Method for transforming sugars and sugar alcohols into mono- and poly-oxidized compounds in the presence of a heterogeneous catalyst
The invention concerns a method for converting a feedstock selected from sugars or sugar alcohols, alone or in a mixture, into mono- or polyoxygenated compounds, wherein the feedstock is contacted with at least one heterogeneous catalyst comprising a support selected from perovskites of formula ABO 3 , in which A is selected from the elements Mg, Ca, Sr and Ba and B is selected from the elements Fe, Mn, Ti and Zr, and the oxides of elements selected from lanthanum, neodymium, yttrium and cerium, alone or in a mixture, which oxides can be doped with at least one element selected from alkali metals, alkaline earths and rare earths, in a reducing atmosphere, at a temperature of 100° C. to 300° C. and at a pressure of 0.1 MPa to 50 MPa.
1. A method for transforming a feedstock that is a sugar or sugar alcohol, alone or in a mixture, into mono- or poly-oxidized compounds, comprising contacting said feedstock with at least one heterogeneous catalyst, in the same reaction chamber, in the presence of at least one solvent, with said solvent being water, an alcohol, a diol, or another solvent, by itself or in a mixture, under a reducing atmosphere, and at a temperature of between 100° C. and 300° C., and at a pressure of between 0.1 MPa and 50 MPa, and in which said heterogeneous catalyst(s) comprise(s) at least one metal that is a metal of groups 8 to 11 of the periodic table and a substrate that is a perovskite of formula ABO 3 in which A is Mg, Ca, Sr or Ba, and B is Fe, Mn, Ti or Zr, or an oxide of lanthanum, neodymium, yttrium, or cerium, by themselves or in a mixture, with said oxide able to be doped by at least one alkali metal, alkaline-earth, or rare earth, by themselves or in a mixture, with said method being performed in the absence of additional catalyst.
2. The method according to claim 1 , in which said method is performed in the absence of additional basic catalyst that is an oxide, hydroxide or alcoholate of alkali or alkaline-earth metal, which may or may not be hydrated, having as a formula M m X n .n′ H 2 O in which the metal M is a metal of group 1 or 2 of the periodic table, m is a whole number of between 1 and 2, n is a whole number of between 1 and 2, and n′ is a number of between 0 and 20, and X is oxygen, a hydroxyl group or an alcoholate groups of formula OR with R an alkyl group.
3. The method according to claim 1 , in which the feedstock is a sugar that is an oligosaccharide or monosaccharide, by themselves or in a mixture.
4. The method according to claim 3 , in which the oligosaccharide is saccharose, lactose, maltose, isomaltose, inulobiose, melibiose, gentiobiose, trehalose, cellobiose, cellotriose, cellotetraose, or an oligosaccharide that is obtained from hydrolysis of starch, inulin, cellulose or hemicellulose, by themselves or in a mixture.
5. The method according to claim 3 , in which the monosaccharide is dihydroxyacetone, erythrose, xylose, arabinose, glucose, mannose, or fructose, by themselves or in a mixture.
6. The method according to claim 1 , in which the feedstock is a sugar alcohol that is lactitol, maltitol, isomaltitol, inulobitol, melibitol, gentiobitol, cellobitol, cellotritol, cellotetritol, glycerol, erythritol, xylitol, arabinitol, sorbitol, or mannitol, by themselves or in a mixture.
7. The method according to claim 1 , in which the metals of groups 8 to 11 of the periodic table of said heterogeneous catalyst(s) are Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag or Au, by themselves or in a mixture.
8. The method according to claim 1 , in which the perovskite of formula ABO 3 is BaTiO 3 , SrTiO 3 , BaZrO 3 , CaZrO 3 , SrZrO 3 , or CaMnO 3 .
9. The method according to claim 1 , in which said oxides are doped by at least one doping element, that is Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, La, Ce, Sm, Gd, Y, or Pr, by themselves or in a mixture.
10. The method according to claim 9 , in which the doping element has a content of between 0.1% and 30% by weight in relation to the total mass of said substrate.
11. The method according to claim 1 , in which the solvent is water, ethylene glycol, propylene glycol, methanol, ethanol, or a propanol, by themselves or in a mixture.
12. The method according to claim 11 , in which solvents comprises a mixture having a content by mass of water that is greater than 5% by weight in relation to the total mass of said mixture.
13. The method according to claim 1 , in which the temperature is between 150° C. and 250° C. and the pressure is between 0.5 MPa and 30 MPa.
14. The method according to claim 1 , in which said heterogeneous catalyst is introduced into the reaction chamber with a ratio by mass of feedstock/heterogeneous catalyst of between 1 and 500.
15. The method according to claim 11 , in which the solvent comprises a mixture having a content by mass of water that is greater than 30% by weight in relation to the total mass of said mixture.
16. The method according to claim 11 , in which the solvent comprises a mixture having a content by mass of water that is greater than 50% by weight in relation to the total mass of said mixture.