Direct fluorination of 1,3-dicarbonyl compound in a continuous flow reactor at industrial scale
Direct fluorination of an Axyntis® 1,3-dicarbonyl compound is investigated at industrial scale in a commercial continuous flow reactor under gas-liquid conditions. The considered flow reactor manufactured by Boostec®, is made of silicon carbide that offers relevant heat transfer performances with regards to reaction exothermicity, as well as corrosion resistance. A screening of the operating conditions and more precisely on solvent and on catalyst was performed to demonstrate the feasibility of the reaction in a continuous mode. To work in a safe and non-hazardous environment regarding the reaction characteristics, experiments have been carried out at the MEPI facility (Maison Européenne des Procédés Innovants). The results show that in slug flow regime full conversion could be achieved with few seconds residence time while reaching a productivity level about 200 g per hour.
In the recent years, there has been an increasing interest in process intensification (1-4) and in the use of continuous intensified reactors, which allow complex chemical reactions to be performed with enhanced heat and mass transfer (5, 6). Such features allow complex chemical reactions to be carried out under unconventional operating conditions and then present significant benefits from process intensification viewpoint: an improved productivity related to the increase of reactants concentration, an improved selectivity related to the plug flow behaviour and the accurate thermal control and a reduced impact on the environment related to the reduction of solvent consumption. With regards to process safety, the concept of heat exchanger reactor also offers many perspectives (7, 8). The accurate thermal control and mixing performances will prevent from side-reactions and thermal runaway and the small reactive volume will limit the risks and consequences of failures in strategic systems. Many technologies are today available at different scales according to the considered objectives: lab scale (micro-reactor) for the screening of new reaction ...