| abstract |
A continuous or semi-continuous process for the preparation of ethylene glycol from a carbohydrate source including: reacting, in a reactor, at a temperature in the range from equal to or more than 170°C to equal to or less than 270°C, at least a portion of a carbohydrate source in the presence of hydrogen, a solvent, and a catalyst system, to yield ethylene glycol; wherein the catalyst system includes: a homogeneous catalyst, which homogeneous catalyst contains tungsten; and a heterogeneous catalyst, which heterogeneous catalyst contains one or more transition metals from groups 8, 9 and 10 of the Periodic Table of the Elements supported on a carrier; and wherein continuously or periodically additional heterogeneous catalyst is added to the reactor. Further described is a catalyst system that can be used in such a process. |