PROCESS FOR OBTAINING CELLULOSE ACETATE FROM AGRICULTURAL BY-PRODUCTS

Authors: Biswas, Atanu; Saha, Badal; Lawton Jr, John; Shogren, Randal; Willett, Julious

Submitted to: Carbohydrate Polymers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/31/2005
Publication Date: 1/4/2006
Citation: Biswas, A., Saha, B.C., Lawton Jr, J.W., Shogren, R.L., Willett, J.L. 2006. Process for obtaining cellulose acetate from agricultural by-products. Carbohydrate Polymers. 64:134-137.

Interpretive Summary: Agricultural residues such as rice-straw, wheat hull and corn fiber are abundant and wasteful, devoid of nutrients, and possess low animal feeding value. Since these hulls do not biodegrade or burn very easily and possess low animal feeding value, our planet ends up with an abundance of this scaly residue and much of it goes to waste and is sometimes available free-of-charge. Moreover, the straw burning practice is unacceptable as it is against good environmental practices. One very limited application is ethanol production. We found a novel process to obtain industrially important cellulose acetate from these by-products. Rice-straw, wheat hull and corn fiber were treated with acid to remove the essentials useful for making ethanol. The leftovers lacking any utility were treated with acetic anhydride and catalytic amount of sulfuric acid to give cellulose acetate in 25% yield. This work is a fine example of utilization of processed byproducts to develop a new market for farm materials. Impact: This research for the first time demonstrated a method of preparation of a commercially useful product, cellulose acetate, from discarded byproducts such as rice-straw, wheat hull and corn fiber. This work will provide potential new markets and applications for low-value agricultural wastes and co-products. By converting the cellulose in these residues into cellulose acetate as opposed to saccharifying cellulose to glucose, the overall cost of producing ethanol from lignocellulosic biomass may be reduced.

Technical Abstract: Agricultural residues such as corn fiber, rice hulls and wheat straw can be used as an abundant low-cost feedstock for the production of fuel ethanol. However, the cost of cellulase enzymes to saccharify cellulose to glucose is a major hindrance. As an alternative, a novel process method was developed to obtain industrially important cellulose acetate from these by-products, once the hemicellulosic sugars were removed. Rice hulls, wheat straw, and corn fiber were treated with dilute acid at a moderate temperature to hydrolyze the hemicellulose to monomeric sugars which can then be fermented to ethanol. The cellulose was then treated with acetic anhydride and a catalytic amount of sulfuric acid to yield cellulose acetate in 25% weight of the agricultural residues. This work is a perfect example of illustrating that processed byproducts can be utilized to develop new markets for farm materials.