616-12-6Relevant academic research and scientific papers
NNNO-Heteroscorpionate nickel (II) and cobalt (II) complexes for ethylene oligomerization: the unprecedented formation of odd carbon number olefins
Zubkevich, Sergey V.,Tuskaev, Vladislav A.,Gagieva, Svetlana Ch.,Kayda, Anatoliy S.,Khrustalev, Victor N.,Pavlov, Alexander A.,Zarubin, Dmitry N.,Bulychev, Boris M.
, (2020/07/04)
The unprecedented observation of odd carbon number olefins is reported during nickel- catalyzed ethylene oligomerization. Two complexes based on Co (II) and Ni (II) with novel tetradentate heteroscorpionate ligand have been synthesized and fully characterized. These complexes showed the ability to oligomerize ethylene upon activation with various organoaluminum compounds (Et2AlCl, Et3Al2Cl3, EtAlCl2, MMAO). Ni (II) based catalytic systems were sufficiently more active (up to 1900 kg·mol (Ni)?1·h?1·atm?1) than Co (II) analogs and have been found to be strongly dependent on the activator composition. The use of PPh3 as an additive to catalytic systems resulted in the increase of activity up to 4,150 kg·mol (Ni)?1·h?1·atm?1 and in the alteration of selectivity. All Ni (II) based systems activated with EtAlCl2 produce up to 5 mol. percent of odd carbon number olefins; two probable mechanisms for their formation are suggested – metathesis and β-alkyl elimination.
Iminobisphosphines to (Non-)symmetrical diphosphinoamine ligands: Metal-induced synthesis of diphosphorus nickel complexes and application in ethylene oligomerisation reactions
Boulens, Pierre,Lutz, Martin,Jeanneau, Erwann,Olivier-Bourbigou, Hlne,Reek, Joost N. H.,Breuil, Pierre-Alain R.
, p. 3754 - 3762 (2015/05/05)
We describe the synthesis of a range of novel iminobisphosphine ligands based on a sulfonamido moiety [R1SO2N=P(R2)2-P(R3)2]. These molecules rearrange in the presence of nickel by metal-induced breakage of the P-P bond to yield symmetrical and nonsymmetrical diphosphinoamine nickel complexes of general formula Ni{[P(R2)2]N(SO2R1)P(R3)2}Br2. The complexes can be isolated and are very stable. Upon activation by MAO, these complexes oligomerise ethylene to small chain oligomers (mainly C4-C8) with high productivity. Surprisingly fast codimerisation reactions of ethylene with butenes is observed, leading to a high content of branched C6 products.
Hydrodesulfurization of 4,6-dimethyldibenzothiophene over noble metals supported on mesoporous zeolites
Sun, Yinyong,Prins, Roel
supporting information; experimental part, p. 8478 - 8481 (2009/04/12)
(Figure Presented) Pores for thought: Noble-metal catalysts supported on mesoporous zeolites have been found to be much more efficient than on microporous zeolites and γ-Al2O3 for the hydrodesulfurization of 4,6-dimethyldibenzothioph
Novel neutral arylnickel(II) phosphine catalysts containing 2-oxazolinylphenolato N-O chelate ligands for ethylene oligomerization and propylene dimerization
Zhao, Wei,Qian, Yanlong,Huang, Jiling,Duan, Jianjun
, p. 2614 - 2623 (2007/10/03)
A series of new neutral arylnickel(II) phosphine complexes 1 bearing 2-oxazolinylphenolato ligands [2-(4-R1-5-R2-C3H2NO) -C6H4O]Ni (2-R4-4-R3-C6H3 (PPh3) were synthesized by reactions of sodium salts of 2-(4,5-dihydro-2-oxazolyl)phenol derivatives with trans-Ni(Ar)(Cl (PPh3)2 or by direct reactions of the ligands with trans-Ni(Ar)(Cl)(PPh3)2 in the presence of NEt3. These neutral Ni(II) complexes 1 exhibited high activities and selectivities in ethylene oligomerization and propylene dimerization. The catalytic activities and the product distributions were dependent on the selection of various organoaluminum cocatalysts and phosphine scavenger (Ni(COD)2). The effects of various reaction conditions on ethylene oligomerization were also examined. The highest activity of 5.51×105 g oligomers/(mol Ni · h) and 83% selectivity of C6 internal olefins were obtained in 1a/MAO catalytic system in ethylene oligomerization. The oligomers consisted mainly of lower carbon olefins in the range of C4-C8. Complexes 1 showed the moderate tolerance of polar additives in ethylene oligomerization. The highest activity of 1a/MAO in propylene dimerization reached to 1.32×105 g oligomers/(mol Ni · h).
Lewis acid-catalysed reaction of (cyclo)alkenes with oxiranes
Munro, David,Newman, Chris
, p. 1483 - 1486 (2007/10/03)
The Lewis acid-catalysed reaction of (cyclo)alkenes with oxiranes can give homologous aldehydes, unsaturated alcohols, and fused furans. Many of these materials are of interest to the fragrance industry. (C) 2000 Elsevier Science Ltd.
