Natrium‐ und kalium‐organische Verbindungen. Teil I: Eigenschaften und Reaktionsweisen [1]

Schlosser, Manfred

doi:10.1002/ange.19640760303

Cited by 50 publications

(1 citation statement)

References 204 publications

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“…It was found that the initiation ability of sodium salts increased with in- It is known that St polymerizes in the presence of catalysts of having pK,, values higher than that of sodium salts of xanthene (pK, = 29)15 and that MMA polymerizes with catalysts having pK, values higher than that of tert-BuONa (pK, = 19). 15 For some monomers [St, MMA, MVK, AN, AA, NPMI, aerolein (AL) and vinylidene cyanide, V(CNz2)] with organometallic compounds or inorganic salts, the relationships between e values of monomers and pK, values of the conjugate acid are shown in Figure 7; however, the reactivities of monomers changed with solvent used. From the curve, we can estimate the lowest pK, which can initiate polymerization when the e value of the monomer is known.…”

Section: Polymerization Of Vinyl Monomers With Sodium Salts Of Bronstmentioning

confidence: 99%

Polymerization of vinyl monomers with salts of bronsted acids

Yamaguchi

Minoura

1970

J. Polym. Sci. A‐1 Polym. Chem.

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The polymerization of vinyl monomers (N‐phenylmaleimide, acrylamide, acrylonitrile, methyl vinyl ketone, methyl methacrylate, vinyl chloride, and styrene) with sodium salts of Brønsted acids (sodium cyanide, sodium nitrite, sodium hydroxide, etc.) were investigated at 0°C in dimethylformamide. N‐Phenylmaleimide, acrylonitrile, and methyl vinyl ketone were found to undergo polymerization with sodium cyanide, however the other monomers were not polymerized with this salt. In the polymerizations of acrylonitrile and N‐phenylmaleimide with sodium cyanide, the rates of the polymerizations were found to be proportinal to the initiator concentration and to the square of the monomer concentration. The activation energy of acrylonitrile polymerization was 3.7 kcal/mole, and that of N‐phenylmaleimide ws 3.0 kcal/mole. The results of the copolymerization of acrylonitrile with methyl methacrylate at 0°C in dimethyl‐formamide with sodium cyanide confirm that these polymerizations proceeded by an anionic mechanism initiated by the Michael addition reaction of the monomers with the salts. In these polymerizations, the monomer reactivity increased with increase in the e values. The initiation ability of sodium salts increased with increasing pKa of the conjugate acids and with decreasing electronegativity of metal ion in the series of lithium, sodium, and potassium cyanide. The polymerizations took place only in aprotic polar solvents, and did not occur in weak polar solvents and in protonic solvents.

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Section: Polymerization Of Vinyl Monomers With Sodium Salts Of Bronstmentioning

confidence: 99%

Polymerization of vinyl monomers with salts of bronsted acids

Yamaguchi

Minoura

1970

J. Polym. Sci. A‐1 Polym. Chem.

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Directedortho-Metalation, a New Insight into Organosodium Chemistry

Gissot¹,

Becht²,

Desmurs

et al. 2002

Angew. Chem.

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From laboratory to industrial scale, the use of strong organoalkali metal bases is almost exclusively restricted to alkyllithium derivatives. [1] They are commercially available as 1 ± 2 m solutions, quite stable and easily generated from alkylhalides and lithium. In contrast, the synthesis of alkylsodium compounds is much more troublesome and requires high-speed mechanical stirring, low temperatures, and excess sodium. [2±6] Under classical conditions, organohalides react with sodium to give mainly Wurtz coupling products. [7,8] Moreover, alkylsodium compounds show poor stability, especially in ethereal solvents. [9,10] As a consequence, in spite of the low cost of metallic sodium and the sometimes demonstrated interesting reactivity, [11] alkylsodium compounds have not been considered so far as valuable organometallic reagents in organic synthesis.Herein we report on a straightforward and efficient one-pot ortho-metalation procedure relying on the generation of sodiated organic bases from RCl and a stoichiometric amount of metallic sodium in the presence of aromatic substrates. [12] Under these conditions, handling and storage of alkylsodium compounds is avoided and ortho-metalation is favored over usual coupling and solvolysis side reactions. [13] 1,3-Dimethoxybenzene (1,3-DMB), known to undergo ortho-metalation with alkyllithium bases in good yields, [14] was selected as a model substrate to investigate the scope of the reaction with alkylsodium compounds [Eq. (1)]. Several parameters, including solvent, temperature, and the nature of the organohalide, were varied (Table 1). All reactions were quenched by addition of dry-ice, and the yield of acid [see Eq. (1)] was considered as indicative of the metalation efficiency. [15] ZUSCHRIFTEN

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Organoalkali Chemistry

Schlosser

2001

Organometallics in Synthesis: A Manual

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Natrium‐ und kalium‐organische Verbindungen. Teil I: Eigenschaften und Reaktionsweisen [1]

Cited by 50 publications

References 204 publications

Polymerization of vinyl monomers with salts of bronsted acids

Polymerization of vinyl monomers with salts of bronsted acids

Directedortho-Metalation, a New Insight into Organosodium Chemistry

Organoalkali Chemistry

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