Selective hydrolysis of lignocellulose materials

Claim 1

A PROCESS FOR THE SELECTIVE HYDROLYSIS OF LIGNOCELLULOSE MATERIAL WHICH COMPRISES: (A) HEATING THE LIGNOCELLULOSE MATERIAL IN A FIRST STAGE WITH A FIRST AQUEOUS TREATING AGENT, (B) USING A TREATING AGENT TO SOLIDS WEIGHT RATIO WITHIN THE RANGE OF FROM 1:1-5:1, (C) THE TREATING AGENT HAVING A MINERAL ACID CONCENTRATION OF NOT OVER 0.3% BY WEIGHT, (D) AT A PRESSURE OF FROM 100-700 P.S.I.G. AND CORRESPONDING TEMPERATURES FOR SATURATED STEAM, (E) FOR A TIME OF FROM 0.3 TO 10 MINUTES USED IN SUBSTANTIALLY INVERSE RELATION TO THE TEMPERATURE, THEREBY HYDROLYZING SUBSTANTIALLY SELECTIVELY THE HEMICELLULOSE CONTENT OF THE LIGNOCELLULOSE MATERIAL WITHOUT SUBSTANTIAL DECOMPOSITION OF THE SUGARS ANF FORMING A FIRST LIQUOR PRODUCT CONTAINING PENTOSE SUGARS AND A FIRST SOLID RESIDUE SUBSTANTIALLY FREE FROM PENTOSANS AND CONTAINING PREDOMINANTLY UNHYDROLYZED LIGNIN AND CELLULOSE, (F) SEPARATING THE FIRST LIQUOR PRODUCT FROM THE FIRST SOLID RESIDUE, (G) HEATING THE FIRST SOLID RESIDUE IN A SECOND STAGE WITH A SECOND AQUEOUS MINERAL ACID TREATING AGENT, (H) USING A TREATING AGENT TO SOLIDS RATIO WITHIN THE RANGE OF FROM 0.1:1-5:1, (I) THE TREATING AGENT HAVING A MINERAL ACID CONCENTRATION OF FROM 0.3-3.0% BY WEIGHT, (J) AT A PRESSURE OF FROM 150-900 P.S.I.G. AND CORRESPONDING TEMPERATURES FOR SATURATED STEAM, (K) FOR A TIME OF FROM 0.3 TO 10 MINUTES, USED IN SUBSTANTIALLY INVERSE RELATION TO THE TEMPERATURE, THEREBY CONVERTING SUBSTANTIALLY SELECTIVELY THE CELLULOSE CONTENT OF THE FIRST SOLID RESIDUE TO HEXOS SUGARS AND FORMING A SECOND LIQUOR PRODUCT CONTAINING PREDOMINANTLY HEXOSE SUGARS AND A SECOND SOLID RESIDUE CONTAINING PREDOMINANTLY UNHYDROLYZED LIGNIN, (L) AND SEPARATING THE SECOND LIQUOR PRODUCT FROM THE SECOND SOLID RESIDUE.