a w ac catalyst comprising 20 wt of tungsten the w ac catalyst obtained as described in example 1 was further soaked in a nickel nitrate solution dried at 120 u00b0 c and reduced at 400 u00b0 c for 2 hrs to yield a ni u2014 w ac catalyst comprising 5 wt of nickel and 18 wt of tungsten active carbon carriers were soaked separately in aqueous solutions of nickel nitrate chloroplatinic acid and ruthenium trichloride the mixtures were dried at 120 u00b0 c for 12 hrs and reduced in the presence of hydrogen at 450 u00b0 c for one hour to yield a ni ac catalyst comprising 5 wt of nickel a pt ac catalyst comprising 0 5 wt of platinum or a ru ac catalyst comprising 5 wt of ruthenium respectively in a separate preparation active carbon was substituted with sio 2 and following the above steps a ni sio 2 catalyst comprising 15 wt of nickel was prepared a carrier of silica was soaked in a 0 2 g ml ammonium metatungstate solution the mixture was dried in an oven at 120 u00b0 c for 12 hrs and reduced in the presence of hydrogen at 700 u00b0 c for one hour to yield a w.