Synthesis
Typically, 20 mg of 2.0 wt% Pd/NC-Tx catalyst (0.4 mol% Pd relative to morpholine), 1.0 mmol of morpholine, and 2 mL of ethanol as solvent were sequentially added to a 25 mL stainless steel autoclave with a PTFE liner. The autoclave was charged with CO2 under hydrogen pressure of 4 MPa until the total pressure reached 7 MPa. Subsequently, the reactor was placed in an oil bath at 130 °C and stirred for a predetermined time. Upon completion of the reaction, the reactor was cooled to room temperature and the pressure was slowly released. Docosane was added to the reaction solution as an internal standard, and the conversion of the amine and the yield of N,N-di-n-propyl formamide were determined using a gas chromatograph (GC, Agilent 7890B, USA) equipped with an FID detector and a nonpolar capillary column (DB-5, 30 m × 0.25 mm × 0.25 μm). High purity nitrogen was used as carrier gas.1H NMR and 13C NMR analyses were performed on a Bruker Avance NMR (400 MHz).
References
[1] New Journal of Chemistry, 2018, vol. 42, # 16, p. 13933 - 13937
[2] Science China Chemistry, 2018, vol. 61, # 6, p. 725 - 731
[3] New Journal of Chemistry, 2017, vol. 41, # 8, p. 2869 - 2872
[4] Chemical Communications, 2017, vol. 53, # 57, p. 8046 - 8049
[5] Catalysis Letters, 2018, vol. 148, # 8, p. 2487 - 2500
