Isomers of some vinyl and allyl compounds

The structures of two rotational isomers of styrene, methyl methacrylate, N-vinylpyrrolidone, and allyl benzoate found by AM1 calculations are discussed. Their formation is indicated by the presence of two minima on the curves of the rotation barriers around the C¹-C², C²-N³ and C(=O)-O, O-C(H₂) bonds. The structures of the isomers of allyl compounds were detected capable of providing the cyclization reaction and hydrogen atom elimination. It was found that both double bonds were of similar reactivity. The suggested structures of the isomers can participate in intermolecular interactions with the formation of self-associates and heteroassociates (molecular complexes) due to the presence of C=C and C=O groups with different degree of conjugation.     

Polymerization of iso-butyl vinyl ether by oxychlorides of group V and VI elements

Chromyl chloride (CrO₂Cl₂) causes facile polymerization of iso-butyl vinyl ether (IBVE). In contradiction to the existing report, CrO₂Cl₂ alone or in combination with conventional modifiers fails to produce stereoregular poly(IBVE). Because of the fast polymerization at ambient temperature (30°), the kinetics of the polymerization of IBVE by CrO₂Cl₂ were studied at 0° and 15°. The polymerization is first order in CrO₂Cl₂ and second order in IBVE upto a threshold monomer concentration thereafter becoming independent of [IBVE]. The polymerization is inhibited by pyridine. Addition of HCl to CrO₂Cl₂ increases both rate of polymerization (R_P) and [η]. Added water does not affect R_P upto [H₂O]/[CrO₂Cl₂] ≈ 1.33 but thereafter enhances it sharply upto [H₂O]/[CrO₂Cl₂] ≈ 5.32. With increasing [H₂O], [η] falls to a limiting value. [η] is independent of [CrO₂Cl₂] but increases with [IBVE] upto 1.0mole/l. Both R_P and [η] show a maximum at 47° in the Arrhenius plot over the range 10–72°. The features have been explained on the basis of a conventional cationic mechanism.     

Vacuum ultraviolet absorption spectra of vinyl compounds containing elements of group IV

Conclusions The substituants MR₃ in the compounds C=C-MR₃ and R₃M-C=C-MR₃ give rise to a bathochromic effect in the UV absorption spectra. The influence of the substituents does not agree with a mechanism of d- conjugation, and its explanation requires a consideration primarily of the - conjugation, and to a lesser degree of the inductive effect.     

Polymerization of vinyl chloride by alkyllithium compounds

The polymerization of vinyl chloride initiated by alkyllithium compounds was investigated. The effect of temperature, initiator concentration, and monomer concentration on the conversion and the properties of the resulting polymers were studied. The optimum temperature in the investigated range (between ?20°C and +20°C) was +5°C. The conversion is directly proportional to the concentration of both the initiator and the monomer. The molecular weight is inversely proportional to the initiator concentration and directly proportional to the monomer concentration. Under optimum conditions the molecular weight of the polymers is as high as 140,000. These results differ by an order from hitherto published data on the nonradical polymerization of vinyl chloride. The proportion of isotactic and syndiotactic structures resulting from the presence of tert-butyllithium does not differ from that obtained by radical polymerization, but the occurrence of anomalous structures is reduced to a minimum. The stability of the macromolecules is higher. A mechanism of the polymerization is suggested.     

Polymerization of allyl(vinyl phenyl) ethers and reactions of the resulting polymers

Solution polymerizations of allyl(o-vinyl phenyl)ether and allyl(p-vinyl phenyl)ether with cationic and radical initiators were investigated. Soluble polymers were formed in polymerizations with boron trifluoride etherate and with benzoyl peroxide. In polymerization with azobisisobutyronitrile the polymerization in dilute solution gave a soluble polymer, whereas that in concentrated solution gave a crosslinked, insoluble one. For informationon the polymerization behavior some infrared and ultraviolet spectroscopic investigations of the soluble polymers were made. From these results it appears that polymers with pendant allyl groups are formed in polymerization with boron trifluoride etherate at low temperature, and polymers containing pendant vinyl groups and allyl groups are obtained with the two types of radical initiator. Copolymerizations of these monomers with ethyl vinyl ether and styrene with the use of boron trifluoride etherate were sucessfully effected. Such reactions as Claisen rearrangement, crosslinking induced with radical initiators, and epoxidation with perbenzoic acid were examined for the polymers prepared in the polymerization with boron trifluoride etherate. Good results were obtained for the former two reactions. However, the latter was unsuccessful.     

Polymerization of vinyl monomers with chlorosilane compounds and metal halides

It was found that styrene was polymerized with chlorosilane compounds and metal halides in 1,2-dichloroethane. The rate of polymerization of styrene was proportional to the concentration of styrene, trimethylchlorosilane, and mercuric chloride. The overall activation energy of polymerization was ?2.9 kcal/mole. The polymer yield decreased markedly on addition of ether into the polymerization system, and the infrared spectrum showed evidence of silicone fragments in the polymer. From the results, it was considered that the polymerization was initiated by a siliconium cation. The formation of a complex between trimethylchlorosilane and metal halides (i.e., ferric chloride) was confirmed by the continuous variation method of ultraviolet and visible absorption spectra.     

