NMR spectroscopic study of chemical equilibria in solutions of formaldehyde, water, and butynediol

Berje, Jürgen; Burger, Jakob; Hasse, Hans; Baldamus, Jens

doi:10.1002/aic.15788

Cited by 12 publications

(44 citation statements)

References 21 publications

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“…Similar results have been obtained in the literature for the addition of formaldehyde to methanol, 9,15 1-butanol 18 and 1,4-butynediol. 20 As in the literature, also in the present work the small differences between K EOH…”

Section: Reactions Of Formaldehyde With Ethanolsupporting

confidence: 84%

“…For the quantitative evaluation of the NMR spectra the same methods were applied as in previous works of our group. 9,20,23,24 These procedures ensure that the peak areas are proportional to the mole numbers of the corresponding functional groups, e.g. methylene groups in oligomeric species.…”

Section: Nmr Experimentsmentioning

confidence: 99%

“…and (○) 1,4-butynediol. 20 Also the chemical equilibrium constant of the prolongation of the acetals (△) OME n 9 is shown. The results from the different sources were re-evaluated to bring them into a consistent form.…”

Section: Generalized Chemical Equilibrium Constantmentioning

confidence: 99%

“…they have to be considered for describing the vapor-liquid equilibrium. [3][4][5][6][7][8][9][10] In the literature, information on the chemical equilibrium of mixtures of formaldehyde with water, [11][12][13][14] with the mono-alcohols methanol, 12,15,16 ethanol, 17 and 1-butanol 18,19 as well as with the diols ethylene glycol 17 and 1,4-butynediol 20 is available. In the present work, the entire set of available data on the oligomerization reactions of formaldehyde was analyzed.…”

Section: Introductionmentioning

confidence: 99%

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Generalized Chemical Equilibrium Constant of Formaldehyde Oligomerization

Kircher

Schmitz

Berje

et al. 2020

Ind. Eng. Chem. Res.

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Formaldehyde reacts with solvents that contain hydroxyl groups (R-OH) in oligomerization reactions to oxymethylene oligomers (R-(OCH 2 ) n -OH). The chemical equilibria of these reactions have been studied in the literature for water, for the mono-alcohols methanol, ethanol, and 1-butanol, as well as for the diols ethylene glycol and 1,4butynediol. In the present work, the collective data were analyzed. It was found that the prolongation of the oxymethylene chains by the addition of formaldehyde can be described very well with a generalized chemical equilibrium constant K R-OHx,n≥2 , which is independent of the substructure (R) of the solvent. This holds for the oligomerization reactions leading to R-(OCH 2 ) n -OH with n ≥ 2. The chemical equilibrium constantof the reaction of formaldehyde with the solvent R-OH depends on the solvent, but simple trends are observed. The hypotheses of the existence of a generalized chemical equilibrium constant K R-OH x,n≥2 was tested for the reactions of formaldehyde with ethanol and 1-propanol, for which neither K R-OHx,1 nor K R-OHx,n were previously available.The corresponding equilibria were studied by 13 C NMR spectroscopy and the equilibrium constants were determined. A novel method was developed and used in these studies to obtain data on K R-OHx,1 by NMR spectroscopy, which is difficult due to the low amount of molecular formaldehyde. It was found that the generalized equilibrium constant is even valid for the acid-catalyzed formation of poly(oxymethylene) dimethyl ethers (OME).

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Section: Reactions Of Formaldehyde With Ethanolsupporting

confidence: 84%

Section: Nmr Experimentsmentioning

confidence: 99%

Section: Generalized Chemical Equilibrium Constantmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Generalized Chemical Equilibrium Constant of Formaldehyde Oligomerization

Kircher

Schmitz

Berje

et al. 2020

Ind. Eng. Chem. Res.

