activation of green sorbents for CO capture upon end group backbiting

Thermolysis of a urethane end group was observed as a first time phenomenon during activation. This unzipping mechanism revealed a new amine tethering point producing a diamine-terminated oligourea ( [10]-OU ), acting as a green sorbent for CO 2 capturing. The oligomer backbites its end group to form propylene carbonate (PC), as proved by in situ TGA-MS, which can reflect the polymer performance by maximizing its capturing capacity. Cross polarization magic angle spinning (CP-MAS) NMR spectroscopy verified the formation of the proven ionic carbamate ( 1:2 mechanism ) with a chemical shift at 161.7 ppm due to activation desorption at higher temperatures, viz. , 100 °C ( in vacuo ) accompanied with bicarbonate ions ( 1:1 mechanism ) with a peak centered at 164.9 ppm. Fortunately, the amines formed from in situ thermolysis explain the abnormal behavior (carbamates versus bicarbonates) of the prepared sample. Finally, ex situ ATR-FTIR proved the decomposition of urethanes, which can be confirmed by the disappearance of the pre-assigned peak centered at 1691 cm −1 . DFT calculations supported the thermolysis of the urethane end group at elevated temperatures, and provided structural insights into the formed products. A first-time, end group thermolysis departing a urethane into propylene carbonate. This exposure produced a new amine tethering point producing a diamine-terminated oligourea ( [10]-OU ) as a green sorbent for CO 2 capturing is reported.