Organolithium Catalysis of Olefin and Diene Polymerization

Halasa, Adel F.; Schulz, D. N.; Tate, D. P.; Mochel, V. D.

doi:10.1016/s0065-3055(08)60306-8

Cited by 64 publications

(17 citation statements)

References 65 publications

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“…In THF with potassium as counter-ion, no change in microstructure is observed between 0° and -78°1 nor does the percentage of cis in the 1,4 units change. The complex lithium: dipiperidinoethane (DIPIP) in hydrocarbon solvents gives 99-100% 1,2 polybutadiene at much more useful temperatures [16]. Again this is in agreement with the supposition that for a given counter-ion trans centers are somewhat more reactive and somewhat more likely to produce in-chain 1,2 units.…”

Section: Convertsupporting

confidence: 62%

Stereospecificity in Anionic Polymerization

Bywater

1987

Recent Advances in Anionic Polymerization

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Active centers in anionic polymerization exist in cis and trans forms. Equilibrium fractions and interconversion rates depend on solvent and counter-ion. with diene polymerization in polar solvents, the isomers equilibrate rapidly down to very low temperatures if lithium is the counter-ion, but only very slowly at room temperature if it is potassium. In such solvents, the kinetic preference is trans but at equilibrium it is cis. Trans centers are more vinyl stereospecific for a given counter-ion and react faster with monomer. In vinyl polymerization, cis-trans interconversion rates are slow with all counter-ions on the reaction time scale. Counter-ion positional exchange is however rapid in THF but slows somewhat in toluene. Diad structure is not defined until the next monomer adds. The determination of 1,2 or 1,4 structure in diene polymerization is decided in the same manner, a common characteristic of anionic polymerization. 187

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Section: Convertsupporting

confidence: 62%

Stereospecificity in Anionic Polymerization

Bywater

1987

Recent Advances in Anionic Polymerization

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“…It failed to randomize SBR's of 20% styrene contents and higher [7]. We would like to report on a new modifier, dodecybenzenesulfonic acid sodium salt in combination with N,N,N 0 N 0 Tetramethylene diamine (TMEDA) [8][9][10] in an anionic polymerization system for making high styrene high vinyl SBR. The glass transition temperature, T g , determines the final tread properties.…”

Section: Introductionmentioning

confidence: 99%

High vinyl high styrene solution SBR

Halasa

Prentis

Hsu

et al. 2005

Polymer

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“…Organolithium compounds have been extensively employed as bases in stoichiometric amounts for metalation reactions, but their use as catalysts, other than in polymerization reactions, is an ongoing research challenge . Although several catalytic processes involving lithium salts have already been documented for lithium chloride, lithium bromide, lithium perchlorate and, to a lesser extent, lithium hydroxide, there is currently only one report dealing with the use of an organic alkali metal compound in catalytic reactions .…”

Section: Methodsmentioning

confidence: 99%

Azomethine Ylides from Nitrones: Using Catalytic nBuLi for the Totally Stereoselective Synthesis of trans‐2‐Alkyl‐3‐oxazolines

Juste-Navarro

Delso

Tejero

et al. 2016

Chemistry A European J

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The cycloaddition of azomethine ylide N-oxides (nitrone ylides) with aldehydes provides 3-oxazolines in a completely stereoselective manner in the presence of a catalytic amount of n-butyllithium. The process involves an initial nucleophilic attack on the aldehyde, followed by intramolecular oxygen addition to the nitrone moiety and lithium-assisted elimination of water, regenerating the catalytic species. Various Li-based catalytic systems are possible and the in situ generated water is required for continuing the catalytic cycle. The best results are observed with 20 mol % of n-butyllithium, whereas the use of stoichiometric amounts inhibit the rate of catalysis. Experimental, spectroscopic, and computational mechanistic studies have provided evidence of lithium-ion catalysis and rationalized several competing catalytic pathways.

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Organolithium Catalysis of Olefin and Diene Polymerization

Cited by 64 publications

References 65 publications

Stereospecificity in Anionic Polymerization

Stereospecificity in Anionic Polymerization

High vinyl high styrene solution SBR

Azomethine Ylides from Nitrones: Using Catalytic nBuLi for the Totally Stereoselective Synthesis of trans‐2‐Alkyl‐3‐oxazolines

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