Abstract: A process for the preparation of glycols from a saccharide-containing feedstock having the steps of: (a) preparing a reaction mixture in a reactor vessel comprising the saccharide-containing feedstock, a solvent, hydrogen, a catalyst component with retro-aldol catalytic capabilities and a first hydrogenation catalyst comprising an element selected from groups 8, 9 and 10 of the periodic table; (b) monitoring the hydrogenation activity in the reactor vessel; (c) when the activity of the first hydrogenation catalyst declines, as indicated by the crossing of a threshold, supplying into the reaction mixture in the reactor vessel a catalyst precursor comprising one or more elements selected from groups 8, 9, 10 and 11 of the periodic table; and (d) converting the catalyst precursor in the presence of hydrogen in the reactor vessel to a second hydrogenation catalyst to supplement the declined hydrogenation activity in the reactor vessel.

Abstract: The invention provides a process for the production of glycols comprising the step of adding to a reactor vessel a saccharide-containing feedstock, a solvent, hydrogen, a retro-aldol catalyst composition and a catalyst precursor and maintaining the reactor vessel at a temperature and a pressure, wherein the catalyst precursor comprises one or more cations selected from groups 8, 9, 10 and 11 of the periodic table, and wherein the catalyst precursor is reduced in the presence of hydrogen in the reactor vessel into an unsupported hydrogenation catalyst.