Abstract: A method for continuous exchange of material includes countercurrent contacting of a first fluid phase and a second fluid phase that are not completely miscible. The contacting is carried out in a single centrifugal partition chromatography (CPC) apparatus into which only the first and second fluid phases introduced. The apparatus includes a plurality of cells, each with a stationary phase immobilized and a mobile phase passing through the stationary phase. The following steps are carried out successively: a) the mobile phase is formed by the first fluid phase, and the stationary phase immobilized in the cells is formed by the second fluid phase; b) the mobile phase is formed by the second fluid phase, and the stationary phase immobilized in the cells is formed by the first fluid phase; c) repetition of the succession of steps a) and b) each step being carried out immediately after the preceding step.

Abstract: A process for oligomerizing isocyanates includes a step of continuous conversion of an isocyanate monomer into polyisocyanate containing carbamate and/or allophanate groups, in the presence of a catalyst, wherein the conversion step is carried out in a reactor having a specific heat exchange coefficient of greater than or equal to approximately 200 kW/m3/° C.

Abstract: A process for oligomerizing isocyanates includes a step of continuous conversion of an isocyanate monomer into polyisocyanate containing carbamate and/or allophanate groups, in the presence of a catalyst, wherein the conversion step is carried out in a reactor having a specific heat exchange coefficient of greater than or equal to approximately 200 kW/m3/° C.