Preparation of 2,5,6-trihydroxy-3-hexenoic acid and 2,5-dihydroxy-3-pentenoic acid and esters thereof from C6 and C5 sugars
Preparation of 2,5,6-trihydroxy-3-hexenoic acid and 2,5-dihydroxy-3-pentenoic acid and esters thereof from C6 and C5 sugars in the presence of a Lewis Acid material, wherein the yield of the 2,5,6-trihydroxy-3-hexenoic acid or 2,5-dihydroxy-3-pentenoic acid or esters thereof exceeds 15%.
1. A process for the preparation of 2,5,6-trihydroxy-3-hexenoic acid and/or 2,5-dihydroxy-3-pentenoic acid or esters thereof of the formula
R′—HC═CH—CHOH—COOR (I)
wherein
R is selected from the group consisting of —H and C 1 -C 8 -alkyl; and
R′ is hydroxymethyl or 1,2-dihydroxyethyl;
the process comprising the steps of:
a. contacting a saccharide composition comprising one or more C6 and/or C5 saccharide units with a Lewis Acid material; and
b. recovering and purifying 2,5,6-trihydroxy-3-hexenoic acid and/or 2,5-dihydroxy-3-pentenoic acid or the esters thereof,
wherein the Lewis Acid material comprises a framework structure and an active metal,
wherein the process results in a yield of 2,5,6-trihydroxy-3-hexenoic acid and/or 2,5-dihydroxy-3-pentenoic acid or esters thereof above 15%,
wherein a concentration of alkali metal ions present in an environment of the Lewis Acid material is kept at a concentration of less than 0.13 mM or at an amount of less than 0.5 wt % of a catalyst composition.
2. The process according to claim 1 , wherein the esters of 2,5,6-trihydroxy-3-hexenoic acid or 2,5-dihydroxy-3-pentenoic acid are 2,5,6-trihydroxy-3-hexenoic acid methyl ester and 2,5-dihydroxy-3-pentenoic acid methyl ester.
3. The process according to claim 1 , wherein the saccharide composition comprises one or more C6 and/or C5 saccharide units selected from the group consisting of sucrose, xylose, mannose, tagatose, galactose, glucose, fructose, arabinose, inulin, amylopectin and sugar syrup.
4. The process according to claim 1 , wherein the saccharide composition contains at least 10% by weight of saccharide units.
5. The process according to claim 1 , wherein the saccharide composition comprises a polar solvent.
6. The process according to claim 5 , wherein the saccharide composition comprises one or more solvents selected from the group consisting methanol, ethanol, DMSO and water.
7. The process according to claim 1 , wherein any alkali metal ion present in the saccharide composition is present in a concentration of less than 0.3 mM.
8. The process according to claim 1 , wherein the concentration of alkali metal ion in the saccharide composition is less than 0.3 mM.
9. The process according to claim 1 , wherein the Lewis acid material contains less than 0.5 wt % of alkali metal ion.
10. The process according to claim 1 , wherein the Lewis Acid material is Sn-BEA.
11. The process according to claim 1 , wherein the Lewis Acid material is Sn-MCM-41.
12. The process according to claim 1 , wherein the saccharide composition is contacted with the Lewis Acid material at a temperature of from 30 to 190° C.
13. The process according to claim 12 , wherein the temperature is from 80 to 170° C.
14. The process according to claim 1 , wherein the saccharide composition is contacted with the Lewis Acid material for a period of at least 10 seconds.
15. The process according to claim 1 , wherein the process is conducted under continuous conditions.
16. The process according to claim 15 , wherein the weight hourly space velocity is between 0.005 and 10 h −1 .
17. The process according to claim 1 , wherein the 2,5,6-trihydroxy-3-hexenoic acid and/or 2,5-dihydroxy-3-pentenoic acid or esters thereof are subjected to a derivatization selected from acylation, silylation, alkylation, hydrolysis, hydrogenation, amidation.
18. The process according to claim 1 , wherein the concentration of alkali metal ions present in the environment of the Lewis Acid material is kept at a concentration of less than 0.13 mM.
19. A process for the preparation of 2,5,6-trihydroxy-3-hexenoic acid and/or 2,5-dihydroxy-3-pentenoic acid or esters thereof of the formula
R′—HC═CH—CHOH—COOR (I)
wherein
R is selected from the group consisting of —H and C 1 -C 8 -alkyl; and
R′ is hydroxymethyl or 1,2-dihydroxyethyl;
the process comprising the steps of:
c. contacting a saccharide composition comprising one or more C6 and/or C5 saccharide units with a Lewis Acid material; and
d. recovering and purifying 2,5,6-trihydroxy-3-hexenoic acid and/or 2,5-dihydroxy-3-pentenoic acid or the esters thereof,
wherein the Lewis Acid material is a tin catalyst,
wherein the process results in a yield of 2,5,6-trihydroxy-3-hexenoic acid and/or 2,5-dihydroxy-3-pentenoic acid or esters thereof above 15%,
wherein a concentration of alkali metal ions present in an environment of the Lewis Acid material is kept at a concentration of less than 0.13 mM or at an amount of less than 0.5 wt % of a catalyst composition.