Papers by Christophe Bouchy
ChemCatChem, 2021
The transformation of cycloalkanes is a key‐reaction in refining and petrochemistry. Herein, we u... more The transformation of cycloalkanes is a key‐reaction in refining and petrochemistry. Herein, we unravel the mechanism and the kinetics of the transformation of ethylcyclohexane, considering a bifunctional catalyst composed of platinum and of the EU‐1 zeolite, by experiments, density functional theory (DFT) calculations and DFT‐based microkinetic modeling. The simulated mechanisms involve carbenium intermediates. DFT shows the central kinetic role of the π‐complexes corresponding to secondary carbenium ions. Cycle contractions and expansions appear to be rate‐limiting. The DFT‐based microkinetic model includes a limited number of kinetic parameters optimized by regression with respect to the experimental data. The agreement with experimental results is very good, showing that the mechanisms proposed, the nature of the intermediates, and the values of the computed rate constants, are relevant. The reaction starts by the cycle contraction of 1‐ethylcyclohexene, then shifts to a second sequence of cycle expansion‐contraction reactions by intercalated methyl‐shifts.
The invention relates to a process for converting a paraffinic feedstock consists of hydrocarbons... more The invention relates to a process for converting a paraffinic feedstock consists of hydrocarbons having a number of carbon atoms between 9 and 25, wherein said waxy feed is produced from renewable resources, with the exception of paraffin obtained loads by a process involving a step of recovery by the Fischer-Tropsch route, said process employing a catalyst comprising at least one hydro-dehydrogenating metal chosen from the group formed by metals from group VIB and group VIII of the classification periodic, taken alone or in admixture and a carrier comprising at least one zeolite Nu-10 and at least one silica-alumina, said process being carried out at a temperature between 150 and 500 ° C, at a pressure between 0.1 MPa and 15 MPa, at an hourly space velocity between 0.1 and 10 h -1 and in the presence of a total amount of hydrogen mixed with the feedstock such that the ratio hydrogen / feed is between 70 and 2000 Nm 3 / m 3 of feed.
Industrial & Engineering Chemistry Research, 2020
Most industrial hydrocracking catalysts contain metal sulfides. It is commonly accepted that sulf... more Most industrial hydrocracking catalysts contain metal sulfides. It is commonly accepted that sulfide-based bifunctional hydrocracking catalysts are less well balanced than Ptbased catalysts, because of their weak (de)hydrogenation activity. However, the difference in catalytic performances between the two catalysts has never been quantified. In the present work, hydrocracking catalysts were prepared by shaping the USY zeolite CBV720 with alumina binder. Acidity was varied by changing the USY content. The extudates were impregnated either with platinum or with nickel-molybdenum-phosphate and evaluated in the hydroconversion of nhexadecane. In the absence of NH 3 , NiMo sulfide was unable to supply the acid sites and to avoid cracking reactions. Cracking became the dominating pathway. In the presence of NH 3 , 2 only a tiny fraction of the acid sites was vacant. This allowed the NiMo sulfide catalysts to become fairly well balanced, if the zeolite loading was low. Increasing zeolite loading led to a deviation from ideality. Pt catalysts were, with one single exception (at very high USY content), always balanced, even in the absence of NH 3 .
Catalysis Science & Technology, 2017
Mixtures of bifunctional catalysts exhibited cooperative effects in the hydroisomerization of n-h... more Mixtures of bifunctional catalysts exhibited cooperative effects in the hydroisomerization of n-hexadecane. The performance of a hybrid can be simulated based on those of individuals, as illustrated.
Http Www Theses Fr, 1998
La reduction-carburation de l'oxyde de molybdene moo#3 sous flux reactionnel hydrogene-hydroc... more La reduction-carburation de l'oxyde de molybdene moo#3 sous flux reactionnel hydrogene-hydrocarbure en isotherme a 350c et sous pression moyenne a ete etudiee. Le moo#3 se transforme en moo#2 et en oxycarbohydrure de molybdene, ce dernier etant catalytiquement actif pour l'isomerisation des alcanes. La transformation de moo#3 en oxycarbohydrure est topotactique, et passe par l'intermediaire de composes de type bronzes de molybdene et d'hydrogene. La synthese de bronzes de molybdene et d'hydrogene h#xmoo#3 a ensuite permis la preparation de la phase oxycarbohydrure massique pure pour la premiere fois, avec les memes proprietes catalytiques. Les proprietes isomerisantes du catalyseur obtenu a partir de bronzes de molybdene et d'hydrogene dependent fortement du mode de preparation des bronzes, et une synthese du precurseur par voie anhydre s'avere necessaire. Des simulations drx montrent que l'oxycarbohydrure, de stoechiometrie moo#2#,#4#2c#0#,#2#3h#0#,#7#8, adopte une structure cubique faces centrees et presente une surstoechiometrie importante en heteroelements par rapport aux nitrures et carbures de molybdene usuels. La synthese d'une phase oxyhydrure, isotype a la phase oxycarbohydrure, s'avere egalement possible par reduction simple de moo#3 sous flux d'hydrogene pur. Les caracterisations par reaction en temperature programmee ont montre qu'au contact du flux reactionnel, l'oxyhydrure fixe instantanement du carbone de l'hydrocarbure pour former en surface la phase active oxycarbohydrure. Bien que la nature de la phase active ne soit pas modifiee, l'activite finale du catalyseur prepare a partir de moo#3 depend de la morphologie initiale des cristallites de l'oxyde, et apparait correlee a la microporosite developpee par le solide apres transformation.
Journal of Catalysis, 2016
Abstract The impact of crystal size and textural properties of * BEA-type zeolites in the convers... more Abstract The impact of crystal size and textural properties of * BEA-type zeolites in the conversion of ethanol-to-hydrocarbons at 350 °C and under 3.0 MPa pressure is investigated. Three * BEA zeolites (molar ratio Si/Al of ca. 23) with important differences concerning their textural properties are synthesized: a material constituted of micron-sized crystals and two hierarchical porous zeolites with a mesoporous network created either by the aggregation of nanometer-sized crystals or by the use of a gemini-type quaternary ammonium surfactant given a nano-sponge zeolite. The micrometric zeolite favors the formation of polyaromatic molecules in same proportion than the concentration of Bronsted acid sites. The deactivation mode of acid sites is poisoning rather than pore blocking. The short thickness of crystal in the nano-sponge zeolite combined with its low acidity, limit the growth of coke molecules as well as their accumulation inside micropores. Coke precursors (alkylbenzenes) are adsorbed on many silanol group located in the ordered mesopores, but the extreme downsizing of the zeolite crystal leads to an unexpected pore blocking by these light molecules.
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Papers by Christophe Bouchy