Solubilities of N-tert-Butylacrylamide and Azobisisobutyronitrile in Carbon Dioxide

Using the synthetic visual method, solubility isotherms of the monomer N-tert-butylacrylamide (NTBA) and the radical polymerization initiator azobisisobutyronitrile (AIBN) in carbon dioxide were obtained in the range of temperatures of 305.0–353.2 K and pressures of 0.1–40.0 MPa. The maximum concentrations of NTBA and AIBN at these state parameters were determined. The features of the phase behavior of “low-melting” low-molecular-weight compounds in CO2 were discussed. It was shown that the solubility of AIBN is not a factor limiting the range of conditions in the polymerization process involving NTBA.