Thermal Oxidation of Biodiesel by Pressurized Differential Scanning Calorimetry: Effects of Heating Ramp Rate

Dunn, Robert O.

doi:10.1021/ef3010543

Cited by 14 publications

(5 citation statements)

References 34 publications

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“…Parameter B 1 is related to the reaction activation energy, E a (kJ/mol), by E a = R g B 1 , in which R g is the gas constant. The regression analysis shows a linear correlation ( R 2 = 0.99), yielding E a = 77.8 kJ/mol, which is in agreement with the literature value for fatty acids and ester obtained by isothermal differential scanning calorimetry . The result provides a correlation for estimating OSI as a function of temperature, although an extrapolation of OSI estimation to reasonable storage temperatures is more problematic …”

Section: Resultssupporting

confidence: 87%

“…The regression analysis shows a linear correlation (R 2 = 0.99), yielding E a = 77.8 kJ/mol, which is in agreement with the literature value for fatty acids and ester obtained by isothermal differential scanning calorimetry. 20 The result provides a correlation for estimating OSI as a function of temperature, although an extrapolation of OSI estimation to reasonable storage temperatures is more problematic. 19 Figure 2 presents the values of mass density, kinematic viscosity, and gross calorific value for all the samples.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Evaluation of Thermo-oxidative Stability of Biodiesel

et al. 2017

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Biodiesel susceptibility to oxidation is one of the major problems concerning its use as an alternative to diesel fuel. Although well-characterized, the oxidation process cannot be completely prevented since it can be affected by a large number of factors, such as fuel composition, storage conditions, contaminants, temperature, and the presence of air and light. In this work, we propose Fourier transform infrared spectroscopy (FTIR) in association with principal components analysis (PCA) and hierarchical cluster analysis (HCA) as a method for monitoring the extent of oxidation degree of biodiesel in the low rate phase, before the end of the induction period, in which the changes in the physical properties such as viscosity, mass density, and chain composition of the sample remain almost undetectable. A detailed investigation of thermo-oxidation of biodiesel is reported for a mixture of 50/50 (%) of soybean oil and animal fat biodiesels. The biodiesel degradation was accelerated when maintaining the temperature of the sample at 110 °C under constant air flux for different times. Oil stability index, mass density, viscosity, gross caloric value, esters composition, UV−vis, and FTIR spectra were measured in order to analyze the degree of degradation of each sample. The multivariate analysis in the FTIR spectra clearly shows the discrimination of the samples in the first stage of the degradation process. These results could be useful as a method for monitoring the fuel quality during storage, helping fuel producers, suppliers, and users.

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Section: Resultssupporting

confidence: 87%

Section: ■ Results and Discussionmentioning

confidence: 99%

Evaluation of Thermo-oxidative Stability of Biodiesel

et al. 2017

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“…Therefore oxidation of biodiesel has attracted a lot of attention. At present, study on biodiesel oxidation almost focuses on the oxidation stability and its evaluation [2][3][4][5][6], oxidation resistance, and antioxidant [7][8][9][10][11] but the research of oxidation mechanism and characterization work is rarely reported. It is significant to fully analyze the biodiesel oxidation mechanism for improving the quality of biodiesel to accelerate the practical engineering applications of biodiesel.…”

Section: Introductionmentioning

confidence: 99%

Anti-Oxidation Stability and its Mechanism of Soybean Biodiesel

Chen

Fang

et al. 2013

AMM

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The anti-oxidation stability of soybean biodiesel (SME) was evaluated on an oxidation simulator set up by the author. The results showed that oxidative stability of SME was worse than that of petrodiesel by exhibiting higher acid values and peroxide values, as well as greater viscosity increases after oxidation. Furthermore, a conjecture was taken about the configurational changes and the oxidation mechanisms of unsaturated fatty acid methyl ester molecules in the oxidation process, according to the principles of free radical reactions and the results of both infrared and ultraviolet spectroscopic analysis. An idea was put forward that, during oxidation, cis-trans isomerization might occur in unsaturated fatty acid methyl ester molecules and conjugated double-bond might produce due to transfer of double-bond.

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“…Increases in the heat flow with increasing temperature were caused by changes in the chemical composition as the oil degraded. Since oxygen was used as the purge gas, initial changes were affected by oxidative degradation of the oil sample accelerated by increasing temperature .…”

Section: Methodsmentioning

confidence: 99%

“…Results from P-DSC analysis of the thermo-oxidative stability of FAME do not correlate to induction period data measured isothermally at high temperature (110°C) by a Rancimat instrument [32]. However, OT data from P-DSC are reliable in the qualitative evaluation of the relative resistance to oxidation of biodiesel (FAME) [33].…”

Section: Thermo-oxidative Stability Evaluationsmentioning

confidence: 99%

Synthesis and low temperature characterization of iso‐oleic ester derivatives

Ngo

Latona

Wagner

et al. 2016

Euro J Lipid Sci & Tech

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Three new iso‐oleic ester derivatives (i.e., isopropyl ester (IOA‐iPrE, 6), n‐butyl ester (IOA‐n‐BuE, 7), and 2‐ethylhexyl ester (IOA‐2‐EHE, 8)) were synthesized from iso‐oleic acid (IOA, 4) using a standard esterification method. These esterified alcohols were chosen because of their bulky and branched‐chain alkyl groups which can reduce melting point in comparison to a smaller alkyl group such as methyl ester. The differential scanning calorimetry (DSC), cloud point and pour point results showed that esters 6, 7, and 8 had much lower melting transition temperatures and cold flow properties than the methyl (IOA–FAME, 5) and parent 4. The oxidative and thermal stability by pressure (P‐DSC) and thermogravimetric analysis (TGA) results also showed a very similar trend where the bulkier and branched‐chain alkyl esters had better stability than the smaller headgroup esters. Practical applications: Since saturated fats have high melting points, they are solids which can be harmful to our health and can cause damage to machinery. There is an urgent need to develop methods to produce fats with low melting points to replace the unwanted fats. In this paper, a series of modified branched‐chain fatty acid ester derivatives (i.e., iso‐oleic acid esters) that are liquid at room temperature with enhanced fluidity were synthesized. These ester fats have been found to perform much better than the original fatty acids and saturated fats. These findings are important as these iso‐oleic ester fats can potentially replace solid materials which are often problematic at low temperatures. Iso‐oleic ester derivatives containing bulky and branched‐chain alkyl groups exhibit reduce melting point in comparison to a smaller alkyl group such as methyl ester.

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Thermal Oxidation of Biodiesel by Pressurized Differential Scanning Calorimetry: Effects of Heating Ramp Rate

Cited by 14 publications

References 34 publications

Evaluation of Thermo-oxidative Stability of Biodiesel

Evaluation of Thermo-oxidative Stability of Biodiesel

Anti-Oxidation Stability and its Mechanism of Soybean Biodiesel

Synthesis and low temperature characterization of iso‐oleic ester derivatives

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