Method for acid treatment conditioning of a catalyst in the production of glycols
Implementations of the disclosed subject matter provide methods for producing ethylene glycol from a carbohydrate feed which may include conditioning a heterogeneous hydrogenation catalyst by treatment with a protic acid resulting in an acid-conditioned heterogeneous hydrogenation catalyst. Next, in a reactor under hydrogenation conditions, the carbohydrate feed may be contacted with a bi-functional catalyst system comprising the acid-conditioned heterogeneous hydrogenation catalyst, and a soluble retro-Aldol catalyst. An intermediate product stream may be obtained from the reactor including ethylene glycol.
1. A method for producing ethylene glycol from a carbohydrate feed comprising:
a) conditioning a heterogeneous hydrogenation catalyst by treatment with a protic acid for a first period of time resulting in an acid-conditioned heterogeneous hydrogenation catalyst;
b) next, in a first reactor under hydrogenation conditions, the carbohydrate feed is contacted for a second period of time, with the carbohydrate feed with a bi-functional catalyst system comprising:
1) the acid-conditioned heterogeneous hydrogenation catalyst, and
2) a soluble retro-Aldol catalyst;
c) obtaining an intermediate product stream, from the first reactor, comprising ethylene glycol,
wherein the second period of time follows the first period of time.
2. The method of claim 1 , wherein the protic acid is at least one selected from the group consisting of: organic acid, mineral acid, and combinations thereof.
3. The method of claim 2 , wherein the organic acid is at least one selected from the group consisting of: formic acid, acetic acid, propionic acid, butyric acid, glycolic acid, lactic acid, citric acid, benzoic acid, and combinations thereof.
4. The method of claim 3 , wherein the organic acid is at least one selected from the group consisting of: lactic acid, glycolic acid, and combinations thereof.
5. The method of claim 2 , wherein the mineral acid is at least one selected from the group consisting of: HCl, H 2 SO 4 , H 3 PO 4 , benzene sulfonic acid and combinations thereof.
6. The method of claim 1 , wherein the conditioning step (a) is carried out with a concentration of protic acid in the range of from 0.001 wt % to 50 wt %.
7. The method of claim 1 , wherein the conditioning step (a) is carried out with an acid solution solvent selected from the group consisting of: H 2 O, alcohol, and combinations thereof.
8. The method of claim 1 , wherein the heterogeneous hydrogenation catalyst comprises at least one selected from the group consisting of: Raney-Ni, Raney-Co, Raney-Cu, Raney-Ru, Ni, Co, Cu, Cu—Zn, Cu—Cr, Ni—Mo, Ni—W, and Ni—Cr.
9. The method of claim 1 , wherein the heterogeneous hydrogenation catalyst is further promoted with one or more selected from the group consisting of: Al, Fe, Cr, Mn, Co, Cu, Mo, Ru, Rh, Pd, Ag, W, Re, Ir, Pt, Au, In, Sn, Sb, and Pb.
10. The method of claim 1 , wherein the heterogeneous hydrogenation catalyst comprises Raney-Ni.