Methyl Octanoate Research Articles

Effect of MnO2 and α-Fe2O3 on organic binders degradation investigated by Raman spectroscopy

Vibrational spectroscopy and GC–MS were used to investigate the effect of MnO2 and α-Fe2O3 on the degradation of methyl linoleate and vegetal and animal fatty. The metal oxides are among the most employed pigments in rock art paintings, whereas the organic compounds were used to mimic organic binders potentially used in such paintings.Both oxides were very effective in the catalytic oxidation of the organic substrates and light had no significant effect, qualitatively or quantitatively, on the final products. In the case of methyl linoleate without metal oxide, the effect of light (visible) was investigated and it was demonstrated that the samples kept in the dark produced relatively less oxidation products, although the main products were the same (hexanal, methyl 9-oxononanoate and methyl octanoate). In the presence of MnO2 and α-Fe2O3 methyl 9-oxononanoate was the main product, followed by hexanal. The spectral patterns of the oxidation products were different for manganese and iron oxide and GC–MS demonstrated that more compounds are formed in the former than with α-Fe2O3. Vegetal and animal fatty presented the same behavior that methyl linoleate did.The results here reported indicated that the two pigments considered actively contribute to fat degradation and the presence of inorganic pigments is the main factor to take into account when organic binders degradation in rock art paintings are investigated.

An application of the reaction class transition state theory to the kinetics of hydrogen abstraction reactions of hydrogen with methyl esters at the methoxy group

The hydrogen abstraction reactions of methyl esters from methyl formate (MF) to methyl decanoate (MD) by hydrogen (H) atom at the methoxy group have been investigated on the basis of isodesmic reactions within the framework of reaction class transition state theory (RC-TST). The rate constants for the four reactions of H with MF, methyl acetate (MA), methyl propanoate (MP), and methyl butanoate (MB) are used as the benchmarking values, and are calculated via the transition state theory (TST) with the Eckart method to account for tunneling effect by employing potential energy surface information computed at the CCSD(T)/CBS//BH&HLYP/6-31G(d,p) level. The calculated rate constants of reactions H with MF and MA are in excellent agreement with experimental results. For the target reactions of H with MA, MP and MB, it is demonstrated that the calculated energy barriers and rate constants at the BH&HLYP/6-31G(d,p) level with a simple correction scheme based on isodesmic reactions within the framework of RC-TST can approach the accuracy of the CCSD(T)/CBS level. Based on the correction scheme, reaction enthalpies, energy barriers and rate constants for large reaction systems including the reactions of H with methyl valerate (MV), methyl hexanoate (MHex), methyl heptanoate (MHep), methyl octanoate (MO), methyl nonanoate (MN) and MD at the methoxy group are computed and fitted into the modified Arrhenius expression in the temperature range 300–2500K for chemical kinetic modeling studies. Further, it is found that the reaction rate constants of H with large methyl ester molecules (from MA to MD) is nearly identical and is slightly larger than that of H with MF at the methoxy group.

Effects of octane derivatives on activity of the volume-regulated anion channel in rat pancreatic β-cells

BackgroundSaturated free fatty acids (FFAs) have a dual action on pancreatic β-cells, consisting of an initial enhancement and subsequent suppression of glucose-induced electrical activity and insulin release. These stimulatory and inhibitory effects have been attributed, at least in part, to the activation and inhibition, respectively, of the volume-regulated anion channel (VRAC) by FFAs. Both effects were independent of their metabolism.We have now investigated the effects of related aliphatic compounds in order to further define the determinants of FFA interaction with VRAC. Methodsβ-Cell VRAC and electrical activity were measured by conventional whole-cell and perforated patch recording, respectively. Cell volume was measured using a video-imaging technique. ResultsIn common with octanoic acid, addition of methyl octanoate or n-octanol resulted in a rapid, pronounced and reversible inhibition of VRAC activity. Addition of n-octane had no significant effect on VRAC activity. n-Octanol had a biphasic effect on β-cell membrane potential, namely a small transient depolarization followed by a marked hyperpolarization. n-Octanol was also found to prevent regulatory volume decrease in cells exposed to a hypotonic medium, consistent with VRAC inhibition. ConclusionIt is suggested that methyl octanoate and n-octanol can mimic the effects of FFAs on the pancreatic β-cell via modulation of VRAC activity. The structural requirements for this effect appear to be a medium or long chain aliphatic compound containing at least one oxygen atom.

