Detailed kinetic modeling of the thermal degradation of lignins

Faravelli, Tiziano; Frassoldati, Alessio; Migliavacca, G.; Ranzi, E.

doi:10.1016/j.biombioe.2009.10.018

Cited by 299 publications

(208 citation statements)

References 50 publications

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“…Cellulose content is set to 44% mass [20] for hardwood and softwood and the hemicellulose content is obtained by difference. The lignin composition (LIG-C, LIG-H and LIG-O) is calculated for the mean values for hardwood and softwood species reported by Faravelli et al [21]. Softwood lignin is richer in LIG-C due to its higher carbon content.…”

Section: Cellulosementioning

confidence: 99%

Application of a detailed biomass pyrolysis kinetic scheme to hardwood and softwood torrefaction

Anca-Couce

Obernberger

2016

Fuel

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Section: Cellulosementioning

confidence: 99%

Application of a detailed biomass pyrolysis kinetic scheme to hardwood and softwood torrefaction

Anca-Couce

Obernberger

2016

Fuel

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“…The background-subtracted signals are normalized for the VUV photon flux at each photon energy. Photoionization spectra are then constructed by integrating the three-dimensional data set first over CH + CH 3 …”

Section: Apparatusmentioning

confidence: 99%

“…Both dimethylketene and ethylketene (C 2 H 5 CHQCQO) are detected in ester flames. 10 Other C 4 H 6 O isomers include methyl vinyl ketone (H 2 CQCH(CO)CH 3 ) and 2-butenal (CH 3 CHQCHCHQO); all are identified as final products of glucose pyrolysis. 11 The likely thermodynamically favorable channels for the CH + acetone reaction are:…”

Section: Introductionmentioning

confidence: 99%

Formation of dimethylketene and methacrolein by reaction of the CH radical with acetone

Goulay

Derakhshan

Maher

et al. 2013

Phys. Chem. Chem. Phys.

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. (2013). Formation of dimethylketene and methacrolein by reaction of the CH radical with acetone. Physical Chemistry Chemical Physics, 15 (11), 4049-4058. Formation of dimethylketene and methacrolein by reaction of the CH radical with acetone AbstractThe reaction of the methylidyne radical (CH) with acetone ((CH3)2CO) is studied at room temperature and at a pressure of 4 Torr (533.3 Pa) using a multiplexed photoionization mass spectrometer coupled to the tunable vacuum ultraviolet synchrotron radiation of the Advanced Light Source at Lawrence Berkeley National Laboratory. The CH radicals are generated by 248 nm multiphoton photolysis of bromoform and react with acetone in an excess of helium and nitrogen gas flow. The main observed reaction exit channel is elimination of a hydrogen atom to form C4H6O isomers. Analysis of photoionization spectra identifies dimethylketene and methacrolein as the only H-elimination products. The best fit to the data gives branching ratios of 0.68 ± 0.14 for methacrolein and 0.32 ± 0.07 for dimethylketene. A methylketene spectrum measured here is used to reanalyze the photoionization spectrum obtained at m/z = 56 for the CH + acetaldehyde reaction, (Goulay et al., J. Phys. Chem. A, 2012, 116, 6091) yielding new H-loss branching ratios of 0.61 ± 0.12 for acrolein and 0.39 ± 0.08 for methylketene. The contribution from methyleneoxirane to the reaction product distribution is revised to be negligible. Coupled with additional product detection for the CD + acetone reaction, these observations pave the way for development of general set of reaction mechanisms for the addition of CH to compounds containing an acetyl subgroup. The reaction of the methylidyne radical (CH) with acetone ((CH 3 ) 2 CQO) is studied at room temperature and at a pressure of 4 Torr (533.3 Pa) using a multiplexed photoionization mass spectrometer coupled to the tunable vacuum ultraviolet synchrotron radiation of the Advanced Light Source at Lawrence Berkeley National Laboratory. The CH radicals are generated by 248 nm multiphoton photolysis of bromoform and react with acetone in an excess of helium and nitrogen gas flow. The main observed reaction exit channel is elimination of a hydrogen atom to form C 4 H 6 O isomers. Analysis of photoionization spectra identifies dimethylketene and methacrolein as the only H-elimination products.The best fit to the data gives branching ratios of 0.68 AE 0.14 for methacrolein and 0.32 AE 0.07 for dimethylketene. A methylketene spectrum measured here is used to reanalyze the photoionization spectrum obtained at m/z = 56 for the CH + acetaldehyde reaction, (Goulay et al., J. Phys. Chem. A, 2012, 116, 6091) yielding new H-loss branching ratios of 0.61 AE 0.12 for acrolein and 0.39 AE 0.08 for methylketene. The contribution from methyleneoxirane to the reaction product distribution is revised to be negligible. Coupled with additional product detection for the CD + acetone reaction, these observations pave the way for development of general set of reaction mechanisms for the additi...

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“…In this stage several degradation reactions occur, involved different E a values. According to Faravelli et al (2010) the first relevant radical initiation reaction in lignin involves the scission of C-O bond in the β-O-4 lignin structure forming phenoxy radicals. A bond energy of about 242,8 kJ.mol -1 , as proposed by Back (1989), allows the activation energy for this reaction in the gas phase.…”

Section: Degradation Kineticsmentioning

confidence: 99%

Assessment of the thermal behavior of lignins from softwood and hardwood species

Poletto

2017

Maderas, Cienc. tecnol.

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The thermal behavior of lignins from softwood and hardwood species has been investigated using thermogravimetry and differential scanning calorimetry. Klason Lignin from Pinus taeda and Klason lignin from Eucalyptus grandis were studied. The differential scanning calorimetry results showed that both Klason lignins studied presented similar glass transition temperature. Thermogravimetric results showed that the lignin degradation occurs in three stages. The Klason lignin of Pinus taeda is more thermally stable than Eucalyptus grandis, probably because of the higher thermal stability of the guaiacyl units in softwood lignin. The degradation of both lignins initiate by a diffusion process. However when the conversion values are higher than 0,1 the lignin degradation mechanism is a complex procedure and involves the degradation of a highly condensed aromatic structure formed at the previous degradation stages.

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Detailed kinetic modeling of the thermal degradation of lignins

Cited by 299 publications

References 50 publications

Application of a detailed biomass pyrolysis kinetic scheme to hardwood and softwood torrefaction

Application of a detailed biomass pyrolysis kinetic scheme to hardwood and softwood torrefaction

Formation of dimethylketene and methacrolein by reaction of the CH radical with acetone

Assessment of the thermal behavior of lignins from softwood and hardwood species

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