Homogeneous Oxidation Reactions of Propanediols at Low Temperatures

Dı́az, Eva; Sad, M.E.; Iglesia, Enrique

doi:10.1002/cssc.201000142

Cited by 39 publications

(52 citation statements)

References 32 publications

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“…Besides these two aldehydes, a trace amount of acetone was also observed but is not plotted in the figure. The results are consistent with the findings of PG thermal oxidation reported by Diaz et al [9] and Bekki et al [16]. When the reactor temperature reached 215°C, formaldehyde and acetaldehyde began to increase noticeably.…”

Section: Resultssupporting

confidence: 93%

“…In fact, the achievable temperature inside e-devices ranges up to 350°C [7, 8], sufficiently high to decompose PG or GL. Diaz et al [9] studied the homogeneous oxidation reaction of PG in a 10% O 2 /He mixture at different temperatures and concluded that PG can be easily oxidized at as low as 127–227°C to form formaldehyde, acetaldehyde, and carbon dioxide via oxidative C-C cleavage and to form acetone via a dehydration route. The dehydration of GL to yield acrolein is another well-known reaction in organic chemistry.…”

Section: Introductionmentioning

confidence: 99%

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A Device-Independent Evaluation of Carbonyl Emissions from Heated Electronic Cigarette Solvents

et al. 2017

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ObjectivesTo investigate how the two main electronic (e-) cigarette solvents—propylene glycol (PG) and glycerol (GL)—modulate the formation of toxic volatile carbonyl compounds under precisely controlled temperatures in the absence of nicotine and flavor additives.MethodsPG, GL, PG:GL = 1:1 (wt/wt) mixture, and two commercial e-cigarette liquids were vaporized in a stainless steel, tubular reactor in flowing air ranging up to 318°C to simulate e-cigarette vaping. Aerosols were collected and analyzed to quantify the amount of volatile carbonyls produced with each of the five e-liquids.ResultsSignificant amounts of formaldehyde and acetaldehyde were detected at reactor temperatures ≥215°C for both PG and GL. Acrolein was observed only in e-liquids containing GL when reactor temperatures exceeded 270°C. At 318°C, 2.03±0.80 μg of formaldehyde, 2.35±0.87 μg of acetaldehyde, and a trace amount of acetone were generated per milligram of PG; at the same temperature, 21.1±3.80 μg of formaldehyde, 2.40±0.99 μg of acetaldehyde, and 0.80±0.50 μg of acrolein were detected per milligram of GL.ConclusionsWe developed a device-independent test method to investigate carbonyl emissions from different e-cigarette liquids under precisely controlled temperatures. PG and GL were identified to be the main sources of toxic carbonyl compounds from e-cigarette use. GL produced much more formaldehyde than PG. Besides formaldehyde and acetaldehyde, measurable amounts of acrolein were also detected at ≥270°C but only when GL was present in the e-liquid. At 215°C, the estimated daily exposure to formaldehyde from e-cigarettes, exceeded United States Environmental Protection Agency (USEPA) and California Office of Environmental Health Hazard Assessment (OEHHA) acceptable limits, which emphasized the need to further examine the potential cancer and non-cancer health risks associated with e-cigarette use.

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Section: Resultssupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

A Device-Independent Evaluation of Carbonyl Emissions from Heated Electronic Cigarette Solvents

et al. 2017

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“…The results revealed that GLY can be directly oxidized to C3 acids (glyceric), and leads to C2 (glycolic) and C1 (formic) acids through a C–C cleavage reaction. This kind of reaction has been reported elsewhere for various alcohols . Hydroxypyruvic acid, mesoxalic acid and CO 2 were not observed in this work, although they have been reported elsewhere .…”

Section: Discussionsupporting

confidence: 81%

Kinetic modeling of the quasi‐homogeneous oxidation of glycerol over unsupported gold particles in the liquid phase

Díaz

Skrzyńska

Girardon

et al. 2015

Euro J Lipid Sci & Tech

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In the present study, kinetic analysis and modelling of the glycerol oxidation reaction over unsupported Au particles were performed. The reaction pathways, which were determined in agreement with the experimental results, comprise two types of reactions, namely oxidation and C–C cleavage. A homogeneous catalytic reaction model was proposed by considering the occurrence of the non‐catalytic reaction, the effect of the temperature, as well as NaOH and catalyst concentrations. The proposed kinetic model could adequately describe the data. The reaction under basic conditions but in the absence of a catalyst favoured the formation of C–C cleavage products (glycolic and formic acids), while in the presence of unsupported Au particles the oxidation to glyceric acid and the direct oxidation of glycerol to formic acid were promoted. Finally, it was observed that the formation of tartronic acid was not promoted by the catalyst and followed the non‐catalytic route. Practical applications: The building of a kinetic model for glycerol oxidation in liquid phase using gold‐based catalyst allows to better understand the mechanism leading to oxidation and C–C cleavage responsible to some change of selectivities in the process. The model parameters obtained in this study would be used to scale an industrial unit in a reactor modeling. The present work describes a homogeneous catalytic kinetic model of the glycerol (GLY) oxidation, by using unsupported Au nanoparticles. The proposed model includes the occurrence of the non‐catalysed reaction in basic media and the effect of the reaction temperature, NaOH/GLY ratio and GLY/Au ratio. The model predicted well the experimental results. Unsupported Au nanoparticles were selective to glyceric acid and C–C cleavage products like formic and glycolic acids.

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“…Studies have reported widely varying carbonyl yields,24 with some exceeding those reported for combustible cigarettes 25. Produced carbonyls in ECIG aerosol was anticipated from the investigation of PG and VG pyrolysis in food chemistry and biomass fuel generation 26 27. Flavourants may present another potent source of ‘vaping toxicants’ 28…”

Section: Introductionmentioning

confidence: 99%

Detection of 5-hydroxymethylfurfural and furfural in the aerosol of electronic cigarettes

et al. 2016

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Homogeneous Oxidation Reactions of Propanediols at Low Temperatures

Cited by 39 publications

References 32 publications

A Device-Independent Evaluation of Carbonyl Emissions from Heated Electronic Cigarette Solvents

A Device-Independent Evaluation of Carbonyl Emissions from Heated Electronic Cigarette Solvents

Kinetic modeling of the quasi‐homogeneous oxidation of glycerol over unsupported gold particles in the liquid phase

Detection of 5-hydroxymethylfurfural and furfural in the aerosol of electronic cigarettes

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