Blending effects on ignition delay times of methyl octanoate/n-nonane/methylcyclohexane

Ignition delay times were measured behind reflected shock waves under highly dilute conditions (99% Ar) for 10 ternary blends of methyl octanoate, n-nonane, and methylcyclohexane (MCH), using a Design of Experiments approach, namely an L9 array. Measurements were obtained over a wide range of temperature (1258<T (K)<1630), pressure (1.5<P (atm)<9.5), and equivalence ratio (ϕ=0.5, 1.0, 2.0). The series of experiments focused on the effects of variation in relative fuel volume fractions to assess respective influence of hydrocarbon class (i.e. methyl ester, n-alkane, cycloalkane) on ignition delay times of blended fuel. The L9 array utilized for the design of the experimental test matrix led to the development of an empirical ignition delay time correlation which was then employed for a broad series of calculations examining the effects of fuel-ratio variation. Results of the calculations show that addition of methyl octanoate to blends of n-nonane and MCH lowers the power-law pressure dependence of ignition delay times of such blends (the latter two species share similar dependence on pressure). The correlation also shows MCH as the most dominant of the three fuels in the blends studied with respect to controlling ignition delay time, a finding supported by ignition delay time-sensitivity calculations. Calculation of blending effects, defined herein as deviation from neat-fuel behavior, using the correlation indicated several key features of the studied blends. First, for fixed MCH concentration in a ternary blend, correlation calculations revealed an insensitivity of ignition delay time to variation in the ratio of methyl octanoate to n-nonane for all conditions. Second, blending effects on ignition delay times depend strongly on blend composition and on experimental conditions (pressure, equivalence ratio, temperature), indicating fuel- and condition-specific complexities, although were generally more pronounced at lower temperature. Third, of the three experimental conditions varied, ignition delay times of fuel blends exhibited the most sensitivity to equivalence ratio. To support experimental results, the study also involved compilation of a detailed chemical kinetics mechanism (4815 reactions, 1082 species) by integrating pertinent reaction chemistry from two independently validated mechanisms into a base model for n-nonane oxidation from a previous study by the authors. Model-based calculations indicate that under stoichiometric conditions near 10atm, blending effects are negligible above 1350K yet become increasingly significant towards lower temperature. Lastly, to assess the importance of blending effects, ignition delay times of fuel blends measured experimentally were compared against times calculated using a linear combination method (i.e. superposition of constituent-fuel ignition delay times). In general, superposition of neat-fuel trends cannot be utilized to reproduce ignition trends of the fuel blends herein, highlighting the importance of and continued need for blended-fuel studies.

Heterogeneous basic catalysis for upgrading of biofuels

The liquid product (biofuel) obtained from biomass pyrolysis has a very complex composition that consists of a mixture of different organic compounds. This mixture presents a high content of oxygenated groups (aldehydes, acids, esters, etc.) that reduce the quality of the biofuel. The deoxygenation of these biofuels improves their quality, reducing the viscosity, increasing the calorific value and improving their thermal stability. In this sense, the deoxygenation of methyl octanoate was carried out over different catalysts with basic properties such as FAU zeolites, SBA-15 ordered mesoporous silicate and clays like sepiolite and hydrolacite. Enhancement of its basic properties was carried out by ion-exchange and/or by impregnation with CsOH. Among these catalysts only over X zeolite was obtained good activity and selectivities to the desired products (C6, C7 and C8 hydrocarbons), especially over the ones with low silicon/aluminum molar ratio. The decrease of the electronegativity of the exchangeable cation in the X zeolite (KNaX1 and CsNaX1) allowed to improve the selectivity to C6 and C7 hydrocarbons (60%). Furthermore, the presence of cesium hydroxide (10wt%) on the zeolite (CsI-NaX1) produced significant conversion of methyl octanoate (70%) with high selectivity to alkenes (53%) reaching a desired/undesired product ratio of 7.3.

