Abstract: Free perfluorosulfonylmethide compounds and metal salts thereof show strong catalytic activity in carbon-carbon bond formation reactions, in amounts as low as 0.1 mole %. Fluorous media may be used, especially biphasic fluorous media enabling ready recycling of the catalyst. The formula thereof is: M[C(SO2R1)3−(m+q)(SO2R2)m(SO2R3)q]x where M is H, Sc, Y, La, Ce, Pr, Nd, Sm Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Zr, Hf, Th, Nb, Ta, U, Bi, Al, Ga, In or Tl, x is the common oxidation state of a said metal M, R1, R2 and R3 are perfluorinated or polyfluoronated hydrocarbon, ether or amine moieties or mixtures thereof and m+q=0, 1, 2 or 3 (m and q being zero or integers).

Abstract: A process for preparing a nitrated arene which comprises reacting an arene and nitric acid in the presence of a water tolerant Lewis acid catalyst under process conditions sufficient to form the nitrated arene and recovering the nitrated arene. Suitable Lewis acid catalysts are represented by the formula M.sup.n (A.sub.1).sub.x (A.sub.2).sub.n-x whereinM is selected from the group consisting of La, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Sc, Hf, Lu and Li;A.sub.1 and A.sub.2 are independently selected from a perfluoroalkylsulfonate, a fluorosulfonate, a hexafluorophosphate or a nitrate;n is the common oxidation state of M andx is 1, 2, 3 or 4 with the proviso that x is never greater than n.The catalysts of the process are isolatable from water and can be recycled for subsequent process cycles.