- Alkyl-Aryl Coupling Catalyzed by Tandem Systems of Pincer-Ligated Iridium Complexes and Zeolites
-
We report that pincer-ligated iridium catalysts for alkane dehydrogenation can operate in tandem with zeolite catalysts for arene-alkene coupling, to effect the overall intramolecular dehydrocoupling of alkyl-H and aryl-H bonds (i.e., the dehydrocyclization of alkyl benzene). Thus, zeolite and soluble iridium cocatalysts in refluxing pentylbenzene (205 °C) gave high yields of 1-methyl-1,2,3,4-tetrahydronaphthalene. Subsequent dehydrogenation and isomerization affords 1- and 2-methylnaphthalene and 2-methyl-1,2,3,4-tetrahydronaphthalene. Total yields of cyclized product as high as 5.4 M (94%) have been obtained, corresponding to 6800 turnovers per mol Ir. Turnover numbers for the tandem-catalyzed dehydrocyclization are much greater than those obtained for simple dehydrogenation by Ir catalysts (to give olefins) in the absence of zeolite.
- Dinh, Long V.,Li, Bo,Kumar, Akshai,Schinski, William,Field, Kathleen D.,Kuperman, Alexander,Celik, Fuat E.,Goldman, Alan S.
-
-
Read Online
- Synthesis of renewable alkylated naphthalenes with benzaldehyde and angelica lactone
-
Herein, we report a new route for the synthesis of renewable alkylated naphthalenes (ANs) with benzaldehyde and angelica lactone, two platform compounds that can be derived from lignocellulose.
- Cong, Yu,Li, Guangyi,Li, Ning,Wang, Aiqin,Wang, Ran,Wang, Xiaodong,Xu, Jilei,Zhang, Tao
-
supporting information
p. 5474 - 5480
(2021/08/16)
-
- Nickel–Tungsten and Nickel–Molybdenum Sulfide Diesel Hydrocarbon Hydrogenation Catalysts Synthesized in Pores of Aromatic Polymer Materials
-
Abstract: Porous aromatic polymer materials based on tetraphenylmethane molecules linked by methylene groups have been synthesized. By impregnating these materials with nickel–tungsten and nickel–molybdenum thiosalts, catalysts for the hydrogenation of bicyclic aromatic hydrocarbons of the diesel fraction have been prepared. Nanoparticles of the active sulfide phase are formed in support pores during the reaction; it is assumed that after the formation of the nanoparticles, the support material will undergo partial degradation to rearrange the mesoporous structure into a macroporous structure providing the best diffusion of substrates to the surface of the sulfide nanoparticles. The synthesized catalysts have been tested in the hydrogenation of naphthalene and naphthalene derivatives at a hydrogen pressure of 5 MPa and a temperature of 380°C.
- Batryshin,Makeeva,Kulikov,Kardasheva, Yu. S.,Maksimov,Karakhanov
-
p. 575 - 580
(2019/06/24)
-
- Liquid-phase oxidation of alkylaromatics to aromatic ketones with molecular oxygen over a Mn-based metal-organic framework
-
Liquid-phase oxidation of alkylaromatics with molecular O2 was examined using a microporous Mn-based metal-organic framework (Mn-MOF-74). Mn-MOF-74 consisting of trimeric Mn clusters and 2,5-dihydroxyterephthalate (dhtp) linkers exhibits superior catalytic activity with good ketone selectivity compared to conventional oxide-supported Mn catalysts without showing any lengthy induction period. Combined analyses by means of XRD, FE-SEM, N2 physisorption and Mn K-edge XAFS reveal that the superior catalytic performance is attributed to the inherently-formed Mn(iii)2(dhtp) moieties embedded in the Mn-MOF-74 framework rather than structural factors associated with the MOF. The catalyst is reusable over multiple catalytic runs along with retaining its original catalytic activity due to the ability of the dhtp ligand to stabilize active Mn(iii) atoms. Owing to high activity, reusability and nontoxicity, Mn-MOF-74 can offer a simple, inexpensive and efficient protocol for the oxidation of some important alkylaromatics, such as ethylbenzene and diphenylmethane to produce the corresponding aromatic ketones.
- Kuwahara, Yasutaka,Yoshimura, Yukihiro,Yamashita, Hiromi
-
supporting information
p. 8415 - 8421
(2017/07/12)
-
- Synthesis of nickel-tungsten sulfide hydrodearomatization catalysts by the decomposition of oil-soluble precursors
-
Nickel-tungsten sulfide catalysts for the hydrogenation of aromatic hydrocarbons have been prepared by the in situ decomposition of an oil-soluble tungsten hexacarbonyl precursor in a hydrocarbon feedstock using oil-soluble nickel salt nickel(II) 2-ethylhexanoate as a source of nickel. The in situ synthesized Ni-W-S catalyst has been characterized by X-ray photoelectron spectroscopy. The activity of the resulting catalysts has been studied in the hydrogenation of bicyclic aromatic hydrocarbons and dibenzothiophene conversion in a batch reactor at a temperature of 350°C and a hydrogen pressure of 5.0 MPa. It has been shown that the optimum W: Ni molar ratio is 1: 2. Using the example of the hydrofining of feedstock with high sulfur and aromatics contents, it has been shown that the synthesized catalyst exhibits high activity in the hydrogenation of aromatic hydrocarbons.
