TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The conditions include heating the combination of the biomass and the composition to 100-220 degrees C. The method further comprises: (a) removing and/or recovering THF from the liquid phase after co-solvent pretreatment of biomass; (b) removing and/or recovering lignin from the co-solvent treated biomass by precipitation as a solid after the removal of THF from the liquid phase; (c) removing and/or recovering furfural from a liquid phase after co-solvent treatment of the biomass by azeotropic distillation or solvent extraction and from the vapor phase during and/or after co-solvent treatment by boiling and/or steam stripping; (d) recovering a liquid product comprising of 5C and 6C monosaccharides and their oligomers; and (e) recovering a solid product (that is a glucan-rich material) after co-solvent treatment of biomass. The method-I further comprises: the steps (a) and (b) as above per se; (c1) removing and/or recovering furfural and/or 5-HMF from a liquid phase after co-solvent treatment of the biomass by azeotropic distillation or solvent extraction and removing and/or recovering furfural from the vapor phase during and/or after co-solvent treatment by boiling and/or steam stripping; extracting and/or recovering furfural and/or 5-HMF from a liquid phase of the co-solvent treatment of the biomass by a water-immiscible organic solvent; and the step (e) as above per se. The furfural is further processed to be catalytically upgraded to produce THF and/or methyl-THF, and is further processed to be catalytically decarbonylated and hydrogenated to produce THF. The liquid product is neutralized by a base. The glucan-rich material: is further treated with one or more enzymes that remove xylooligomers and higher chain length polymers of xylose to produce xylose monomers and remove glucooligomers and higher chain length polymers of glucose to produce glucose monomers; is incubated with microorganisms and/or with added enzymes to produce an alcohol or other products by fermentation; is used as paper pulp; is further catalytically converted to 5-HMF and/or levulinic acid; and is hydrolyzed to glucose and glucose-oligomers using an acid consisting of formic acid, acetic acid and trifluoroacetic acid. The lignin is further processed and captured by THF or dimethylsulfoxide (DMSO) as a liquid. Preferred Components: The co-solvent mixture is monophasic at standard temperature and pressure (STP). The acid catalyst is mineral acid, organic acid, metal halide acid and solid acid catalyst, preferably sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, formic acid, acetic acid, trifluoroacetic acid, Lewis acid, Bronsted acid, aluminum chloride, copper chloride, chromium chloride, iron(III) chloride, and zirconyl chloride. The alcohol is ethanol, and contains 1 or more carbon molecules. The microorganism is a yeast, a bacteria, a mold, and a fungi. The aqueous THF comprises a THF and water at volume ratio of 1:5-5:1, 1:1-7:1 or 1:3-7:1. The immiscible organic solvent is an ether, ketone, alcohol, and/or alkane. Preferred Composition: The composition further comprises an acid catalyst. EXAMPLE - 800 g of Xylose solution was introduced in a 1 l Parr reactor. 6.4 g L-1 of Furfural in THF solvent and non-solvent acid solutions was introduced in a 1 L Parr reactor. Two glass bottles each with 5 wt.% Maplewood were used, where one bottle contained a 1:1 ratio of THF to water and the other contained an aqueous solution with no solvent. The contents of these bottles were transferred to the Parr reacted and reacted at 170 degrees C to obtain furfural in the presence of solvent.