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“…Such species are known to readily form from short-chain aldehydes to generate new hemi-acetal species 20 – 24 . In water, for example, formaldehyde will combine with water to exothermically generate methylene glycol 25 , 26 . This can undergo subsequent additions to itself to generate n-methyl glycol, releasing water from the newly oligomerized methylene glycol according to the scheme below: …”

Section: Resultsmentioning

confidence: 99%

Low-temperature (< 200 °C) degradation of electronic nicotine delivery system liquids generates toxic aldehydes

Jaegers

Weber

et al. 2021

Sci Rep

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Electronic cigarette usage has spiked in popularity over recent years. The enhanced prevalence has consequently resulted in new health concerns associated with the use of these devices. Degradation of the liquids used in vaping have been identified as a concern due to the presence of toxic compounds such as aldehydes in the aerosols. Typically, such thermochemical conversions are reported to occur between 300 and 400 °C. Herein, the low-temperature thermal degradation of propylene glycol and glycerol constituents of e-cigarette vapors are explored for the first time by natural abundance 13C NMR and 1H NMR, enabling in situ detection of intact molecules from decomposition. The results demonstrate that the degradation of electronic nicotine delivery system (ENDS) liquids is strongly reliant upon the oxygen availability, both in the presence and absence of a material surface. When oxygen is available, propylene glycol and glycerol readily decompose at temperatures between 133 and 175 °C over an extended time period. Among the generated chemical species, formic and acrylic acids are observed which can negatively affect the kidneys and lungs of those who inhale the toxin during ENDS vapor inhalation. Further, the formation of hemi- and formal acetals is noted from both glycerol and propylene glycol, signifying the generation of both formaldehyde and acetaldehyde, highly toxic compounds, which, as a biocide, can lead to numerous health ailments. The results also reveal a retardation in decomposition rate when material surfaces are prevalent with no directly observed unique surface spectator or intermediate species as well as potentially slower conversions in mixtures of the two components. The generation of toxic species in ENDS liquids at low temperatures highlights the dangers of low-temperature ENDS use.

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Investigation of Partial Oxidation of Methane in a Cold Plasma Reactor with Detailed Product Analysis

Müller

Ströfer

Kohns

et al. 2022

Plasma Chem Plasma Process

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Cold plasma is a partially ionized state of matter that unites high reactivity and mild conditions. Therefore, cold plasma reactors are intriguing for reaction engineering. In this work, a laboratory scale dielectric barrier discharge (DBD) cold plasma reactor was designed, set up, and used for studying the influence of the specific energy input (SEI) on the product spectrum of the partial oxidation of methane. In total, 23 experiments were carried out near ambient conditions with a molar reactant ratio of methane to oxygen of 2:1 at SEI between 0.3 and 6.0 J cm−3. The feed also contained argon at a mole fraction of 0.75 mol mol−1. The product stream was split into a fraction that was condensed in a cold trap and the remaining gaseous fraction. The latter was analyzed at-line in a gas chromatograph equipped with a dual column and two carrier gases. The condensed fraction was analyzed by qualitative and quantitative 1H and 13C NMR spectroscopy, Karl Fischer titration, and sodium sulfite titration. In the product stream, 16 components were identified and quantified: acetic acid, acetone, carbon dioxide, carbon monoxide, ethanol, ethane, ethene, ethylene glycol, formaldehyde, formic acid, hydrogen, methanol, methyl acetate, methyl hydroperoxide, methyl formate, and water. A univariant influence of the SEI on the conversions of methane and oxygen and the selectivities to the products was observed. The experimental results provided here are an asset for developing reaction kinetic models of the partial oxidation of methane in DBD plasma reactors.

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NMR spectroscopic study of chemical equilibria in solutions of formaldehyde, water, and butynediol

Cited by 12 publications

References 21 publications

Generalized Chemical Equilibrium Constant of Formaldehyde Oligomerization

Generalized Chemical Equilibrium Constant of Formaldehyde Oligomerization

Low-temperature (< 200 °C) degradation of electronic nicotine delivery system liquids generates toxic aldehydes

Investigation of Partial Oxidation of Methane in a Cold Plasma Reactor with Detailed Product Analysis

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