The influence of phosphorus containing compounds on steam cracking of n-hexane

Wang, Jidong; Reyniers, Marie-Françoise; Marin, Guy

doi:10.1016/j.jaap.2006.02.008

Cited by 24 publications

(26 citation statements)

References 29 publications

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“…[29][30][31][32][33][34][35][36][37][38] Experimental evidence supports the idea that additives provide a film to passivate the metal surface of the thermal cracker and therefore prevent its catalyzing coke formation. [29][30][31][32][33][34][35][36] However, a variety of reactions between the additives and the coke surface are also expected to take place. A recent experimental study using SEM and EDX techniques showed that addition of organophosphorus compounds to the naphtha feed not only lowers metal concentration in the coke, but also leads to an altered morphology (i.e., softer coke), in line with the idea that reactions between additives and the coke surface also occur.…”

Section: Introductionmentioning

confidence: 71%

Competitive Reactions of Organophosphorus Radicals on Coke Surfaces

Çatak

Hemelsoet

Hermosilla

et al. 2011

Chemistry A European J

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The efficacy of organophosphorus radicals as anticoking agents was subjected to a computational study in which a representative set of radicals derived from industrially relevant organophosphorus additives was used to explore competitive reaction pathways on the graphene-like coke surface formed during thermal cracking. The aim was to investigate the nature of the competing reactions of different organophosphorus radicals on coke surfaces, and elucidate their mode of attack and inhibiting effect on the forming coke layer by use of contemporary computational methods. Density functional calculations on benzene and a larger polyaromatic hydrocarbon, namely, ovalene, showed that organophosphorus radicals have a high propensity to add to the periphery of the coke surface, inhibiting methyl radical induced hydrogen abstraction, which is known to be a key step in coke growth. Low addition barriers reported for a phosphatidyl radical suggest competitive aptitude against coke formation. Moreover, organophosphorus additives bearing aromatic substituents, which were shown to interact with the coke surface through dispersive π-π stacking interactions, are suggested to play a nontrivial role in hindering further stacking among coke surfaces. This may be the underlying rationale behind experimental observation of softer coke in the presence of organophosphorus radicals. The ultimate goal is to provide information that will be useful in building single-event microkinetic models. This study presents pertinent information on potential reactions that could be taken up in these models.

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Section: Introductionmentioning

confidence: 71%

Competitive Reactions of Organophosphorus Radicals on Coke Surfaces

Çatak

Hemelsoet

Hermosilla

et al. 2011

Chemistry A European J

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“…and as transition metal ligands in both laboratory synthesis and industrial production [2,3]. These compounds can also be used as efficient coke-reducing additives within thermal cracking processes [4,5]. However, experimental thermochemical and kinetic data are either unavailable or available but with relatively large uncertainties [6,7].…”

Section: Introductionmentioning

confidence: 99%

A simple way to predict vibrational zero point energy of organophosphorus (III) compounds

Rahal

Bouabdallah

Malek

et al. 2015

Computational and Theoretical Chemistry

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“…3,4 Our interest in phosphorus-containing species stems from the (experimental) observation that these molecules can be used as efficient coke-reducing additives within thermal cracking processes. 5,6 Unfortunately, the development of kinetic models for this industrially important process has been hampered by a lack of accurate thermochemical and kinetic data as experimental enthalpies of formation are often unknown or known with relatively large uncertainties. Computational results can hence offer a viable alternative.…”

Section: Introductionmentioning

confidence: 99%

“…60 Phosphorus-containing additives have been shown to be effective in inhibiting coking rates during thermal cracking processes. 5,6,[32][33][34][35][36][37] It is believed that the additives provide a film to passivate the metal surface to prevent it from catalyzing the coke formation, however reactions between the additives and the coke surface are also present and are the subject of a next study. A recent experimental study using SEM-and EDX-techniques reports on the changed morphology, i.e., softer coke, and lower concentration of metals in the coke when organophosphorus molecules are added to the naphtha feed.…”

Section: Introductionmentioning

confidence: 99%

Bond Dissociation Energies of Organophosphorus Compounds: an Assessment of Contemporary Ab Initio Procedures

et al. 2010

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Thermodynamic properties of phosphorus-containing compounds were investigated using high-level ab initio computations. An extended set of contemporary density functional theory (DFT) procedures was assessed for their ability to accurately predict bond dissociation energies of a set of phosphoranyl radicals. The results of meta-and double-hybrids as well as more recent methods, in particular M05, M05-2X, M06 and M06-2X, were compared with benchmark G3(MP2)-RAD values. Standard heats of formation, entropies and heat capacities of a set of ten organophosphorus compounds were determined and the low-cost BMK functional was found to provide results consistent with available experimental data. In addition, bond dissociation enthalpies (BDEs) were computed using the BMK, M05-2X and SCS-ROMP2 procedure. The three methods give the same stability trend. The BDEs of the phosphorus(III) molecules were found to be lower than their phosphorus(V) counterparts. Overall the following ordering is found: BDE(P-OPh) < BDE(P-CH 3 ) < BDE(P-Ph) < BDE(P-OCH 3 ).

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The influence of phosphorus containing compounds on steam cracking of n-hexane

Cited by 24 publications

References 29 publications

Competitive Reactions of Organophosphorus Radicals on Coke Surfaces

Competitive Reactions of Organophosphorus Radicals on Coke Surfaces

A simple way to predict vibrational zero point energy of organophosphorus (III) compounds

Bond Dissociation Energies of Organophosphorus Compounds: an Assessment of Contemporary Ab Initio Procedures

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