The Hydrodenitrogenation Reaction

The mechanisms of heterogeneous HDN have been studied in some detail, albeit in much less depth than those of HDS, and the reader is referred to other reviews and to the original literature cited therein for further details [5, 13, 15, 20, 81-86]. The 

The influence of HjS in the overall HDN rate is explained in this model by a nucleophilic attack on a metal- -pentylamine adduct causing the displacement of ammonia and the consequent formation of a thiolate intermediate which is readily desulfurized under the reaction conditions. 

In conclusion, this first Chapter attempts to provide the non specialist with and a general basis for understanding the importance and the major advances and drawbacks of heterogeneous HDS and HDN reactions, as well as the principal challenges that need to be addressed in the future. It is also meant to provide the context in which the organometallic chemistry related to these processes will be discussed in the rest of the book. Chapter 2 will be devoted to the description of metal complexes of the thiophenes, their syntheses, structures, bonding characteristics and reactivity patterns. 

Mitchell The Chemistry of Some Hydrodesulphurisation Catalysts Containing Molybdenum, Climax Molybdenum Co. Ltd., London (1967). 

Weisser, O. Landa Sulfide Catalysts. Their Properties and Applications, Pergamon, Oxford (1973). F. E. Massoth Adv. Catal. 27, 265 (1978). 

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ER.15 The hydrodenitrogenation reaction was carried out in a batch reactor at 100°C, containing 20g/L C0M0/AI2O3 catalyst. Samples were collected and conversion is calculated with time as shown in the table below ... 

Reaction Kinetics of the Hydrodenitrogenation of Decahydroquinoline over NiMo(P)/Al203 Catalysts... 

P.R. Raithby (eds), vol 2, Wiley-VCH, Weinheim, 1999, 741 (b) R.A. Sanchez-Delgado, Organometallic Modeling of the Hydrodesulfurization and Hydrodenitrogenation Reactions, Kluwar Academic Publishers, Dordrecht, 2002. 

R.A. Sanchez-Delgado, Organometallic Modeling of the Hydrodesuljurization and Hydrodenitrogenation Reactions. Kluwer, Dordrecht, 2002. 

The distribution of bases in the upgraded anthracene oil reflects the various rate constants for the hydrodenitrogenation networks under the specified reaction conditions and catalysts. Consequently, the chemistry of the first homologs in the -11(N) and in the -17(N) series, which account for 0.9 and 1.4% of the feedstock, respectively, is qualitatively considered in terms of the reaction networks for hydrodenitrogenation of known compounds. For ease of presentation, the discussion is formulated in terms of the relevant analytical data for the feedstock and reactor-sample 1. 

A trickle-bed reactor was used to study catalyst deactivation during hydrotreatment of a mixture of 30 wt% SRC and process solvent. The catalyst was Shell 324, NiMo/Al having monodispersed, medium pore diameters. The catalyst zones of the reactors were separated into five sections, and analyzed for pore sizes and coke content. A parallel fouling model is developed to represent the experimental observations. Both model predictions and experimental results consistently show that 1) the coking reactions are parallel to the main reactions, 2) hydrogenation and hydrodenitrogenation activities can be related to catalyst coke content with both time and space, and 3) the coke severely reduces the pore size and restricts the catalyst efficiency. The model is significant because it incorporates a variable diffusi-vity as a function of coke deposition, both time and space profiles for coke are predicted within pellet and reactor, activity is related to coke content, and the model is supported by experimental data. 

The general hydrodenitrogenation reaction mechanism often presented for compounds like quinoline which boils ca. 260°C (500°F) at 760 mm Hg is as follows (2,4) ... 

C) Under the reaction conditions of this study there seems to be no difference in the hydrodenitrogenation activity of MD and BD catalysts for hydrotreating raw anthracene oil. 

Volcano plots, as in this figure, have been measured for very different reactions, e.g., the formic acid decomposition, the ammonia synthesis reaction, hydrodesulfurization, or hydrodenitrogenation reactions. 

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