Process for transformation of a feedstock comprising a lignocellulosic biomass using an acidic homogeneous catalyst in combination with a heterogeneous catalyst comprising a specific substrate

A process for transformation of a feedstock that is selected from among a lignocellulosic biomass and carbohydrates, by themselves or in a mixture, into mono-oxidized or poly-oxidized compounds, in which said feedstock is brought into contact, simultaneously, with a catalytic system that comprises one or more homogeneous catalyst(s) and one or more heterogeneous catalyst(s), in the same reaction chamber, in the presence of at least one solvent, with said solvent being water by itself or in a mixture with at least one other solvent, under a reducing atmosphere, and at a temperature of between 50° C. and 300° C., and at a pressure of between 0.5 MPa and 20 MPa, in which

• said homogeneous catalyst(s) is/are selected from among inorganic Brønsted acids and organic Brønsted acids
• said heterogeneous catalyst(s) is/are selected from among heterogeneous catalyst(s) comprising:
• at least one metal that is selected from among the metals of groups 6 to 11 and the metals of group 14 of the periodic table;
• and a substrate that is selected from among perovskites of formula ABO3, in which A is selected from among elements Mg, Ca, Sr and Ba, and La, and B is selected from among:
• elements Fe, Mn, Ti, and Zr;
• oxides of elements selected from among lanthanum (La), neodymium (Nd) and yttrium (Y), cerium (Ce) and niobium (Nb), by themselves or in a mixture;
• and mixed oxides that are selected from among aluminates of zinc (Zn), copper (Cu), and cobalt (Co), by themselves or in a mixture.