Process intensification and micro-structured reactor design can be relevant means to improve the safety of a process involving hazardous substances. This work deals with the intensification of a chlorination reaction usually performed in batch mode, using thionyl chloride (SOCl2) to chlorinate a sterically hindered carboxylic acid dissolved in dimethylacetamide (DMAC). This chlorination reaction involves the exothermic formation of a species called Vilsmeier reagent, resulting from a reaction between SOCl2 and DMAC. In order to intensify this process, a reaction scheme with kinetic and thermal data is identified in the first place. This model is then used to suggest how the chlorination reaction could be carried out in a continuous mode and under which optimal operating conditions it should be operated. Tests are then conducted using a lab-scale microreactor providing good mixing and heat exchange, resulting in better performances than the batch process, within seconds of residence time. Further tests are performed at larger scale using a pilot-scale microreactor, designed to achieve the same yield and quality performances as the lab-scale microreactor with a higher throughput, as long as residence time, ratio between reactants and temperature remain constant. (C) 2016 Elsevier B.V. All rights reserved.