# Gas-Phase Formation of Trioxy Acid via OH-Initiated Aldehyde Oxidation under Atmospheric Conditions

**Authors:** Emelda Ahongshangbam, Avinash Kumar, Shawon Barua, Melissa Meder, Matti Rissanen, Nanna Myllys

PMC · DOI: 10.1021/acs.jpclett.5c03582 · The Journal of Physical Chemistry Letters · 2026-01-16

## TL;DR

A new compound called trioxy acid is formed when certain radicals react under atmospheric conditions, which could impact chemical processes in the air.

## Contribution

The study identifies the gas-phase formation of trioxy acid via OH-initiated oxidation of aldehydes under atmospheric conditions.

## Key findings

- Trioxy acid (RC(O)O3H) is formed from benzaldehyde-derived acyl peroxy radicals and OH radicals.
- The formation occurs under atmospherically relevant conditions using flow reactor experiments and chemical ionization mass spectrometry.
- Quantum chemistry supports the investigation of reaction channels leading to trioxy acid formation.

## Abstract

The formation of a new carbonyl compound containing three
linearly
bonded oxygen atoms attached to the carbonyl carbon with a chemical
formula of RC­(O)­O3H (trioxy acid) has been detected. The
trioxy acid is formed in the reaction of benzaldehyde-derived acyl
peroxy radicals and OH radicals under atmospherically relevant conditions.
We employed flow reactor experiments with chemical ionization mass
spectrometry, supported by quantum chemistry, to investigate the competitive
reaction channels of acyl peroxy radicals formed during OH-initiated
oxidation of aldehydes. While the role of trioxy acid in oxidation
chemistry and cluster formation is not understood, this study provides
insights in their formation and stability under atmospherically relevant
conditions.

## Linked entities

- **Chemicals:** benzaldehyde (PubChem CID 240)

## Full-text entities

- **Genes:** PMAIP1 (phorbol-12-myristate-13-acetate-induced protein 1) [NCBI Gene 5366] {aka APR, NOXA}
- **Chemicals:** BP (MESH:C038809), carbon (MESH:D002244), Th (MESH:D013910), toluene (MESH:D014050), unsaturated hydrocarbons (MESH:D006838), alpha-pinene (MESH:C005451), C7H14O (-), D (MESH:D003903), isoprene (MESH:C005059), nitrate (MESH:D009566), PAN (MESH:C041728), O2 (MESH:D010100), OH (MESH:C031356), H (MESH:D006859), Aldehyde (MESH:D000447), benzaldehyde (MESH:C032175), tetramethylethylene (MESH:C040216), trimethylamine (MESH:C023336), dimethyl sulfide (MESH:C004784), D2O (MESH:D017666), Hg (MESH:D008628), 1-butene (MESH:C058602), O3 (MESH:D010126), hydroxyl radicals (MESH:D017665), acetic acid (MESH:D019342), Bromide (MESH:D001965), H2O2 (MESH:D006861), water (MESH:D014867), ketones (MESH:D007659)

## Full text

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## Figures

7 figures with captions in the complete paper: https://tomesphere.com/paper/PMC12862793/full.md

## References

20 references — full list in the complete paper: https://tomesphere.com/paper/PMC12862793/full.md

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Source: https://tomesphere.com/paper/PMC12862793