Polyetheretherketone fiber-supported TBD as an efficient fibrous superbase catalyst for organic conversions in continuous-flow processing

Abstract

The development of clean catalytic technologies in continuous-flow processing for efficient organic conversions has a positive influence on the fine chemicals and pharmaceutical manufacturing. Herein, the commonly used organic superbase 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) was immobilized on the commercially available ultra-high strength textile fiber polyetheretherketone (PEEK) to report a polymer-supported basic catalyst (PEEK-TBD) for three types of organic conversions in cleaner continuous-flow processing. The fiber catalyst was prepared through an improvement strategy and verified as a heterogeneous fibrous superbase catalyst in the microtubule reactor to mediate the Knoevenagel condensation-cyclization between salicylaldehydes and activated nitriles for the synthesis of iminocoumarins in ethanol (10 samples, yields 91–97%) after turning the flow rate, substrate concentration, and catalyst padding quantity, additionally, PEEK-TBD was also effective for the cyanosilylation of carbonyl compounds for the synthesis of cyanogen compounds in acetonitrile, as well as the substitution reaction of aniline and carbonate for the synthesis of N,N’-substituted urea in toluene in continuous-flow processing. Moreover, the resulting fiber samples were characterized in detail by sorts of analytical methods and techniques to further confirm the dependability of this methodology, and the clean and valid gram-scalable procedure of PEEK-TBD in continuous-flow processing has extensive application prospects on the chemical productions.