Phase-transfer catalyst separation and re-use by solvent resistant nanofiltration membranes

This communication describes the use of nanofiltration (NF) membranes for efficient separation and recycling of phase-transfer catalysts, using the conversion of bromoheptane into iodoheptane with tetraoctylammonium bromide, as the PT catalyst, as an example, a solvent flux of > 10 L m(-2) h(-1) was achieved with > 99% catalyst recycle and no loss in PT catalyst activity over a cycle of three consecutive reactions.