(496a) Characterization of TFA Regenerated Cellulose with a Two-Step Treatment to Understand the Impact of Cellulose Structure on Hydrolysis

Authors: 
Zhang, X., Purdue University
Concentrated trifluoroacetic acid (TFA) is known to depolymerize cellulose. In this paper we report the effect of temperature and treatment time on physiochemical and morphological changes to cellulose. We present x-ray diffraction, SEM, degree of polymerization, and FTIR characterizations and compare them to acid-catalyzed hydrolysis of the decrystalized cellulose and conversion of the resultant glucose to HMF and levulinic acid by maleic acid-AlCl3 catalysis. Treatment with concentrated TFA for 2 hrs at 0°C resulted in a 28% reduction in crystallinity index (CrI) of the cellulose. Additional treatment for 5 hrs at 50°C resulted in a CrI of 0. Both changes of crystallinity index (CrI) resulted in about 40% improvement in overall yield of HMF and levulinic acid. Enzymatic hydrolysis study shows that TFA treatment for 2 hrs at 0°C results a 52% glucose conversion yield, which had higher conversion yield than the additional treatment for 5 hrs at 50°C with 45% glucose conversion yield. Results showed the additional reduction in CrI through heating step does not further improve yields from enzymatic hydrolysis.