Polymerization of vinyl compounds in the presence of perfluoroisopropenyl ester

To report a new polymerization reaction phenomenon, this article examines the polymerization of butyl vinyl ether and N‐vinylcarbazole in the presence of 2‐benzoxypentafluoropropene [CF₂?C(CF₃)OCOC₆H₅ or BPFP]. The homopolymer of butyl vinyl ether was produced in the presence of a catalytic amount of BPFP in high yields. N‐Vinylcarbazole, which is a monomer well‐known for producing its homopolymer under cationic polymerization conditions, also yielded its homopolymer in the presence of BPFP. It was concluded that some cationic species would be yielded by the addition of BPFP. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 908–910, 2007.     

Polymerization of allyl phenyl ether

Allyl phenyl ether polymerized rapidly and quantitatively to a resin with a structure similar to a phenolic thermoset in the presence of boron trifluoride etherate at 50°C. The structure and properties of this polyphenol were studied. A reaction mechanism involving rearrangement was discussed.     

A spectroscopic study of atomic interactions in aryl derivatives of group iv elements

Spectroscopic features (quantitative IR, Raman, and UV spectra) are discussed for group IV (M=C, Si, Ge, Sn) aryls, mainly R₃MC₆H₅ and R₃MCH₂C₆H₅, in order to distinguish features of the intramolecular interactions. Confirmation is obtained for the existing view on the electron-acceptor behavior of heteroatoms joined to aromatic rings. The effect is seen in the IR and UV spectra, which implies that the ground and excited states are perturbed. The effect of M on the ring is shown to be an over-all one; the positive (induction) component follows the electronegativity of M in a scale close to Gordy's, while the negative one increases somewhat from Si to Ge and Sn.The effects in M aryls are analogous to those in M alkenyls, in particular the - conjugation in a phenyl radical attached to Si, which is already known for M allyls.     

Relative thermodynamic stabilities of allyl vinyl and propenyl vinyl ethers

The relative thermodynamic stabilities of a number of isomeric allyl vinyl and propenyl vinyl ethers were determined by chemical equilibration in DMSO solution with KOBu-t as catalyst. From the temperature dependence of the values of the equilibrium constant the parameters G _m , H _m and S _m of isomerization at 298.15 K were evaluated. Propenyl vinyl ethers, owing to their low enthalpy contents, are much more stable than the isomeric allyl vinyl ethers. It appears that in the parent propenyl vinyl ether, the Me group attached to C- of the divinyl ether skeleton has a strong stabilizing effect, comparable to that of alkyl groups in ordinary olefins, on the unsaturated system. In more heavily alkyl-substituted divinyl ethers, however, the stabilizing effects of alkyl groups are less prominent, being comparable to the low stabilization energies of alkyl groups in vinyl ethers, and depend moreover, on the pattern of substitution.     

Fluorine functionalized compounds of group 13 elements

The review gives a short survey of some developments in the synthetic chemistry of organoaluminum fluorides. Into the focus is brought the Janus-faced Lewis base-Lewis acid Al compound, group 13 difluorodiorganometalates, fluorine functionalized carbaalane derivatives, fluorination of aluminum imide clusters, diamidoaluminum fluoride, and some group 13 β-diketiminate mono- and difluorides.     

On the vinyl group photooxygenation of bilirubin-like model compounds

The photooxygenation of z-3-vinyl-4-methyl-5-(phenylmethylidene)-3-pyrrolin-2-one (1) and z-5′-oxo-4′-viny1–4-ethyl-3′,3,5-trimethyl-1′,5′-dihydro(2,2′)dipyrromethene (2) reveals no reaction at the vinyl groups; hence, none is expected at the vinyl groups of bilirubin IXα, and none has been found.     

Polymerization of vinyl monomers initiated by organoaluminium compounds/benzoyl peroxide systems

The free-radical polymerization of methyl methacrylate (MMA) initiated by systems comprizing benzoyl peroxide (BPO) and different organoaluminium compounds (OACs) has been studied. The influence of the type of OAC, concentration of components of the initiation system, temperature, and time on the reaction yield have been determined. Systems containing BPO and diethylaluminium chloride (Et₂AlCl) have been found to enable us to obtain, in high yields at room temperature, of homopolymers of MMA, methyl acrylate, acrylonitrile (AN), vinyl acetate, and the alternating AN/styrene (St) copolymer; they are, however, not very active in the homopolymerization of St and vinyl chloride. Factors affecting the polymerization yield have been discussed in terms of the mechanism of the reaction between BPO and OACs, reactivity of alkyl radicals formed in these systems, and catalytic effect of OAC in the propagation step.     

Polymerization of vinyl chloride

Polymerization of vinyl chloride (VC) was studied. natural evolution of HCl from VC occurred in the polymerization. VC, VC-αd₁, VC-β,βd₂ and VC-d₃ were used to study the reactivities of the hydrogen atoms in the polymerization and the β-hydrogen atoms contributed to the chain transfer. Chemical and physical methods were used to observe irregular structures, such as branching, double bonds, and head-to-head or tail-to-tail addition, and also to confirm the relation between conversion and the irregular structures.