Method for producing mannitol

A continuous process for preparing mannitol from fructose wherein the concentration of fructose in water is 50%-55%, by weight, comprising hydrogenating fructose in the presence of a Raney copper and aluminum catalyst without a binder comprising a copper-aluminum ratio of 61:39 wt. % prepared by grinding a copper/aluminum alloy to an effective particle size and activating the surface with a 10-20% aqueous sodium hydroxide solution at 20-80° C. wherein the space velocity is an LSHV of 0.5 h−1-10.0 h−1.