Question

7. Devise a LLE setup to separate a sample that contains trace levels of three compounds: an organic acid, an organic base, and a neutral organic compound. The goal is to have three solutions at the end, each in methylene chloride, one of which contains only the organic acid, the second contains only the organic base, and the third contains only the neutral compound.

Answer 1

Step 1. Dissolve the mixture in DCM and add aq. NaHCO3 solution acid will form salt and will go in aqueous layer while base and neutral compound will go in to DCM layer.

RcooH & RNHO & R-R Acid base neutral Dissolve the mindre in bom stepa Add aq, NaHCog soluson organic layer [Dom layer) a R-NHAR-R aqueous layer R COONG Step 2 Add ag. HCl L extracte with Dom DCM Step. 8 Add ag. Hel nayer I Naol В соон nom layer neid compound aqueoul Ilayer ROR R-WH2C1 neutral compound Step 4 Add og NooH extract with Dom Ocm) Jaqueous layer. layer Nach R-NH, borse compound

Step2. Aq. layer of step 1 on treatment with aq. HCl acid will get protonated and will go in to DCM layer.

Step3. Organic layer of step 1 contain base and neutral compound which on treatment with aq. HCl, base will form salt and will go in aqueous layer whereas neutral compound will remain in DCM layer.

Step4. Aq. layer of step 3 on treatment with aq. NaOH salt form basic compound will be free base and which will go in DCM layer.