Ionic Liquid Functionalized Chitosan Catalyst with Optimized Hydrophilic/Hydrophobic Structural Balance for Efficient CO₂ Fixation

Abstract

In this work a series of chitosan‐based catalysts with ranging hydrophobic/hydrophilic balance are successfully prepared by varying the ionic liquid and hydrocarbon chain length attached to chitosan. The chitosan modified with eight carbon units displayed efficient catalytic activity for the conversion of a wide range of epoxides to their corresponding cyclic carbonates under 1 atmosphere pressure of carbon dioxide without cocatalyst and solvent. The optimized catalyst was able to convert even diepoxides and sterically bulky epoxides like t‐butyl glycidyl ether to their corresponding cyclic carbonates. This study provides an insight into catalyst designing based on possible molecular interaction between reactants and active sites of the catalyst.

Alumina-Based Bifunctional Catalyst for Efficient CO2 Fixation into Epoxides at Atmospheric Pressure

“…The cyclic carbonate is formed in the final step through intramolecular ring closure. 101 In this work, the Al 3+ ions present in alumina act as the Lewis acid centers. 45,65 The interaction of Al 3+ ions with the O atom of epoxide is expected to enhance the electrophilicity of the epoxide ring.…”

Organocatalytic Polymers from Affordable and Readily Available Building Blocks for the Cycloaddition of CO2 to Epoxides

“…95,162,163 In this context, Mahalingam et al recently reported a convenient strategy to functionalize chitosan to afford a fully heterogeneous biobased catalyst active under atmospheric pressure. 164 Chitosan was reacted with 4-pyridinecarboxaldehyde by formation of an imine bond, followed by quaternarization of the pyridine nitrogen with bromoalkanes of different chain lengths (see Scheme 3h for IL-CS-8-Br prepared from bromooctane). While under identical conditions (105 °C, 1 bar CO 2 ) all catalysts provided similarly high conversion values for a highly reactive substrate such as epichlorohydrin, IL-CS-8-Br was generally the most active catalyst for a broader selection of substrates.…”

“…Despite numerous reports on the use of chitosan-based catalysts for the synthesis of 5CCs, such materials were generally applied under harsh conditions and/or in the presence of homogeneous additives. ,, In this context, Mahalingam et al recently reported a convenient strategy to functionalize chitosan to afford a fully heterogeneous biobased catalyst active under atmospheric pressure . Chitosan was reacted with 4-pyridinecarboxaldehyde by formation of an imine bond, followed by quaternarization of the pyridine nitrogen with bromoalkanes of different chain lengths (see Scheme h for IL-CS-8-Br prepared from bromooctane).…”

Chitosan‐Derived N‐Doped Carbon for Light‐Mediated Carbon Dioxide Fixation into Epoxides

“…The PXRD pattern of the pristine chitosan shows two peaks characteristics of CS structure at 9.8 and 20.4 2θ assigned to (020) and (110) planes, respectively (Figure 2(B)). [39] On the other hand, PXRD pattern of Cal-CS-300 consist of one broad peak from 15-30 2θ assigned to (002) and a weak peak at 45°assigned to (100) planes of graphite structure. Other calcined products also show similar kind of PXRD patterns.…”

“…In this regard, our idea is to use chitosan (CS), the 2 nd most abundant biopolymer after cellulose on earth, to design and develop a suitable catalysts for the transformations of CO 2 . [38,39,40] Our objective is to derive N-doped carbon by taking advantage of the presence of large number of À OH and À NH 2 groups in the chitosan. This methodology of catalyst preparation as well as the use of light for the reaction makes the whole approach more sustainable.…”