Abstract:Derivatization of compounds containing -OH groups can be accomplished quantitatively with 1,3,2-dioxaphospholanyl chloride. The chemical shifts of phosphorus in the derivatives clearly differentiate alcohols from phenols and carboxylic acids. Quantitation is obtained by use of 31P FT-NMR spectroscopy in the presence of 2,2,6,6-tetrameth-ylpiperidinyloxy free radical to shorten relaxation times. Compounds with phosphorus chemical shifts differing by as little as 0.1 ppm can be separately determined.
“…This analytical technique was first described by Schiff et al in 1986 and then further developed and practically applied by Argyropoulos et al to study lignin and wood chemistry. , In addition to its use in lignin characterization, − the above method has also been widely applied in the study of hydroxyl compounds in tannins and flavonoids, , extra-virgin olive oil, biodiesel, pyrolysis oil, − hydrothermal liquefaction (HTL) biocrude, and upgraded bio-oil . The quantitative reaction between hydroxyl groups and a phosphitylating agent, such as 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane (TMDP), in the presence of a Brønsted base (Scheme ) has been employed for this purpose. , Reaction of hydroxyl groups with TMDP replaces hydroxyl protons with a nonionizable phosphorus-containing moiety (PO 2 C 6 H 12 ). As illustrated in Scheme , the phosphitylation reaction employed in this work is driven to completion in the presence of pyridine base (Pyr), which neutralizes the HCl liberated during condensation of the hydroxyl group with TMDP.…”
Section: Introductionmentioning
confidence: 99%
“…16 Hydroxyl group types in a wide range of biomass-derived products have been effectively quantified by phosphitylation and 31 P NMR analysis. This analytical technique was first described by Schiff et al in 1986 20 and then further developed and practically applied by Argyropoulos et al to study lignin and wood chemistry. 21,22 In addition to its use in lignin characterization, 23−25 the above method has also been widely applied in the study of hydroxyl compounds in tannins and flavonoids, 26,27 extra-virgin olive oil, 28 biodiesel, 29 pyrolysis oil, 30−44 hydrothermal liquefaction (HTL) biocrude, 19 and upgraded bio-oil.…”
Section: Introductionmentioning
confidence: 99%
“…45 The quantitative reaction between hydroxyl groups and a phosphitylating agent, such as 2-chloro-4,4,5,5tetramethyl-1,3,2-dioxaphospholane (TMDP), in the presence of a Brønsted base (Scheme 1) has been employed for this purpose. 20,46 Reaction of hydroxyl groups with TMDP replaces hydroxyl protons with a nonionizable phosphorus-containing moiety (PO 2 C 6 H 12 ). As illustrated in Scheme 1, the phosphitylation reaction employed in this work is driven to completion in the presence of pyridine base (Pyr), which neutralizes the HCl liberated during condensation of the hydroxyl group with TMDP.…”
A useful method for quantifying concentrations of various hydroxyl group containing molecular species in biocrudes involves chemically converting species into nonionizable, P-functionalized derivatives independently observed and quantified by phosphorus-31 nuclear magnetic resonance ( 31 P NMR) spectroscopy. Full validation of this method requires improved understanding of its applicability to different biocrude matrixes. The limits of detection (LODs) and limits of quantitation (LOQs) for this method are herein determined for concentrations of hydroxyl group containing analytes, grouped by molecular class, within three different biocrude matrixes: a biocrude (BC) product, a fast pyrolysis (FP) product, and an artificial matrix (AM). Matrix water content, known to affect method sensitivity, varies from <1 to 18.31 wt %. Each matrix is used to prepare a series of samples spiked to varying concentrations with three hydroxyl group containing model compounds, which represent (aliphatic) alcohol, phenolic, and carboxylic acid analyte types. Samples are then phosphitylated with 2-chloro-4,4,5,5tetramethyl-1,3,2-dioxaphospholane to enable 31 P NMR spectroscopic determination of native hydroxyl analyte concentrations. LODs and LOQs are determined for each analyte type and for each matrix. Analytical precision is affected by matrix concentrations of interfering analytes and water. Among the matrixes examined, AM, which contains no hydroxyl analytes and has the lowest water content, expectedly exhibits the lowest LODs and LOQs. Matrix LODs range from 0.04 to 0.14 mmol of OH/g, while their LOQs range from 0.10 to 0.41 mmol of OH/g, with both sets of values generally increasing in the order AM < BC < FP.
