Exploring the high-temperature kinetics of diethyl carbonate (DEC) under pyrolysis and flame conditions

Abstract

To pursue insights into the high-temperature kinetics of diethyl carbonate (DEC), a potential clean oxygenated additive for diesel fuels, a systematical kinetic investigation was carried out in this work. Species mole fraction variations were recorded by a gas chromatography (GC) system during the pyrolysis of DEC in a flow reactor under three different pressures (30, 150 and 780 Torr). And quantitative measurements were conducted for over thirty species in a fuel-rich (ϕ=1.5) premixed DEC/O 2 /argon flame using synchrotron vacuum ultraviolet photoionization mass spectrometry. Pressure-dependent rate coefficients for DEC unimolecular decompositions were obtained with RRKM/master equation calculations. A kinetic model for DEC high-temperature pyrolysis and combustion was developed employing the calculated kinetic parameters, which could well predict all available measurements. Model analysis revealed that a two-step molecular elimination pathway exclusively led to the fuel decomposition under pyrolysis conditions, while in the premixed flame the fuel was consumed mainly by hydrogen abstractions from the secondary carbon atoms. The pyrolysis and combustion behaviors of DEC were compared with those of dimethyl carbonate (DMC), a simpler homologue of DEC, under similar conditions. It was found that DEC was of less thermal stability during the pyrolysis and that C 2 intermediates were of much higher concentrations in the DEC flame. Furthermore, it was found that DEC shared combustion characteristics with some other oxygenated fuels possessing specific common structural features.

Diethyl Carbonate Synthesis from CO₂, Ethanol and Propylene Oxide in the presence of Dehydrating Agent of Ethylene over the novel catalysts of Supported Ni-Cu@Na₃PW₁₂O₄₀ and Mixed Ni-Cu@Na₃PW₁₂O₄₀

“…The best result of supported method was less than the result of mixed method. Compared with the literatures [42][43][44][45][46][47][48][49][50][51][52] reported in recent years, this result was a major breakthrough.…”

Review of the Influence of Oxygenated Additives on the Combustion Chemistry of Hydrocarbons

“…By decomposing via route , two oxygen atoms remain bonded to a single carbon atom in the form of CO 2 , and with that the oxygen atoms are not effectively contributing to the removal of carbon atoms from the reactive medium, thus participating less in the reduction of soot precursor formation . While recent theoretical work , indicates that route is more energy favored under combustion conditions, which means oxygen atoms in oxygenated compounds with ROC­(O) structures are not effective in reducing soot formation. A recent work by Salamanca et al not only tested the effects of two different oxygenates, but also compared the flame species pools using different hydrocarbon base fuels.…”

Biodiesel at the Crossroads: A Critical Review

“…A DMC and diesel blend may also have potential in the reduction of yet unregulated carcinogenic emissions such as benzene and 1,3-butadiene [250][251][252][253][254]. Similarly to these processes, the use of diethyl carbonate (DEC) instead of DMC has been much less investigate [221,227,234], although the available results in literature [255][256][257][258][259][260][261][262][263][264][265][266] allow us to conclude that they exhibit a behavior very similar to those obtained with DMC.…”