Bio-oil from coconut fibers: fractionation by preparative liquid chromatography for phenols isolation

Abstract

The great potential of bio-products generated from agro-industrial residues from the biomass processing, as is the case with the green coconut fibers (Cocos nucifera L. var. dwarf), makes Brazil stand out in the field of transformation of these residues, mainly due to its high biodiversity and favorable climatic conditions. In this work, residual green coconut fibers were used in the production of bio-oil by pyrolysis. The bio-oil was fractionated using preparative liquid chromatography (PLC) in silica using solvents of different polarities: hexane, hexane/toluene, toluene/dichloromethane, dichloromethane/acetone, and methanol. Bio-oil and its fractions were analyzed by gas chromatograph /quadrupole mass spectrometer (GC/qMS). The concentration of each compound was carried out by multiplying the percentage area of the corresponding peak by the mass yield of the respective fraction. PLCof bio-oil increased the number of compounds identified by about 170% compared to the original bio-oil (non-fractionated), besides allowing the isolation of nonpolar compounds (mostly hydrocarbons) from polar compounds (mainly phenols, aldehydes, and ketones). Anotheradvantage of PLC was the increase in the number of hydrocarbons identified in the fractions, as opposed to the crude bio-oil analysis. Among the major compounds, phenols can be highlighted, besides furfural derivatives and hydrocarbons, which indicates the potential use of bio-oil mainly for industrial purposes.

Keywords

• agricultural waste; biomass; fast pyrolysis; plc; gas chromatography.