About This Article
This is an AI-generated summary of a research paper. The original authors did not write or review this article. See full disclosure ↓
Overview
A computational investigation of the kinetic mechanisms governing reactions between hydroxyl radicals and gamma-heptalactone, a volatile organic compound relevant to atmospheric chemistry. The study employs quantum chemical methods to characterize the potential energy surface and predict reaction rate coefficients across a physiologically relevant temperature range.
Methods and approach
The potential energy surface was computed using coupled cluster theory with single and double excitations and perturbative triple excitations (CCSD(T)) at the 6-311++G(d,p) basis set level, with geometry optimization performed at the M06-2X/6-311++G(d,p) level. Rate coefficients were derived from transition state theory incorporating tunneling corrections. Calculations covered the temperature range of 260-420 K at atmospheric pressure, with validation against experimental measurements at room temperature.
Results
The computed rate coefficient at 298 K and 1 atm pressure is 6.37 × 10-12 cm3 molecule-1 s-1, demonstrating agreement with experimental values. Temperature-dependent rate coefficients are parameterized by the expression k = 5.79 × 10-23 × T3.6 × exp(1464.4/T) for the specified temperature range. The dominant reaction pathway involves hydrogen atom abstraction from the C5 carbon position adjacent to the lactone oxygen, forming the radical intermediate IM3. Secondary atmospheric oxidation of IM3 yields succinic anhydride, peroxy n-butyryl nitrate, and peroxy propionyl nitrate as the primary products.
Implications
The mechanistic characterization of gamma-heptalactone oxidation elucidates the role of this compound in atmospheric secondary organic aerosol formation. The validated kinetic parameters enable improved representation of lactone chemistry in regional and global atmospheric models. The preferential abstraction pathway at the C5 position provides structural insight applicable to predicting oxidation mechanisms of analogous cyclic ether compounds in the atmosphere.
Disclosure
- Research title: Kinetic Study of OH Radicals’ Reactions with Gamma-Heptalactone in the Atmosphere
- Authors: Benni Du, Jingwen Ni, Weichao Zhang
- Publication date: 2026-02-23
- DOI: https://doi.org/10.1021/acsearthspacechem.6c00002
- OpenAlex record: View
- Image credit: Photo by Innovalabs on Pixabay (Source • License)
- Disclosure: This post is an AI-generated summary of a research work. It was prepared by an editor. The original authors did not write or review this post.