Process for the oxidation of di-, tri-, Oligo- and polysaccharides into polyhydroxycarboxylic acids, catalyst used and products thus obtained
AssigneeRoquette Freres
InventorsPatrick M. Fuertes, Guy M. Fleche
Life of this patent
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Abstract
Process for the selective oxidation of di-, tri-, oligo- and polysaccharides comprising a reducing terminal function of the aldose type into polyhydroxycarboxylic acids, wherein the oxidation is carried out in an alkaline medium by means of an oxygen-containing gas, in the presence of a noble metal based catalyst selected from the group constituted by palladium, platinum, rhodium and osmium and fixed on an inert support, said catalyst being "doped" with one or several metals, or promoters, of Groups IV, V or VI of the Periodic Table.
Claims26
A process for the preparation of polyhydroxycarboxylic acids by way of the selective oxidation of polysaccharides having a reducing terminal function of the aldose type, the said process comprising:
- selecting at least one polysaccharide having a reducing function of the aldose type in the form of an aqueous solution,
- dispersing into the said polysaccharide solution a catalyst based on a noble metal selected from the group consisting of palladium, platinum, rhodium and osmium and fixed on an inert support, said catalyst being "doped" with at least one metal, called promoter and selected from the group consisting of those of the Groups IV, V and VI of the Periodic Table,
- starting the reaction by supplying the polysaccharide solution, having dispersed therein the catalyst, with an oxygen containing gas and with an alkaline agent.
A process for the preparation of polyhydroxycarboxylic acids by way of the selective oxidation of polysaccharides having a reducing terminal function of the aldose type from the group consisting of starch hydrolysates and glucose syrups whose D.E. (dextrose equivalent) is comprised between 90 and 5, the said process comprising:
- selecting at least one starch hydrolysate or glucose syrup in the form of an aqueous solution,
- dispersing into the said solution of starch hydrolysate or glucose syrup a catalyst based on a noble metal selected from the group consisting of palladium, platinum, rhodium and osmium and fixed on an inert support, said catalyst being "doped" with at least one metal, called promoter and selected from the group consisting of those of the Groups IV, V and VI of the Periodic Table,
- starting the reaction by supplying the starch hydrolysate or glucose syrup solution, having dispersed therein the catalyst, with an oxygen containing gas and with an alkaline agent.
Dependencies are inferred from the claim text.