“…This analytical technique was first described by Schiff et al in 1986 and then further developed and practically applied by Argyropoulos et al to study lignin and wood chemistry. , In addition to its use in lignin characterization, − the above method has also been widely applied in the study of hydroxyl compounds in tannins and flavonoids, , extra-virgin olive oil, biodiesel, pyrolysis oil, − hydrothermal liquefaction (HTL) biocrude, and upgraded bio-oil . The quantitative reaction between hydroxyl groups and a phosphitylating agent, such as 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane (TMDP), in the presence of a Brønsted base (Scheme ) has been employed for this purpose. , Reaction of hydroxyl groups with TMDP replaces hydroxyl protons with a nonionizable phosphorus-containing moiety (PO 2 C 6 H 12 ). As illustrated in Scheme , the phosphitylation reaction employed in this work is driven to completion in the presence of pyridine base (Pyr), which neutralizes the HCl liberated during condensation of the hydroxyl group with TMDP.…”
Section: Introductionmentioning
confidence: 99%
“…16 Hydroxyl group types in a wide range of biomass-derived products have been effectively quantified by phosphitylation and 31 P NMR analysis. This analytical technique was first described by Schiff et al in 1986 20 and then further developed and practically applied by Argyropoulos et al to study lignin and wood chemistry. 21,22 In addition to its use in lignin characterization, 23−25 the above method has also been widely applied in the study of hydroxyl compounds in tannins and flavonoids, 26,27 extra-virgin olive oil, 28 biodiesel, 29 pyrolysis oil, 30−44 hydrothermal liquefaction (HTL) biocrude, 19 and upgraded bio-oil.…”
Section: Introductionmentioning
confidence: 99%
“…45 The quantitative reaction between hydroxyl groups and a phosphitylating agent, such as 2-chloro-4,4,5,5tetramethyl-1,3,2-dioxaphospholane (TMDP), in the presence of a Brønsted base (Scheme 1) has been employed for this purpose. 20,46 Reaction of hydroxyl groups with TMDP replaces hydroxyl protons with a nonionizable phosphorus-containing moiety (PO 2 C 6 H 12 ). As illustrated in Scheme 1, the phosphitylation reaction employed in this work is driven to completion in the presence of pyridine base (Pyr), which neutralizes the HCl liberated during condensation of the hydroxyl group with TMDP.…”
A useful method for quantifying concentrations of various hydroxyl group containing molecular species in biocrudes involves chemically converting species into nonionizable, P-functionalized derivatives independently observed and quantified by phosphorus-31 nuclear magnetic resonance ( 31 P NMR) spectroscopy. Full validation of this method requires improved understanding of its applicability to different biocrude matrixes. The limits of detection (LODs) and limits of quantitation (LOQs) for this method are herein determined for concentrations of hydroxyl group containing analytes, grouped by molecular class, within three different biocrude matrixes: a biocrude (BC) product, a fast pyrolysis (FP) product, and an artificial matrix (AM). Matrix water content, known to affect method sensitivity, varies from <1 to 18.31 wt %. Each matrix is used to prepare a series of samples spiked to varying concentrations with three hydroxyl group containing model compounds, which represent (aliphatic) alcohol, phenolic, and carboxylic acid analyte types. Samples are then phosphitylated with 2-chloro-4,4,5,5tetramethyl-1,3,2-dioxaphospholane to enable 31 P NMR spectroscopic determination of native hydroxyl analyte concentrations. LODs and LOQs are determined for each analyte type and for each matrix. Analytical precision is affected by matrix concentrations of interfering analytes and water. Among the matrixes examined, AM, which contains no hydroxyl analytes and has the lowest water content, expectedly exhibits the lowest LODs and LOQs. Matrix LODs range from 0.04 to 0.14 mmol of OH/g, while their LOQs range from 0.10 to 0.41 mmol of OH/g, with both sets of values generally increasing in the order AM < BC < FP.
“…In addition, Schiff et al found in the experiment that the quantitative information of the product derived from hydroxyl-functional compound and a phosphorylating reagent can be determined through 31 P NMR, and corresponding chemical shift of phosphorus in the derivatization product is significantly different. 34 It has been reported that an unprecedented analytical method-quantitative 31 P NMR was used to quantitatively characterize all functional groups by labelling of all unstable hydroxyls with a phosphorus-containing reagent. 35 A study of the Li Mi's research team on the chemical shifts of phosphorylated products from 54 different compounds and TMDP in 31 P NMR can provides valuable and precise spectral information for characterizing lignocellulose-based compounds.…”
“…In recent years we have had substantial success in utilizing reagents such as 1 as 31 P NMR spectroscopic tags for speciating and quantitating total phenolic contents in mixtures. − Here we report our progress in establishing the complementarity of RP HPLC and 31 P NMR spectroscopy in speciating and quantitating phenols in two coal liquefaction resids. …”
Two Illinois No. 6 coal liquids (SOH and ASOH) were separated into polar
and non-polar
fractions and the polar fractions were analyzed to identify the phenols
by RP HPLC in tandem
with 31P NMR spectroscopy of samples derivatized with
ClPOCMe2CMe2O
(1). The results
obtained from both methods complement one another quite well despite
numerous cases of more
than one phenol displaying equal retention times or the same
31P chemical shift when derivatized
with 1. The total amount of phenolic oxygen was
quantitatively determined by 31P NMR
spectroscopy for both coal liquids. The results agree very well
with values reported by others by
an FTIR method.
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