Optically Active Microspheres Constructed by Helical Substituted Polyacetylene and Used for Adsorption of Organic Compounds in Aqueous Systems

This article reports optically active microspheres consisting of chiral helical substituted polyacetylene and beta-cyclodextrin-derivative (beta-CD-A). The microspheres showed remarkable adsorption toward various organic compounds in water. To prepare the microspheres, an acetylenic-derived helical macro-monomer was synthesized and then underwent aqueous suspension copolymerization with octadecyl acrylate and butyl acrylate by using azobis(isobutyronitrile) as initiator and beta-CD-A simultaneously as comonomer and cross-linking agent. The helical macromonomer chains enabled the microspheres to exhibit desirable enantio-differentiating adsorption capacity toward chiral compounds respectively dissolved in organic solvent, dispersed in water, and dissolved in water. The saturated absorbency toward (R)-(+)- and (S)-(-)-1-phenylethylamine was 29 and 12 mg-CI, respectively. The microspheres also showed large oil absorbency (e.g., 22 g.g(-1) (CCL4) and a large adsorption toward methyl red (as a model for organic dyes) dispersed in water. The presence of beta-CD-A moieties improved the adsorption performance of the microspheres. The present optically active microspheres open a new approach for preparing adsorbents particularly chiral adsorbents with potentials for wastewater treatment.