Heat pipes used for cooling of microstructured reactors are a new approach for sustainable processing also in the lab-scale within a temperature range from ambient to more than 180 degrees C. The main advantage of heat pipe cooling is the dynamic behavior, i.e., the cooling rate depends on the heat released. Heat pipes can also suppress thermal runaways due to their extremely short response times on momentary temperature rises. As an example, the highly exothermal synthesis of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate from the respective reactants 1-ethyl-imidazole and methyltrifluoromethanesulfonate was investigated. By transferring the protocol to continuous-flow conditions in the microscale and by applying cooling with heat pipes, an out-of-control processing can be avoided.