Condensations of benzene or toluene, xylene and paraformaldehyde to diphenylmethane (DPM) or its derivatives were performed using acidic ionic liquids Et3NHCl-AlCl3, Et3NHCl-FeCl3, Et3NHCl-ZnCl2, Et3NHCl-CuCl2, Et3NHCl-CuCl, Et3NHCl-SnCl2 as catalysts. The catalytic activity of Et3NHCl-AlCl3 proved to be superior to that of other catalysts for the condensation of benzene and paraformaldehyde, giving 92.4% conversion of HCHO and 76.1% selectivity to diphenylmethane at 80 degrees C and atmospheric pressure. The effect of various reaction conditions on the reaction and reaction kinetics of DPM synthesis were explored.