Formation of ketenes by reaction of carboxylic acids over alkali metal-exchanged zeolites

Parker, L.M.; Bibby, D.M.; Miller, IJ

doi:10.1016/0021-9517(91)90047-8

Cited by 16 publications

(5 citation statements)

References 3 publications

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“…This mechanism has also been proposed for the formation of acetone by the reaction of acetic acid on alkali-exchanged faujasites [39]. Grootendorst et al [33] reported that the partial pressure of ketene started to drop as soon the concentration of acetone started to increase.…”

Section: Discussionmentioning

confidence: 94%

Ketonization of acetic acid on titania-functionalized silica monoliths

Martinez

Huff

Barteau

2004

Journal of Catalysis

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Section: Discussionmentioning

confidence: 94%

Ketonization of acetic acid on titania-functionalized silica monoliths

Martinez

Huff

Barteau

2004

Journal of Catalysis

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“…However, the formation of methane in all cases was negligible and so acetic acid would be likely to proceed via dehydration to give an acylium ion which later would undergo a nucleophilic attack by another molecule, thus resulting in acetone and CO 2 [ 1 ]. This reaction may also occur via the reaction between acetic acid and ketene, which is known to be produced by decomposition of acetic acid in zeolites [ 27 ]. Moreover, 1,3,5-trimethylbenzene (mesitylene) could be formed by reaction of mesityl oxide and acetone on strong acid sites [ 28 ].…”

Section: Resultsmentioning

confidence: 99%

Metal-Exchanged β Zeolites as Catalysts for the Conversion of Acetone to Hydrocarbons

et al. 2012

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Various metal-β zeolites have been synthesized under similar ion-exchange conditions. During the exchange process, the nature and acid strength of the used cations modified the composition and textural properties as well as the Brönsted and Lewis acidity of the final materials. Zeolites exchanged with divalent cations showed a clear decrease of their surface Brönsted acidity and an increase of their Lewis acidity. All materials were active as catalysts for the transformation of acetone into hydrocarbons. Although the protonic zeolite was the most active in the acetone conversion (96.8% conversion), the metal-exchanged zeolites showed varied selectivities towards different products of the reaction. In particular, we found the Cu-β to have a considerable selectivity towards the production of isobutene from acetone (over 31% yield compared to 7.5% of the protonic zeolite). We propose different reactions mechanisms in order to explain the final product distributions.

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“…Vaping devices employ heating filaments that have metallic components that include nickel, chromium, iron, and aluminum . These metals, including copper, titanium, silver, and other metal oxides, are known to serve as catalysts in the production of ketene under industrial application conditions. − Indications are emerging that the metal components within vaping devices play a role in ketene formation, with reports showing that the thermal decomposition of VEA occurs at 356 °C in vaping, considerably lower than in a laboratory tube furnace (800–1200 °C), which does not contain metal components . Ketene is difficult to measure using conventional chromatography from collected air samples due to its highly reactive and transient nature.…”

Section: Introductionmentioning

confidence: 99%

Conditions Leading to Ketene Formation in Vaping Devices and Implications for Public Health

Wang,

Jacob,

Wang

et al. 2024

Chem. Res. Toxicol.

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The outbreak of e-cigarette or vaping use-associated lung injury (EVALI) in the United States in 2019 led to a total of 2807 hospitalizations with 68 deaths. While the exact causes of this vaping-related lung illness are still being debated, laboratory analyses of products from victims of EVALI have shown that vitamin E acetate (VEA), an additive in some tetrahydrocannabinol (THC)containing products, is strongly linked to the EVALI outbreak. Because of its similar appearance and viscosity to pure THC oil, VEA was used as a diluent agent in cannabis oils in illicit markets. A potential mechanism for EVALI may involve VEA's thermal decomposition product, ketene, a highly poisonous gas, being generated under vaping conditions. In this study, a novel approach was developed to evaluate ketene production from VEA vaping under measurable temperature conditions in real-world devices. Ketene in generated aerosols was captured by two different chemical agents and analyzed by gas chromatography−mass spectrometry (GC-MS) and liquid chromatography with tandem mass spectrometry (LC-MS/MS). The LC-MS/MS method takes advantage of the high sensitivity and specificity of tandem mass spectrometry and appears to be more suitable than GC-MS for the analysis of large batches of samples. Our results confirmed the formation of ketene when VEA was vaped. The production of ketene increased with repeat puffs and showed a correlation to temperatures (200 to 500 °C) measured within vaping devices. Device battery power strength, which affects the heating temperature, plays an important role in ketene formation. In addition to ketene, the organic oxidant duroquinone was also obtained as another thermal degradation product of VEA. Ketene was not detected when vitamin E was vaped under the same conditions, confirming the importance of the acetate group for its generation.

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Formation of ketenes by reaction of carboxylic acids over alkali metal-exchanged zeolites

Cited by 16 publications

References 3 publications

Ketonization of acetic acid on titania-functionalized silica monoliths

Ketonization of acetic acid on titania-functionalized silica monoliths

Metal-Exchanged β Zeolites as Catalysts for the Conversion of Acetone to Hydrocarbons

Conditions Leading to Ketene Formation in Vaping Devices and Implications for Public Health

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