A Bifunctional Tungstate Catalyst for Chemical Fixation of CO₂ at Atmospheric Pressure

Abstract

Ohne Druck: Ein einfaches monomeres Wolframat, [WO4]2−, dient als homogener Katalysator für verschiedene Umsetzungen von CO2 bei Atmosphärendruck. Die Wolfram‐Oxo‐Gruppierung aktiviert gleichzeitig CO2 und das Substrat. Das Katalysatorsystem liefert hohe Ausbeuten und kann auf eine Bandbreite von Substraten wie Amine (siehe Schema), 2‐Aminobenzonitrile und Propargylalkohole angewendet werden.

A Protic Ionic Liquid Catalyzes CO2 Conversion at Atmospheric Pressure and Room Temperature: Synthesis of Quinazoline‐2,4(1H,3H)‐diones

“…On the basis of the experimental results and previous reports,5g, 9–16 a possible mechanism for the [HDBU + ][TFE − ]‐catalyzed reaction of CO 2 with 2‐aminobenzonitrile to give quinazoline‐2,4(1 H ,3 H )‐dione ( E ) is proposed (Scheme ). In [HDBU + ][TFE − ], 2‐aminobenzonitrile is activated by hydrogen bonding with both the cation and anion of the IL to form the intermediate A , while CO 2 is activated by the anion [TFE − ] to form the intermediate B .…”

“…Kimura et al. reported [(n‐C 4 H 9 ) 4 N] 2 + [WO 4 ] 2− as a bifunctional catalyst which could catalyse the reactions of CO 2 with various aromatic diamines at atmospheric pressure around 100 °C 5g. More recently, cobalt‐coordinated conjugated microporous polymers were reported to function as heterogeneous catalysts for the reaction of CO 2 with propylene oxide at atmospheric pressure and room temperature 5h.…”

“…Quinazoline‐2,4(1 H ,3 H )‐diones can serve as intermediates for the synthesis of pharmaceuticals 8. The reaction of CO 2 with 2‐aminobenzonitriles is an atom‐economical route for the synthesis of these compounds, and it has been widely investigated using various catalysts including DBU,9 Cs 2 CO 3 ,10 MgO‐ZrO 2 ,11 [Bmim]OH,12 N ‐methyl‐tetrahydropyrimidine,13 guanidines,14 [( n ‐C 4 H 9 ) 4 N] 2 + [WO 4 ] 2− ,5g, 15 and 1‐butyl‐3‐methylimidazolium acetate ([Bmim]Ac) 16. However, in these studies a high CO 2 pressure and temperature were generally required.…”

“…To our delight, [HDBU + ][TFE − ] as the catalyst showed high efficiency for this reaction (see Figures S3 and S4 in the Supporting Information), thus producing quinazoline‐2,4(1 H ,3 H )‐dione in 97 % yield, without any byproducts, within 24 hours (Table 1, entry 2). Moreover, [HDBU + ][TFE − ] served as a solvent, which allowed the reaction to proceed more rapidly than the reported systems 5g. For comparison, three other ILs were examined for catalyzing this reaction.…”

“…[c] determined by LC analysis. [d] DMSO (1 mL), catalyst (0.02 mmol), CO 2 (0.1 MPa), 373 K, 120 h 5g…”