Safe and selective operation of fine chemical reactions through the semi batch recycle reactor (SBRR)

In the fine chemical industry, a number of exothermic reaction processes are better performed under reflux conditions. Such an operating regime of the reactor allows for removing the reaction heat at a self-controlling temperature, hence preventing peaks of the conversion rate with their related thermal effects. Moreover, when the desired reaction generates a low volatility product, which can further react with a non-selective reactant, dosing such a reactant under reflux conditions potentially allows for removing the target species from the reactor, hence subtracting it from its further degradation. However, there exist also a number of processes that must be operated at temperature values lower than the normal boiling point of the low volatility product and for which vacuum conditions cannot be adopted, because of a number of process constraints. This prevents the possibility of taking advantage, from a safety point of view, of the aforementioned self-controlling feature of the processes operated under reflux conditions. The semibatch recycle reactor allows for achieving both a satisfactory process selectivity and productivity (strictly connected with the operating temperature range defined by the recipe) as well as the safer process conditions related to the reflux conditions thanks to its intrinsic possibility of operating even at atmospheric pressure the reaction vessel and the boiler at different temperature values.