably use something more volatile for ease of separation (eg CH2Cl2, diethylether).