During the past two years, Friedel-Crafts reactions have been a fertile field for research and have also produced notable commercial applications in the dyestuffs, intermediates, and polymer industries. Current research of a fundamental character has added to our knowledge of the groups in the isomerization niechamechanism of reaction and the function of intermediate complexes, particularly as applied to nism does not involve the formation isomerization, disproportionation, and alkylation. of a carbonium ion in the alkyl halide. For example, under the proper conditions for isomerization, with HE numerous and varied applications of the Friedel-Crafts either HAIBra or HBFl catalysts, n-propyl derivatives fail to give reactions, appearing in the literature in the past two years, any isopropyl compound. These changes are therefore Intra-