1-Hexene Oligomerization in Liquid, Vapor, and Supercritical Phases over Beidellite and Ultrastable Y Zeolite Catalysts
Pater, Jerome P. G.,Jacobs, Pierre A.,Martens, Johan A.
, p. 477 - 482 (2007/10/03)
1-Hexene was oligomerized at 200°C and a pressure of 5 MPa in a down-flow fixed-bed tubular reactor filled with beidellite or ultrastable Y zeolite catalysts. Vapor, liquid, and supercritical states of the reacting hydrocarbons in the reactor tube were established by using propane, pentane, octane, and dodecane as solvents. The initial activity, stability with operation time, and selectivity are very dependent on the physical state of the hydrocarbons. Highest activity and stability are reached in the liquid phase using octane and dodecane solvent. The chain length of the solvent has a strong influence on the deactivation of the catalyst, on the oligomerization selectivity and on the formation of C6 saturates and cracked products.
Thermal reaction of (CH3)2C=CHCH3 in the presence of di-tert-butyl peroxide: reactions of the radicals (.)CH3 and (CH2)2(.)CCH(CH3)2
Koertvelyesi, T.,Fekete, Z.,Seres, L.
, p. 77 - 96 (2007/10/02)
The reaction between the radical (.)CH3 and 2-methylbutene-2 (2MB2) was studied in the temperature range 405-444 K.The (.)CH3 source was di-t-butyl peroxide (PODBT).The rate constants relative to that of recombination were determined for H-abstraction from 2MB2 by (.)CH3 and addition of (.)CH3 to 2MB2: (.)CH3 + (CH3)2C=CHCH3 -> CH4 + (.)CH2CH=CH(CH3)2 (3), -> CH4 + (.)CH2(CH3)C=CHCH3 (4), (.)CH3 + (CH3)2C=CHCH3 -> (CH3)2(.)CCH(CH3)2 (9), 2(.)CH3 -> C2H6 (14).The values are log(k3+4/k141/2 = (3.31+/-0.28) - 34.6+/-3.1)/Θ, log(k9/k141/2) = (3.50+/-0.32) - (36.5+/-3.8)/Θ where Θ = RT ln 10 and the units are dm3/2mol-1/2s-1/2 for k3+4/k141/2 and k9/k141/2 and kJ mol-1 for the energy of activation.For the disproportionation to combination ratios of the 1,1,2-trimethylpropyl radical (112TMP(.)), the following value was obtained: Δ2(112TMP(.),112TMP(.)) = 1.2+/-0.3, where the subscript 2 refers to the formation of a 2-olefin as one of the products. - Keywords: (.)CH3 radical - 1,1,2-trimethylpropyl radical - 2-methylbutene-2 - Gas phase reaction
Catalytic activity of cluster ruthenium complexes: oligomerization of ethylene
Bianchi, Mario,Menchi, Gloria,Matteoli, Ugo,Piacenti, Franco
, p. 139 - 146 (2007/10/02)
, one of a series of ruthenium carbonyls tested, shows good catalytic activity in the oligomerization of ethylene in several organic solvents at temperatures above 80 deg C and olefin pressures exceeding 5 atm.Olefin conversions up to 90percent are reached.C4-C12 olefins are the main rection products, with prevalence of the C4 species.Branched isomers are prevalent among the higher oligomers.Evidence has been obtained for a key role for ruthenium hydride intermediates in this catalytic cycle.
METAL COMPLEXES IN CATALYTIC CONVERSIONS OF OLEFINS. 4. HETEROGENIZATION OF NICKEL COMPLEXES ON CHEMICALLY MODIFIED SILOCHROME SURFACE; ACTIVITY AND SELECTIVITY IN ETHYLENE DIMERIZATION
Furman, D. B.,Ivanov, A. O.,Olenin, A. Yu.,Vasil'kov, A. Yu.,Munshieva, M. K.,et al.
, p. 448 - 451 (2007/10/02)
When activated by Et2AlCl phosphine-containing homogeneous nickel complexes and their heterogenized analogs (HMC) formed on silochrome S-120 modified by NH2 and N(PPh2)2 groups differ significantly in their effectiveness in ethylene dimerization.The catalytic activity of Ni-HMC-Et2AlCl depends on how the HMC was formed.Ni-HMC-I obtained by ligand exchange on chemically modified silochrome is ca. 5-15 times more effective than Ni-HMC-II synthesized from the gas phase.The selectivity in formation of α-olefins (ΣC4 + ΣC6) is ca. 4-5 times higher in the presence of Ni-HMC than for its homogeneous analogs.
Enthalpies of hydrogenation of the hexenes
Rogers, D. W.,Crooks, Evon,Dejroongruang, Kosol
, p. 1209 - 1216 (2007/10/02)
The enthalpies of hydrogenation are given for all isomers of hexene.The enthalpy of isomerization of 2,3-dimethylbut-1-ene to 2,3-dimethylbut-2-ene is discussed in relation to the enthalpies of endocyclic isomerization of methylenecyclopentane and methylenecyclohexane to the corresponding methylcycloalk-1-enes, which have also been determined by hydrogen thermochemistry.
