Kinetic Modeling of α-Hydrogen Abstractions from Unsaturated and Saturated Oxygenate Compounds by Hydrogen Atoms

Paraskevas, Paschalis; Sabbe, Maarten; Reyniers, Marie-Françoise; Papayannakos, N.; Marin, Guy

doi:10.1021/jp503570e

Cited by 20 publications

(32 citation statements)

References 57 publications

(119 reference statements)

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“…The CBS-QB3 composite method is widely used and has been shown to produce accurate enthalpies of formation 22,24,25 and rate coefficients. [32][33][34][35] It was the method of choice for deriving GAV and NNI parameters in the previous studies by Sabbe et al, 22 Vandeputte et al, 24 and Paraskevas et al 25 and it would be the preferred method to extend the GAV database for aromatic species. However, CBS-QB3 calculated bond dissociation energies for the CAH bond in benzene (483.0 kJ mol 21 36 and 415.5 6 3.8 kJ mol 21 , 37 respectively).…”

Section: Electronic Structure Calculationsmentioning

confidence: 99%

First‐principles based group additivity values for thermochemical properties of substituted aromatic compounds

et al. 2015

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A set of 7 Benson group additive values (GAV) together with 15 correction terms for non-nearest neighbor interactions (NNI) is developed to calculate the gas phase standard enthalpies of formation, entropies and heat capacities of monocyclic aromatic compounds containing methyl, ethyl, vinyl, formyl, hydroxyl, and methoxy substituents. These GAVs are obtained through least squares regression of a database of thermodynamic properties of 143 molecules, calculated at the post-Hartree-Fock G4 composite method. Out of the 15 NNIs, which account for several well-known substituent effects in aromatic molecules, 13 have been determined for the first time. All but two group additively calculated standard enthalpies of formation agree within 4 kJ mol 21. The entropies and the heat capacities generally deviate less than 4 J mol 21 K 21 from the ab initio results. Natural bond orbital analysis is utilized to identify the underlying causes of the observed NNIs.

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Section: Electronic Structure Calculationsmentioning

confidence: 99%

First‐principles based group additivity values for thermochemical properties of substituted aromatic compounds

et al. 2015

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“…Reaction rate coefficients of reactions belonging to the reaction families (i) hydrogen abstraction by carbon-centered radicals, (ii) hydrogen abstraction by hydrogen atoms, (iii) carbon-centered β-scission/carbon-centered radical addition and (iv) hydrogen-centered β-scission/hydrogen atom addition were calculated using the group additive databases developed by Marin and coworkers [56][57][58][59]. These authors applied Benson's group additivity concept to transition state theory and derived group additive values from CBS-QB3 calculations at the high-pressure limit.…”

Section: Hydrogen Abstraction and Radical Decomposition Reactionsmentioning

confidence: 99%

Understanding the reactivity of unsaturated alcohols: Experimental and kinetic modeling study of the pyrolysis and oxidation of 3-methyl-2-butenol and 3-methyl-3-butenol

Bruycker

Herbinet

Carstensen

et al. 2016

Combustion and Flame

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. Understanding the reactivity of unsaturated alcohols: Experimental and kinetic modeling study of the pyrolysis and oxidation of 3-methyl-2-butenol and 3-methyl-3-butenol. Combustion and Flame, Elsevier, 2016, 171, pp.237-251. 1 Understanding the reactivity of unsaturated alcohols: Experimental and kinetic modeling study of the pyrolysis and oxidation of 3-methyl-2-butenol and 3-methyl-3-butenol AbstractThe reactivity of unsaturated alcohols with a C=C double bond in the β-and γ-positions to the hydroxyl group is not well established. The pyrolysis and oxidation of two such unsaturated alcohols have been studied, i.e. 3-methyl-2-butenol (prenol) and 3-methyl-3-butenol (isoprenol). Experiments at three equivalence ratios, i.e. φ = 0.5, φ = 1.0 and φ = ∞ (pyrolysis), were performed using an isothermal jet-stirred quartz reactor at temperatures ranging from 500 to 1100 K, a pressure of 0.107 MPa and a residence time of 2 s. The reactant and product concentrations were quantified using gas chromatography. A kinetic model has been developed using the automatic network generation tool "Genesys". Several important rate coefficients are obtained from new quantum chemical calculations. Overall, there is a good agreement between model calculated mole fraction profiles and experimental data. Reaction path analysis reveals that isoprenol consumption is dominated by a unimolecular reaction to formaldehyde and isobutene. At the applied operating conditions, the equivalence ratio has no effect on the isoprenol conversion profile. Pyrolysis and oxidation of prenol is dominated by radical chemistry, with hydrogen abstractions from prenol forming resonantly stabilized radicals as dominating conversion path. Oxidation and decomposition of the resulting radicals are predicted to form 3-methyl-2-butenal and 2-methyl-1,3-butadiene, which have been detected as important products in the reactor effluent.

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“…During coke formation, the reactor cross-sectional area is reduced, increasing the pressure drop over the length of the steam cracker [2]. Consequently, the ethylene selectivity decreases [3,4], while the highly insulating coke layer blocks the heat transfer from the burners to the reactive gas. In order to keep the process productivity stable over the run length, i.e., counterbalance the additional heat resistance, the energy load to the process increases, leading to increased fuel consumption and reactor tube metal temperature.…”

Section: Introductionmentioning

confidence: 99%

Alumina-based Coating for Coke Reduction in Steam Crackers

et al. 2020

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Alumina-based coatings have been claimed as being an advantageous modification in industrial ethylene furnaces. In this work, on-line experimentally measured coking rates of a commercial coating (CoatAlloy™) have pointed out its superiority compared to an uncoated reference material in an electrobalance set-up. Additionally, the effects of presulfiding with 500 ppmw DMDS per H2O, continuous addition of 41 ppmw S per HC of DMDS, and a combination thereof were evaluated during ethane steam cracking under industrially relevant conditions (Tgasphase = 1173 K, Ptot = 0.1 MPa, XC2H6 = 70%, dilution δ = 0.33 kgH2O/kgHC). The examined samples were further evaluated using online thermogravimetry, scanning electron microscopy and energy diffractive X-ray for surface and cross-section analysis together with X-ray photoelectron spectroscopy and wavelength-dispersive X-ray spectroscopy for surface analysis. The passivating coating illustrated a better performance than the reference Ni-Cr Fe-base alloy after application of an improved pretreatment, followed by piddling changes on the product distribution. Presulfiding of the coating affected negatively the observed coking rates in comparison with the reference alloy, so alternative presulfiding and sulfur addition strategies are recommended when using this barrier coating.

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Kinetic Modeling of α-Hydrogen Abstractions from Unsaturated and Saturated Oxygenate Compounds by Hydrogen Atoms

Cited by 20 publications

References 57 publications

First‐principles based group additivity values for thermochemical properties of substituted aromatic compounds

First‐principles based group additivity values for thermochemical properties of substituted aromatic compounds

Understanding the reactivity of unsaturated alcohols: Experimental and kinetic modeling study of the pyrolysis and oxidation of 3-methyl-2-butenol and 3-methyl-3-butenol

Alumina-based Coating for Coke Reduction in Steam Crackers

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