Patent ID: 6720466
Filing Date: 2004-04-13
Classification: C07C,Y02P

Abstract:
A process for preparing a desired haloalkane comprising:(a) contacting a haloalkene feedstock and a haloalkane feedstock in the presence of effective amounts of catalyst components, ferrous chloride, ferric chloride, and a trialkylphosphate compound, under conditions effective to promote an addition reaction and to form a product stream containing said haloalkane product, higher boiling haloalkane by-products, unreacted feedstocks, and catalyst components, and (b) separating the desired haloalkane product from the high-boiling undesired haloalkane byproducts and the catalyst components using a two-stage catalyst recovery unit (CRU), wherein i. the bottom fraction from the first stage flows into the second stage, and the overhead fractions from the two stages are combined for further purification steps, and, ii. the first stage of the CRU recovers, in the distillate, between 50 and 90% of the desired haloalkane product contained in the reactor effluent, leaving more than 98% of the high-boiling undesired haloalkane byproducts in the bottom fraction, and, iii. the second stage of the CRU recovers, in the distillate, more than 70% of the remaining desired haloalkane product, leaving more than 33% of the high-boiling undesired haloalkane byproducts in the bottom fraction, together with the catalyst components, and (c) recycling most of the bottom fraction from the second stage of the CRU to the reactor, and purging a small fraction of it from the system to control byproduct concentrations in the reactor and to avoid excessive catalyst degradation.