نتایج جستجو برای: olefin copolymerization
تعداد نتایج: 5669 فیلتر نتایج به سال:
Results of ab initio molecular orbital studies are presented for one elementary reaction and two full catalytic cycles of organo-transition metal complexes: (i) the oxidative addition of H-H, C-H, N-H, 0-H and Si-H bonds to CpRh(C0) in gas phase, (ii) the full catalytic cycle of hydroboration of olefin with Rh(PR3)2Cl, and (iii) the full catalytic cycle of hydroformylation of olefin with RhH(C0...
A meso-palladioporphyrin intermediate was isolated from a Heck reaction between an iodoporphyrin and a non-activated olefin using a Pd(PPh3)2Cl2/Et3N system; its structure was characterized by NMR, MS and X-ray crystallography. Studies on its formation indicate that the Pd(II) catalyst was reduced in situ by Et3N with the assistance of water. The catalytic activity of the intermediate was confi...
Post-metallocenes were constructed for olefin polymerization using 1,2,3,4,7,8,9,10-octahydro[1,10]phenanthroline and 1,2,3,4-tetrahydro[1,10]phenanthroline derivatives. A series of zirconium complexes - LZrCl2(NHMe2)2 [L = 2,9-H2-C12H12N2 (4), 2,9-Me2-C12H12N2 (5), 2,9-nBu2-C12H12N2 (6), and 2,9-iPr2-C12H12N2 (7)] - and hafnium complexes - LHfCl2(NHMe2)2 [L = 2,9-H2-C12H12N2 (8), 2,9-Me2-C12H1...
Of all polymerization methods, catalytic polymerization offers the broadest scope of microstructure control. Stereoregularity, comonomer incorporation and sequences, molecular weights, and molecular weight distributions can be controlled by the catalyst structure. Polyolefins are produced on a vast scale of nearly 100 million tons annually, predominantly by catalytic polymerization. High-densit...
Asymmetric amplification in the copolymerization of cyclohexene oxide and carbon dioxide was demonstrated using chiral zinc complexes, prepared from diethylzinc, diphenyl(pyrrolidin-2-yl)methanol, and ethanol.
Patterning functional materials is a central challenge across many fields of science. The ability to lithographically fabricate micro- and nanostructures has been one of the most impactful technological breakthroughs of the last century. In part due to the complexity of the chemical processes in photoresists, there is a limited variety of materials that can currently be patterned by photolithog...
[Reaction: see text]. The total synthesis of the natural product Bengamide E, one of the members of a new class of antitumor natural products of marine origin, is reported based on a convergent and flexible synthetic route featuring an oxirane ring-opening reaction and an olefin cross metathesis. In a similar way, analogues structurally modified at C-2 and at the terminal vinyl positions were p...
The radical copolymerization of vinylidene fluoride (VDF) with 4-bromo-1,1,2-trifluorobut-
The preparation of several graft copolymers obtained by radiation induced graft copolymerization of typical monomers onto poly (3hydroxybutyrate) is reviewed. The general mechanisms by which graft copolymerization reaction proceed under various irradiation conditions are described. Main attention is given to the structure, properties, synthesis and characterization of the graft product, as well...
Micrococcus luteus naturally produces alkenes, unsaturated aliphatic hydrocarbons, and represents a promising host to produce hydrocarbons as constituents of biofuels and lubricants. In this work, we identify the genes for key enzymes of the branched-chain amino acid catabolism in M. luteus, whose first metabolic steps lead also to the formation of primer molecules for branched-chain fatty acid...
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