NOVELTY - Upgrading (M1) biomass derived products using liquid-liquid extraction, comprises: (a) contacting extraction solvent with first mixture comprising water and biomass derived carbon containing compounds to form second mixture comprising extract and raffinate; (b) separating the second mixture thus forming an intermediate product stream comprising at least a portion of the extract and a waste water stream comprising substantially all of raffinate; and removing a portion of extraction solvent from intermediate product stream to form recovered extraction solvent and bio-oil product.    USE - The method is useful for upgrading biomass derived products using liquid-liquid extraction (claimed) to convert biomass to liquid products and gaseous hydrocarbons, which are useful as fuels.    ADVANTAGE - The method: reduces the solids content of biomass derived oil; transfers undesirable carbon containing compounds from the oil phase to the water phase and desirable carbon containing compounds from the water phase to the oil phase, thus phase, thus increasing the yield of high quality bio-oil for upgrading to fuels; is economical.    DETAILED DESCRIPTION - Upgrading (M1) biomass derived products using liquid-liquid extraction, comprises: (a) contacting an extraction solvent with a first mixture comprising water and biomass derived carbon containing compounds including organics A comprising compounds including aldehydes, ketones having 3-4 carbon atoms per molecule and/or carboxylic acids having 2-3 carbon atoms per molecule, and organics B comprising compounds having at least four carbon atoms per molecule, thus forming a second mixture comprising an extract and a raffinate; (b) separating the second mixture thus forming an intermediate product stream comprising at least a portion of the extract and a waste water stream comprising substantially all of raffinate; and (c) removing at least a portion of the extraction solvent from the intermediate product stream forming a recovered extraction solvent and a bio-oil product. The organics B are substantially free of aldehydes, ketones having 3-4 carbon atoms per molecule, and carboxylic acids having 2-3 carbon atoms per molecule, and the extract and the raffinate are immiscible, where the extract comprises substantially all of the extraction solvent and substantially all of the organics B, the raffinate comprises substantially all of the water and substantially all of the organics A, and the extraction solvent has a dipole moment greater than 1 debye, a density less than 1, a water solubility of less than 2.5 g/100 ml of water at 20 degrees C, and a boiling point of 90-300 degrees F. An INDEPENDENT CLAIM is also included for a method (M2) for upgrading biomass derived products using liquid-liquid extraction, comprising: (a1) providing the first mixture comprising water and biomass derived carbon containing compounds including organics A and organics B, where the first mixture includes a first oil phase comprising at least a portion of the biomass derived carbon containing compounds and at least a portion of the water and a first aqueous phase comprising at least a portion of the water and at least a portion of the biomass derived carbon containing compounds, and the first oil phase and first aqueous phase are immiscible; (b1) contacting the first mixture with the extraction solvent thus forming an extraction mixture comprising an extraction oil phase and an extraction aqueous phase, where substantially all of the organics A present in the first oil phase are partitioned from the first oil phase to first aqueous phase and substantially all of organics B present in first aqueous phase are partitioned from first aqueous phase to first oil phase, thus forming the extraction oil phase comprising substantially all of organics B and substantially all of extraction solvent and the extraction aqueous phase comprising substantially all of the water and substantially all of the organics A, where the extraction oil phase and the extraction aqueous phase are immiscible; and (c1) separating the extraction mixture thus forming an intermediate product stream comprising at least a portion of the extraction oil phase and a waste water stream comprising substantially all of the extraction aqueous phase.