Impact of the Mediterranean fruit fly (Medfly) Ceratitis capitata on different peach cultivars: The possible role of peach volatile compounds

The relationship between susceptibility of different peach cultivars (cvs) to the Mediterranean fruit fly (medfly), Ceratitis capitata, and the volatile composition of ripe fruit of each cv has been investigated, since understanding the fruit-insect interaction mechanism is crucial for developing control strategies for such a pest. Volatile compounds were analyzed by SPME–GC–MS in three cvs highly susceptible to medfly attack (Fair Time, Flaminia, Sicilia Piatta), and in two less susceptible cvs (Percoca Romagnola 7 and Doctor Davis). Among the volatile compounds detected, 88 could be identified. The main differences found in the volatile composition of the cvs, concerned the relative abundance of esters. The least susceptible cvs, above all Percoca Romagnola 7, contained the higher amounts of hexenyl, hexyl, 3-methylbutyl, butyl and 2-methylpropyl esters; among these, some C6 derivatives detected, such as (Z)-3-hexenyl acetate, are known to act as priming agents, enhancing plant defence response to insects. Instead, a lower relative content of methyl esters, such as methyl hexanoate and methyl octanoate, known to act as medfly pheromone and attractant respectively, was found in the least susceptible cvs.

Effect of Unsaturated Bond on NOx and PAH Formation in n-Heptane and 1-Heptene Triple Flames

Various engine and shock tube studies have observed increased NOx emissions from the combustion of biodiesels relative to regular diesel and linked them to the degree of unsaturation or the number of double bonds in the molecular structure of long-chain biodiesel fuels. We report herein a numerical investigation on the structure and emission characteristics of triple flames burning n-heptane and 1-heptene fuels, which represent, respectively, the hydrocarbon side chain of the saturated (methyl octanoate) and unsaturated (methyl octenoate) biodiesel surrogates. Our objective is to examine the effect of unsaturated (double) bond on NOx and soot emissions in a flame environment containing regions of lean premixed, rich premixed, and nonpremixed combustion. A validated detailed kinetic model with 198 species and 4932 reactions was used to simulate triple flames in a counterflow configuration with different levels of premixing and strain rates. Results indicate that although the global structures of n-heptane and 1-heptene triple flames are quite similar, there are significant differences with respect to NOx and polycyclic aromatic hydrocarbon (PAH) emissions from these flames. The NOx production rates in the rich premixed, lean premixed, and nonpremixed zones are higher in 1-heptene flames than in n-heptane flames, and the differences become more pronounced as the level of premixing is increased. The NOx formed through the prompt, thermal, N2O, and NNH mechanisms is also higher in 1-heptene flames. NOx formation in the rich premixed zone is primarily due to the prompt NO, that in the nonpremixed zone is through the thermal NO, and that in the lean premixed zone is due to the NNH and N2O routes. The PAH species are mainly formed in the rich premixed zone, and their emissions are significantly higher in 1-heptene flames than in n-heptane flames. The reaction pathway analysis indicated that the dominant path for benzene formation involves the recombination of two propargyl (C3H3) radicals, and the presence of the double bond in 1-heptene provides a significant route for its production through the formation of C3H5. This path is not favored in the oxidation of n-heptane, as it decomposes directly to smaller alkyl radicals. Whereas the NOx and PAH emissions decrease with the increase in strain rate, they are consistently higher in 1-heptne flames than in n-heptane flames, irrespective of the strain rate.

