Experimental and modeling study of the thermal decomposition of methyl decanoate

Abstract

The experimental study of the thermal decomposition of methyl decanoate was performed in a jet-stirred reactor at temperatures ranging from 773 to 1123 K, at residence times between 1 and 4 s, at a pressure of 800 Torr (106.6 kPa) and at high dilution in helium (fuel inlet mole fraction of 0.0218). Species leaving the reactor were analyzed by gas chromatography. Main reaction products were hydrogen, carbon oxides, small hydrocarbons from C to C, large 1-olefins from 1-butene to 1-nonene, and unsaturated esters with one double bond at the end of the alkyl chain from methyl-2-propenoate to methyl-8-nonenoate. At the highest temperatures, the formation of polyunsaturated species was observed: 1,3-butadiene, 1,3-cyclopentadiene, benzene, toluene, indene, and naphthalene. These results were compared with previous ones about the pyrolysis of n-dodecane, an n-alkane of similar size. The reactivity of both molecules was found to be very close. The alkane produces more olefins while the ester yields unsaturated oxygenated compounds. A detailed kinetic model for the thermal decomposition of methyl decanoate has been generated using the version of software EXGAS which was updated to take into account the specific chemistry involved in the oxidation of methyl esters. This model contains 324 species and 3231 reactions. It provided a very good prediction of the experimental data obtained in jet-stirred reactor. The formation of the major products was analyzed. The kinetic analysis showed that the retro-ene reactions of intermediate unsaturated methyl esters are of importance in low reactivity systems.

Detailed chemical kinetics for thermal decomposition of low molecular weight‐methyl esters generated by using biodiesel fuel

“…Therefore, the results of this work will be helpful in future diesel engine technologies to mitigate toxic emissions from BDF combustion. Among the LMWMEs, the decomposition of higher carbon number esters was faster than that of smaller carbon number esters, except for C 8 . C 4 was stable and abundant in the decomposition products and the rate constant increased with increasing temperature.…”

“…E a decreased with increasing carbon number but increased above C 8 . These values may be important in further simulation studies, BDF productions and diesel engine technologies to mitigate LMW-ME emissions during biodiesel usage.…”

“…These results are consistent with the results of our previous study; however, Ratcliff et al did not provide a detailed explanation or report their concentrations. C 4 through C 10 have been observed in the thermal decomposition of methyl decanoate (C 11 H 22 O 2 ) [8], whereas C 4 through C 7 have been detected in the oxidation of methyl decanoate, which has been proposed as a possible BDF surrogate [9]. Pedersen et al [10] conducted the oxidation of rapeseed BDF at 823 K and observed LMW-MEs, such as C 4, C 5 , C 7, and C 8 , of which C 4 was a significant product.…”

“…Numerous kinetic studies of BDFs, including oxidations of BDF blend surrogates [8,9,11], small methyl esters [12], soybean and rapeseed BDF [13], and thermal decompositions of soybean BDF [14] and methyl decanoate [8,15], have been conducted either experimentally or theoretically by using computational modeling. To investigate these kinetic studies, the following laboratory experimental Additional Supporting Information may be found in the online version of this article.…”

Finite Element Simulation of an Unimolecular Thermal Decomposition inside a Reactor

“…The authors conclude that the decomposition proceeds via the molecular path to produce acetylene and carbon monoxide. Recently in [6], an experimental and modelling study of the thermal decomposition of methyl decanoate is performed in a jet-stirred reactor at constant temperature and pressure. A model for the thermal decomposition of methyl decanoate is generated using the software EXGAS.…”