Functionalised polyorganosiloxanes as selective liquid extractants

Abstract

The cyclic ether 2-(hex-5-enyl)-1,4,7,10-tetraoxacyclododecane has been synthesised and attached to a siloxane backbone to produce linear polyorganosiloxanes functionalised with 12-crown-4 terminated alkyl chains, Me₃SiO(Me₂SiO)_x[MeSiO(CH₂)₆-12-crown-4]_ySiMe₃(x= 47, y= 1, or x= 286, y= 12); the preferential complexation of 12-crown-4-for secondary amine salts in mixtures of protonated secondary and tertiary amines is maintained in the functionalised liquid polymers, which are thus effective selective extractants for the separation of secondary and tertiary amine mixtures including norcodeine and codeine present in low concentrations in bioreactor broth.