Carbohydrate pyrolysis mechanisms from isotopic labeling

Paine, John B.; Pithawalla, Yezdi B.; Naworal, John D.; Thomas, Charles E.

doi:10.1016/j.jaap.2007.03.007

Cited by 91 publications

(83 citation statements)

References 22 publications

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“…Dehydrogenation to glyceraldehyde or dihydroxyacetone is another thermal decomposition mechanism and proceeds according to Equation (6).…”

Section: Non-equilibrium Productsmentioning

confidence: 99%

“…[12] Nevertheless, the reported selectivity to acrolein as a pyrolysis product of glycerol indicates that the kinetics for dehydration and dehydrogenation are competitive. [5,6] www.chemsuschem.org…”

Section: Non-equilibrium Productsmentioning

confidence: 99%

“…[5,6,21,24] Perhaps as a result of the great quantity of products that can form from glycerol, and an even greater number that can form under oxidative conditions, such studies are typically limited to two or three product species, such as acrolein, acetaldehyde, [5] and formaldehyde. [6] Selectivity to acrolein and acetaldehyde display high correlations over Pt, consistent with observations by Stein et al [5] These products are likely due to dehydration reactions observed in glycerol pyrolysis. [6] Nimlos et al modeled the thermal decomposition of glycerol, suggesting that acetaldehyde and acrolein occur from unimolecular dehydrations involving concerted cyclic reactions.…”

Section: Thermal Decomposition and Non-equilibrium Chemicalsmentioning

confidence: 99%

“…[5,6] Pyrolysis, gasification, and steam reforming of glycerol have been examined over noble metals. [7][8][9] Previous research has indicated that glycerol can be converted into syngas with high conversion over noble-metal catalysts.…”

Section: Introductionmentioning

confidence: 99%

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Autothermal Catalytic Partial Oxidation of Glycerol to Syngas and to Non‐Equilibrium Products

2009

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Glycerol, a commodity by-product of the biodiesel industry, has value as a fuel feedstock and chemical intermediate. It is also a simple prototype of sugars and carbohydrates. Through catalytic partial oxidation (CPOx), glycerol can be converted into syngas without the addition of process heat. We explored the CPOx of glycerol using a nebulizer to mix droplets with air at room temperature for reactive flash volatilization. Introducing this mixture over a noble-metal catalyst oxidizes the glycerol at temperatures over 600 degrees C in 30-90 ms. Rhodium catalysts produce equilibrium selectivity to syngas, while platinum catalysts produce mainly autothermal non-equilibrium products. The addition of water to the glycerol increases the selectivity to H(2) by the water gas shift reaction and reduces non-equilibrium products. However, water also quenches the reaction, resulting in a maximum in H(2) production at a steam/carbon ratio of 2:3 over a Rh-Ce catalyst. Glycerol without water produces a variety of chemicals over Pt, including methylglyoxal, hydroxyacetone, acetone, acrolein, acetaldehyde, and olefins.

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“…Dehydrogenation to glyceraldehyde or dihydroxyacetone is another thermal decomposition mechanism and proceeds according to Equation (6).…”

Section: Non-equilibrium Productsmentioning

confidence: 99%

Section: Non-equilibrium Productsmentioning

confidence: 99%

Section: Thermal Decomposition and Non-equilibrium Chemicalsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Autothermal Catalytic Partial Oxidation of Glycerol to Syngas and to Non‐Equilibrium Products

2009

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“…It was possibly the reason why the aromatic flavor component would dramatically decrease at high temperature according to previous Py-GC-MS analysis. 22,23 Scheme II shows the principal pyrolysis products of BGLU observed in PIMS study. The thermal decomposition of glycon moiety was almost the same both by Route 1 and Route 2 mode.…”

Section: Possible Pyrolysis Mechanism Of Bglumentioning

confidence: 99%

Photoionization Mass Spectrometry: A Useful Method to Evaluate the Pyrolysis Process of Glycoside Flavor Precursor

Ding¹,

Cai²,

Qi³

et al. 2011

J Chinese Chemical Soc

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The thermal decomposition behavior and the pyrolysis products of benzyl-2,3,4,6-tetra-O-acetyl-b-D-glucopyranoside (BGLU) were studied with synchrotron vacuum ultraviolet (VUV) photoionization mass spectrometry at temperatures of 300, 500 and 700°C at 0.062 Pa. Several pyrolysis products and intermediates were identified by the measurement of photoionization mass spectra at different photon energies. The results indicated that the primary decomposition reaction was the cleavage of O-glycosidic bond of the glycoside at low temperature, proven by the discoveries of benzyloxy radical (m/z = 107) and glycon radical (m/z = 331) in mass spectra. As pyrolysis temperature increased from 300 to 700°C, two possible pyrolytic modes were observed. This work reported an application of synchrotron VUV photoionization mass spectrometry in the study of the thermal decomposition of glycoside flavor precursor, which was expected to help understand the thermal decomposition mechanism of this type of compound. The possibility of this glycoside to be used as a flavor precursor in high temperature process was evaluated.

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