Polyetheretherketone fiber-supported polyethylene glycols for phase-transfer catalysis in its surface layer

Abstract

Cleaner and more efficient catalytic processes are becoming more relevant to the synthetic chemistry for reducing wastes. And herein, a commercially available ultra-high strength textile fiber polyetheretherketone (PEEK) was directionally modified by post-functionalization procedure to graft polyethylene glycols (PEG) into its surface layer to form a hydrophilic interface, and the resulted PEEK-PEG materials capable of acting as the supported phase-transfer catalysts for sorts of organic conversions in a cleaner manner were reported. The fiber samples generated during the preparation and utilization processes were observed and characterized in detail by various techniques such as morphology, mechanical properties, elemental analysis, FTIR spectroscopy and X-ray diffraction and TG analysis, and rest assured that the strategy was dependable. Moreover, the phase-transfer catalytic performance of the fiber-supported catalyst PEEK-PEG was verified in different kinds of substitution reactions, and the effects of PEG type, PEG loading and the correspondingly reaction conditions on the phase-transfer catalytic system were inspected meticulously, which were further conducive to sustain the proposed phase-transfer catalytic mechanism, and with the synergistic effect of the fiber support and PEG chain in the hydrophilic interface to afford the substitutions proceeded smoothly to obtain good to excellent product yields. Additionally, the fiber catalyst could be recycled simply and reused over 15 cycles with excellent stability under the strong caustic condition, and the catalytic system could be enlarged to the gram-scale in a spinning basket reactor, to provide a cleaner manner for phase-transfer catalysis in organic conversions with the potential of industrial application.