Ketene Formation From the Pyrolysis of Carbohydrates

Kang, John C.; Chen, Paul H.; Johnson, William R.

doi:10.1016/b978-0-12-637750-7.50019-4

Cited by 3 publications

(2 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thermochemical conversion of biomass generates a complex mixture that includes organic functional groups such as ketones, carboxylic acids, aldehydes, ketenes and cyclic ethers. [3][4][5][6] Despite their critical importance, mechanistic trends for the reaction of these primary products with combustion relevant radicals have not yet been fully developed.…”

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.

View full text Add to dashboard Cite

. (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...

show abstract

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.

View full text Add to dashboard Cite

show abstract

“…5,19,20,25,27,28 As discussed in sub-section 3.1.2, the acetic acid formation from GA was observed during pulsepyrolysis of GA. GA is known to dehydrate to ketene. 29 It is probable that, ketene rehydrate to form acetic acid, 30,31 as depicted in Fig. 6.…”

Section: Reaction Network Development Of Glucose Crackingmentioning

confidence: 99%

Hydrous pyrolysis of glucose using a rapid pulsed reaction technique

et al. 2023

View full text Add to dashboard Cite

show abstract

Thermogravimetric/mass spectrometric characterization of the thermal decomposition of (4‐O‐methyl‐D‐glucurono)‐D‐xylan

Simkovic

Várhegyi

Antal

et al. 1988

J of Applied Polymer Sci

View full text Add to dashboard Cite

SynopsisA thermogravimetric/mass spectrometric (TG/MS) system was used to characterize the thermolysis reactions of (4-O-methyl-D-g~ucurono)-D-xy~an. The mass spectrometric peaks, measured as function of time, were attributed to water, methanol, carbon monoxide, carbon dioxide, formaldehyde, formic acid, acetic acid, acetone, acrolein, 2-furaldehyde, and 3-hydroxy-2-penteno-1,5-lactone. The time derivative of the thermogravimetric curve (DTG) consisted of two partially overlapping peaks, indicating a multistep mechanism. The mass spectrometric intensities of the peaks assigned to methanol and 2-furaldehyde coincided with the first DTG peak, suggesting that the first DTG peak represents both dehydration and fragmentation pathways. Methanol, water, formyl group, and carbon dioxide contributed to both of the DTG peaks. This indicates that the dehydration, decarboxylation, and decarbonylation took place in two steps. The compounds observed only in the second DTG peak and later (acetone, formic acid, formaldehyde, acrolein, acetic acid, and 3-hydroxy-2-penteno-1,5-lactone) are probably products of reactions which occur after the collapse of the original polysaccharide structure.

show abstract

Ketene Formation From the Pyrolysis of Carbohydrates

Cited by 3 publications

References 17 publications

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

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

Hydrous pyrolysis of glucose using a rapid pulsed reaction technique

Thermogravimetric/mass spectrometric characterization of the thermal decomposition of (4‐O‐methyl‐D‐glucurono)‐D‐xylan

Contact Info

Product

Resources

About