Cool-flame chemistry of the representative bio-hybrid fuel 1,3-dioxane

IF 6.2 2区工程技术 Q2 ENERGY & FUELS

Combustion and Flame Pub Date : 2025-10-17 DOI:10.1016/j.combustflame.2025.114545

Jiabiao Zou , Caroline Smith Lewin , Huanhuan Wang , Weiye Chen , Cheng Xie , Zhandong Wang , Jérémy Bourgalais , Olivier Herbinet , Frédérique Battin-Leclerc , Aamir Farooq

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引用次数: 0

Abstract

The low-temperature oxidation of 1,3-dioxane was systematically investigated in two atmospheric pressure jet-stirred reactors (JSRs) at temperatures ranging from 450 to 850 K and equivalence ratios ranging from 0.25 to 0.5. A suite of oxidation intermediates, including carbonyl compounds, conjugated olefins, cyclic ethers, and reactive hydroperoxides, were identified and quantified using synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) and gas chromatography (GC). The experiments reveal strong low-temperature reactivity and a pronounced negative temperature coefficient (NTC) behavior, that had not previously been reported for 1,3-dioxane to such an extent. A detailed kinetic model was developed to interpret the observed phenomena. Rate constants for hydrogen abstraction reactions by OH radicals, identified as the dominant fuel consumption pathways, are calculated using ab initio methods. The model also incorporates theoretically derived rate constants from the literature for key β-scission ring-opening reactions and first-stage oxygen addition pathways of three 1,3-dioxanyl radicals. These inclusions improve the model's predictive capability and highlight the complex cool-flame chemistry associated with 1,3-dioxane. Model validation against experimental datasets from this study and literature—including JSR oxidation, flow reactor pyrolysis and oxidation, and ignition delay time (IDT) measurements—demonstrates good agreement. Mechanistic insights reveal that the ether group in the 1,3-dioxane ring facilitates hydrogen abstraction at the ortho positions (e.g., methylene bridge and ortho–CH₂–) while suppressing abstraction at meta sites. These structural effects also influence intramolecular hydrogen shifts in ROO and OOQOOH radicals. Additionally, the presence of ring oxygen atoms weakens radical stabilization through inductive effects, promoting ring-opening reactions of R and QOOH species. Collectively, these factors contribute to the observed NTC behavior and the unique cool-flame characteristics of 1,3-dioxane.

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代表性生物混合燃料1,3-二氧六烷的冷焰化学

在两个常压喷射搅拌反应器（JSRs）中系统地研究了1,3-二恶烷在450 ~ 850 K温度和0.25 ~ 0.5当量比下的低温氧化反应。采用同步加速器真空紫外光电离质谱（SVUV-PIMS）和气相色谱（GC）对羰基化合物、共轭烯烃、环醚和活性氢过氧化物等氧化中间体进行了鉴定和定量。实验结果表明，1,3-二恶烷具有较强的低温反应活性和显著的负温度系数（NTC）行为，这是以前从未报道过的。建立了一个详细的动力学模型来解释所观察到的现象。氢氧根抽氢反应的速率常数被确定为主要的燃料消耗途径，用从头算方法计算。该模型还纳入了从文献中得到的β-键断开环反应和三个1,3-二氧酰自由基的第一阶段氧加成途径的理论推导速率常数。这些内含物提高了模型的预测能力，并突出了与1,3-二恶烷相关的复杂冷火焰化学。根据本研究和文献的实验数据集（包括JSR氧化、流动反应器热解和氧化以及点火延迟时间（IDT）测量）对模型进行验证，结果显示出良好的一致性。机理分析表明，1,3-二氧六环中的醚基团促进邻位（如亚甲基桥和邻ch 2 -）的氢提取，而抑制间位的氢提取。这些结构效应也影响分子内ROO和OOQOOH自由基中的氢位移。此外，环氧原子的存在通过诱导效应减弱自由基的稳定性，促进R和QOOH的开环反应。总的来说，这些因素有助于观察到的NTC行为和1,3-二恶烷独特的冷焰特性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Combustion and Flame 工程技术-工程：化工

CiteScore

9.50

自引率

20.50%

发文量

631

审稿时长

3.8 months

期刊介绍： The mission of the journal is to publish high quality work from experimental, theoretical, and computational investigations on the fundamentals of combustion phenomena and closely allied matters. While submissions in all pertinent areas are welcomed, past and recent focus of the journal has been on: Development and validation of reaction kinetics, reduction of reaction mechanisms and modeling of combustion systems, including: Conventional, alternative and surrogate fuels; Pollutants; Particulate and aerosol formation and abatement; Heterogeneous processes. Experimental, theoretical, and computational studies of laminar and turbulent combustion phenomena, including: Premixed and non-premixed flames; Ignition and extinction phenomena; Flame propagation; Flame structure; Instabilities and swirl; Flame spread; Multi-phase reactants. Advances in diagnostic and computational methods in combustion, including: Measurement and simulation of scalar and vector properties; Novel techniques; State-of-the art applications. Fundamental investigations of combustion technologies and systems, including: Internal combustion engines; Gas turbines; Small- and large-scale stationary combustion and power generation; Catalytic combustion; Combustion synthesis; Combustion under extreme conditions; New concepts.