DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Broadband Microwave Spectroscopy of 2-Furanyloxy Radical: Primary Pyrolysis Product of the Second-Generation Biofuel 2-Methoxyfuran

Journal Article · · Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory

Broadband microwave spectra over the 2–18 GHz range have been recorded for the resonance-stabilized 2-furanyloxy radical, formed in the first step of pyrolysis of the second-generation biofuel 2-methoxyfuran by methyl loss. Using a flash pyrolysis source attached to a pulsed valve, a 0.7% mixture of 2-methoxyfuran in argon was pyrolyzed at a series of temperatures ranging from 300 to 1600 K. Subsequent cooling in a supersonic expansion produced rotational temperatures of ~2 K in the interrogation region. Using chirped-pulse Fourier transform microwave (CP-FTMW) methods, combined with strong-field coherence breaking (SFCB), a set of transitions due to the radical were identified and assigned. The experimental rotational constants (A = 8897.732(93), B = 4019.946(24), C = 2770.321(84)), centrifugal distortion constants, and spin-rotation coupling constants have been determined for the radical and compared with ab initio predictions at the CCSD(T) level of theory. Compared to the 2-methoxyfuran precursor, the 2-furanyloxy radical has allylic C–C bond lengths intermediate between single and double bonds, a shortened C(5)–O(6) bond characteristic of partial double-bond character, and an O(1)–C(5)–O(6) bond angle of 121°, which resembles the O–C–O angle of an ester. Atomic spin densities extracted from the calculations confirm that the 2-furanyloxy radical is best viewed as a carbon-centered allylic lactone radical, with 80% of the spin density on the two allylic carbons and 20% on the pendant O(6) atom.

Research Organization:
Purdue Univ., West Lafayette, IN (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
FG02-96ER14656; FG02-07ER15885
OSTI ID:
1465211
Alternate ID(s):
OSTI ID: 1508607
Journal Information:
Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory, Vol. 122, Issue 34; ISSN 1089-5639
Publisher:
American Chemical SocietyCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 13 works
Citation information provided by
Web of Science

References (27)

Natural products as biofuels and bio-based chemicals: fatty acids and isoprenoids journal January 2015
Global land-use implications of first and second generation biofuel targets journal October 2011
Potential routes for thermochemical biorefineries journal April 2013
Furfural-A Promising Platform for Lignocellulosic Biofuels journal December 2011
Bio-oils Upgrading for Second Generation Biofuels journal January 2013
Chirped-pulse millimeter-wave spectroscopy for dynamics and kinetics studies of pyrolysis reactions journal January 2014
A chirped-pulse Fourier-transform microwave/pulsed uniform flow spectrometer. II. Performance and applications for reaction dynamics journal December 2014
Dissociation Pathways of 2,3-Dihydrofuran Measured by Chirped-Pulse Fourier Transform Microwave Spectroscopy journal April 2010
Chirped-Pulse Fourier Transform Microwave Spectroscopy Coupled with a Flash Pyrolysis Microreactor: Structural Determination of the Reactive Intermediate Cyclopentadienone journal June 2014
Pseudo-equilibrium geometry of HNO determined by an E-Band CP-FTmmW spectrometer journal July 2017
Structure and Thermochemical Properties of 2-Methoxyfuran, 3-Methoxyfuran, and Their Carbon-Centered Radicals Using Computational Chemistry journal August 2010
A Quantum Chemical Study of the Abnormal Reactivity of 2-Methoxyfuran: QUANTUM CHEMICAL STUDY OF THE ABNORMAL REACTIVITY OF 2-METHOXYFURAN journal June 2013
Pyrolysis Pathways of the Furanic Ether 2-Methoxyfuran journal August 2015
Computational Study of the Mechanisms for the Reaction of O 2 ( 3 Σ g ) with Aromatic Radicals journal October 1999
Flash pyrolytic production of rotationally cold free radicals in a supersonic jet. Resonant multiphoton spectrum of the 3p2A2" .rarw. X2A2" origin band of methyl journal May 1986
The properties of a micro-reactor for the study of the unimolecular decomposition of large molecules journal September 2014
Broadband multi-resonant strong field coherence breaking as a tool for single isomer microwave spectroscopy journal September 2016
General contraction of Gaussian basis sets. I. Atomic natural orbitals for first‐ and second‐row atoms journal April 1987
Calculation of fundamental frequencies for small polyatomic molecules: a comparison between correlation consistent and atomic natural orbital basis sets journal May 2013
Vibration–Rotation Structure in Asymmetric- and Symmetric-Top Molecules book January 1972
Gaussian basis sets for use in correlated molecular calculations. V. Core‐valence basis sets for boron through neon journal September 1995
First-Principles Calculation of Electron Spin-Rotation Tensors journal September 2010
Conformer-specific microwave spectroscopy of 3-phenylpropionitrile by strong field coherence breaking journal July 2018
The fitting and prediction of vibration-rotation spectra with spin interactions journal August 1991
Propargyl Radical:  Ab Initio Anharmonic Modes and the Polarized Infrared Absorption Spectra of Matrix-Isolated HCCCH 2 journal May 2005
Electron spin resonance studies of vinyl, propargyl, and butatrienyl radicals isolated in argon matrices journal August 1972
Differential Polarization of Spin and Charge Density in Substituted Phenoxy Radicals journal July 2009

Cited By (4)

Multiplexed characterization of complex gas-phase mixtures combining chirped-pulse Fourier transform microwave spectroscopy and VUV photoionization time-of-flight mass spectrometry journal September 2018
Propagating molecular rotational coherences through single-frequency pulses in the strong field regime journal August 2019
Strong-field coherence breaking as a tool for identifying methyl rotor states in microwave spectra: 2-hexanone journal July 2019
An Experimental and Theoretical Investigation of 1-Butanol Pyrolysis journal May 2019

Figures / Tables (6)