Formation of Gas-Phase Hydrogen Peroxide via Multiphase Ozonolysis of Unsaturated Lipids

Zhou, Zilin; Abbatt, Jonathan P. D.

doi:10.1021/acs.estlett.0c00757

Cited by 32 publications

(52 citation statements)

References 64 publications

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“…A compound that closely resembles fatty acid residues in mono-unsaturated lipids is methyl oleate, which showed an H 2 O 2 yield of 17% and was taken as a reference for this study . The exact yield of H 2 O 2 will also depend on the water content in the lipid layer of the ELF, which determines Criegee intermediate fate, and warrants further investigation. , …”

Section: Results and Discussionmentioning

confidence: 99%

“…43 A compound that closely resembles fatty acid residues in mono-unsaturated lipids is methyl oleate, which showed an H 2 O 2 yield of 17% and was taken as a reference for this study. 72 The exact yield of H 2 O 2 will also depend on the water content in the lipid layer of the ELF, which determines Criegee intermediate fate, and warrants further investigation. 43,72 Compared to momentary concentrations of individual ROS, which span 10−12 orders of magnitude (Figure 2a), the individual gross chemical productions are within about 2 S4).…”

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confidence: 99%

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Hydroxyl Radical Production by Air Pollutants in Epithelial Lining Fluid Governed by Interconversion and Scavenging of Reactive Oxygen Species

Lelieveld

Wilson

Dovrou

et al. 2021

Environ. Sci. Technol.

104

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Air pollution is a major risk factor for human health. Chemical reactions in the epithelial lining fluid (ELF) of the human respiratory tract result in the formation of reactive oxygen species (ROS), which can lead to oxidative stress and adverse health effects. We use kinetic modeling to quantify the effects of fine particulate matter (PM2.5), ozone (O 3 ), and nitrogen dioxide (NO 2 ) on ROS formation, interconversion, and reactivity, and discuss different chemical metrics for oxidative stress, such as cumulative production of ROS and hydrogen peroxide (H 2 O 2 ) to hydroxyl radical (OH) conversion. All three air pollutants produce ROS that accumulate in the ELF as H 2 O 2 , which serves as reservoir for radical species. At low PM2.5 concentrations (<10 μg m −3 ), we find that less than 4% of all produced H 2 O 2 is converted into highly reactive OH, while the rest is intercepted by antioxidants and enzymes that serve as ROS buffering agents. At elevated PM2.5 concentrations (>10 μg m −3 ), however, Fenton chemistry overwhelms the ROS buffering effect and leads to a tipping point in H 2 O 2 fate, causing a strong nonlinear increase in OH production. This shift in ROS chemistry and the enhanced OH production provide a tentative mechanistic explanation for how the inhalation of PM2.5 induces oxidative stress and adverse health effects.

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Section: Results and Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Hydroxyl Radical Production by Air Pollutants in Epithelial Lining Fluid Governed by Interconversion and Scavenging of Reactive Oxygen Species

Lelieveld

Wilson

Dovrou

et al. 2021

Environ. Sci. Technol.

104

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“…We do not include reaction of the CI with carboxylic acids in this aqueous system, because available experimental evidence suggests that this pathway is not observed in the presence of large water concentations. 78,79 Thus, our assumptions about the fate of the CI do not alter the overall decay rate of AA, which is the main focus of this study.…”

Section: Bulk Reactionmentioning

confidence: 99%

Coupled interfacial and bulk kinetics govern the timescales of multiphase ozonolysis reactions

Willis

Wilson

2022

Preprint

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Chemical transformations in aerosol impact the lifetime of particle-phase species, the fate of atmospheric pollutants, and both climate and health-relevant aerosol properties. Timescales for multiphase reactions of ozone in atmospheric aqueous phases are governed by coupled kinetic processes between the gas-phase, the particle interface and its bulk, which respond dynamically to reactive consumption of O3. However, models of atmospheric aerosol reactivity often do not account for the coupled nature of multiphase processes. To examine these dynamics, we use new and prior experimental observations of aqueous droplet reaction kinetics, including three systems with a range of surface affinities and ozonolysis rate coefficients (trans-aconitic acid (C6H6O6), maleic acid (C4H4O4) and sodium nitrite (NaNO2)). Using literature rate coefficients and thermodynamic properties, we constrain a simple two-compartment stochastic kinetic model, which resolves the interface from the particle bulk and represents O3 partitioning, diffusion and reaction as a coupled kinetic system. Our kinetic model accurately predicts decay kinetics across all three systems, demonstrating that both the thermodynamic properties of O3 and the coupled kinetic and diffusion processes are key to making accurate predictions. An enhanced concentration of adsorbed O3, compared to gas and bulk phases, is rapidly maintained and remains constant even as O3 is consumed by reaction. Multiphase systems dynamically seek to achieve equilibrium in response to reactive O3 loss, but this is hampered at solute concentrations relevant to aqueous aerosol by the rate of O3 arrival in the bulk by diffusion. As a result, bulk-phase O3 becomes depleted from its Henry’s Law solubility. This bulk-phase O3 depletion limits reaction timescales for relatively slow-reacting organic solutes with low interfacial affinity (i.e., trans-aconitic and maleic acids, with krxn ~ 10^3 - 104 M-1 s-1), which is in contrast to fast-reacting solutes with higher surface affinity (i.e., nitrite, with krxn ~ 10^5 M-1 s-1) where surface reactions strongly impact observed decay kinetics.

