In this 13-part series of articles, The Combustion Institute recognizes the 2023 Distinguished Papers selected from among the scientific papers presented during the 39th International Symposium on Combustion. Congratulations to Luna Pratali Maffei, Matteo Pelucchi, Tiziano Faravelli, and Carlo Cavallotti for winning the DPA in the Gas-Phase Reaction Kinetics colloquium.

When asked why they chose to conduct the research in their paper, “Theoretical kinetics of HO2 + C5H5: A missing piece in cyclopentadienyl radical oxidation reactions,” Luna Pratali Maffei, representing her group, said that they focused on gas-phase precursors of soot. They strive to understand the reactions in particulate matter oxidation. To understand their behavior, they conducted a fundamental accurate study of a relevant oxidation reaction for a structure that is a simple model system for larger structures of the same kind, often found in larger particles.

The concentration of cyclopentadienyl radical, which is an important precursor of large aromatics and therefore soot, is sensitive to the reaction that was studied for this paper. Among oxidation reactions of cyclopentadienyl radical, this reaction was very poorly assessed in the literature. These scientists conducted successful research in determining accurate kinetic behavior of the system and the products formed.

There are models in existence for the combustion of conventional and novel fuels into which the research for this paper can be readily integrated. The behavior of the specific structure that was studied here (as well as larger ones that have similar chemical functionality), can be described in a more physically accurate manner with the help of this investigation.

The long-term impact of the study by Pratali Maffei, Pelucchi, Faravelli, and Cavallotti is beneficial as it can pave the way to the development of novel biofuels and e-fuels without the need for numerous expensive experimental campaigns. Kinetic simulations with the models updated with the findings of this work aid in determining combustion properties, the global warming potential, and the pollutant formation of both conventional and novel fuels.

The benefits of this recognized study are several. The methodologies used in the work are useful for generic gas-phase chemical reactions and allow for the integration into both more detailed and more macroscopic modeling approaches. Therefore, the study benefits those working on theoretical calculations of gas phase reactions. They also provide a connection to the world of macroscopic kinetic simulations which would appeal to researchers with a more engineering-like background who may prefer to work with relatively simple models.

Research in Theoretical Kinetics of HO2 + C5H5 began in early 2021 at Politecnico di Milano in Italy and was completed about 10 months later in mid-2022.

Over 1,500 papers were submitted to the 39th International Symposium on Combustion. All papers were categorized into one of 13 colloquia, and then distributed to Colloquium Coordinators and Co-Chairs. Each paper received at least three reviews from qualified individuals through the peer-   review process. Less than 50 percent of the papers submitted were accepted for presentation.

Following the symposium, one paper presented in each colloquium is awarded the distinction of Distinguished Paper. Visit here to view the presentation. The 13 Distinguished Papers undergo committee review for consideration for the Silver Combustion Medal. A paper selected for this honor exemplifies quality, achievement, and significance to advance a field of combustion science, and will be awarded during the 40th International Symposium in Milan, Italy.