Hydrolysis of lignocellulose materials with solvent extraction of the hydrolysate

Claim 1

A PROCESS FOR THE 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 AND FORMING A FIRST LIQUOR, PRODUCT CONTAINING PENTOSE SUGARS AND A FIRST SOLID RESIDUE 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 AN AQUEOUS MINERAL ACID TREATING AGENT, (H) USING A TREATING AGENT TO SOLIDS RATIO WITHIN THE RANGE FROM 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 A 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 HEXOSE SUGARS AND FORMING A SECOND SOLID RESIDUE CONTAINING PREDOMINANTLY UNHYDROLYZED LIGNIN AND A SECOND LIQUOR PRODUCT CONTAINING PREDOMINANTLY HEXOSE SUGARS CONTAMINATED WITH HYDROLYTIC DEGRADATION PRODUCTS OF THE LIGNIN AND CELLULOSE, (L) SEPARATING THE SECOND LIQUOR PRODUCT FROM THE SECOND SOLID RESIDUE, (M) EXTRACTING THE SECOND LIQUOR PRODUCT WITH AN ORGANIC SOLVENT WHICH IS SUBSTANTIALLY INSOLUBLE IN AND CHEMICALLY INERT TOWARD THE LIQUOR, AND IN WHICH THE SAID HYDROLYTIC DEGRADATION PRODUCTS SELECTIVELY ARE SOLUBLE, (N) AND SEPARATING THE EXTRACTED SECOND LIQUOR PRODUCT FROM THE ORGANIC SOLVENT.