Processes for making ethylene glycol and/or propylene glycol from aldose- and/or ketose-yielding carbohydrates with integrated tungsten catalyst recovery
Integrated processes are disclosed for the catalytic conversion of carbohydrate to ethylene glycol and/or propylene glycol using a homogeneous, tungsten-containing retro-aldol catalyst. In these processes, the carbohydrate is subjected to retro-aldol conversion and hydrogenation to provide a reaction product containing ethylene glycol and/or propylene glycol, other reaction process including organic acids, itols and tungsten species. Ethylene glycol and propylene glycol are separated from the reaction product for purification, and at least a portion of the remaining fraction is subjected to ion exclusion chromatography to provide an eluant containing tungsten species and a subsequent eluant containing organic acids and a substantially reduced concentration of tungsten species. At least a portion of the eluant containing tungsten species can be recycled for reuse directly or with intervening unit operations to enhance the catalytic activity of the tungsten species. The organic-containing fraction can be subjected to one or more unit operations to provide salable products or subjected to selective hydrogenolysis to lower glycols.
1. A producer composition of matter comprising dissolved tungsten compound and one or more higher boiling point polyols comprising sorbitol, erythritol, threitol and glycerin wherein the mass ratio of total higher boiling polyol to tungsten compounds calculated as the metal is less than about 5:1.
2. The producer composition of claim 1 wherein the mass ratio of total higher boiling polyol to tungsten compounds calculated as the metal is between about 0.01:1 and 1:1.