In‐situ hydrolysis/methylation pyrolysis CGC for the characterization of polyaramides

Abstract

Abstract. Some parameters influencing the in-situ methylation by tetramethylammonium hydroxide (TMAH) during pyrolysis have been investigated with model compounds and polyaramides. Both pyrolysis temperature and excess TMAH (pH effect) influence the methylation of carboxy-, aromatic amino-, and hydroxyl-functional groups. While the solvent of TMAH, i.e., methanol or water hardly influenced the methylation of the model compounds, the solvent effect was significant for the polyaramides. This can be explained by assuming a transesterification mechanism rather than hydrolysis/methylation. N-methylation prior to the decomposition of polyaramides also may not be excluded. o 1995 John Wiley & Sons, Inc

Identification and quantification of plastic additives using pyrolysis-GC/MS: A review

“…The purpose of this derivatization reaction is to modify the sample to produce a more volatile derivate. It will enable to enhance chromatographic separation and detection results for the compounds that are not suitable for efficient detection, and will also improve the pyrolysis process for qualitative and quantitative analysis (González-Vila et al, 2001;Rial-Otero et al, 2009;Venema and Boom-Van Geest, 1995).…”

“…Different methods of derivatization have been reported such as hydrogenation, silylation, butylation, alkylation and methylation with addition of different derivative agents (Derenne and Quénéa, 2015;Rial-Otero et al, 2009;Sobeih et al, 2008). Methylation is the most common derivatization reaction which is mainly performed with TMAH (Becerra and Odermatt, 2012;Derenne and Quénéa, 2015;Jeknavorian et al, 1998;Manabe et al, 1999;Rial-Otero et al, 2009;Venema and Boom-Van Geest, 1995). However, this reagent needs to be handle with special care due to its potential hazard for the laboratory technician.…”

“…After the addition of TMAH in excess, the pH can be adjusted by adding acetic acid for example. However, Venema and Boom-Van Geest (1995) demonstrated that pyrolysis temperature has a less pronounced effect than pH on derivatization efficiency. The role of the solvent is also subject to debate (Challinor, 2001;Venema and Boom-Van Geest, 1995).…”

“…However, Venema and Boom-Van Geest (1995) demonstrated that pyrolysis temperature has a less pronounced effect than pH on derivatization efficiency. The role of the solvent is also subject to debate (Challinor, 2001;Venema and Boom-Van Geest, 1995). In general, the solvent of the derivatizing agents, i.e.…”

“…The use of water as a solvent for TMAH increases hydrolysis degradation mechanisms and creates different by-products, such as tetramethyl ammonium salt, which have to be pyrolysed at high inlet temperatures to form the corresponding methyl esters. However, in the case of methanol, TMAH behaves like a transesterification catalyst, resulting in the direct formation of methyl esters, even if the hydrolysis reaction is expected to be the most likely mechanism (Venema and Boom-Van Geest, 1995). Pyrolysis temperature may influence the success of the pyrolysis-derivatization process.…”