Key words: supercritical fluids, density, fibre-optic densitometer, CO2 hydrogenation, phenol conversion
The dependences of the reaction mixture density on temperature are analyzed for the following processes: 1) catalytic hydrogenation of CO2; 2) conversion of phenol and cyclohexanol in sub- and supercritical water. The density measurements were performed using «Lazerokhim» fiber-optic densitometer. The state of the waveguide end face surface after measurements at elevated temperature was analyzed using scanning electron microscopy (SEM). It was found that for non-aqueous reaction mixtures, the laser-optical method of density monitoring is applicable in a wide range of temperatures and pressures. In the case of water and water-organic mixtures, correct determination of the densities is possible only at temperatures of 25—190°C, since an increase in temperature above 200°C leads to irreversible etching of the silicate optical waveguide end face surface by water-containing fluid.
doi:10.1134/S1990793125701003