Hydrodenitrogenation of quinoline and its intermediates over sulfided NiW/γ‐Al₂O₃ in the absence and presence of H₂S

Abstract

Hydrodenitrogenation (HDN) reactions of quinoline and its intermediates were carried out at 300-420• C and 2-6 MPa over sulfided NiW/γ -Al 2 O 3 in the absence and presence of H 2 S. The results show that temperature and pressure have a drastic effect on nitrogen removal and production distribution in the HDN of quinoline. 1,2,3,4-tetrahydroquinoline THQ1 mainly underwent dehydrogenation to quinoline and then hydrogenated to 5,6,7,8-tetrahydroquinoline (THQ5), and decahydroquinoline (DHQ) following by ring opening elimination to give 2-propylcyclohexylamine (PCHA) and hydrocarbons. The HDN of THQ5 mainly proceeded the path of DHQ-PCHA, the reactions between THQ5, DHQ, THQ1 and quinoline are so fast that a quasi equilibrium between the four compounds is established quickly at a very low space time. The addition of H 2 S promotes the reaction of DHQ, but retards the pathway of OPA. The promoting effect of H 2 S is dominant at low concentration of H 2 S. However, its inhibiting effect prevails at high concentrations. The HDN via the pathway of DHQ is much easier than OPA over the sulfided NiW/γ -Al 2 O 3 . The HDN of OPA was suppressed by the presence of Q, THQ1, THQ5, and DHQ, maybe due to their stronger adsorption on the catalyst. 

Hydroprocessing of low-temperature coal tar to produce jet fuel

“…According to the related research, for the hydrogenation reaction, the temperature should not be too high. 39 In addition, the appropriate pressure and the lower LHSV [40][41][42][43] are benecial to the hydrogenation reaction. In this study, the temperature, pressure and LHSV varied in the range of 340-400 C, 4-10 MPa and 0.4-1.0 h À1 , respectively.…”

Hydrodenitrogenation of 2-Methyl Quinoline - Effect of Steric Hindrance in Liquid Phase Catalytic Hydrogenation

“…Postulated HDN mechanisms of model compounds such as indoles, pyridines, quinoline and iso-quinoline have been summarized by few authors [2][3][4][5][6][7][8][9][10]. Also, number of studies has been reported on the steric effect of methyl groups on HDS model compounds such as thiophenes, benzothiophene and dibenzothiphene, but only few studies reported on HDN model compounds such as indoles and pyridines [11][12][13][14][15][16][17].…”

“…Quinoline HDN led to two intermediates formation, such as 1,2,3,4-tetra hydro quinoline (1-THQl) and 5,6,7,8-tetra hydro quinoline in which HYD to 1-THQl was faster as compare to 5-THQl though equilibrium attained [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Also, HYD steps assessed first order but dependent on H2 partial pressure, hydrogenolysis represented by lower-order reaction.…”

Catalytic Hydroconversion of a High-Temperature Coal Tar over Two Attapulgite Powder-Supported Nickel Catalysts

“…It is a complex mainly consisting of condensed arenes along with small amounts of heteroatom-containing species. − Many efforts have been attempted on the catalytic hydroconversion (CHC) of model compounds due to the complexity of HTCT. The CHC includes the hydrogenation of aromatic rings (ARs) and heteroatom removal. − …”