Advances in the chemistry of tetrahydroquinolines.

Novel catalysts for advanced hydroprocessing: transition metal phosphides

A high level of hydrodenitrogenation (HDN) is required to achieve a desirable conversion of other hydroprocessing reactions. This results from a strong adsorption of nitrogen‐containing compounds on catalytic sites that slows down the hydrogen activation process and hinders the adsorption of other reactants. Studies on model compounds and real feeds indicate that less than 50 ppm of nitrogen in the feed can poison catalytic sites. Kinetic studies determined adsorption constants of various nitrogen‐containing compounds and concluded that at least four different catalytic sites are required to interpret experimental observations in contrast with a dual site site≅concept, which only considered two sites. The advancements in experimental techniques allowed identification of products formed during very early stages of hydrodenitrogenation. These results confirmed that the removal of the amino group from saturated amines, as the last step in hydrodenitrogenation, is governed by the type of carbon to which the a...

Hydrodenitrogenation of Petroleum

High-resolution (100 000 < m/Δm50% < 250 000, in which Δm50% denotes mass spectral peak full width at half-maximum height) electrospray ionization Fourier transform ion cyclotron resonance positive-ion mass spectra of unprocessed (and processed) diesel fuels resolves approximately 500 (and 200) chemically different constituents over a mass range from 200 to 452 Da, with as many as 6 resolved elemental compositions at a given nominal mass. Molecular formulas were assigned from accurate mass measurement to within ±1 ppm. Compound types were identified by Kendrick mass analysis. On the basis of the experimental behavior of model compounds, electrospray ionization was found to ionize selectively basic pyridine homologuescompounds responsible for deactivation of hydrotreatment catalysts and instability of fuels during storage. Compound classes identified in the unprocessed diesel fuel include those containing N, N2, NS, NO, N2O, O2, and SO and, in the processed diesel, N, N2, NO2, and SO. Comparison of unproce...

Elemental Composition Analysis of Processed and Unprocessed Diesel Fuel by Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

https://epublications.marquette.edu/cgi/viewcontent.cgi?article=1693&context=chem_fac

Charge-transfer bonding in metal–arene coordination

Homogeneous models for hydrodenitrogenation catalysis

The reactions of TaCl5 with Me3SiNC9H10 or LiNC9H10, where [NC9H10]- = tetrahydroquinolinyl (the amido anion of tetrahydroquinoline), afford selective preparative routes to the complete series of amido halide complexes of tantalum(V) Ta(NC9H10)nCl5-n for n = 1−5 (compounds 1−5, respectively). The monokis(tetrahydroquinolinyl) complex is isolated as an ether adduct Ta(NC9H10)Cl4(OEt2) while the complexes Ta(NC9H10)nCl5-n (n = 2−5) are found to be base-free, monomeric species. The related complexes of indolinyl [NC8H8]- (the amido anion of indoline), Ta(NC8H8)nCl5-n(THF) for n = 1 (6) or 2 (7), have been prepared from TaCl5, Me3SiNC8H8, and THF. An X-ray structural determination of Ta(NC9H10)2Cl3 (2) reveals that it adopts a trigonal bipyramidal geometry with equatorial amido ligands that are closer to lying parallel (within) than perpendicular to the TBP equatorial plane. Routes to mixed-ligand aryloxide−amide complexes have been developed from either aryloxide or amido precursors but not from both. Thus, ...

Peter A. Fox

Papers

Homogeneous models for hydrodenitrogenation catalysis

Tetrahydroquinolinyl amido and indolinyl amido complexes of tantalum as models for substrate-catalyst adducts in hydrodenitrogenation catalysis

Structural Models for the Substrate−Catalyst Adduct in Hydrodenitrogenation Catalysis: Oxygen vs Sulfur Ligation

Synthetic, Structural, and Redox Studies of Arene Alkyl Complexes of Tantalum(III) Supported by Aryloxide and Arenethiolate Ligands