Here, the nascent steps in the pyrolysis of the lignin components salicylaldehyde (o-HOC6H4CHO) and catechol (o-HOC6H4OH) were studied in a set of heated microreactors. The microreactors are small (roughly 1 mm ID x 3 cm long); transit times through the reactors are about 100 us. Temperatures in the microreactors can be as high as 1600 K, and pressures are typically a few hundred torr. The products of pyrolysis are identified by a combination of photoionization mass spectrometry, photoelectron photoion concidence mass spectroscopy, and matrix isolation infrared spectroscopy. The main pathway by which salicylaldehyde decomposes is a concerted fragmentation: o-HOC6H4CHO (+ M) → H2 + CO + C5H4-C-O (fulveneketene). At temperatures above 1300 K, fulveneketene loses CO to yield a mixture of HC=C-C=C-CH3, HC=C-CH2-C=CH, and HC=C-CH-C-CH2. These alkynes decompose to a mixture of radicals (HC=C-C=C-CH2 and HC=C-CH-C=CH) and H atoms. H-atom chain reactions convert salicylaldehyde to phenol: o-HOC6H4CHO + H → C6H5OH + CO + H. Catechol has similar chemistry to salicylaldehyde. Electrocyclic fragmentation produces water and fulveneketene: o-HOC6H4OH (+ M) → H2O + C5H4-C-O. These findings have implications for the pyrolysis of lignin itself.
Ormond, Thomas K., et al. "Thermal Decompositions of the Lignin Model Compounds: Salicylaldehyde and Catechol." Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory, vol. 122, no. 28, Jun. 2018. https://doi.org/10.1021/acs.jpca.8b03201
Ormond, Thomas K., Baraban, Joshua H., Porterfield, Jessica P., Scheer, Adam M., Hemberger, Patrick, Troy, Tyler P., Ahmed, Musahid, Nimlos, Mark R., Robichaud, David J., Daily, John W., & Ellison, G. Barney (2018). Thermal Decompositions of the Lignin Model Compounds: Salicylaldehyde and Catechol. Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory, 122(28). https://doi.org/10.1021/acs.jpca.8b03201
Ormond, Thomas K., Baraban, Joshua H., Porterfield, Jessica P., et al., "Thermal Decompositions of the Lignin Model Compounds: Salicylaldehyde and Catechol," Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory 122, no. 28 (2018), https://doi.org/10.1021/acs.jpca.8b03201
@article{osti_1461365,
author = {Ormond, Thomas K. and Baraban, Joshua H. and Porterfield, Jessica P. and Scheer, Adam M. and Hemberger, Patrick and Troy, Tyler P. and Ahmed, Musahid and Nimlos, Mark R. and Robichaud, David J. and Daily, John W. and others},
title = {Thermal Decompositions of the Lignin Model Compounds: Salicylaldehyde and Catechol},
annote = {Here, the nascent steps in the pyrolysis of the lignin components salicylaldehyde (o-HOC6H4CHO) and catechol (o-HOC6H4OH) were studied in a set of heated microreactors. The microreactors are small (roughly 1 mm ID x 3 cm long); transit times through the reactors are about 100 us. Temperatures in the microreactors can be as high as 1600 K, and pressures are typically a few hundred torr. The products of pyrolysis are identified by a combination of photoionization mass spectrometry, photoelectron photoion concidence mass spectroscopy, and matrix isolation infrared spectroscopy. The main pathway by which salicylaldehyde decomposes is a concerted fragmentation: o-HOC6H4CHO (+ M) → H2 + CO + C5H4-C-O (fulveneketene). At temperatures above 1300 K, fulveneketene loses CO to yield a mixture of HC=C-C=C-CH3, HC=C-CH2-C=CH, and HC=C-CH-C-CH2. These alkynes decompose to a mixture of radicals (HC=C-C=C-CH2 and HC=C-CH-C=CH) and H atoms. H-atom chain reactions convert salicylaldehyde to phenol: o-HOC6H4CHO + H → C6H5OH + CO + H. Catechol has similar chemistry to salicylaldehyde. Electrocyclic fragmentation produces water and fulveneketene: o-HOC6H4OH (+ M) → H2O + C5H4-C-O. These findings have implications for the pyrolysis of lignin itself.},
doi = {10.1021/acs.jpca.8b03201},
url = {https://www.osti.gov/biblio/1461365},
journal = {Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory},
issn = {ISSN 1089-5639},
number = {28},
volume = {122},
place = {United States},
publisher = {American Chemical Society},
year = {2018},
month = {06}}
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Bioenergy Technologies Office (EE-3B); USDOE Office of Science (SC)
Grant/Contract Number:
AC02-05CH11231; AC36-08GO28308
OSTI ID:
1461365
Alternate ID(s):
OSTI ID: 1532312
Report Number(s):
NREL/JA--5100-71987
Journal Information:
Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory, Journal Name: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory Journal Issue: 28 Vol. 122; ISSN 1089-5639
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 610, Issue 2https://doi.org/10.1016/j.nima.2009.08.069
Journal Article
·
Tue Mar 15 20:00:00 EDT 2016
· Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory
·OSTI ID:1464135
