Designing of amino functionalized imprinted polymeric resin for enantio-separation of (±)-mandelic acid racemate

Abstract S-Mandelic acid (MA) enantio-selective resinous material functionalized with –NH2 groups has been developed and effectively utilized in chiral separation of (±)-MA racemate solution. S-MA has first combined with the polymerizable p-aminophenol and form the corresponding amide derivative, which was then polymerized with phenol/formalin using HCl as a catalyst. The stereo-selective –NH2 functionalized binding sites were then generated within the resin upon the alkaline degradation of the amide linkages followed by acidic treatments that will expel the resin incorporated S-MA out of the polymeric material to get the S-MA imprinted polymer (S-MAPR). The synthesized S-MA chiral amide derivative along with the developed polymeric resin was investigated by various techniques including FTIR and NMR spectra that confirmed the executed chemical modifications. In addition, the morphological appearance of the obtained resins were observed using SEM images. Moreover, the S-MAPR resin was examined to optimize the enantio-selective separation conditions and the studies indicated that the adsorption reached the highest value at pH 7 and the maximum capacity was 243 ± 1 mg/g. In addition, the chiral separation of (±)-MA racemic solution was successfully executed by the S-MAPR separation column with 55% and 82% enantiomeric excess of R- and S-MA within both the initial loading and recovery eluant solutions, respectively.