[Zeolite catalysis in conversion of cellulosics]
To transform biomass into fermentable substrate for yeast, we are using zeolites instead of enzymes to catalyze the two bottleneck reactions in biomass conversion, xylose isomerization and ceuobiose hydrolysis. The experimental results on these reactions carried out over various zeolites and other catalysts are presented herein. The advantages and disadvantages of using these catalysts over enzymes are also discussed. Heterogeneous solid catalysts other than zeolites has been employed for cellobiose-to-glucose hydrolysis. The size and shape selectivity that makes zeoutes unique for some reactions can add diffusional hindrance. We have spent some time screening various known solid acidic catalysts. We report that a class of cationic ion exchange resins in the acidified form (e.g. Amberlite) has worked well as an acidic catalyst in hydrolyzing cellobiose to glucose. Our experimental results, together with those obtained from a homogeneous acid catalyst (e.g. sulfuric acid) for comparison are provided. Having succeeded in finding an alternative solid acid catalyst for hydrolysis, we explored other solid resin or other homogeneous but non-enzyme catalyst to carry out the xylose-to-xylulose isomerization. A fairly extensive search has been made. We explored the use of sodium aluminates in the homogeneous phase isomerization of glucose to fructose and obtained a very high conversion of glucose to fructose with the final mixture containing 85% of fructose instead of the common 45%. Fructose apparently complexes with aluminates, and its equilibrium concentration is shifted to considerably higher values than permitted by simple glucose/fructose equilibrium. We have recently found a number of catalysts capable of promoting isomerization between aldoses and ketoses. One solid resin, known as polyvinyl pyridine (PVP), is able to convert xylose to xylulose at a pH below 7. Our usage of alternative isomerization catalysts, including PVP, are described.
- Research Organization:
- Purdue Research Foundation, Lafayette, IN (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG02-92ER12125
- OSTI ID:
- 10122903
- Report Number(s):
- DOE/ER/12125-1; ON: DE93006259
- Resource Relation:
- Other Information: PBD: [1992]
- Country of Publication:
- United States
- Language:
- English
Similar Records
Simultaneous upgrading of biomass-derived sugars to HMF/furfural via enzymatically isomerized ketose intermediates
Zeolite catalysis in conversion of cellulosics. Annual report