A detailed chemical kinetic model for pyrolysis of the lignin model compound chroman

Bland, James R.; Silva, Gabriel da

doi:10.3934/environsci.2013.1.12

Cited by 10 publications

(13 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Conversion of 1 into 6 + 7 is akin to the pyrolysis of a chroman ring. Chroman pyrolysis occurs through a retro Diels-Alder reaction to produce orthoquinone methide and ethane by C-C and C-O bond cleavage in the dihydropyran ring (21). Employing gas-phase M06-2X/6-311G (d,p) calculations, the TS energy barrier for the formation of 6 from 1 was determined to be 58.8 kcal/mol (SI Appendix, Fig.…”

Section: Significancementioning

confidence: 99%

Potential for release of pulmonary toxic ketene from vaping pyrolysis of vitamin E acetate

O’Shea

2020

Proc. Natl. Acad. Sci. U.S.A.

108

View full text Add to dashboard Cite

A combined analytical, theoretical, and experimental study has shown that the vaping of vitamin E acetate has the potential to produce exceptionally toxic ketene gas, which may be a contributing factor to the upsurge in pulmonary injuries associated with using e-cigarette/vaping products. Additionally, the pyrolysis of vitamin E acetate also produces carcinogen alkenes and benzene for which the negative long-term medical effects are well recognized. As temperatures reached in vaping devices can be equivalent to a laboratory pyrolysis apparatus, the potential for unexpected chemistries to take place on individual components within a vape mixture is high. Educational programs to inform of the danger are now required, as public perception has grown that vaping is not harmful.

show abstract

Section: Significancementioning

confidence: 99%

Potential for release of pulmonary toxic ketene from vaping pyrolysis of vitamin E acetate

O’Shea

2020

Proc. Natl. Acad. Sci. U.S.A.

108

View full text Add to dashboard Cite

show abstract

Section: Resultsmentioning

confidence: 99%

“…The barrier height for this process, at 57.1 kcal/mol, is considerably lower than those leading to the direct production of ketene. This reaction mechanism is common to the chroman functional group [ 18 , 19 ], and has been proposed as the dominant initial step in VEA decomposition [ 9 ]. For this key reaction we tested the effect that the aliphatic chain length in the model compound has on the barrier height, with the results shown in S1 Fig in S1 File .…”

Section: Resultsmentioning

confidence: 99%

“…In the other two channels, 1,3-and 1,7-H shifts to an oxygen atom (TS2Q) and to the methylene group (TS3Q) transpire, with respective barrier heights of 61.7 and 56.0 kcal/mol. Note also that the quinone methide moiety itself can decompose via ejection of CO, although this requires substantially higher barriers and will be uncompetitive with ketene formation [19,20].…”

Section: Plos Onementioning

confidence: 99%

See 1 more Smart Citation

Does ‘Dry Hit’ vaping of vitamin E acetate contribute to EVALI? Simulating toxic ketene formation during e-cigarette use

Narimani

Silva

2020

PLoS ONE

Self Cite

View full text Add to dashboard Cite

Vitamin E acetate (VEA) is strongly linked to the outbreak of electronic-cigarette or vaping product use-associated lung injury (EVALI). It has been proposed that VEA decomposition to ketene-a respiratory poison that damages lungs at low ppm levels-may play a role in EVALI. However, there is no information available on the temperature at which VEA decomposes and how this correlates with the vaping process. We have studied the temperaturedependent kinetics of VEA decomposition using quantum chemical and statistical mechanical modelling techniques, developing a chemical kinetic model of the vaping process. This model predicts that, under typical vaping conditions, the use of VEA contaminated e-cigarette products is unlikely to produce ketene at harmful levels. However, at the high temperatures encountered at low e-cigarette product levels, which produce 'dry hits', ketene concentrations are predicted to reach acutely toxic levels in the lungs (as high as 30 ppm). We therefore hypothesize that dry hit vaping of e-cigarette products containing VEA contributes to EVALI.

show abstract

“…One of advantages of slow pyrolysis is to allow adjustment of residence time of gas to determine yields of pyrolysis. Using slow pyrolysis in biomass pyrolysis with longer residence time of gas in the reactor, lower molecular weight will be increased 13) . Shorter residence time in seconds is required to suppress secondary pyrolysis and enhance yield of oil 14) .…”

Section: Introductionmentioning

confidence: 99%

Yield and Composition of Bio-oil from Co-Pyrolysis of Corn Cobs and Plastic Waste of HDPE in a Fixed Bed Reactor

Supramono

Kusrini

Yuana

2016

J. Jpn. Inst. Energy

View full text Add to dashboard Cite

Pyrolysis, a thermal cracking process in inert environment, may be used to produce bio-oil from biomass and plastic waste thus accommodating the use of renewable energy. Abundant amount of biomass wastes in Indonesia are not utilised and plastic wastes are not well processed for clean environment. The aim of present work was to evaluate effect of mass ratio of plastic material to biomass in the feed blend of corn cobs and high density polyethylene (HDPE) of co-pyrolysis on bio-oil yield and chemical composition of bio-oil products. The heating rate of the co-pyrolysis was kept low and residence time was in the order of seconds to accommodate high yield of oil originating from plastic pyrolysis. Corn cobs have high cellulose and hemicellulose content (84%) which is potential to produce bio-oil. The pyrolysis was conducted in a laboratory-scale using a fixed bed reactor with final temperature of 500 °C, heating rate 5 °C/min, flow rate N2 750 mL/min, total weight of biomass and plastic material of 20 g, and hold time after peak temperature of 30 min. Mass ratio of plastics to biomass in the feed blend was varied 0:100, 25:75, 50:50, 75:25 and 100:0. It was found that by increasing HDPE content up to 100% in the feed blend above, the yields of bio-oil decreased, i.e. 28.05, 21.55, 14.55, 9.5, and 6.3 wt%, respectively. Furthermore, for the same variation of the mass ratio, yields of the non-oxygenate mixture of paraffins, olefins and cycloalkanes contained in bio-oil increased, i.e. 0, 28.35, 40.75, 47.17, and 67.05 wt%, respectively. Analysis of the synergetic effect indicates that this effect did work effectively both in bio-oil and non-oxygenate yields due to improper conductive heat transfer from N 2 gas to melting plastics, which contained biomass particles. By increasing composition of HDPE in the feed blend, viscosity and pH of bio-oil changed approaching to those of commercial diesel oil.

show abstract

A detailed chemical kinetic model for pyrolysis of the lignin model compound chroman

Cited by 10 publications

References 23 publications

Potential for release of pulmonary toxic ketene from vaping pyrolysis of vitamin E acetate

Potential for release of pulmonary toxic ketene from vaping pyrolysis of vitamin E acetate

Does ‘Dry Hit’ vaping of vitamin E acetate contribute to EVALI? Simulating toxic ketene formation during e-cigarette use

Yield and Composition of Bio-oil from Co-Pyrolysis of Corn Cobs and Plastic Waste of HDPE in a Fixed Bed Reactor

Contact Info

Product

Resources

About