(327g) Novel Multifunctional Organocatalysts and Continuous Flow Platform for Sustainable Chemical Transformation

The use of multifunctional organocatalysts and continuous flow platform are commonplace in modern chemical transformation.[1-4] Herein, we describe a method for immobilization of trifunctional organocatalysts on porous composite hollow fiber and demonstrate their application as heterogeneous catalyst and continuous-flow microfluidic reactor for chemical transformation. The polyamide imide hollow fibers (PAIHF’s) are functionalized with aminosilanes and bromine source to immobilize covalently hydrogen-bond donor groups (-OH and -NH), and nucleophilic [Br^−] species upon the fiber surface and provide trifunctional acid-base-nucleophilic organocatalysts and microfluidic reactors. The cooperative effects of Br/APS/PAIHF trifunctional organocatalysts are elucidated in the CO₂ cycloaddition and hydroxyalkylation of aniline under batch and continuous flow synthesis. Our results indicated that the synergistic cooperative effect of trifunctional organocatalyst on PAIHF leads to a maximum 1-(phenylamino)propan-2-ol selectivity of 97.1% at 61% aniline conversion and 0.02 cm³/min flow rate. While knowledge of the acid-base-nucleophilic trifunctional cooperativity is still limited, these findings demonstrate useful structure-property trends that can be used to design more efficient organocatalysts for sustainable chemical transformation.

References:

1. A.-A. Alwakwak, Y. He, A. Almuslem, M. Senter, A. K. Itta, F. Rezaei, A. Rownaghi, Metal- and solvent-free synthesis of aminoalcohols under continuous fl ow conditions, React. Chem. Eng. 5 (2020) 289-299.

2. Y. He, F. Rezaei, S. Kapila, A.A. Rownaghi, Engineering Porous Polymer Hollow Fiber Microfluidic Reactors for Sustainable C-H Functionalization, ACS Appl. Mater. Interfaces. 9 (2017) 16288–16295.

3. Y. He, A. Jawad, X. Li, M. Atanga, F. Rezaei, A.A. Rownaghi, Direct aldol and nitroaldol condensation in an aminosilane-grafted Si/Zr/Ti composite hollow fiber as a heterogeneous catalyst and continuous-flow reactor, J. Catal. 341 (2016) 149–159.

4. Y. He, A.K. Itta, A. Alwakwak, M. Huang, F. Rezaei, Aminosilane-Grafted SiO2-ZrO2 Polymer Hollow Fibers as Bifunctional Microfluidic Reactor for Tandem Reaction of Glucose and Fructose to 5-Hydroxymethylfurfural, ACS Sustain. Chem. Eng. 6 (2018) 17211–17219.