Thermochemistry of Hydroxyl and Hydroperoxide Substituted Furan, Methylfuran, and Methoxyfuran

Document Type

Article

Publication Date

6-15-2017

Abstract

Reaction pathways are influenced by thermochemical properties, species stability, and chemical kinetics. Understanding these factors allows for an understanding of the reaction paths and formation of intermediate species. Enthalpies of formation (ΔHf,298°), entropies (S298°), heat capacities (Cp(T)), oxygen-hydrogen (O-H), oxygen-oxygen (O-O), and (R-O) bond dissociation energies (BDEs) are reported for hydroxyl and hydroperoxide substituted furan, methylfuran, and methoxyfuran species. Standard enthalpies of formation for parent and radical species have been determined using density functional theory B3LYP/6-31G(d,p), B3LYP/6-311G(2d,2p), and M06-2X/6-31G(d,p) along with higher-level CBS-QB3 and CBS-APNO composite methods. Isodesmic work reactions were employed to improve accuracy by canceling error and show consistency between the levels of theory. Corresponding O-H and O-O BDEs are determined and compared to other similar structures. The stability of the furan moiety coupled with the double-bond-forming capability of the oxygen moiety results in a number of bond energies significantly lower than one might have expected. Substituted hydroperoxides are calculated to have ROO-H BDEs between 86.9 and 94.2 kcal mol-1, and their RO-OH BDEs show a large 49 kcal mol-1 range of -2.3-46.8 kcal mol-1. Substituted alcohols also show a wide 48 kcal mol-1 range with RO-H BDEs, ranging from 59.3 to 106.9 kcal mol-1. Bond lengths of parent and radical species are presented to highlight potential bonds of interest leading to furan ring opening. Group additivity is discussed, and groups for substituted furan, methylfuran, and methoxyfuran species are derived. Structures, moments of inertia, vibrational frequencies, and internal rotor potentials are calculated at the B3LYP/6-31G(d,p) density functional level and are used to determine the S298°and Cp(T) values. (Graph Presented).

Identifier

85021095187 (Scopus)

Publication Title

Journal of Physical Chemistry A

External Full Text Location

https://doi.org/10.1021/acs.jpca.7b02343

e-ISSN

15205215

ISSN

10895639

PubMed ID

28459571

First Page

4523

Last Page

4544

Issue

23

Volume

121

Fund Ref

Nanjing Institute of Technology

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