A process for converting a sugar, sugar alcohol, or glycerol to a valuable chemical is described. The process may use a support comprising zirconium oxide promoted by a polyacid or promoter material. A catalytically active metal may be impregnated on the polyacid-promoted zirconium oxide support and the catalyst may then be introduced the sugar, sugar alcohol, or glycerol a source of hydrogen under reaction conditions. At least 40 wt % of the sugar, sugar alcohol or glycerol may be converted to a polyol and/or a shorter carbon-chain alcohol that may include at least one of propylene glycol, ethylene glycol, glycerin, methanol, ethanol, propanol and butandiols. Specific processes for converting glycerin having a selectivity for propylene glycol and for converting sorbitol with a selectivity for propylene glycol, ethylene glycol, and/or glycerin are also described.