Polymerization of Unsaturated Compounds by Bis-benzenechromium. I-III. I. Effect of Addition of Bis-benzenechromium to Radical

博史, 山崎; 信衛, 萩原

doi:10.1246/nikkashi1948.81.5_819

Cited by 5 publications

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“…Previously, we reported the polymerization of styrene with bis-benzenechromium and di-tert-butylperoxide. 9 The polymerization was accelerated by the redox reaction of di-tert-butylperoxide with bis-benzenechromium according to Equation 8 and a new tetravalent chromium compound, chromium tetra-tertbutoxide,1° was obtained as a reaction product.…”

Section: Some Catalytic Activities Of Rarene-and -Andyclopentadienyl Comentioning

confidence: 99%

Some Recent Problems on the Field of Organometallic Compounds of Transition Metals

Hagihara

1965

Annals of the New York Academy of Sciences

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Since the discovery of ferrocene by Pauson and Miller in 1951 and the discovery of the coordinated polymerization catalysts by Ziegler and Natta, the chemistry of organic derivatives of transition metals has developed rapidly and is now extending its range. There have been extensive research activities concerning the syntheses, structure and the nature of bonding of various organotransition metal compounds including, for example, metal carbonyls; r-complexes having olefins, di-olefins, acetylenes and aromatic nuclei as ligands; and generally unstable cr-bonded alkyl and aryl transition metals, and many others. The investigation of the reactivities of the organic part attached to the transition metal and the investigation of the catalytic activities of this sort of complexes have also been made.The author and his coworkers have been continuing researches on thisorganometallic field since several years. He wishes to mention about some of the recent results of their work. Interaction of Cumulene Systems with Transition MetalsMuch interest has been focused in the recent years on the field of organometallic n-complexes of mono-and polyolefins. However, interaction of cumulene systems with organic derivatives of transition metals has not been investigated extensively. It is interesting to see whether cumulene type double bonds in a straight chain form stable r-complexes or not. Investigation of this interaction would be also important in connection with the catalytic action of metal carbonyls in the known polymerization and carbonylation of allenic compounds.At the outset, we have found that the cumulene systems yield stable r-cornplexes with iron. In the course of our study, allene has been reported by Green and Ariyaratnel to be in a .rr-complexed form in a cation: [C5H5Fe(C0)2(C3H4)]+. In this cation, the iron is probably coordinated through one double bond of allene as in ordinary olefin complexes.Tetraphenylallene-and tetraphenylbutatriene-iron carbonyl c~r n p l e x e s .~.~ We have found that reaction of iron pentacarbonyl with tetraphenylallene or tetraphenylbutatriene gave red crystals according to Equation 1 or 2, respectively.The products, I and 11, were quite stable in air and found to be monomeric and diamagnetic. The pyrolysis and the substitution reaction of these complexes showed that the tetraphenylallene and tetraphenylbutatriene retained its skeletal structure on the v-complex formation.The bondings and structures of I and I1 are interesting ones to discuss. The presence of three carbonyl groups in I prefers the idea that the two double bonds 98

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Section: Some Catalytic Activities Of Rarene-and -Andyclopentadienyl Comentioning

confidence: 99%

Some Recent Problems on the Field of Organometallic Compounds of Transition Metals

Hagihara

1965

Annals of the New York Academy of Sciences

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Ethylene polymerization studies with supported cyclopentadienyl, arene, and allyl chromium catalysts

Karol¹,

Johnson²

1975

J. Polym. Sci. Polym. Chem. Ed.

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Highly active catalysts for low pressure ethylene polymerization are formed when chromocene, bis (benzene)‐ or bis (cumene)‐chromium or tris‐ or bis (allyl)‐chromium compounds are deposited on high surface area silica‐alumina or silica supports. Each catalyst type shows its own unique behavior in preparation, polymerization, activity, isomerization, and response to hydrogen as a chain transfer agent. The arene chromium compounds require an acidic support (silicaalumina) or thermal aging with silica to form a highly active catalyst. At 90°C polymerization temperature arene chromium catalysts produced high molecular weight polyethylene and showed, in contrast to supported chromocene catalysts, a much lower response to hydrogen as a chain transfer agent. An increase in polymerization temperature caused a significant decrease in polymer molecular weight. Addition of cyclopentadiene to supported bis (cumene)‐chromium catalyst led to a new catalyst which showed a chain transfer response to hydrogen typical of a supported chromocene catalyst. Polymerization activity with tris‐ or bis (allyl)‐chromium appears to depend on the divalent chromium content in the catalyst. Changes in the silica dehydration temperature of supported allyl chromium catalyst have a significant effect on the resulting polymer molecular weight. High molecular weight polymers were formed with catalysts that were prepared using silica dehydration temperatures below about 400°C. Dimers, trimers, and oligomers of ethylene were usually formed with catalysts that were prepared on silica dehydrated much above 400°C. The order of activity of the different types of catalysts was chromocene/silica > chromocene/silica‐alumina > bis (arene)‐chromium/silica‐alumina ≃ allyl chromium/silica.

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Sneeden¹

1975

Organochromium Compounds

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Polymerization of Unsaturated Compounds by Bis-benzenechromium. I-III. I. Effect of Addition of Bis-benzenechromium to Radical

Cited by 5 publications

References 0 publications

Some Recent Problems on the Field of Organometallic Compounds of Transition Metals

Some Recent Problems on the Field of Organometallic Compounds of Transition Metals

Ethylene polymerization studies with supported cyclopentadienyl, arene, and allyl chromium catalysts

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