Method for the production of glycols from a carbohydrate feed
View Patent ↗Implementations of the disclosed subject matter provide methods for producing ethylene glycol from a carbohydrate feed may include contacting, in a first reactor under hydrogenation conditions, the carbohydrate feed with a bi-functional catalyst system. The bi-functional catalyst system may include a heterogeneous hydrogenation catalyst, and a soluble retro-Aldol catalyst. The carbohydrate feed may include a concentration of carbohydrate, in the total solution entering the first reactor, of 5-40 wt % in a solvent. An intermediate product stream may be obtained from the first reactor including ethylene glycol. The hydrogenation conditions may include a temperature in the range of from 180-250° C.
1. A method for producing ethylene glycol from a carbohydrate feed comprising:
a) contacting, in a first reactor under hydrogenation conditions, the carbohydrate feed with a bi-functional catalyst system comprising:
1) a heterogeneous hydrogenation catalyst, and
2) a soluble retro-Aldol catalyst;
and, wherein the carbohydrate feed comprises a concentration of carbohydrate, in the total solution entering the first reactor, of 5-40 wt % in a solvent;
b) running the reaction under pH controlled conditions for at least 24 hours and wherein the pH of the reaction is in the range of from 2-7, wherein the pH is controlled using at least one pH controlling agent selected from the group consisting of: alkali- and alkaline-earth metal salts of carbonic acid or carboxylic acids or combinations thereof, alkali- and alkaline-earth metal salts of phosphoric acid, zinc carbonate, and zinc salts of carboxylic acids;
c) obtaining an intermediate product stream, from the first reactor, comprising ethylene glycol; and wherein the hydrogenation conditions comprise a temperature in the range of from 180-250° C.
2. The method of claim 1 , wherein the carbohydrate feed comprises a concentration of carbohydrate, in the total solution entering the first reactor, of 10-40 wt % in a solvent.
3. The method of claim 2 , wherein the solvent is H 2 O.
4. The method of claim 1 , wherein the first reactor is pre-loaded with the heterogeneous hydrogenation catalyst and the soluble retro-Aldol catalyst is continuously added to the first reactor.
5. The method of claim 4 , wherein the soluble retro-Aldol catalyst is continuously added to the first reactor via the carbohydrate feed.
6. The method of claim 1 , wherein the carbohydrate feed comprises one or more selected from the group consisting of: glucose, sucrose, xylose, sugar cane molasses, starch, and cellulose.
7. The method of claim 1 , wherein the heterogeneous hydrogenation catalyst is a Raney-type catalyst.
8. The method of claim 7 , wherein the heterogeneous hydrogenation catalyst comprises at least one selected from the group consisting of: Raney-Ni, Raney-Co, Raney-Cu, Raney-Ru, Cu, Co, Ru, and nano-particle metal.
9. The method of claim 8 , wherein the heterogeneous hydrogenation catalyst is further promoted with one or more promoters selected from the group consisting of: Fe, Cr, Mn, Mo, W, Re, Rh, Pd, Ag, Au, Pt, Ir, and La.
10. The method of claim 1 , wherein the soluble retro-Aldol catalyst comprises at least one selected from the group consisting of: silver tungstate, sodium meta-tungstate, ammonium meta-tungstate, sodium poly-tungstate, tungstic acid, alkali- and alkaline-earth metal tungstates, sodium phospho-tungstate, phospho-tungstic acid, alkali- and alkaline-earth metal phospho-tungstates, alkali- and alkaline-earth metal molybdates, alkali- and alkaline-earth metal phospho-molybdates, phospho-molybdic acid, heteropoly acids, mixed tungstates and molybdates, niobic acid, silicotungstic acid, alkali- and alkaline-earth metal niobates.
11. The method of claim 1 , wherein the temperature is in the range of from 210-250° C.
12. The method of claim 1 , wherein the intermediate product stream comprises at least 5 wt % concentration of glycols.
13. The method of claim 1 , wherein the intermediate product stream comprises a yield of no more than 10 wt % sorbitol.
14. The method of claim 1 , wherein the intermediate product stream comprises a yield of at least 60 wt % EG.
15. The method of claim 1 , wherein the intermediate product stream comprises an EG/PG wt % yield ratio of at least 7:1.
16. The method of claim 1 , wherein the intermediate product stream comprises a yield of less than 3 wt % 1,2-butanediol.
17. The method of claim 1 , further comprising running the reaction for a time period of at least 100 hours.
18. The method of claim 1 , further comprising feeding the intermediate product stream to a second reactor comprising:
(a) contacting the intermediate product stream from the first reactor with hydrogen in the presence of a heterogeneous hydrogenation catalyst; and
(b) obtaining a final product stream comprising ethylene glycol.