Article pubs.acs.org/EF
Characterization of Red Pine Pyrolysis Bio-oil by Gas Chromatography−Mass Spectrometry and Negative-Ion Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Yang Liu,† Quan Shi,*,† Yahe Zhang,† Yuling He,† Keng H. Chung,‡ Suoqi Zhao,† and Chunming Xu*,† †
State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China Well Resources Inc., 3919-149A Street, Edmonton, Alberta T6R 1J8, Canada
‡
S Supporting Information *
ABSTRACT: A red pine fast pyrolysis bio-oil was subjected to sequential solvent fractionation into n-hexane soluble (HS), ether soluble (ES), ether insoluble (EIS), dichloromethane soluble (DS), and methanol soluble (MeS) fractions. The volatile components of bio-oil were analyzed by gas chromatography−mass spectrometry (GC−MS), indicating the presence of acids, aldehydes, ketones, alcohols, phenols, and anhydromonosaccharides, which consisted of methoxy, hydroxy, and carbonyl functional groups. These results imply that the bio-oil was similar to the most reported fast pyrolysis bio-oil samples in molecular composition. The bio-oil and its five subfractions were analyzed by negative-ion electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The predominant compounds in bio-oil were O2−O17 class species with 1−22 double-bond equivalent (DBE) values and 4−39 carbon numbers. The most abundant class species in biocrude oil, HS, ES, EIS, DS, and MeS subfractions were O7, O6, O8, O10, O7, and O8 class species, respectively. The predominant EIS subfraction presented an obvious relative low DBE value, sustaining the tentative identification as “sugar fraction”. The predominant compounds in DS subfraction were likely lignin dimers, whereas those in MeS subfraction should be lignin dimers and trimers. The number of oxygen atoms of the bio-oil compounds was negatively correlated with the average DBE value, indicating that oxygen atoms were present in various functional groups of the bio-oil compounds. The N1Ox class species were also identified, which contained 1−16 DBE and 6−30 carbon numbers.
1. INTRODUCTION Fast pyrolysis of biomass is an emerging environmental technology for producing liquid fuels and chemicals.1,2 It is a thermal decomposition process at 400−600 °C with short reaction time (
