A novel type of phase-contacting device has been researched and is currently being developed at this institution. These high-intensity jet reactors provide significant improvement over conventional phase-contacting equipment due to the impingement of high-velocity feed streams upon each other in relatively small reactor volumes, resulting in a highly turbulent mixing of phases. Due to this intimate contact between phases, mass transfer coefficients (k(L)) of up to 1.5 x 10(-3) m/s have been realised, which, coupled with values of the specific interfacial area (a) of 8-18 000 m(2)/m(3), have yielded volumetric mass transfer coefficients (k(L)a) of up to 22 s(-1) which are orders of magnitude higher than typical values obtained by conventional systems. A model for the prediction of the interfacial area production in these new reactors has also been proposed. It is implemented in the form of a Monte Carlo simulation, based on the fact that bubble breakup in a turbulent environment is governed by the interactions of bubbles with turbulent eddies. Although the model is only a first attempt, it has proved to be highly practical and flexible, reasonably predicting trends in the experimental data.