Fundamental hydrodenitrogenation studies of polycyclic N-containing compounds found in heavy oils. 1. 5,6-benzoquinoline
The hydrodenitrogenation reactions of 5,6-benzoquinoline (1), a component of heavy oils, were systematically investigated as a function of reaction time, temperature, sulfided catalyst type, and CS/sub 2/ (H/sub 2/S) concentration in the reactant solution. Kinetic rate constants and activation energies were determined for each step of a complex reaction network, which comprises fast hydrogenation of the pyridine ring in 1 (kappa/sub 1/) to yield 1,2,3,4-tetrahydro-5,6-benzoquinoline (2), followed by two competing reactions, i.e., slow C-N hydrogenolysis (kappa/sub 2/) versus fast ring hydrogenation (kappa/sub 3/) of 2 to yield 1-propylnaphthalene (5) and 1,2,3,4,7,8,9,10-octahydro-5,6-benzoquinoline (3a), respectively. The intermediate compound 3a likewise undergoes competing C-N hydrogenolysis (kappa/sub 5/) versus further ring hydrogenation (kappa/sub 6/) to yield 1-propyl-1,2,3,4-tetrahydronaphthalene (4a) and perhydro-5,6-benzoquinole (6), respectively. Under the experimental conditions (temperature, 79-330/sup 0/C; H/sub 2/ pressure, 2500 psig; sulfided CoMo and NiMo catalysts), kappa/sub 3/ >> kappa/sub 2/, while kappa/sub 5/ > kappa/sub 6/, indicating that (aromatic) C-N bond hydrogenolysis is much slower, whereas (aliphatic) C-N bond hydrogenolysis is faster, as compared with competing ring hydrogenation. Activation energies (kilocalories/mole) determined were 12.4 for hydrogenation of a conjugated pyridine ring, 12.7 for a conjugated benzene ring, and 39.4 for a nonconjugated (single) benzene ring; 24.4 for (aliphatic) C-N bond hydrogenolysis, and 49.4 for (aromatic) C-N bond hydrogenolysis. The high H/sub 2/ consumption in the overall HDN process underlines the need for improved sulfided catalysts, possessing augmented C-N hydrogenolysis versus ring hydrogenation selectivity.
- Research Organization:
- Dept. of Fuels Engineering, Univ. of Utah, Salt Lake City, UT (US)
- OSTI ID:
- 6160359
- Journal Information:
- Ind. Eng. Chem. Res.; (United States), Journal Name: Ind. Eng. Chem. Res.; (United States) Journal Issue: 2 Vol. 28:2; ISSN IECRE
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020400* -- Petroleum-- Processing
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
AROMATICS
AZAARENES
AZINES
BENZENE
BENZOQUINONES
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL BONDS
CHEMICAL COMPOSITION
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COBALT
DATA
DENITRIFICATION
ELEMENTS
ENERGY SOURCES
EXPERIMENTAL DATA
FOSSIL FUELS
FUELS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROGEN SULFIDES
HYDROGENATION
INFORMATION
KINETICS
METALS
MOLYBDENUM
NICKEL
NITRO COMPOUNDS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PETROLEUM
PETROLEUM PRODUCTS
POLYCYCLIC NITRO COMPOUNDS
PYRIDINE
PYRIDINES
QUINOLINES
QUINONES
REACTION KINETICS
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENTS
VISCOSITY