Process for acylation or alkylation of aromatic compounds in hydrogen fluoride

A continuous process is disclosed for the acylation or alkylation of aromatic compounds in hydrogen fluoride. The aromatic compound is sufficiently insoluble in hydrogen fluoride that a two phase reaction medium forms. However, surprisingly, the product acylated or alkylated aromatic compound is soluble in hydrogen fluoride. The present invention particularly relates to use of a continuous, multi-stage process for carrying out the acylation or alkylation reaction. In the multi-stage process, the continuous phase can be either the hydrogen-fluoride rich phase or the aromatic compound-rich phase. The movement of the continuous phase relative to the non-continuous (dispersed) phase can be countercurrent or concurrent. The multi-stage process can be operated in a manner such that the aromatic compound feed to the reaction is entirely consumed or such that unreacted aromatic compound is recycled.