Pre-extraction and solvent pulping of lignocellulosic material

A process of treating a lignocellulosic material comprising:

• in a pre-extraction step, extracting hemicellulose from the lignocellulosic material by contacting the lignocellulosic material with an aqueous solution of a basic material in water, the aqueous solution having a pH sufficiently basic at the beginning of the pre-extraction step so that the aqueous solution at the end of the pre-extraction step has a pH within a range of from about 4.5 to about 9.5 measured at a temperature of 20° C.;
• then
• in a solvent pulping step, separating the lignocellulosic material into pulp by contacting the lignocellulosic material with a cooking liquor comprising an organic solvent having a standard boiling point of at least about 150° C.;
• then
• in an adsorption step, adsorbing the extracted hemicellulose on the pulp while controlling the adsorption step pH from about 9 to about 14, recovering a sugar rich extract not adsorbed in the adsorption step and producing value-added materials from said sugar rich extract, wherein the pulp yield at the end of the adsorption step is higher than the pulp yield of the same process without the pre-extraction and adsorption steps.