Analysis of oxidized paraffins by combined techniques

Brown, Ralph Andreas.; Kay, Morris I.; Kelliher, James M.; Dietz, Walter A.

doi:10.1021/ac50157a051

Cited by 12 publications

(10 citation statements)

References 7 publications

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“…Some water is likely to also be contributing to the O-H stretching band. As previously stated, alcohols, ketones and aldehydes can result from the oxidation of oils [16][17][18]. Although these types of compounds are known to be present in natural oils and waxes, the lack of spectral bands due to fatty acid esters, free fatty acids and aromatic compounds supports the idea that synthetic rather than natural oil/wax has been used in the modelling clay employed in this work [24,25].…”

Section: Hinder Artworksupporting

confidence: 57%

“…There is, however, an indication of some change to the red modelling clay utilised in this work. The appearance of small bands near 1730 and 1720 cm −1 in the spectrum collected for the red Dwyer sample is likely to be associated with oxidation products of paraffin, such as ketones and esters [16][17][18]. Initially paraffins oxidise in air to form hydroperoxides that decompose to form oxidation products including ketones, aldehydes and esters.…”

Section: Dwyer Artworkmentioning

confidence: 99%

“…A small band at 766 cm −1 and a contribution to the broad O-H stretching region indicates goethite is present [21,22]. SEM-EDS analysis of the Hinder sample indicates the presence of goethite, [10,11,13,14] 849, 872 CaCO 3 C-O bending [6][7][8][9] 1030 Oxidation products C-O stretching [17,23] 1190 Oxidation products C-C stretching [17,23] 1367, 1378 Paraffin C-H bending [10,11,13,14] 1414 CaCO 3 C-O stretching [6][7][8][9] 1463, 1470 Paraffin C-H bending [10,11,13,14] 1720, 1730 Oxidation products C=O stretching [16][17][18] 1790 CaCO 3 C=O stretching [6][7][8][9] 2520 CaCO 3 overtone/combination band [7,8] 2847, 2874, 2916, 2950 Paraffin C-H stretching [10,11,13,14] with the presence of a small quantity of Fe detected ( Table 2). The detection of sulphur also supports the presence of gypsum.…”

Section: Hinder Artworkmentioning

confidence: 99%

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Modelling clay materials used in artworks: an infrared spectroscopic investigation

et al. 2019

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Modelling clays are utilised by artists for their malleable properties. One of the challenges in managing collections containing such materials is the variety of commercial compositions available and, therefore, the variation in the requirements for storage and maintenance of such artefacts. The Art Gallery of New South Wales in Australia is responsible for the care of a range of artworks that contain modelling materials, some of which show detrimental property changes and there is concern for the longevity of such works. The aim of the current research is to determine the compositions of the modelling materials utilised in works produced by different artists in the gallery's collection. Infrared spectroscopy was used to identify the main constituents of samples collected from the works of four different artists and a variety of material types were determined. Oil-based, air-hardening and polymer clays of varying composition were identified in the survey of artworks. Signs of deterioration in particular artworks were able to be characterised using spectroscopy, with the mechanisms identified including loss and oxidation of the oil component. Where a polymer clay was chosen by one artist, the distortion of the artwork was due to flow of the material over time and demonstrates the need for an understanding of the long term properties of the materials being used. The study has highlighted the need for conservators to have a detailed understanding of modelling materials to ensure the longevity of artworks containing this class of materials.

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Section: Hinder Artworksupporting

confidence: 57%

Section: Dwyer Artworkmentioning

confidence: 99%

Section: Hinder Artworkmentioning

confidence: 99%

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Modelling clay materials used in artworks: an infrared spectroscopic investigation

et al. 2019

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“…We conclude that the C-2 position is favored if the reasonable assumption is made that each of the 3 isomers determined in the combined C-4, -5, and -6 peak constitutes 113 of the total peak. Favored attack at C-2 was not observed in some studies performed in the kinetic reaction region by other workers (4,8,18,23). Recent studies by Dawkins (13) tend to support preferential attack at C-2.…”

Section: Resultsmentioning

confidence: 82%

“…The detailed mechanism of the early stages (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) and the general mechanism of later stages have been examined (4,10,(13)(14)(15)(16). Often the materials used are complex mixtures of hydrocarbons (13,17,18). In some studies, the effect of pertinent variables, such as the solid surface, have not been considered.…”

mentioning

confidence: 99%

Oxidation of hydrocarbons in the liquid phase: n-dodecane in a borosilicate glass chamber at 200 °C

Boss¹,

Hazlett²

1969

Can. J. Chem.

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The 5-h oxidation of 12-dodecane at 200 "C by air at 1 atm is reported for experiments in a borosilicate glass reaction chamber equipped with a gas bubbler. The rate of reaction was limited by the rate of oxygen diffusion from the gas phase due to the rapid reaction of dissolved oxygen. The reaction products were analyzed in aliquots taken periodically from the reaction chamber. Chemical analyses, gas-liquid phase chromatography (g.l.p.c.), tandem g.1.p.c.-mass spectroscopy, infrared, and ultraviolet were used to identify products accounting for 98% of the oxygen reacted. The isomer distribution of the dodecenes, dodecanols, and dodecanones formed, as well as the distribution of carboxylic acids, were determined. Three classes of intramolecular reaction products, cyclic ethers, cyclic hydrocarbons, and lactones, were detected. Many volatile products were detected. A filterable precipitate obtained after 10 h of oxidation was studied using infrared attenuated total reflectance techniques. A reaction mechanism is discussed based on current knowledge of other systems, the products identified, and the stoichiometry of the reaction.

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Ester formation during fatty acid methyl esters oxidation

Savel'ev,

Cherepanova,

Sapunov

2024

J Americ Oil Chem Soc

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The oxidation processes of unsaturated fatty acid methyl esters (FAMEs) and vegetable oils with molecular oxygen, proceeding through a radical mechanism, lead to the formation of a wide range of compounds. The primary oxidation products, hydroperoxides, undergo further decomposition to form products with a lower molecular weight or participate in cross‐linking reactions leading to the accumulation of products with a higher molecular weight than the raw material. A number of researches note an increase concentration of oligomeric products and esters during the oxidation of FAME. The study of literary sources made it possible to establish that the accumulation of these substances correlates with each other. The mechanisms of ester formation described in the literature suggest the direct participation of either acids or hydroperoxides in these reactions. The work examines the main ways of accumulation of heavy products and “new” esters during the oxidation of FAMEs.

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Analysis of oxidized paraffins by combined techniques

Cited by 12 publications

References 7 publications

Modelling clay materials used in artworks: an infrared spectroscopic investigation

Modelling clay materials used in artworks: an infrared spectroscopic investigation

Oxidation of hydrocarbons in the liquid phase: n-dodecane in a borosilicate glass chamber at 200 °C

Ester formation during fatty acid methyl esters oxidation

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