Patent ID: 8883451

Claim:
A method of producing soluble C 5 saccharides from lignocellulosic biomass, comprising: providing a fractionated lignocellulosic biomass comprising: a solid fraction comprising: optionally, insoluble C 5 oligosaccharide; cellulose; and lignin; and a first liquid fraction at a first temperature and a first pressure comprising: soluble C 5 saccharides selected from the group consisting of C 5 oligosaccharides, xylose, arabinose, lyxose, ribose, and mixtures thereof; wherein said soluble C 5 saccharides are present at a first level; optionally, separating said solid fraction from said first liquid fraction at a second pressure; contacting said first liquid fraction with a solid acid catalyst to form a second liquid fraction comprising said soluble C 5 saccharides at a second level and at a second temperature; wherein said second level is greater than said first level; and wherein said second temperature is less than said first temperature; optionally, hydrolyzing said second liquid fraction to form C 5 saccharides selected from the group consisting of C 5 oligosaccharides having fewer mer units, xylose, arabinose, lyxose, ribose, and mixtures thereof; wherein said fractionated lignocellulosic biomass is formed by contacting said lignocellulosic biomass with a first reaction fluid comprising hot compressed water and, optionally, carbon dioxide; wherein said first reaction fluid further comprises acid, when said lignocellulosic biomass comprises softwood; and wherein said first reaction fluid is at a temperature of at least 100° C. under a pressure sufficient to maintain all of said first reaction fluid in liquid form.