13643-02-2Relevant articles and documents
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Schuikin,Naryschkina
, p. 508; engl. Ausg. S. 489 (1958)
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Steric Acceleration in the Pyrolysis Kinetics of 2-Substituted Ethyl Acetates
Martin, Ignacio,Chuchani, Gabriel
, p. 3902 - 3904 (1981)
The rates of elimination of several cyclo and branched alkyl substituents at the β carbon of ethyl acetates have been determined in a static system over the temperature range of 360-420 deg C and pressure range of 34-337 torr.The reactions are homogeneous in both clean and seasoned vessels, follow a first-order rate law, and are unimolecular.The rate coefficients are given by the following Arrhenius equations: for 2-cyclohexylethyl acetate, log k1 (s-1)=(13.30+/-0.28)-(208.1+/-3.4) kJ mol-1 (2.303RT)-1; for 2-cyclopentylethyl acetate, log k1 (s-1)=13.20+/-0.26)-(207.4+/-3.2) kJ mol-1 (2.303RT)-1; for 3-methyl-1-pentyl acetate, log k1 (s-1)=(13.62+/-0.09)-(211.9+/-1.2) kJ mol-1 (2.303RT)-1; for 4-methyl-1-pentyl acetate, log k1 (s-1)=12.82+/-0.05)-(203.1+/-0.6) kJ mol-1 (2.303RT)-1.The present data together with those reported in the literature give a good correlation line only, when plotting log k/k0 against Hancock's Esc values (r=0.916, δ=-0.121, and intercept=-0.020 at 400 deg C).This work ratifies that steric acceleration is responsible for the rate of elimination of alkyl and several polar substituents interposed by at least three methylene groups with respect to Cα-O bond of ethyl acetates.Unreported Esc values of several substituents are defined.
Asymmetric Synthesis in the Nickel-complex-catalysed Formation of Olefins from Allyl Alcohols and Grignard Reagents
Cherest, Marc,Felkin, Hugh,Umpleby, J. David,Davies, Stephen G.
, p. 681 - 682 (1981)
The reaction of three isomeric pentenols with methyl magnesium bromide catalysed by (-)DIOP nickel dichloride leads to optically active 3-methylpent-1-ene, with the optical yield and product configuration related to the configuration of the initially formed (η3-allyl)nickel intermediates.
Simple Access to Highly Enantiomerically Enriched (S)-3-Methyl-1-pentanol, (S)-3-Methyl-1-pentene, (2R,3S)-2-Deuterio-3-methyl-1-pentanol, and (2S,3S)-3-Methyl-2-pentanol from Natural L-Isoleucine
Schurig, Volker,Leyrer, Ulrich,Wistuba, Dorothee
, p. 242 - 245 (1986)
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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, Hélène,Reek, Joost N. H.,Breuil, Pierre-Alain R.
, p. 3754 - 3762 (2015/04/27)
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. Alkyl-substituted symmetrical and nonsymmetrical diphosphinoamine nickel complexes have been prepared by using sulfonamido-based iminobisphosphines as ligand promoters. The complexes with basic substituents, activated by methylaluminoxane, oligomerise ethylene to short oligomers (C4-C8) with high activity. Fast codimerisation is observed, leading to highly branched C6 product distribution.
