'Phosphine Imide' Reaction on Peracetylated β-Cyclodextrins: Comparison between Supercritical CO_2 and Organic Solvent Processes

摘要

This works deals with three sets of experiments. Two sets of experiments were designed, both at a pressure of 200 bars, in a 100 mL reactor which is stirred by impeller at 1400 rpm and temperature between 20°C and 55°C. The first set was commonly carried at low reactants concentrations (1 mg of reactive cyclodextrines for 1 mL of reactor) in order to follow the kinetic without transport limitations. The second set was carried at high reactants concentrations (5 mg of reactive cyclodextrines for 1 mL of reactor) in order to observe the behavior of the reaction in these non conventional conditions. An additional experiment was carried out in DMF at 33°C to compare organic solvent and supercritical solvent performances. In DMF, the kinetic of the reaction is well fitted by a model were A→r_1 B→r_2 C, were r_1 and r_2 follow first order kinetic. The reaction in scCO_2 showed a first order kinetic at low concentrations with yields from 75% up to 86%. The behavior is widely different at high concentration: a lag-time is observed and yields are lower.