Process for production of sugars and optionally cellulose and lignin from lignocellulosic raw materials

A process for treating vegetable material essentially comprised of cellulose, lignin and hemicelluloses, comprising the steps of:

• (a) treating said vegetable material under elevated pressure with a first solution comprising (i) water and acetone in a volume ratio between about 70:30 and 30:70, and (ii) at least one acid, said acid having a concentration, relative to the total volume of said first solution, of between about 0.001 and about 1N, at a temperature between about 170.degree. and about 220.degree. C., such that substantially all of said lignin and said hemicelluloses are dissolved in said first solution and a residue comprising microcrystalline cellulose is formed;
• (b) separating said residue from said first solution;
• and
• (c) after step (b), treating said residue with a second solution comprising (i) water and acetone in a volume ratio between about 70:30 and 30:70, and (ii) at least one acid, said acid having a concentration, relative to the total volume of said first solution, of between about 0.001 and about 1N, at a temperature between about 170.degree. and about 220.degree. C., such that said microcrystalline cellulose is substantially completely hydrolyzed to glucose, said glucose being dissolved in said second solution.