Solid Acid Hydrolysis
Solid acid catalyst mediated hydrolysis is an attractive direction in biomass saccharification and cellulosic ethanol research. Homogeneous catalysis is the first choice from the mass transfer point of view and reaction efficiency. However, homogeneous acid catalysis methods have certain drawbacks in product separation, reactor and equipment corrosion, catalyst recycling, and treatment of waste effluents. It is a well known fact that many catalytic systems have not been commercialized due to the difficulty in separating the homogeneous catalysts from product solutions. Solid acids, on the other hand, can overcome many of the disadvantages of homogenous catalysts, and also have some unique properties and advantages.
There are some excellent reviews in recent literature regarding the development of solid acid systems for the cellulosic ethanol process. These include the recent reviews by Guo, Fang and others [2, 70, 71]. Several types of solid acids have been used for biomass hydrolysis. Selected examples of the use of solid acid catalysts for hydrolysis of cellulose and corn cob to glucose/reducing sugars in water are shown in Table 7.3.