Glycerol: A Possibly General Method for Changing Solvents in Process Chemistry Reactors

The reaction solvent is distilled out of the reactor chased by the minimal stirrable volume of glycerol.

Since neither acetone nor methylene chloride are miscible with glycerol and they do not form any binary azeotrope:

 (i) A mixture of some useful proportion of acetone and methylene chloride is used to extract the non-volatile substrate. Cut away the glycerol phase.

or (ii) the desired second solvent, if it is immiscible with glycerin, is used to extract the non-volatile substrate. Cut away the glycerol phase.

Then

If (i) above is used, distill the methylene chloride away from the acetone leaving an acetone solution.

If (ii ) above is used, then wash the desired second solvent solution with water or brine to remove traces of glycerin.

Then

If (i)  above have been followed, add the new second solvent and distill away the lower boiling acetone (almost all solvents are higher boiling than acetone). If this second solvent is to be both protic and miscible with water, residual glycerol needs to have been removed at the stage of the acetone-methylene chloride extract by passing it through a plug of silica or alumina.