A simple two-step process was conducted to scrutinize new catalytic action of chromium fluoride (CrF3) by evaluating its effect on the yield of hydroxylmethylfurfural (HMF) in ionic liquid (1-octyl-3-methylimidazolium chloride) using raw tapioca root biomass with high starch, and hydrolysis efficiency of the biomass extract was characterized by FT-IR spectrometry and FESEM image analysis. The FT-IR absorbance bands confirmed the presence of starch and other soluble sugars in the acidic biomass extract by presenting its frequency signals in the 950-1200 cm(-1) regions. FESEM image showed that the efficiency of the biomass hydrolysis is time-dependent. The concentration of CrF3 significantly affected the yield of HMF. Its highest yield (52.6 +/- 4.8 dwt%) was achieved at 1% CrF3, but over 1% CrF3 its yields began to decline. The combined addition of CrF3 and CrBr3 showed ca. 1.3-fold higher yield than CrF3 alone. The reaction rates of HMF synthesis were considerably influenced by the stoichiometry ratio of CrF3 to biomass. The highest reaction rate (0.41 g/g biomass/h) occurred at 0.2 ratio value. (C) 2011 Elsevier By. All rights reserved.