Chemical Shifts and Lifetimes for Nuclear Magnetic Resonance (NMR) Analysis of Biofuels

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• 作者：Jincy Joseph ; Cirila Baker ; Saikrishna Mukkamala ; Sedat H. Beis ; M. Clayton Wheeler ; William J. DeSisto ; Bruce L. Jensen ; Brian G. Frederick
• 刊名：Energy & Fuels
• 出版年：2010
• 出版时间：September 16, 2010
• 年：2010
• 卷：24
• 期：9
• 页码：5153-5162
• 全文大小：982K
• 年卷期：v.24,no.9(September 16, 2010)
• ISSN：1520-5029

文摘

Determination of the molecular composition of biofuels is critical to process development. Because biofuels, such as pyrolysis oil, contain hundreds of compounds, quantitative determination of the mixtures is a formidable task and is often not necessary for routine development work. ¹³C and ¹H nuclear magnetic resonance (NMR) offer a reasonable trade-off between functional group identification and analytical measurement effort. However, accuracy depends upon selection of chemical-shift regions, baseline compensation, and correction for incomplete longitudinal relaxation effects. We propose chemical-shift assignments and T₁ correction factors based on ¹³C and ¹H NMR measurements of over 50 compounds that have been previously identified in pyrolysis oils and several plant natural products, especially terpenes. The results are intended to allow for a semiquantitative assessment of molecular composition of bio-oils on a time scale of 1−8 h to provide feedback for process development.