Moschetta EG, Negretti S, Chepiga KM, Brunelli NA, Labreche Y, Feng Y, Rezaei F, Lively
RP, Koros WJ, Davies HM. L, * Jones CW. * Georgia Institute for Technology and Emory
University, Atlanta, USA
Composite Polymer/Oxide Hollow Fiber Contactors: Versatile and Scalable Flow Reactors
for Heterogeneous Catalytic Reactions in Organic Synthesis.
Angew. Chem. Int. Ed. 2015;
54: 6470-6474
Key words
flow chemistry - heterogeneous catalysis - hollow fibers - rhodium
Significance
Flow reaction systems using composite hollow cellulose acetate fibers containing embedded
catalysts {ZSM-5 (aluminosilicate MFI zeolite), 3-aminopropyl (APS)-functionalized
silica, and the immobilized analogue of Rh2(S-DOSP)4 [DOSP = N-(4-dodecylphenylsulfonyl)prolinato]} were developed for heterogeneous catalytic reactions.
The acid-catalyzed hydrolysis of (dimethoxymethyl)benzene (1) to benzaldehyde (2) on ZSM-5/fiber, the Knoevenagel condensation of benzaldehyde (2) with malononitrile (3) on APS fiber, and a rhodium-catalyzed enantioselective cyclopropanation on the Rh2(S-DOSP)4 fiber all proceeded efficiently.
Comment
The catalysts were embedded within the permeable fiber walls (approximately 300–400
µm thick), and the reactants were fed through the bores of the composite hollow fibers.
The fiber was surrounded by a sweeping flow of organic solvent that facilitated product
collection. The fiber was capped at the end furthest from the inlet to ensure the
reactants flowed through the walls and contacted to the catalyst.