Assessing Separation processes for an aromatic and a chiral amine using Polybenzimidazole (PBI) membranes

Sara Alexandra da Silva Lopes

Key information

Authors:

Sara Alexandra da Silva Lopes (Sara Alexandra da Silva Lopes)

Supervisors:

Teresa Sofia Araújo Esteves (Teresa Sofia Araújo Esteves); Frederico Castelo Alves Ferreira (Frederico Castelo Alves Ferreira)

Published in

12/13/2017

Abstract

Amines are important chemical building block used in the organic synthesis and for production of compounds of pharmaceutical interest. In this context, it is important to develop separation processes and techniques to purify these types of compounds. Two types of separation processes are addressed in this thesis: resolution of chiral amines and removal of potential genotoxic impurities present in active pharmaceutical ingredients. Two amines were used as model for these studies in this thesis: Lupanine is a chiral amine and 4-dimethylaminopyridine (DMAP) is regarded as a potentially genotoxic impurity. Several processes have been developed to solve the above-described problems, such as enzymatic resolution, chromatography, nanofiltration and molecularly imprinted polymers. This thesis explores the use of a material, polybenzimidazole polymer (PBI), in various separation techniques. It was used successfully as scavenger, due to its ability to adsorb amines, either in beads or membranes or was used as a material to molecularly imprinted membranes, used in nanofiltration and adsorption experiments. The attempts to make molecularly imprinted membranes for enhanced separation efficiencies and of using membranes to improved diastereomeric resolution by membrane recrystallization proved to be unsuccessfully. Additionally, optimization of diastereomeric resolution was assessed, which resulted in enantiomerically the pure D- (+)- Lupanine using L-tartaric acid as resolving agent. However, using DTTA as resolving agent only a maximum of 89.16% of L-(-)- Lupanine was obtained We also prepared membranes molecularly imprinted with Lupanine in order to separate their enantiomers; however these were not efficient for this purpose.