³¹P-NMR analysis of bio-oils obtained from the pyrolysis of biomass

Abstract

Background: The use of 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane followed by ³¹P-NMR analysis has been frequently employed to quantitatively characterize the structure of hydroxyl groups in lignin and, more recently, biodiesel. This technique serves as a valuable tool to determine aliphatic hydroxyls, phenolics and carboxylic acid groups in lignin and aliphatic hydroxyl groups in partially substituted glycerols. Results: This study demonstrates the application of this analytical technique to pyrolysis oils to allow efficient analysis and identification of important functional groups present in bio-oils and the measurement of moisture content. Conclusion: Phosphitylation followed by ³¹P-NMR analysis was used to show that the moisture content of the loblolly pine bio-oil used in this study was 11.94%. The results also established that the bio-oils obtained from loblolly pine cellulose had higher levoglucosan content than the bio-oil obtained from the starting pine itself. In addition, the total phenolic content of bio-oil derived from loblolly pine milled wood lignin was greater than that obtained from the bio-oil from the loblolly pine cellulose. The data also highlighted the ability to track chemical transitions that take place during pyrolysis using ³¹P-NMR.

Financial & competing interests disclosure

Financial assistance from the Chevron Corp. to conduct this study is greatly appreciated and acknowledged. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.