Supercritical fluid rectification of lignin microwave-pyrolysis oil

Abstract

Supercritical fluid rectification selectively extracts single ring phenols from lignin microwave-pyrolysis oil.

Thermal conversion of lignin to phenols: Relevance between chemical structure and pyrolysis behaviors

“…These amounts were similar with Guo and co-workers' results [22], in which the raw material and the preparation method were the same. Moreover, the 13…”

“…Excepting as liquid fuels, pyrolysis bio-oil could be used to produce value-added chemicals, such as modified phenolic resins because of the enriched phenols [9][10][11]. Moreover, supercritical carbon dioxide is also introduced to extract the bio-oil to enrich the value-added phenols [12,13]. Catalytic upgrading is another efficient way to add the value of bio-oil.…”

“…The target of the work is to reveal the relevance between lignin chemical structure and pyrolysis behaviors, which is meaningful for the efficient thermal conversion of lignin to phenol compounds. Therefore, the Fourier transform infrared (FTIR) spectrometry and the 13 C-H correlation two-dimensional (2D) heteronuclear single-quantum coherence (HSQC) nuclear magnetic resonance (NMR) were introduced to characterize the chemical structure of two typical lignin samples (soda alkali lignin and Alcell organosolv lignin). Then, the relevance between chemical structure of lignin samples and their pyrolysis behaviors under various temperature parameters was studied by thermogravimetric analysis (TGA) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS).…”

Supercritical Carbon Dioxide Extraction of Lignocellulosic Bio-Oils: The Potential of Fuel Upgrading and Chemical Recovery

“…Table 6 summarizes these works and their main aspects, regarding the nature of the biomass feedstock, the thermochemical conversion process producing the bio-oil, the system size, and the year of publication. All data so far are limited to laboratory-scale sCO 2 extraction systems and the semi-continuous single-stage mode of operation, with the exception of Mudraboyina et al [126], where the extractor was coupled with a rectification column with a temperature gradient, allowing an internal reflux operation. The data selection was delimited to literature referring to extraction of LC bio-oils obtained by phase separation (e.g., gravity settling) of the reaction products of the thermochemical process.…”

“…A generalized laboratory scale system is shown in Figure 5, which represents all literature studies except for Mudraboyina et al [126], where the extractor was coupled with a rectification column. Such a typical system utilizes a CO 2 cylinder for supplying the solvent.…”