Determination of the solubilities of mixed gases in mixed solvents using a novel HPNMR continuous flow system.
Advancing the chemical engineering fundamentals
Chemical Reaction Engineering (T2-2P)
Keywords: Gas solubility, NMR, homogeneous catalysis
Homogeneous catalytic processes are widely used and important in industry. In gas-liquid homogeneous catalytic reactions the solubility of gases is a crucial parameter in the process. To obtain the desired performance of the reactions, the solubility of gases in liquids must be appropriate (high enough). Since the reaction occurs in the bulk of the liquid, the reactor design and the reaction kinetics are highly dependent on gas solubilities and vice versa. For kinetic modelling of the process it is essential to know/be able to predict reliably the concentrations of dissolved gases/gas solubility values in the working reactor. However, the modelling of gas solubilities in complex mixtures (mixed solvent-mixed feed gas), far from regions of “ideal” behaviour, is not trivial and relies on empirical correlations, thus the experimental determination of gas concentrations is necessary.
A new, high pressure NMR protocol has been developed for the quantitative measurement of gas solubilities in the pressure range 1 to 25 bar and a temperature range from 295 K to 373 K. This new experimental method consists of a gas flow recycling system in which the equilibrium cell is in the magnet at all times. The liquid phase partially fills the equilibrium cell and a gas stream is bubbled through these solvents continuously. The composition of the liquid phase in the equilibrium cell can be measured at all times. This system allows equilibrium to be established rapidly, and the temperature and pressure of the equilibrium cell can be readily varied. Thus, the composition of the liquid phase in equilibrium with the gas phase, as a function of temperature and pressure, can be rapidly and reliably determined.
In this work the solubilities, in liquid mixtures, of the gaseous reagents used have been determined experimentally using a novel high pressure NMR system and used to validate empirically predicted (Aspen Plus) data.
Presented Tuesday 18, 13:30 to 15:00, in session Chemical Reaction Engineering (T2-2P).
