Triazine‐based Organic Polymer‐catalysed Conversion of Epoxide to Cyclic Carbonate under Ambient CO₂ Pressure

Abstract

In this work we have achieved epoxide to cyclic carbonate conversion using a metal-free polymeric catalyst under ambient CO 2 pressure (1.02 atm) using a balloon setup. The triazine containing polymer (CYA-ANIS) was prepared from cyanuric chloride (CYAÀ Cl) and o-dianisidine (ANIS) in anhydrous DMF as solvent by refluxing under the N 2 gas environment. The presence of triazine and amine functional groups in the polymer results in the adsorption of CO 2 up to 7 cc/g at 273 K. This inspired us to utilize the polymer for the conversion of a series of functionalised epoxides into their corresponding cyclic carbonates in the presence of tetrabutyl ammonium iodide (TBAI) as cocatalyst. The product has wide range of applications like solvent in lithium ion battery, precursor for polycarbonate, etc. The catalyst was efficient for the conversion of different mono and di-epoxides into their corresponding cyclic carbonates under atmospheric pressure in the presence of TBAI as co-catalyst. The study indicates that epoxide attached with electron withdrawing groups (like, CH 2 Cl, glycidyl ether, etc.) displayed better conversion compared to simple alkane chain attached epoxides. This is mainly due to the stabilization of electron rich intermediates produced during the reaction (e. g. epoxide ring opening or CO 2 incorporation into the halo-alkoxide anion). This catalyst mixture was capable to maintain its reactivity up to five cycles without losing its activity. Post catalytic characterization clearly supports the heterogeneous and recyclable nature of the catalyst.[a] Dr.

para-Aminobenzoic acid-capped hematite as an efficient nanocatalyst for solvent-free CO2 fixation under atmospheric pressure

“…as well as heterogeneous catalysts like nitrogen-based polymers, ionic liquids, metal-organic frameworks (MOFs), porous-organic polymers (POPs), ion-exchange resins, metal oxides, supported metal catalysts, and more have been reported for the conversion of epoxides into cyclic carbonates utilizing CO 2 . [16][17][18][19][20][21][22][23][24][25][26][27][28] In particular, heterogeneous, porous nanocatalysts are advantageous due to their easy separation, good recyclability and large surface area. 29 Furthermore, it could be more sustainable if catalysts can be designed using abundant and non-toxic material resources for cyclic carbonate formation under mild conditions.…”

Prudent Choice of Iron‐Based Metal‐Organic Networks for Solvent‐Free CO2 Fixation at Ambient Pressure

“…Similarly, higher extent of conversion (>80 %) was observed for allyl glycidyl ether, methyl glycidyl ether and phenyl glycidyl ether (Table 2, entry 4, 5, and 6). The observed higher conversion is likely because of the presence of highly electronegative oxygen atom to promote the ring opening of the epoxides, using −I effect [59] . Likewise, use of glycidyl methacrylate having ester functionality resulted in 86 % conversion to the corresponding cyclic carbonate (entry 7).…”

“…The observed higher conversion is likely because of the presence of highly electronegative oxygen atom to promote the ring opening of the epoxides, using À I effect. [59] Likewise, use of glycidyl methacry-late having ester functionality resulted in 86 % conversion to the corresponding cyclic carbonate (entry 7). Despite possessing electronegative oxygen atom, tertiary butyl glycidyl ether shows only 62 % conversion (entry 8).…”

“…The observed relatively lower conversion can be attributed to the presence of sterically bulky tertiary butyl group (À CMe 3 ). [59] Similarly, use of epoxide containing long non-polar carbon chain like 1, 2-epoxy 9decene resulted in very less extent of conversion (entry 9). The presence of long alkyl chain resulted in larger size of this epoxide which reduces the diffusion rate of the reactant through the pores of the catalyst.…”

“…Despite possessing electronegative oxygen atom, tertiary butyl glycidyl ether shows only 62 % conversion (entry 8). The observed relatively lower conversion can be attributed to the presence of sterically bulky tertiary butyl group (−CMe 3 ) [59] . Similarly, use of epoxide containing long non‐polar carbon chain like 1, 2‐epoxy 9‐decene resulted in very less extent of conversion (entry 9).…”