An original simplified mathematical model of the process of tert-butyl alcohol dehydration in a catalytic zone of the reactive distillation unit with the downward concurrent flow of liquid and vapor phases is developed. The system of heat and mass balance equations includes relationships that allow determining changes in temperature as well as gas and liquid compositions caused by a chemical reaction along the catalyst bed height. Results of calculation of the temperature profile along the catalyst bed height, carried out using the developed model, are in good agreement with data from our previous laboratory studies as well as with data obtained during trial operation of an industrial reactor. (C) 2019 Elsevier Ltd. All rights reserved.