Ignition behavior of pure and blended methyl octanoate, n-nonane, and methylcyclohexane

Excited-state species profiles and ignition delay times were obtained under dilute conditions (99% Ar) using a heated shock tube for methyl octanoate (C9H18O2), n-nonane (n-C9H20), and methylcyclohexane (MCH) over a broad range of temperature and equivalence ratio (ϕ=0.5, 1.0, 2.0) at pressures near 1 and 10atm. Measurements were then extended to include two ternary blends of the fuels using 5% and 20% (vol.) of the methyl ester under stoichiometric conditions. Using three independently validated chemical kinetics mechanisms, a model was compiled to assess the influence of methyl ester concentration on ignition delay times of the ternary blends. Under near-atmospheric pressure, ignition delay times were of the following order for the pure fuels: methyl octanoate<n-nonane<methylcyclohexane. Experimental results indicate that the ignition behavior of the higher-order methyl ester approaches that of the higher-order linear alkane with increased pressure regardless of equivalence ratio. Methyl octanoate also displayed significantly lower pressure dependence relative to the linear alkane and the cycloalkane species. Both of these results are supported by model calculations. Blending of methyl octanoate with n-nonane and methylcyclohexane impacted ignition delay time results more strongly at 1.5atm, yet had only a small effect near 10atm for temperatures above 1400K. The study provides the first shock-tube data for a ternary blend of a linear alkane, a cycloalkane, and a methyl ester. Ignition delay time measurements for the C9:0 methyl ester were also measured for the first time.

Experimental and Numerical Study of F-T/Biodiesel/Bioethanol Surrogate Fuel Oxidation in Jet-Stirred Reactor

Blends of Fischer–Tropsch (F-T) fuels, biodiesel, and ethanol seem to be a promising fuel for compression ignition (CI) engine applications. An advanced control of current diesel engines requires a detailed comprehension of the fuel chemistry in terms of auto-ignition and pollutant formation. However, neither experimental data, nor convenient combustion models are available for such an alternative fuel. Therefore, the kinetics of oxidation of F-T, F-T/biodiesel, and F-T/biodiesel/bioethanol surrogate fuel (n-decane, iso-octane, methyl octanoate, and ethanol) were studied experimentally in a jet-stirred reactor (JSR) at 10 atm and constant residence time of 1 s, over the temperature range of 560–1160 K, and for several equivalence ratios (0.5–2.0). The oxidation of these fuels was modeled using a detailed chemical kinetic reaction mechanism consisting of 9919 reactions and 2202 species. The proposed kinetic reaction mechanism yields a good representation of the kinetics of oxidation of the tested biofuel blends. Supplemental materials are available for this article. Go to the publisher's online edition of Combustion Science and Technology to view the free supplemental file.

Applicability of a simple laboratory setup for the extractive hydrolysis using immobilized enzymes

The enzymatic hydrolysis of methyl octanoate performed in a simple laboratory packed-bed reactor arrangement using immobilized Candida antarctica lipase B as catalyst was studied. The reaction system comprised two liquid phases (aqueous and organic), which were formed only by the reacting species, and the solid catalyst phase. The experimental arrangement could be operated in two modes which enabled passing either only the organic phase through the packed bed (mixer-settler mode), or an emulsion. The analysis of the achieved conversion courses and the explanation of the reaction behavior were done based on a previously published model. The mathematical model was parameterized from experiments with two-phase flow through the packed bed and then applied to the singular phase flow mode. From the model calculations and experimental results it could be concluded that both operation modes are capable to exhibit the same reaction rates. With the model based analysis, measuring of the density courses is sufficient to retrieve the kinetic parameters when the thermodynamic parameters are known.

