abstract |
A continuous or semi-continuous process for the preparation of ethylene glycol from a carbohydrate source including: n 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;n nwherein the catalyst system includes:n na homogeneous catalyst, which homogeneous catalyst contains tungsten; andn na 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; andn nwherein continuously or periodically additional heterogeneous catalyst is added to the reactor.n n Further described is a catalyst system that can be used in such a process. |