Polymérisation anionique de l'isoprène: Nature de la paire d'ions et stéréospécificité. II. Influence de la nature du solvant

Essel, Alain; Sallé, Robert; Golé, Jean; Pham, Quang Tho

doi:10.1002/pol.1975.170130809

Cited by 18 publications

(4 citation statements)

References 13 publications

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“…[76, 771 suggested the formation of either the same complexes or other donor-acceptor adducts of a diene with the counter ion of AC (even in polar media) [8,60,[81][82][83][84][85][86][87][88][89][90][91][92].…”

Section: Polymerization Of Butaddene and Isoprene In Non-polarmentioning

confidence: 99%

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Modern views on the stereospecifity of anionic active centers. Review

1981

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Modern views on the stereospecifity of anionic active centersAda Polyrncria 32 (1981) Heft rC 183 B. L. ERUSSALIDNKY, E. Yu. MELENEVSKAYA and V. N. SGONNIK Academy of Sciences of the USSR, Institute for High Molecular Weight Compounds, Leningrad 199 004, USSRThe results of recent investigations concerning the structural effects of the anionic polymerization of unsaturated non-polar and polar monomers are summarized. The main attention is given to the mechanism of corresponding processes. Gegenwartige Vorstellungen uber die Stereospezifitat von anionischen aktiven Zentren. FortschrittsberichtDie Ergebnisse neuerer Untersuchungen der strukturellen Effekte, die bei der anionischen Polymerisation von unpolaren und polaren ungesattigten Monomeren auftreten, werden zusammengefalt. Insbesondere wird der Mechanismus der entsprechenden Prozesse betrachtet. Coepe.+eennace npedcmaenenm o cmepeocnequ@uunocmu anuonnm aEmuanMx yenmpoe. Obaop06061qe~b1 pe8ynwran.I HenaBmx nccaexosamt CTPYKTYPHHX a@@ewroB, xapaweprrbnr ~X H amomrot nommepa-3aqHH HelIOJIfZpHbIX II lIOJMpHbIX HeHaCbIIIJeHHbIX MOHOMepOB. OCHOBHOe BHEIMaHRe yneJEH0 MeXaHH8My COOTBeT-CTBYIOIIJIIX lIpOqeCCOB.

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Section: Polymerization Of Butaddene and Isoprene In Non-polarmentioning

confidence: 99%

“…Under these conditions the sensitivity of the polymer structure to the nature of the counter ion becomes much lower [85,86,881. However, some dependence on the temperature remains, a t any rate in a solvent of moderate polarity (THF).…”

Section: Specifity Of Structural Effects Induced By the Nature Of Thementioning

confidence: 99%

Modern views on the stereospecifity of anionic active centers. Review

1981

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“…It was also implied2 that this mechanism was responsible for the initiation of the anionic polymerization of dienes by the aromatic radical-ions. Survey of the literature reveals, however, that the anionic polymerization of butadiene and isoprene has usually been initiated by alkali metal^,^ butyl l i t h i~m ,~ and carb-anion^.^^^ The initiation of the anionic polymerization of isoprene by alkali naphthalenides was reported by Essel et al 7 and Boileau et a1.8 These investigators studied the structure of polymers obtained under such conditions but did not discuss the mechanism of the initiation. Difficulties in the initiation of the anionic polymerization of isoprene by sodium naphthalenes were noted by Levy.9 Polymerization of 1.3-CHD initiated by alkyl lithium compounds was studied by several investigators.lO-ll Reactions were conducted in ethers and hydrocarbons.…”

Section: Introductionmentioning

confidence: 99%

Kinetics and mechanism of the anionic polymerization of cyclohexadienes initiated by naphthalene radical anions and dianions

Sharaby

Jagur‐Grodzinski

Martan

et al. 1982

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

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SynopsisThe anionic polymerization of 1.3-cyclohexadiene (1.3-CHD) was investigated in temperatures that ranged from 25 to -77OC. Initiation by lithium naphthalene (N;,Li+) in tetrahydrofuran at -2OOC yields polymers with fairly narrow molecular weight distribution. The of t.hese polymers so prepared is ca. 20,000. Polymerization of 1.3-CHD conducted a t room temperature is accompanied by the dehydrogenation and disproportionation of the monomer, especially when NT,K+ acts as initiator.The mechanism of the initiation of the polymerization of 1.3-CHD by N:,Li+ was elucidated and the rate constants at -2OOC in tetrahydrofuran of the elementary reactions were determined. It was established that the dianions formed by disproportionation of N;,Li+ act as effective initiators for 1.3-CHD. The adducts formed constitute the cyclohexanyl and naphthyl carbanionic groups. The former carbanions ( A , , ,-275 nm) propagate the polymerization. The initially formed dimeric adducts are stabilized by the separation of the carbanionic end groups by the additional monomer units. Chain transfer to the monomer limits the growth of the polymers. The isomerization of the cyclohexadienyl anions, formed as result of chain transfer, may be followed by the elimination of lithium hydride. The latter reaction represents a termination step. Addition of 1.4-CHD to the reaction mixture enhances the chain transfer and the termination.Oligomers are formed when hexamethylphosphoramide is used as a solvent.

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“…As monomers, commonly vinylic and aprotic molecules like styrene, isoprene, 1,3-butadiene (Bd) and others can be used. Until now, many groups have investigated the LAP and thus the effects of solvent polarity [17], initiators [18], ligands [19], and temperature [20] are well known. In the anionic polymerization of Bd as a monomer, the first addition of one monomer unit to the initiator, here n-butyllithium (BuLi), is the initial step, see Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Investigations on the anionic polymerization of butadiene in capillaries by kinetic measurements and reactor simulation

Schulze

Cortese

Rupp

et al. 2013

Green Processing and Synthesis

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For the first time the anionic polymerization of 1,3-butadiene (Bd) is successfully transferred from semibatch into a continuous microfluidic setup with comparable product properties. The molecular weight distribution described by the polydispersity index (PDI) is commonly used as a key criterion for product quality. The steady state and the local resolution of a continuous setup provide the opportunity to investigate the progress of the PDI during anionic polymerization. In this work, the influence of kinetics (statistics) and fluid dynamics (FD) on the PDI of the product is investigated. Therefore a dedicated setup was designed and erected to keep Bd in the liquid phase and provide a pulsation free constant liquid flow. With optimized parameter settings, a separation of initiation and propagation is obtained and the intrinsic kinetics of propagation are determined. To explain the experimental results, an ideal plug flow and an ideal laminar flow model are applied and compared to computational fluid dynamics (CFD) simulations. Finally, it is concluded which FD and statistical contributions lead to the very low PDI of 1.04 found in the experiments.

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Polymérisation anionique de l'isoprène: Nature de la paire d'ions et stéréospécificité. II. Influence de la nature du solvant

Cited by 18 publications

References 13 publications

Modern views on the stereospecifity of anionic active centers. Review

Modern views on the stereospecifity of anionic active centers. Review

Kinetics and mechanism of the anionic polymerization of cyclohexadienes initiated by naphthalene radical anions and dianions

Investigations on the anionic polymerization of butadiene in capillaries by kinetic measurements and reactor simulation

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