Numerical Study of NOx Emissions from n-Heptane and 1-Heptene Counterflow Flames

Several engine studies have observed higher amounts of nitric oxide (NO) during the combustion of biodiesel fuels than from regular diesel. One hypothesis for the increased NO formation is that unsaturated components in biodiesel fuels produce higher amounts of acetylene, especially during fuel-rich oxidation, which results in higher prompt NO. In this study, we examine this hypothesis by considering partially premixed flames (PPFs) in an opposed jet configuration, burning prevaporized n-heptane and 1-heptene fuels, which represent the hydrocarbon side chain of the two surrogate biodiesel esters, methyl octanoate (C9:0) and methyl octenoate (C9:1), respectively. The configuration involves two opposing jets, one containing a fuel–air mixture issuing from the bottom nozzle and the other containing air issuing from the top nozzle. It provides a nearly one-dimensional flat flame for detailed measurements and simulations and is well-suited for fundamental investigations of kinetics and transport processes. Using a comprehensive chemistry and transport model, PPFs are simulated for a range of equivalence ratios (ϕ). Results indicate that the β-scission and oxidation reactions related to the C═C double bond lead to a higher amount of C2H2 and, thus, increased NO through the prompt mechanism in 1-heptene flames compared to that in n-heptane flames. However, differences in the NO formation between the two fuels become less noticeable as the level of partial premixing is reduced or as ϕ is increased toward the diffusion flame limit. In addition, analysis of the various NO production pathways indicate that the total NO formed is mainly due to the prompt NO and intermediate N2O mechanisms, followed by the NNH and thermal NO mechanisms.

Consideration on the Relationship Between Dielectric Breakdown Voltage and Water Content in Fatty Acid Esters

AbstractMineral oil is commonly used as an electrical insulating oil in transformers because of its relatively high electrical insulating ability and fluidity. Considering the depletion of resources and environmental problems, however, fatty acid esters synthesized from natural plant oils are attracting attention as an environmentally friendly insulating oil. In addition, fatty acid esters such as methyl octanoate, methyl dodecanoate, 2‐ethylhexyl octanoate, and 2‐ethylhexyl dodecanoate have high fluidity, and also show excellent moisture tolerance against dielectric breakdown compared to mineral oil. In the present study, to clarify the reason for the superior moisture tolerance of fatty acid esters, the status of dissolved water in esters is investigated with IR spectroscopic measurements and density functional theory (DFT) calculations. It is revealed that water molecules in fatty acid esters are trapped by the ester moiety of fatty acid esters. As a result, fatty acid esters have a higher moisture tolerance against dielectric breakdown than mineral oil.

Characterization of the volatile profile of Brazilian Merlot wines through comprehensive two dimensional gas chromatography time-of-flight mass spectrometric detection

Wine aroma is an important characteristic and may be related to certain specific parameters, such as raw material and production process. The complexity of Merlot wine aroma was considered suitable for comprehensive two-dimensional gas chromatography (GC×GC), as this technique offers superior performance when compared to one-dimensional gas chromatography (1D-GC). The profile of volatile compounds of Merlot wine was, for the first time, qualitatively analyzed by HS-SPME-GC×GC with a time-of-flight mass spectrometric detector (TOFMS), resulting in 179 compounds tentatively identified by comparison of experimental GC×GC retention indices and mass spectra with literature 1D-GC data and 155 compounds tentatively identified only by mass spectra comparison. A set of GC×GC experimental retention indices was also, for the first time, presented for a specific inverse set of columns. Esters were present in higher number (94), followed by alcohols (80), ketones (29), acids (29), aldehydes (23), terpenes (23), lactones (16), furans (14), sulfur compounds (9), phenols (7), pyrroles (5), C13-norisoprenoids (3), and pyrans (2). GC×GC/TOFMS parameters were improved and optimal conditions were: a polar (polyethylene glycol)/medium polar (50% phenyl 50% dimethyl arylene siloxane) column set, oven temperature offset of 10°C, 7s as modulation period and 1.4s of hot pulse duration. Co-elutions came up to 138 compounds in 1D and some of them were resolved in 2D. Among the co-eluted compounds, thirty-three volatiles co-eluted in both 1D and 2D and their tentative identification was possible only due to spectral deconvolution. Some compounds that might have important contribution to aroma notes were included in these superimposed peaks. Structurally organized distribution of compounds in the 2D space was observed for esters, aldehydes and ketones, alcohols, thiols, lactones, acids and also inside subgroups, as occurred with esters and alcohols. The Fischer Ratio was useful for establishing the analytes responsible for the main differences between Merlot and non-Merlot wines. Differentiation among Merlot wines and wines of other grape varieties were mainly perceived through the following components: ethyl dodecanoate, 1-hexanol, ethyl nonanoate, ethyl hexanoate, ethyl decanoate, dehydro-2-methyl-3(2H)thiophenone, 3-methyl butanoic acid, ethyl tetradecanoate, methyl octanoate, 1,4 butanediol, and 6-methyloctan-1-ol.

