PROCESS FOR PRODUCING UNSATURATED MONONITRILES

摘要

The invention relates to a process for preparing unsaturated mononitriles selected from a group consisting of acrylonitrile and methacrylonitrile and comprising: a) the reaction of an olefin selected from a group consisting of propylene and isobutylene with ammonia and oxygen, in a reaction zone, in the presence of a catalyst, to produce an effluent of the reactor containing the corresponding unsaturated mononitrile; b) the transfer of the reactor effluent containing the corresponding unsaturated mononitrile to a blast cooling column where the reactor effluent containing the corresponding unsaturated mononitrile is cooled by contact with a first aqueous flow; c) the transfer of the cooled effluent from the reactor containing the unsaturated mononitrile to an absorption column where the cooled effluent from the reactor containing the unsaturated mononitrile is contacted to at least a second aqueous flow in order to separate and remove the unsaturated mononitrile as a flow from the bottom of the absorption column; d) the transfer of the flow from the bottom of the absorption column to a recovery column where the overhead product is removed and separated in a raw unsaturated mononitrile phase and an aqueous phase with a low content of unsaturated mononitrile, containing traces of oxidizing impurities and also the lowering of the aqueous phase pH value with a view to reducing the level of oxidative impurities and the recycling of the above mentioned aqueous phase.