A system of chem. reactors involving two types of nonconventional energies, i.e. microwave and ultrasound, for promoting chem. reactions of a various nature is provided with one or more reaction cells where irradn. with microwave and​/or ultrasound takes place either simultaneously or subsequently, as well as with a cooling app. for the entire system. The system enables a decrease in the reaction time and an improvement in the yield of reaction products.