Textile Catalysts—An unconventional approach towards heterogeneous catalysis

Abstract

Textile catalysts are a new approach utilizing immobilization of different classes of catalysts onto textile materials such as polyethylene terephthalate and polyamide. Robust, inexpensive fibrous materials are chosen because they are available in many variations. By a photochemical approach a series of different supported organocatalysts (organotextile catalysts) has been prepared, showing high catalytic activity and good reusability. The aim of this concept article is to present the scope, limits and open questions of our innovative approach. The working principle of the immobilization and its control parameters will be explained and the scope of useable catalysts is shown. Therefore we will show the significant influence of the anchoring group on loading and more importantly on catalyst activity. This concept is also applicable to organometallic catalysts and enzymes. Understanding the different phenomena allows us to develop “textile catalysts” as a new powerful tool for heterogeneous catalysis.

Chiral catalysts immobilized on achiral polymers: effect of the polymer support on the performance of the catalyst

“…267 Textiles have been recently reported as excellent polymeric supports for the immobilization of a variety of organocatalytic systems using photochemical approaches for their functionalization. 268 The incorporation of a chiral cinchona derivative provided an efficient chiral organocatalyst for the alcoholytic desymmetrization of a cyclic anhydride that could be reused for 300 runs. 269 The activity and the corresponding enantioselectivity were maintained essentially constant for the first 200 cycles and the further deactivation could be compensated, at least partly, by an increase in the catalyst loading.…”

Immobilization of Molecular Catalysts for Enhanced Redox Catalysis

“…The immobilization of homogeneous catalysts on various insoluble supports such as a siliceous material makes the immobilized catalyst insoluble in the reaction solution, providing great advantages for the easy separation of the catalyst from the reaction mixture, the fast isolation of the reaction products, and catalyst recovery and recycling by simple filtration . The immobilization of homogeneous catalysts also allows insoluble catalysts, which would otherwise be aggregated, to be well dispersed in the reaction medium such as water, resulting in the significant enhancement in the catalytic activity.…”

“…In general, the supported catalyst may be more sterically hindered and hence less accessible to substrates as compared to its non‐supported counterpart, while the selectivity may be enhanced by the steric effect. Catalyst instability in the homogeneous phase is mainly caused by bimolecular deactivation pathways, which are prevented by immobilization of the catalyst to isolate the catalyst reactive sites …”

“…The immobilization of homogeneous catalysts on various insoluble supports such as as iliceous material makes the immobilized catalysti nsoluble in the reactions olution,p roviding great advantages for the easy separation of the catalystf rom the reaction mixture, the fast isolation of the reaction products, and catalyst recovery and recycling by simple filtration. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] The immobilization of homogeneous catalysts also allows insoluble catalysts, which would otherwise be aggregated, to be well dispersed in the reaction medium such as water, resultingi nt he significant enhancement in the catalytic activity.T he use of water as solvent with immobilizedc atalysts also call attentiont ot he importance of the requirements of green chemistry. [21][22][23][24][25][26] In general,t he supported catalyst may be more sterically hindered and hence less accessible to substrates as compared to its non-supported counterpart,w hile the selectivity may be enhanced by the steric effect.…”

Wolf–Lamb‐type Catalysis in One Pot Using Electrospun Polymeric Catalyst Membranes

“…Organic fibers and textile immobilized with organocatalysts have also been explored as heterogenous catalysts . The textile fibers, such as cotton, polypropylene, nylon, and polyethylene terephthalate, are modified either with the functional groups for catalysis by photografting or immobilized with metal nanoparticles …”