- Sizova,Kulikov,Onishchenko,Serdyukov,Maksimov
-
-
- The hydrogenation of aromatic-naphthalene with Ni2P/CNTs
-
Ni2P/CNTs was synthesized using an impregnation method. XPS revealed that CNTs could affect the electronic properties of bulk Ni2P. The catalyst shows superior activity for HYD of naphthalene with a conversion of 99%, and demonstrates superior tolerance towards potential catalyst poisons, which is higher than Ni/CNTs with a conversion of 89%.
- Ruan, Minzhi,Guan, Jun,He, Demin,Meng, Tao,Zhang, Qiumin
-
p. 57700 - 57703
(2015/07/20)
-
- Nickel-tungsten sulfide aromatic hydrocarbon hydrogenation catalysts synthesized in situ in a hydrocarbon medium
-
Nickel-tungsten sulfide nanocatalysts for the hydrogenation of aromatic hydrocarbons (HCs) have been prepared by the in situ decomposition of a nickel thiotungstate precursor in a HC feedstock using 1-butyl-1-methylpiperidinium nickel thiotungstate complex [BMPip]2Ni[WS4]2 as the precursor. The in situ synthesized particles have been characterized by X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. It has been shown that the resulting Ni-W-S particles are nanoplates associated in multilayer agglomerates; the average length of the Ni-W-S particles is 6 nm; the average number of layers in the multilayer packaging is three. The catalytic activity of the synthesized catalysts has been studied in the hydrogenation of model mixtures of mono- and bicyclic aromatic HCs and in the conversion of dibenzothiophene in a batch reactor at a temperature of 350°C and a hydrogen pressure of 5.0 MPa. It has been shown that the studied catalysts can be used for the hydrofining of light cycle oil.
- Sizova,Serdyukov,Maksimov
-
p. 470 - 480
(2015/11/23)
-
- Conversion of decalin and 1-methylnaphthalene over AlSBA-15 supported Pt catalysts
-
Platinum catalysts (1.5 wt.%) containing AlSBA-15 obtained with various aluminium precursors were tested for activity in 1-methylnaphthalene hydrogenation. Experiments were carried out in a continuous-flow system at atmospheric pressure (240-350 °C, W/F = 0.8 g s/cm3). It was found that 1-methylnaphthalene conversion over Pt-loaded catalysts was not influenced by the aluminium precursor used in the preparation of the Pt/AlSBA-15 catalysts. However, the Pt catalyst prepared with AlSBA-15 obtained from aluminium sulphate provided a higher cis-methyldecalins/trans-methyldecalins ratio in the reaction products as compared to the catalysts obtained with aluminium nitrate or aluminium isopropoxide. Consideration was also given to the influence of platinum amount (0.5, 2.5 and 4.5 wt.%) on the catalytic performance of bifunctional Pt/AlSBA-15 catalysts (AlSBA-15 obtained with aluminium sulphate) in decalin hydroconversion. It was shown that impregnation of AlSBA-15 with H2PtCl6 increased Bronsted acidity. Investigations into decalin conversion were conducted in a continuous-flow system with a fixed-bed reactor (5 MPa, 300-380 °C, H2:CH = 500 N m3/m3; WHSV = 2 h-1). Incorporation of 0.5 wt.% Pt into AlSBA-15 yielded a catalyst with the highest dispersion of the platinum phase and the highest yield of ring opening products, amounting to 26.4 wt.% at 380 °C.
- Jaroszewska,Masalska,Ba?czkowska,Grzechowiak
-
p. 110 - 118
(2013/01/15)
-
- Catalyses of Fe and FeS2 on the Reaction of Di(1-naphthyl)methane
-
Reactions of di(1-naphthyl)methane (DNM) over Fe and FeS2 at 300 deg C were carried out to investigate the catalytic activities and selectivities of the two catalysts.Both catalysts showed high activities for the reaction of DNM but Fe catalyzed DNM hydrogenation whereas FeS2 catalyzed DNM hydrocracking.This difference can be ascribed to the presence of sulfur.