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“…In the latter case, a variety of products can be formed such as epoxides, diols, aldehydes, ketones, and carboxylic mono- and diacids, depending on the oxidant, catalyst, and reaction conditions. Ozonolysis, both in the presence or absence of a metal promoter, is the most industrially applied process and produces aldehydes and carboxylic acids with very good yields (over 80%) but has drawbacks such as ozone toxicity and production costs. − High performance is shown by ruthenium tetroxide RuO 4 formed in situ in a biphasic system under ultrasound technique using a catalytic amount of RuCl 3 or RuO 2 : this procedure, however, needs a stoichiometric supply of co-oxidants such as NaIO 4 , HIO 4 , NaClO, NaBrO 3 , or CH 3 CO 3 H that must be regenerated via an electrochemical process . Hydrogen peroxide is widely used in epoxidation reactions and in any case does not over-oxidize aldehydes into carboxylic acids by itself but needs metal assistance in the form of an Fe-complex, molybdenum peroxo-complex, or vanadium catalyst followed by the cleavage of the diol with a cobalt halide catalyst .…”

Section: Resultsmentioning

confidence: 99%

One-Pot Aerobic Cleavage of Monounsaturated Lipids Catalyzed by Mixed Oxides

Nocito

Orlando²,

Digioia

et al. 2021

ACS Sustainable Chem. Eng.

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The oxidative cleavage of nonedible monounsaturated lipids such as restaurant olive oil or oil extracted from high oleic sunflowers (HOSO) is a method to produce useful C9 mono-and dicarboxylic acids, namely, pelargonic and azelaic acids. In this study, we describe the synthesis and application of mixed oxides as cheap, recoverable, and reusable catalysts for the one-pot conversion of nonedible oils into products that may find application in several fields, from the cosmetic industry to the agrochemical sector (pelargonic acid) and to the biopolymer technologies (azelaic acid). The catalysts developed use oxygen as an oxidant and the alcohol selected for producing esters as a solvent or can operate in solventless conditions. The same catalyst is used for oxidation and transesterification/esterification. Oxidation is carried out under moderate P O 2 (0.6−0.8 MPa) and temperature (413−433 K) for 2− 3 h. The conversion yield and selectivity toward the target products depend on both the catalyst composition and the reaction conditions. In best cases, 63−72% of a mixture of C7−C9 acids with 40−56% of C9 (% yield of C9 with respect to the starting oil) has been obtained, which represents the best cases so far available. The reaction pathway has been detected using a flow reactor that has allowed us to detect the species formed with time and measure their concentration using gas chromatography−mass spectrometry (GC−MS). This research has produced five key innovations: (i) a one-pot one-or two-step process for the conversion of monounsaturated oils into mono-and dicarboxylic acids; (ii) use of oxygen as an oxidant instead of ozone or hydrogen peroxide; (iii) elimination of sulfuric acid in the esterification/transesterification reaction; (iv) use of cheap, recoverable, and reusable mixed oxides as catalysts; and (v) use of a single catalyst for both the oxidation and esterification−transesterification reactions.

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Formation of Gas-Phase Hydrogen Peroxide via Multiphase Ozonolysis of Unsaturated Lipids

Cited by 32 publications

References 64 publications

Hydroxyl Radical Production by Air Pollutants in Epithelial Lining Fluid Governed by Interconversion and Scavenging of Reactive Oxygen Species

Hydroxyl Radical Production by Air Pollutants in Epithelial Lining Fluid Governed by Interconversion and Scavenging of Reactive Oxygen Species

Coupled interfacial and bulk kinetics govern the timescales of multiphase ozonolysis reactions

One-Pot Aerobic Cleavage of Monounsaturated Lipids Catalyzed by Mixed Oxides

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