PROCEDE POUR DELIGNIFIER LE BOIS ET AUTRES PRODUITS LIGNOCELLULOSIQUES

A method for delignifying ligno-cellulosic materials and efficiently separate from each other the constituents thereof. Said materials which optionally may be prehydrolized are heated in an aqueous acid medium in the presence of phenol compounds whereby the ratio by weight of liquid to solid is at least 0,5. In the case of low liquid solid ratios i.e. below about 4:1 further aqueous liquid is added to the reaction mass after pulping to aid filtration and draining. After isolating the purified solid cellulose pulp, the liquid phase separates into two layers: an aqueous layer rich with pentoses and an organic layer rich with phenols and lignin, the latter providing, by distillation and pyrolysis of the residue, a quantity of phenols at least equal to that of the phenols used in the delignification stage.