Hydroxide Degradation Pathways for Substituted Benzyltrimethyl Ammonium: A DFT Study

Long, Hai; Pivovar, Bryan S.

doi:10.1149/2.0041501eel

Cited by 22 publications

(17 citation statements)

References 28 publications

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“…Nevertheless, at current stage, we believe the alkyl chain attached in para-or meta-position to polymer backbone would not make much influence. This assumption has already been confirmed 18 . Commercialized boronic acid can also be employed in this reaction as demonstrated in Fig.…”

supporting

confidence: 53%

A strategy to construct alkali-stable anion exchange membranes bearing ammonium groups via flexible spacers

et al. 2015

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supporting

confidence: 53%

A strategy to construct alkali-stable anion exchange membranes bearing ammonium groups via flexible spacers

et al. 2015

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“…TMAH is very useful for the liberation of polar molecules from macromolecules and the volatilization of fatty acids, but the decomposition of TMAH at elevated temperatures above 500°C (Morisson et al, 2017) can cause additional issues that complicate organics detection. The degradation of TMAH at relatively low temperatures (lower than 200°C) has been studied, and different TMAH degradation mechanisms have been reported (Musker, 1967;Chempath et al, 2008Chempath et al, , 2010Long and Pivovar, 2012), but no study has reported on the by-products of TMAH pyrolysis at elevated temperatures.…”

Section: Research Articlementioning

confidence: 99%

“…The Hofmann elimination is a vulnerable pathway for degradation of n-alkyl-tetramethylammonium (TMA + ) cations (Long and Pivovar, 2012). However, this barrier is also found to depend on the carbon chain length because of steric interference and number of hydrogens susceptible to the Hofmann elimination (Long and Pivovar, 2012). OHcan attack the a-carbon atom and the cation degrades by the S N 2 pathways.…”

Section: Research Articlementioning

confidence: 99%

Influence of Calcium Perchlorate on the Search for Martian Organic Compounds with MTBSTFA/DMF Derivatization

Buch

Szopa

et al. 2021

Astrobiology

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The Mars Organic Molecule Analyzer (MOMA) and Sample Analysis at Mars (SAM) instruments onboard the Exomars 2022 and Mars Science Laboratory rovers, respectively, are capable of organic matter detection and differentiating potentially biogenic from abiotic organics in martian samples. To identify organics, both these instruments utilize pyrolysis-gas chromatography coupled to mass spectrometry, and the thermochemolysis agent tetramethylammonium hydroxide (TMAH) is also used to increase organic volatility. However, the reactivity and efficiency of TMAH thermochemolysis are affected by the presence of calcium perchlorate on the martian surface. In this study, we determined the products of TMAH pyrolysis in the presence and absence of calcium perchlorate at different heating rates (flash pyrolysis and SAM-like ramp pyrolysis with a 35°C$min -1 heating rate). The decomposition mechanism of TMAH pyrolysis in the presence of calcium perchlorate was studied by using stepped pyrolysis. Moreover, the effect of calcium perchlorate (at Mars-relevant concentrations) on the recovery rate of fatty acids with TMAH thermochemolysis was studied. Results demonstrate that flash pyrolysis yields more diversity and greater abundances of TMAH thermochemolysis products than does the SAM-like ramp pyrolysis method. There is no obvious effect of calcium perchlorate on TMAH degradation when the [ClO 4 -] is lower than 10 weight percent (wt %). Most importantly, the presence of calcium perchlorate does not significantly impact the recovery rate of fatty acids with TMAH thermochemolysis under laboratory conditions, which is promising for the detection of fatty acids via TMAH thermochemolysis with the SAM and MOMA instruments on Mars. Key Words: Calcium perchlorate-TMAH thermochemolysis-Pyrolysis-GC-MS-Mars-SAM and MOMA. Astrobiology 21, xxx-xxx.

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“…Also, the ylide pathway can give rise to unstable intermediates with side reactions including the Stevens rearrangement reaction [288], Sommelet-Hauser rearrangement, and Hofmann elimination [289]. Hofmann elimination is a vulnerable pathway for degradation of n-alkyl TMA þ cations [290]; the barrier is dependent on the carbon chain length because of steric interference and the number of hydrogens susceptible to Hofmann elimination [290]. On the other side, the Hofmann elimination is the preferred decomposition pathway for ammonium cations bearing behydrogens, and ylide formation scrambles protons from water into trimethylamine which is formed with a low activation barrier [291].…”

Section: The Mechanism Of Tmah Degradationmentioning

confidence: 99%

The search for organic compounds with TMAH thermochemolysis: From Earth analyses to space exploration experiments

He¹,

Buch²,

Szopa³

et al. 2020

TrAC Trends in Analytical Chemistry

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Tetramethylammonium hydroxide (TMAH) is one of the most popular methylation reagents that have been increasingly used for the detection of organic compounds within a wide range of samples, such as soil, coal, lacquer, lignin, polymers and for in situ analysis of solid samples by space experiments. The analytical methods and instruments, experimental conditions, and the qualitative and quantitative analysis of organic compounds using TMAH thermochemolysis for the last 10 years were reviewed; additionally, the mechanism of TMAH thermochemolysis and TMAH degradation are overviewed herein. The objective of this paper is to give a broad view of the TMAH thermochemolysis analysis, to demonstrate how the technique can be used for the detection of organics on Mars and other planets, and to promote cooperation between different disciplines which may use thermochemolysis.

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Hydroxide Degradation Pathways for Substituted Benzyltrimethyl Ammonium: A DFT Study

Cited by 22 publications

References 28 publications

A strategy to construct alkali-stable anion exchange membranes bearing ammonium groups via flexible spacers

A strategy to construct alkali-stable anion exchange membranes bearing ammonium groups via flexible spacers

Influence of Calcium Perchlorate on the Search for Martian Organic Compounds with MTBSTFA/DMF Derivatization

The search for organic compounds with TMAH thermochemolysis: From Earth analyses to space exploration experiments

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