- Wei, Xian-yong,Ogata, Eisuke,Niki, Etsuo
-
p. 2199 - 2202
(2007/10/02)
-
- Photochemistry of 3-methyl- and 4-methyl-1,2-dihydronaphthalene in solution
-
Photolysis of 3-methyl-1,2-dihydronaphthalene (3-MDHN) in hexane solution with 254-nm light produces one major product, 5-methylbenzobicyclo[3.1.0]hex-2-ene(5-MBBH; φ = 4.7 × 10-4). Photolysis in hexane in the presence of trifluoroacetic acid produces exclusively 2-methylene-1,2,3,4-tetrahydronaphthalene (2-MTHN). The 254-nm photolysis of 4-methyl-1,2-dihydronaphthalene (4-MDHN) in hexane produces 2-(o-tolyl)-1,3-butadiene (T13B; φ= 2.2 × 10-3), 1-methylbenzobicyclo[3.1.0]hex-2-ene (1-MBBH; φ= 1.4 × 10-3), 1 -methyl- 1,4-dihydronaphthalene (1-M-1,4-DHN; φ= 8.7 × 10-3), 1-methyltetralin (1-MT; φ= 1.5 × 10-3), and 1-methylnaphthalene (1-MN; φ= 2.7 × 10-3). Triplet sensitization of 4-MDHN produces only 1-MN in small amounts, suggesting that the direct photolyses proceed via singlet chemistry. The products appear to derive from a combination of electrocyclic opening of the cyclohexadienyl ring to generate an o-quinodimethane intermediate, disproportionation leading to net oxidation-reduction and, in 4-MDHN, a [1,3] hydrogen shift to form 1-M-1,4-DHN. The o-quinodimethane intermediates further react to form benzobicyclo[3.1.0]hex-2-ene derivatives (via a photochemical [4 + 2] cycloaddition; Scheme VI) and, in the case of 4-MDHN, the 1,3-butadiene T13B (via a thermal [1,5] hydrogen shift; Scheme VII).
- Duguid, Robert J.,Morrison, Harry
-
p. 1265 - 1271
(2007/10/02)
-
- Reduction of Polycyclic Arenes by BH-Boranes, II Borane Catalyzed Hydrogenation of Naphthalenes to Tetralins
-
Tetrapropyldiborane(6) (TPDB) and triethylborane (TEB) catalyze the regioselective and partial hydrogenation of naphthalene (N) and a number of substituted naphthalenes at 170 deg C to 200 deg C and hydrogen pressures of 25-100 bar.Tetralin (T) is formed quantitatively.Naphthalene derivatives are mainly hydrogenated in the least substituted ring.In the case of alkyl substituents, Lewis acid catalyzed migration and, to a lesser extent C-C bond rupture, lower the yield of the main tetralin derivative.Chlorinated naphthalenes and at the O-atom derivatized naphthols undergo also partial loss of the chloro or oxygen functional groups.The i nitially added borane acts only as a precatalyst and its slowly converted to catalytically active polyboranes of as yet unknown structures.Keywords: Hydroboranes/ Hydrogenation/ Naphthalenes/ Tetralins
- Yalpani, Mohamed,Lunow, Thomas,Koester, Roland
-
p. 687 - 694
(2007/10/02)
-
- Intramolecular Friedel-Crafts Alkylation and Chloroalkylation of 5-Aryl-1,1,1-trifluoropentan-2-ones. A Route to (Trifluoromethyl)dihydronaphthalenes and (Trifluoromethyl)tetrahydronaphthalenes
-
The Friedel-Crafts cyclization of some 5-aryl-1,1,1-trifluoropentan-2-ones yields selectively either 1-(trifluoromethyl)dihydronaphthalenes or 1-chloro-1-(trifluoromethyl)tetrahydronaphthalenes or 1-aryl-1-(trifluoromethyl)tetrahydronaphthalenes, depending on the solvent and the acid.
- Bonnet-Delpon, D.,Charpentier-Morize, M.,Jacquot, R.
-
p. 759 - 762
(2007/10/02)
-
- Radical Pathways of Coal Dissolution in Hydrogen Donor Media. 2. β Scission and 1,2 Aryl Migration Reactions of Radicals Derived from Methylindans and Tetralin at 327-627 deg C
-
The 1,2-aryl migration and fragmentation reactions of 1-indanylmethyl (1), 2-tetralyl (2), 2-indanylmethyl (3), 1-tetralyl (4), 2-methyl-1-indanyl (5), and 1-methyl-2-indanyl (6) radicals were studied by flash vacuum pyrolysis of the tert-butyl perester precursors at 327-627 deg C and 10-2 torr.Radicals 1 and 2 are interconverted via 1,2 aryl migration which is readily reversible at all temperatures.This equilibrium is depleted by β scission of 1 and recyclization to 4 and by β scission of 2 followed by recyclization to 2 or 3 in modest yields.The reverse neophyle-like rearrangement of 2 to 1 occurs with a lower activation barrier than β-scission of 1 to form a 2-(o-vinylphenyl)ethyl radical.Enthalpies, entropies, and free energies of reactions were calculated for the above reactions from group additivity parameters, and activation energies were estimated from values reported for simple alkyl radicals.It is shown that the β scission of 4 and recyclization to 1 is important only at very high temperatures (>500 deg C) as a mechanism for the isomerization of tetralin and related hydroaromatic structures to alkylindans and that the reverse neophyl-like rearrangement of 2 to 1 is the favored pathway for isomerizations observed during dissolution of coal in hydroaromatic media at elevated temperatures.
- Franz, James A.,Camaioni, Donald M.
-
p. 5247 - 5255
(2007/10/02)
-