Adsorptive Separation of o‐/p‐Aminoacetophenones using Acidic Ion Exchange Resins

Abstract

Separation of o‐/p‐aminoacetophenones (o‐/p‐AAPs) is investigated by a two‐step process: selective solubilization in an organic solvent followed by reactive adsorption on functionalized polymers. Since, p‐AAP and o‐AAP show inter‐ and intra‐molecular hydrogen bonding, respectively, the former is solubilized to a much lesser extent than the latter in an organic solvent. For example, o‐AAP dissolves completely while p‐AAP shows only 1.8% saturation solubility in toluene. Selective solubilization of o‐AAP in toluene, therefore, gives pure p‐AAP as residual solid in high yields. In the subsequent adsorption step, a strongly acidic ion exchange resin removes selectively the trace amounts of p‐AAP from the toluene phase giving pure o‐AAP.