A Practical Guide for Buffer-Assisted Isolation and Purification of Primary, Secondary, and Tertiary Amine Derivatives from Their Mixture

Abstract

A number of reactions involving primary amines such as N-alkylation, reductive amination, Mannich reaction, etc. produce mixtures of primary, secondary, and tertiary amines. The isolation and purification of individual constituents of these mixtures is often carried out by column chromatography or fractional distillation. For an industrial large-scale process, it would be desirable to avoid column chromatography and distillation (if the product is temperature sensitive) without significantly losing the product yield. We have devised an elegant method which uses relatively inexpensive buffer medium of varying pH to selectively separate primary, secondary, and tertiary amines.