fig6

Figure 6. Optimization of the reaction conditions. General reaction conditions: n-BuOH (48 mL, 524 mmol), total pressure (10 MPa) of CO₂ and H₂ (CO₂:H₂ = 4:6), Ir dosage (0.83 μmol), Et₃N (20 mL), reacted at 160 °C for 12 h. Yield, TON, and TOF were determined by GC analysis using m-xylene as the internal standard. (A) Screening of the Ir dosage of the Ir/POP-Phen; (B) Screening of the reaction temperature; (C) Screening of the pressure of CO₂ and H₂; (D) Screening of the organic bases. TON: Turnover number; TOF: turnover frequency; GC: gas chromatography; Ir/POP-Phen: porous phenanthroline-based polymer-supported single-iridium-atom catalyst; NMM: 4-methylmorpholine, NMP: 1-methylpyrrolidine, DMCha: N, N-dimethylcyclohexylamine.