Thermal Degradation Kinetic Study of Rubber Seed Oil and Its Methyl Esters under Inert Atmosphere

Abstract

Nonedible vegetable oil feedstocks are promising for sustainable production of biodiesel. Thermal decomposition characteristics of the feedstocks and their biodiesel are crucial for handling and quality control. Thermal degradation of rubber seed oil (RSO) and rubber seed oil methyl esters (ROME) was investigated with the help of thermogravimetry. The samples were pyrolyzed from 30 to 800 °C at heating rates of 10 °C/min to 50 °C/min with a 10 °C/min increment under a nitrogen atmosphere. The temperature window for thermal degradation of RSO and ROME was shifted toward a higher range as the heating rate increased from 10 °C/min to 50 °C/min. A transesterification reaction leads to a decrease in the molecular weight of triglycerides present in the sample (RSO), and this causes a lower thermal stability of the produced product (ROME). Fourier transform infrared (FT-IR) analysis of evolved gaseous products during pyrolysis revealed the formation of water, carbon dioxide, carbon monoxide, and saturated (alkanes) and unsaturated (alkenes) aliphatic hydrocarbons. Friedman (FRD), Flynn−Wall− Ozawa (FWO), modified Coat−Redfern (MCR), and Kissinger (KM) methods and Avrami theory were applied to calculate the values of activation energy (E), order of reaction (n), and enthalpy (ΔH). Furthermore, the pre-exponential factor (A), entropy (ΔS), and Gibbs free energy (ΔG) were also calculated.

Assessment of the Thermal Degradation of Sodium Lauroyl Isethionate Using Predictive Isoconversional Kinetics and a Temperature-Resolved Analysis of Evolved Gases

“…Renewably sourced biofuels exhibit some chemical similarity to SLI, with a common presence of alkyl chains, as well as a prevalence of C–C, C–O, and CO bonds. The triglyceride systems exhibited similar average Friedman values of 124 and 167 kJ/mol, respectively. The reported degradation onsets of ∼300 °C for these species were also similar to those observed in the current study and much higher than the corresponding methyl esters where decomposition commenced between 100 and 150 °C. , This may suggest that the additional electron density donated by the isethionate group, when compared to that of a methyl group, stabilizes the ester bond similar to the glycerol group and fatty acid chains in the triglyceride system, thus resulting in a greater thermal stability in an inert atmosphere.…”

“…. 50,54 This may suggest that the additional electron density donated by the isethionate group, when compared to that of a methyl group, stabilizes the ester bond similar to the glycerol group and fatty acid chains in the triglyceride system, thus resulting in a greater thermal stability in an inert atmosphere.…”

“…While carboxylic acids were identified as the primary carbonyl constituent, decomposition within the alkyl chains was also likely to result from oxidative combustion, resulting in the evolution of independent alkyl fragments. 54,69 The alkyl and carbonyl bands were therefore integrated individually to determine the relative quantities of each functional group. Figure 8.…”

Robust, remeltable and remarkably simple to prepare biomass–sulfur composites

“…Triglycerides, however, undergo transesterification in the absence of catalyst at temperatures above 170 1C, 55 below the polymerization temperature used in the current study. [56][57][58][59] Increased strength is thus expected to arise from ester functionalities in the peanut shell triglycerides undergoing facile transesterification with alcohol functionalities in lignin and cellulose during heating to 180 1C. Such thermal transesterification would provide a mechanism for covalent bonding of the cellulose and lignin backbones to the network structure, accounting for the improved strength of the materials.…”

Palm oil-based bio-PCM for energy efficient building applications: Multipurpose thermal investigation and life cycle assessment

“…The obtained overall mean value of activation energy (83 ± 25 kJ•mol −1 ) for both methods) is lower than that calculated for other vegetable oils (146, 151, 144, 157 kJ•mol −1 for mustard, soybean, olive and karanja oils, respectively [57]) during thermal decomposition in inert atmosphere. This result is probably due to a higher content of impurities such as free fatty acids, monoand diacylglycerols, phospholipids and oxidation products [58].…”