Specific heat capacities of pure triglycerides by heat-flux differential scanning calorimetry (original) (raw)
Related papers
The liquid specific heat capacity of fatty acids can be accurately estimated using the Rowlinson-Bondi method. This method requires the specific heat capacity of ideal gases, the critical temperature, and the acentric factor for each acid. The liquid specific heat capacity of triacylglycerols and vegetable oils can be estimated using mixture properties corresponding to the fatty acid composition and a correction factor, which accounts for the triacylglycerol form. The experimental data of triacylglycerols were used to produce the generalized correction factor. The estimated values were compared to experimental values and the error was found to be within ± 5%.
Journal of Thermal Analysis, 1995
Reproducible specific heat capacities (Cp) of triglyeerides can be obtained by using heat-flux DSC under improved operating conditions. The improved operating parameters, such as the scanning rate, the sample mass and the atmosphere within the DSC chamber, were established via statistical analysis of the experimental data with trilaurin as a sample. The specific heat capacity results on trilaurin were compared with the values calculated by using estimation methods. The precision of the specific heat capacity measured for trilaurin under these conditions was within +1%.
Grasas Y Aceites - GRASAS ACEITES, 1999
Determinación del punto de fusión de aceites y grasas vegetales por técnica de calorimetría diferencial de barrido (DSC). El punto de fusión de grasas es usado para caracterizar aceites y grasas, y está relacionado con sus propiedades físicas, tales como dureza y comportamiento térmico. El presente trabajo muestra la utilización de la técnica de Calorimetría Diferencial de Barrido (DSC) en* la determinación del punto de fusión de grasas. En comparación con el punto de ablandamiento (AOCS método Ge 3-25), los valores de DSC fueron más altos que los obtenidos por los métodos de AOCS. Esto ha ocurrido debido al hecho que los valores obtenidos por la técnica de DSC fueron tomados cuando la grasa había fundido completamente. DSC fue también útil para determinar puntos de fusión de aceites líquidos, tales como los de soya y algodón.
Chemistry and Physics of Lipids, 2019
was involved in the conception and design of the study, in acquisition, analysis and interpretation of data from physical chemical characterization of milk fat mixtures, in drafting the article, revising it critically for important intellectual content. Dr Cécile Vors was involved in the conception and design of the study, in drafting the article, revising it critically for important intellectual content. Damien Agopian was involved in acquisition, analysis and interpretation of data from in vitro digestion, in drafting the article. Annie Durand was involved in the conception and design of the study, in acquisition, analysis of data from in vitro digestion. Romain Guyon was involved in acquisition of data from in vitro digestion. Frédéric Carrière was involved in the conception of the study, in acquisition, analysis and interpretation of data of in vitro digestion, in drafting the article, revising it critically for important intellectual content. Carole Knibbe was involved in the design of the study, in acquisition, analysis and interpretation of data of in vitro digestion, in drafting the article, revising it critically for important intellectual content. Marion Letisse was involved in the design of the study, in acquisition, analysis and interpretation of data of in vitro digestion, in drafting the article, revising it critically for important intellectual content. Dr Marie-Caroline Michalski was involved in the conception and design of the study, in data interpretation, in drafting the article, revising it critically for important intellectual content and final Funding:
Evaluation of the Self‐Heating Tendency of Vegetable Oils by Differential Scanning Calorimetry
Journal of Forensic Sciences, 2008
The evaluation of the self-heating propensity of a vegetable (or animal) oil may be of significant importance during the investigation of a fire. Unfortunately, iodine value and gas chromatographic-mass spectrometric analysis do not lead to meaningful results in this regard. To the contrary, differential scanning calorimetry (DSC), which does not measure the chemical composition of the oil, but rather its thermodynamic behavior, produces valuable results. After a thorough literature review on the autooxidation of vegetable oils, several oils with different self-heating tendencies were analyzed using a Mettler-Toledo differential scanning calorimeter DSC 25 between 40°C and 500°C. Analyses were carried out both under air and nitrogen atmosphere to identify the phenomena due to autooxidation reactions. Using DSC, it was possible to observe the induction period of the oil (when available), the three different exothermic events, and the autoignition temperature (relatively independent of the oil type).
2011
Thermal properties for pure fatty acids and its mixtures were analyzed by differential scanning calorimetry (DSC). Solid-liquid and liquid-solid phase transitions were observed on heating and cooling curves. Results of melting temperature and enthalpy of melting for pure palmitic acid were in good agreement with the majority of the published values. For pure oleic acid, a reversible solid-solid phase transition from γ to α phase was observed on the heating curve. For ternary mixtures containing palmitic acid, oleic acid and n-decane, solid-liquid and liquid-solid phase transitions result from the quantities of fatty acids in the mixtures, while n-decane dose not affect the phase transition at the analyzed temperature range. Keyword: Differential scanning calorimetry, Palmitic acid, Oleic acid, Phase transition, Melting temperature, Crystallization temperature, Fatty acids
Quality of Brazilian vegetable oils evaluated by (modulated) differential scanning calorimetry
Journal of Thermal Analysis and Calorimetry, 2012
Vegetable oils are increasingly replacing fossiloil-based polymers, and therefore aimed at being used in polymerization reactions from -20 to 100°C. Therefore, phase transitions and heat capacities in this temperature range should be well characterized to optimize processing conditions and energy inputs. By using the DSC analysis, only small primary correspondence or divergence between different oil types are seen as a function of their degree of unsaturation, but it does not clearly distinguish detailed features such as shoulder bands related to the separate melting processes of single fatty acid components. By using modulated DSC analysis, the combined analysis of reversing and non-reversing heat signals provides better results. The latter confirms that the melting is not a physical one-step process, but equilibrates between phase transitions and enthalpic reorganizations of the fatty acids that can be monitored separately. The specific heat capacities measured during modulated DSC are somewhat lower than traditional calorimetric measurements, but relate to the degree of unsaturation. The thermal behavior of palm-, soy-, sunflower-, corn-, castor-, and rapeseed-oil is discussed in relation to their composition, by applying a first or second heating scan.
Journal of Chemical & Engineering Data, 2020
This paper reports liquid heat capacity data on members of the linear saturated dicarboxylic acid family and one dicarboxylic acid derivative measured using modulated differential scanning calorimetry. The dicarboxylic acids range in carbon number from 4 to 14. The compounds studied are dimethyl oxalate (CAS RN 553-90-2), adipic acid (1,6-hexanedioic acid, CAS RN 124-04-9), pimelic acid (1,7-heptanedioic acid, CAS RN 111-16-0), suberic acid (1,8-octanedioic acid, CAS RN 505-48-6), azelaic acid (1,9-nonanedioic acid, CAS RN 123-99-9), sebacic acid (1,10-decanedioic acid, CAS RN 111-20-6), dodecanedioic acid (1,12-dodecanedioc acid, CAS RN 693-23-2), and tetradecanedioic acid (1,14-tetradecandioic acid, CAS RN 821-38-5). The experimental results show a consistent family trend and are compared to prediction methods and data from other chemical families. A discussion of the differences in liquid heat capacity between carboxylic acids, n-alkanes, and dicarboxylic acids is presented, the accuracy of prediction through thermodynamic equations is analyzed for the family, and a correction factor for the Ruzicka−Domalski prediction method (