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), Vol. 28:2, Issue 2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
HYDROCARBONS
CHEMICAL COMPOSITION
PETROLEUM
DENITRIFICATION
HYDROGENATION
QUINOLINES
CHEMICAL REACTIONS
BENZENE
BENZOQUINONES
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
COBALT
EXPERIMENTAL DATA
HYDROGEN SULFIDES
MOLYBDENUM
NICKEL
PETROLEUM PRODUCTS
POLYCYCLIC NITRO COMPOUNDS
PYRIDINE
VISCOSITY
AROMATICS
AZAARENES
AZINES
CHALCOGENIDES
DATA
ELEMENTS
ENERGY SOURCES
FOSSIL FUELS
FUELS
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
INFORMATION
KINETICS
METALS
NITRO COMPOUNDS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PYRIDINES
QUINONES
REACTION KINETICS
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENTS
020400* - Petroleum- Processing
400201 - Chemical & Physicochemical Properties