Contribution No. 2620. Central Research and Development Department, Experimental Station. EI du Pont de Nemours & Company, Wilmington, Delauare 19898 Received "Vowmber 2, 1978 ... Toluene derivatives bearing electronegative substituents are fluorinated on the methyl group when reacted with lead dioxide, nickel dioxide, cobalt trifluoride, cobalt triacetate, silver difluoride, or silver(I1) oxide in liquid hydro- gen fluoride. For example, 4-nitrotoluene ...