Supercritical CO2 phosphine imide reaction on peracetylated β-cyclodextrins

The aim of this research was to investigate the capability of using supercritical CO2 (scCO2) as reagent and solvent in the syntheses of ureas and other sensitive compounds (e.g., carbamate, isocyanate carbodiimide, …) in smooth reaction conditions. In this way 3 sets of experiments have been designed, two both in scCO2 at 200 bars pressure in a 100 mL reactor and one in DMF at atmospherical pressure. The results show that the reaction in scCO2 showed a first order kinetic at low concentrations with yields from 75% up to 86%. The behavior is widely different at high concentration: a time delay is observed and yields are lower. The kinetic of the reaction in DMF is well fitted by a model A ⟶ r 1 B ⟶ r 2 C , were r1 and r2 follow first order kinetic.