Oxidation of Methyl Linoleate Mixed with Methyl Octanoate, Laurate or Palmitate

Oxidation of Methyl Linoleate Mixed with Methyl Octanoate, Laurate or Palmitate

Effect of extra-framework cesium on the deoxygenation of methylester over CsNaX zeolites

The deoxygenation of methyl octanoate has been investigated over Cs-containing NaX zeolite catalysts at atmospheric pressure with He carrier gas and methanol as a co-feed. By varying the preparation procedures, different amounts of extra-framework Cs were left on the catalyst. The presence of extra-framework Cs affects the acid–basic characteristics of the catalysts and consequently their activity, stability, and particularly the product selectivity. That is, when the amount of extra-framework Cs increases, the corresponding increase in basicity enhances decarbonylation activity as well as catalyst stability. In this case, the deoxygenation of methyl octanoate on CsNaX catalysts was found to yield heptenes and hexenes as main products via surface decomposition of octanoate-like species. When the amount of extra-framework Cs was reduced, the hexene yield readily increased. The enhancement in hexene production can be ascribed to both, a decreased basicity that reduces decarbonylation and to a greater space available within the zeolite cavity for formation of a rather bulky cyclic-like intermediate that leads to hexene. In addition, weakly acidic sites, generated after the excess Cs was removed, resulted in relatively higher yield of inner-olefin product. When Cs was not present in the catalyst (i.e., NaX), other products such as aromatics and coupling compounds were observed. These compounds are less desirable for transportation fuel applications.

Biologically derived diesel fuel and NO formation: An experimental and chemical kinetic study, Part 1

Pyrolysis and oxidation experiments have been conducted on two representative biodiesel surrogate components, methyl octanoate (C9:0) and methyl trans-2-octenoate (C9:1), using the UIC High-Pressure Shock Tube (HPST). The nominal experimental pressures ranged from 27 atm to 53 atm and temperatures varied from 900 to 1450 K with nominal reaction times of 1.65 ms. Dilute reagent mixtures of ∼100 ppm of each fuel were prepared in bulk argon and shock heated to study the stable intermediates. The experimental data have been used to develop and validate a kinetic model for the pyrolysis and oxidation of saturated and unsaturated C 8 methyl esters. The developed model has also been coupled to an existing NO mechanism to predict prompt NO formation spanning the experimental temperature regime. It has been predicted that an increased amount of NO is formed from the unsaturated methyl ester, methyl trans-2-octenoate (C9:1) compared to the saturated methyl ester, methyl octanoate (C9:0) over the intermediate temperature range of 1050–1450 K.

Volatile compounds and descriptive odor attributes in umbu (Spondias tuberosa) fruits during maturation

