73022-52-3Relevant academic research and scientific papers
Producing cyclic fuels from conjugated diene
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Page/Page column 6-9, (2021/04/21)
A method for making a fuel includes reacting a conjugated diene or a mixture of conjugated dienes with a catalyst selected from the group consisting of a low valent iron catalyst stabilized with a pyridineimine ligand, an iron precatalyst coordinated to the pyridineimine ligand that is activated with a reducing agent, a low oxidation state Fe complex stabilized with a pyridineimine ligand and a coordinating ligand, and combinations thereof, thereby forming a substituted cyclooctadiene. The substituted cyclooctadiene is then hydrogenated, thereby forming cyclooctane fuel.
[4 + 4]-cycloaddition of isoprene for the production of high-performance bio-based jet fuel
Rosenkoetter, Kyle E.,Kennedy, C. Rose,Chirik, Paul J.,Harvey, Benjamin G.
, p. 5616 - 5623 (2019/10/23)
Isoprene was efficiently converted to 1,6-dimethyl-1,5-cyclooctadiene (DMCOD) by selective [4 + 4]-cycloaddition with a catalyst formed by in situ reduction of [(MePI)FeCl(μ-Cl)]2 (MePI = [2-(2,6-(CH3)2-C6H3-NC(CH3))-C4H5N]). DMCOD was isolated in 92% yield, at the preparative scale, with a catalyst loading of 0.025 mol%, and a TON of 3680. Catalytic hydrogenation of DMCOD yielded 1,4-dimethylcyclooctane (DMCO). The cyclic structure and ring strain of DMCO afforded gravimetric and volumetric net heats of combustion 2.4 and 9.2% higher, respectively, than conventional jet fuel. In addition, the presence of methyl branches at two sites resulted in a-20 °C kinematic viscosity of 4.17 mm2 s-1, 48% lower than the maximum allowed value for conventional jet fuel. The ability to derive isoprene and related alcohols readily from abundant biomass sources, coupled with the highly efficient [Fe]-catalyzed [4 + 4]-cycloaddition described herein, suggests that this process holds great promise for the economical production of high-performance, bio-based jet fuel blendstocks.
Regio- and Diastereoselective Iron-Catalyzed [4+4]-Cycloaddition of 1,3-Dienes
Kennedy, C. Rose,Zhong, Hongyu,MacAulay, Rachel L.,Chirik, Paul J.
supporting information, p. 8557 - 8573 (2019/06/04)
A family of single-component iron precatalysts for the [4+4]-cyclodimerization and intermolecular cross-[4+4]-cycloaddition of monosubstituted 1,3-dienes is described. Cyclooctadiene products were obtained with high regioselectivity, and catalyst-controlled access to either cis- or trans-diastereomers was achieved using 4-substituted diene substrates. Reactions conducted either with single-component precatalysts or with iron dihalide complexes activated in situ proved compatible with common organic functional groups and were applied on multigram scale (up to >100 g). Catalytically relevant, S = 1 iron complexes bearing 2-(imino)pyridine ligands, (RPI)FeL2 (RPI = [2-(2,6-R2-C6H3-Na-CMe)-C5H4N] where R = iPr or Me, L2 = bis-olefin), were characterized by single-crystal X-ray diffraction, M??bauer spectroscopy, magnetic measurements, and DFT calculations. The structural and spectroscopic parameters are consistent with an electronic structure description comprised of a high spin iron(I) center (SFe = 3/2) engaged in antiferromagnetically coupling with a ligand radical anion (SPI = -1/2). Mechanistic studies conducted with these single-component precatalysts, including kinetic analyses, 12C/13C isotope effect measurements, and in situ M??bauer spectroscopy, support a mechanism involving oxidative cyclization of two dienes that determines regio- and diastereoselectivity. Topographic steric maps derived from crystallographic data provided insights into the basis for the catalyst control through stereoselective oxidative cyclization and subsequent, stereospecific allyl-isomerization and C-C bond-forming reductive elimination.
Chirality control of tropos diphenylmethane-derived phosphoramidites by chiral dienes: Its application to asymmetric Michael addition
Wakabayashi, Kazuki,Aikawa, Kohsuke,Mikami, Koichi
experimental part, p. 927 - 943 (2010/10/20)
The Rh complex of tropos diphenylmethane-derived phosphoramidite could be chirally controlled to adopt single chiral conformation upon addition of a chiral diene. In the asymmetric Michael addition of α-cyanocarboxylates catalyzed by the Rh complexes, the
METHOD FOR PRODUCING TRIMETHYLCYCLODODECATRIENE
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Page/Page column 12, (2008/06/13)
The invention relates to the production of trimethylcyclododecatriene in a continuous or discontinuous method, by the trimerisation of isoprene in the presence of a catalyst system and a solvent. The raw trimethylcyclododecatriene obtained can be isolated by distillation. The dimethylcyclooctadiene formed as a by-product can also be isolated from the raw product.
On the mechanism of the nickel-catalysed regioselective cyclodimerization of isoprene
van Leeuwen,Roobeek
, p. 1973 - 1983 (2007/10/02)
A study of various Ni-ligand catalysed oligomerizations of isoprene has shown that with π-acidic P ligands the selectivity to cyclodimers amount to 97%. A new type of ligand is introduced, viz. fluoroalkyl phosphites having π-acceptor properties comparable to those of, e.g. PCl3. With tris(hexafluoroisopropyl) phosphite the main product is 1,4-dimethy1-4-vinylcyclohexene. A detailed explanation based on a two-step mechanism is given. As to the first step, for a series of ligands having similar steric properties the changes in product distribution as a function of the electronic ligand parameter are explained in terms of a gradual change in HOMO-LUMO interactions between Ni and the olefins, with strong π-acidic ligands promoting the head-to-head coupling of the isoprene molecules. The second step, involving reductive elimination of a cyclodimer from the metal, shows an increasing selectivity towards substituted cyclohexenes for the head-to-head and tail-to-tail intermediates with increasing π-acidity of the ligand. The qualitative orbital treatment presented as an explanation is also applicable to reactions found for other metallacyclopentanes.
