Polymerization of vinyl chloride by the AlEt3/benzoyl-peroxide/Lewis-base system and the role of the Lewis base in initiation

Milovskaya, E. B.; Kopp, Erwin; Mikhailicheva, O.S.; Денисов, В. М.; Kol'tsov, A. I.

doi:10.1016/0032-3861(72)90009-2

Cited by 13 publications

(3 citation statements)

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“…These charges for the compounds under consideration are as follows: This means that the ability of the vinyl group to coordinate with an electron-donor center increases when a complex is formed with a Lewis acid. This conclusion agrees with the ideas formulated in ref 5,47. In contrast to propagation reaction which occurs only if the ultimate link of the growing chain approaches the f,-C atom of the monomer vinyl group, the total charge of the vinyl group is of importance in the case considered in the ref 5,47 where the reaction of complexation of CB's with the metal alkyls was studied.…”

Section: The Complexation Of Methyllithium With Some Monomerssupporting

confidence: 87%

“…This conclusion agrees with the ideas formulated in ref 5,47. In contrast to propagation reaction which occurs only if the ultimate link of the growing chain approaches the f,-C atom of the monomer vinyl group, the total charge of the vinyl group is of importance in the case considered in the ref 5,47 where the reaction of complexation of CB's with the metal alkyls was studied. The calculated weakening of the vinyl bond in MA and the absence of this calculated weakening in VF also agree with the experimental data since the effect of the vinyl bond elongation in MMA and its absence in VA were observed spectroscopically.…”

Section: The Complexation Of Methyllithium With Some Monomerssupporting

confidence: 87%

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Electronic Structure and Energy of the Complexes: Methyllithium—Unsaturated Polar Monomer

Éizner¹,

Erussalimsky²,

Milovskaya³

1973

Polym J

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The electronic structure and the energy of CHaLi and its dimer have been calculated using a CNDO/2-method. The geometry of a planar rhombus was adopted for (LiCHa)2. Variation of the rhombus dimensions led to equilibrium distances of Li-Li=l.65 A and C-C=3.85 A. The dimerization energy was equal to 430 kcal/ mol. Dimerization decreased the energy of all molecular orbitals including the frontier ones, i.e., it increased the acidity. The calculations for the complexes of LiCH3 with formaldehyde and acrylonitrile were carried out for various relative positions of the components. Sometimes the energy minimum was found when LiCHa was located out of the plane of the Lewis base near to C atom which is adjacent to the heteroatom. The complexation energies of LiCHa with acrolein, vinyl formate and methyl acrylate were also calculated and found to be 120, 80 and 140 kcal/mol respectively. It corroborates the assumption that conjugated bases should form with organometallics complexes of higher stability than the unconjugated ones (the complexation energy with formaldehyde was equal to 100 kcal/mo!). The complexation energy with acrylonitrile was found to be 180 kcal/mol. This correlates with the higher activity of this monomer when compared to methyl acrylate in anionic systems and correlates with the lower activity of acrylonitrile compared to methyl acrylate if they are in the same system but in the presence of a small amount of strong Lewis base competing for the complexing conter.

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Section: The Complexation Of Methyllithium With Some Monomerssupporting

confidence: 87%

Section: The Complexation Of Methyllithium With Some Monomerssupporting

confidence: 87%

Electronic Structure and Energy of the Complexes: Methyllithium—Unsaturated Polar Monomer

Éizner¹,

Erussalimsky²,

Milovskaya³

1973

Polym J

View full text Add to dashboard Cite

show abstract

“…This inactivity is at variance with the reported results of the polymerization of vinyl chloride, where monodentate Lewis bases, such as ethyl acetate and n-butyl ether, when combined with AlEta-benzoyl peroxide, were found to give active catalyst systems. 4 As a first step to account for such differences in activity, the possibility of its being due to the disparity in the electrondonating ability of the Lewis bases toward AlEta was studied. The NMR internal chemical shift, i.e., the difference between the chemical shifts of methyl and of methylene protons of AlEta, has been proposed as a measure of the electron-donating ability.6 The internal chemical shifts of AlEta and of the AlEta-Lewis base mixture were determined in the same way as was done by Hata et al 7 The results, listed in Table I, show that the values of the internal chemical shifts are in no Lewis base Z AlEta ( molar ratio ) mmol; ethylene, 60 kg/cm2 (7 g); n-hexane, 15 ml; at 20 °C for 16 h.…”

Section: Resultsmentioning

confidence: 99%