The umbu fruit is appreciated in north and northeast region of Brazil mainly because of its refreshing and acidic flavor. The objective of this work was to determine the volatile compounds in half-ripe and ripe stages of umbu fruit and to identify important characteristic compounds which could contribute for its aroma by performing sniffing evaluation of volatile extracts. The principal volatile compounds identified in the ripe umbu fruit pulp were 4-methyl-3-penten-2-one, ethyl benzene, 1-penten-3-one, 2-acetyl thiazone, p-xylene, limonene, 2,2-dimethyl 4-octenal, 3-hexanol, 2-nonanol, 1-nonanol, 2-pentanol, 2-octanol, 3-methylethyl 2-butanoate, butyl benzoate, 3-allyl cyclohexene, 2-acetyl furan, 2-hexyl furan, β-caryophyllene and methyl pyrazine. A total of 37 volatile compounds were diagnosed with characteristic aroma attributes. The principal volatile compounds which could be responsible for the characteristic aroma of ripe umbu fruit pulp were β-(Z)-ocimene, methyl pyrazine, 2-butyl-thiophene, methyl octanoate, 2-hexyl furan, 2-octanol, (E)-2-cyclohexen-1-one, 3-bromo-cyclohexene, 1-heptanol, 2-nonanol and 1-octanol.

Oxidation of commercial and surrogate bio-Diesel fuels (B30) in a jet-stirred reactor at elevated pressure: Experimental and modeling kinetic study

The oxidation of a commercial B30 (30% FAME by vol.) bio-Diesel fuel and a B30 bio-Diesel surrogate fuel (49% n-decane, CAS 124-18-5; 21% 1-methylnaphthalene, CAS 90-12-0; 30% methyl octanoate, CAS 111-11-5, in mole) was performed using a pressurized fused-silica jet-stirred reactor under the same initial experimental conditions (560–1030K, 6 and 10atm, equivalence ratios of 0.25–1.5, 10,300ppm of carbon). The results of this series of experiments consisted of concentration profiles of reactants, stable intermediates and products measured as a function of temperature by low-pressure probe sampling followed by Fourier transform infrared absorption spectrometry and gas chromatography analyses. The results obtained with the commercial and surrogate B30 mixtures were compared with each other, showing that the mixture n-decane/1-methylnaphthalene/methyl octanoate 49/21/30% in mole is an excellent simple B30 Diesel fuel surrogate. A detailed chemical kinetic reaction mechanism consisting of 7748 reactions involving 1964 species was proposed based on previous chemical kinetic reaction mechanisms for the oxidation of n-decane, methyl octanoate, and 1-methylnaphthalene under similar conditions. The kinetic modeling showed reasonable agreement between the present data and computations over the entire range of conditions considered in this study.

Experimental and kinetic modeling of methyl octanoate oxidation in an opposed-flow diffusion flame and a jet-stirred reactor

New experimental results, consisting of concentration profiles of stable species as a function of temperature, were obtained for the oxidation of methyl octanoate in a jet-stirred reactor (JSR) at 0.101MPa, 0.5<φ<2 and 800<T (K)<1350. In addition, new experimental data, consisting of concentration profiles of stable species as a function of distance from fuel port, generated in an opposed-flow diffusion flame at 0.101MPa are presented. A detailed chemical kinetic model was developed to study the oxidation of methyl octanoate (CAS 111-11-5), a model compound for biodiesel fuels, under the present conditions. The kinetic model consists of 383 chemical species and 2781 chemical reactions (most of them reversible). Experimentally, the oxidation of methyl octanoate in the JSR at atmospheric pressure does not show low temperature and negative temperature coefficient behavior, whereas hot ignition occurs at about 800K. The present modeling results are in reasonably good agreement with the experimental data, describing the intermediate species measured in the jet-stirred reactor and in opposed-flow diffusion flame experiments.

Infuence of MHC on odour perception of 43 chemicals and body odour

AbstractThe Major Histocompatibility Complex (MHC) is a large gene family that is found in most vertebrates and has an important influence on body odour preference and mate selection in animals. In this research we found, that human leukocyte antigen (HLA) phenotype is strongly connected with the strength and pleasantness of perceived odour of selected chemical compounds found in sweat. Among different chemical classes of compounds tested, the esters of fatty acids such as methyl undecanoate, methyl decanoate, methyl nonanoate, methyl octanoate and methyl hexanoate show strongest connection to HLA. On the other hand, our experiment did not confirm the connection of MHC to the perceived strength and pleasantness of body odour.