A core–shell structure of β-cyclodextrin polyisocyanate boosts selective recovery of acetophenone from petrochemical by-products

Efficient separation of acetophenone (AP) and 1-phenylethanol (1-PE) is crucial but challenging for high-value utilization of petrochemical by-products. To boost the AP/1-PE separation performance, a core–shell structure consisting of polyisocyanate layer grown on β-cyclodextrin (β-CD) particles (CD@PTDIT) was successfully fabricated by in-situ self-polymerization of toluene-2,4-diisocyanate trimer (TDIT) onto β-CD surface. The unique micro-architecture and chemical compositions of CD@PTDIT were comprehensively investigated by X-ray diffraction (XRD), solid-state 13 C CP/MAS NMR, X-ray photoelectron spectroscopy (XPS), elemental analysis, etc. Results indicated the well-maintained crystallinity of β-CD backbone and tunable thickness of polyisocyanate shell were integrated in CD@PTDIT. The unprecedented selectivity of CD@PTDIT for AP over 1-PE (6.9–9.4) combined with high AP uptake as well as the excellent recyclability was confirmed by both static adsorption and dynamic breakthrough experiments. Multicomponent breakthrough experiments using petrochemical by-product further demonstrated that CD@PTDIT maintained this selectivity in the practical applications. In-depth mechanism study using theoretical and structural investigations defined the essential host–guest interactions that produce the observed separation performance.