Process for the preparation of ethylene glycol from sugars
A process for the preparation of ethylene glycol comprising the steps of pyrolyzing a monosaccharide and hydrogenating the product composition in the presence of a catalyst and a solvent, wherein the pressure of the hydrogenation reaction is 40 bar or greater.
1. A process for the preparation of ethylene glycol comprising the steps of:
a. pyrolysing a sugar to obtain a pyrolysis product composition comprising formaldehyde; and
b. hydrogenating the pyrolysis product composition in the presence of a catalyst and a solvent,
wherein hydrogenation pressure of the reaction of step b. is 40 bar or greater.
2. A process according to claim 1 , wherein the product of hydrogenation reaction is purified.
3. A process according to claim 1 , wherein the sugar comprises one or more sugars selected from the group consisting of glucose, sucrose, fructose, xylose, mannose, arabinose and galactose.
4. A process according to claim 1 , wherein the solvent is selected from the group consisting of water, alcohol and water and alcohol.
5. A process according to claim 4 , wherein the alcohol is selected from one or more of the group consisting of methanol, ethanol, ethylene glycol and propylene glycol.
6. A process according to claim 1 , wherein the pyrolysis product composition comprises one or more C 2-3 oxygenate compounds selected from the group consisting of glycolaldehyde, glyoxal, pyruvaldehyde and acetol.
7. A process according to claim 1 , wherein the catalyst comprises a metal component selected from the group consisting of ruthenium, ruthenium alloy, palladium, platinum and nickel.
8. A process according to claim 1 , wherein the catalyst metal component is present in a ratio of formaldehyde:catalyst metal component of from 1:1 to 1:15.
9. A process according to claim 1 , wherein the hydrogenation is carried out at a pressure of from 40 bar to 120 bar.
10. A process according to claim 1 , wherein the hydrogenation is carried out at a temperature of from 40° C. to 160° C.
11. A process according to claim 1 , wherein the conversion of C 2 oxygenate compounds to ethylene glycol of the hydrogenation is at least 70%.
12. A process according to claim 1 , wherein the selectivity of C 2 oxygenate compounds to ethylene glycol of step b. is at least 75%.
13. A process according to claim 1 , wherein the pyrolysis product composition of step a. comprises formaldehyde in a ratio of formaldehyde:glycolaldehyde of from 1:2 to 1:20.
14. A process according to claim 1 , wherein the product of the hydrogenation comprises a 1, 2-butanediol:ethylene glycol wt/wt ratio of equal to or less than 0.01:1.
15. A process according to claim 1 , wherein the process is a two-step process and the pyrolysis product composition of step a. is directly hydrogenated in step b.
16. A process according to claim 1 , wherein the pyrolysis product composition comprises one or more C 2 oxygenate compounds selected from the group consisting of glycolaldehyde, glyoxal and acetic acid.
17. A process according to claim 8 , wherein the C 2 -oxygenate compound of the composition comprising C 1 -C 3 oxygenate compounds is 10 wt % or greater.