Abstract: A process for preparing an emulsion is disclosed comprising: injecting a first liquid as dispersed phase liquid through a central inlet of a microchannel system with a cross junction geometry chip and injecting a second liquid as continuous phase liquid through the outer cross inlet, which continuous phase liquid does not instantly mix with said injected first liquid prior to the cross junction, wherein the flow rate QC of the continuous phase in cubic meters per second is given by Q C = f × A ? ? ? ? d , where A is the exit area of the microchannel in square meters, ? the interfacial tension between the first liquid and the second liquid in Newtons per meter and ?d the viscosity of the dispersed phase in Pascal-seconds, characterized in that f is in the range from 0.04 to 0.25.

Abstract: A process for preparing an emulsion is disclosed comprising: injecting a first liquid as dispersed phase liquid through a central inlet of a microchannel system with a cross junction geometry chip and injecting a second liquid as continuous phase liquid through the outer cross inlet, which continuous phase liquid does not instantly mix with said injected first liquid prior to the cross junction, wherein the flow rate QC of the continuous phase in cubic meters per second is given by Q C = f × A ? ? ? ? d , where A is the exit area of the microchannel in square meters, ? the interfacial tension between the first liquid and the second liquid in Newtons per meter and ?d the viscosity of the dispersed phase in Pascal-seconds, characterized in that f is in the range from 0.04 to 0.25.