Reaction Of Vinyl Chloride Research Articles

Mechanism of the Reaction of Vinyl Chloride with (α-diimine)PdMe+ Species

The reaction of vinyl chloride (VC) with (α-diimine)PdMe+ species yields (α-diimine)PdCl(propene)+. Isotope labeling experiments using the deuterium-labeled vinyl chlorides 1-VC-d1 and Z-VC-d1 combined with DFT computations establish that this reaction proceeds by 2,1-insertion of VC to produce β-H agostic (α-diimine)Pd(CHClCH2Me)+, chain-walking isomerization to generate β-Cl dative (α-diimine)Pd(CHMeCH2Cl)+, and syn β-Cl elimination. The labeling experiments rule out mechanisms involving initial 1,2-insertion or C−Cl oxidative addition. The computational results and the observation of small amounts of propene-d2 argue against mechanisms involving 2,1-insertion followed by α-Cl elimination and a 1,2 H-shift.

Structure of the 1,N2-Etheno-2′-Deoxyguanosine Adduct in Duplex DNA at pH 8.6

The structure of the 1,N(2)-etheno-2'-deoxyguanosine (1,N(2)-epsilondG) adduct, arising from the reaction of vinyl chloride with dG, was determined in the oligonucleotide duplex 5'-d(CGCATXGAATCC)-3'.5'-d(GGATTCCATGCG)-3' (X=1,N(2)-epsilondG) at pH 8.6 using high resolution NMR spectroscopy. The exocyclic lesion prevented Watson-Crick base-pairing capability at the adduct site and resulted in an approximately 17 degrees C decrease in Tm of the oligodeoxynucleotide duplex. At neutral pH, conformational exchange resulted in spectral line broadening near the adducted site, and it was not possible to determine the structure. However, at pH 8.6, it was possible to obtain well-resolved (1)H NMR spectra. This enabled a total of 385 NOE-based distance restraints to be obtained, consisting of 245 intra- and 140 inter-nucleotide distances. The (31)P NMR spectra exhibited two downfield-shifted resonances, suggesting a localized perturbation of the DNA backbone. The two downfield (31)P resonances were assigned to G(7) and C(19). The solution structure was refined by molecular dynamics calculations restrained by NMR-derived distance and dihedral angle restraints, using a simulated annealing protocol. The generalized Born approximation was used to simulate solvent. The emergent structures indicated that the 1,N(2)-epsilondG-induced structural perturbation was localized at the X(6).C(19) base pair, and its 5'-neighbor T(5).A(20). Both 1,N(2)-epsilondG and the complementary dC adopted the anti conformation about the glycosyl bonds. The 1,N (2)-epsilondG adduct was inserted into the duplex but was shifted towards the minor groove as compared to dG in a normal Watson-Crick C.G base pair. The complementary cytosine was displaced toward the major groove. The 5'-neighbor T(5).A(20) base pair was destabilized with respect to Watson-Crick base pairing. The refined structure predicted a bend in the helical axis associated with the adduct site.

Molecular Structure and Vinyl Chloride Insertion of a Cationic Zirconium(IV) Acyl Carbonyl Complex

The reaction of vinyl chloride (VC) with the cationic Zr acyl complex [Cp2Zr{C(O)Me}(CO)][MeB(C6F5)3] (1a/b, O-inside and O-outside isomers) yields an unusual dinuclear dicationic μ-acyl μ-keto-alkoxide complex, [Cp2Zr{μ-C(O)Me}{μ-OCMe(CHCH2)C(O)Me}ZrCp2][MeB(C6F5)3]2 (3), which was characterized by NMR spectroscopy and X-ray crystallography. This reaction proceeds by 1,2 insertion into the Zr−acyl bond of Cp2Zr{C(O)Me}+ to yield Cp2Zr{CH2CHClC(O)Me}+, which undergoes β-Cl elimination to form methyl vinyl ketone (MVK) and Cp2ZrCl+ (8). The MVK is trapped by Cp2Zr{C(O)Me}+ to form [Cp2Zr{η2-C(O)Me}(MVK)][MeB(C6F5)3] (9), which rearranges to [Cp2Zr{κ2-OC(Me)(CHCH2)C(O)Me}][MeB(C6F5)3] (10). Intermediate 10 is trapped by Cp2Zr{C(O)Me}+ to form 3. 3 is also formed by the reaction of 1a/b with 0.5 equiv of MVK. 1,2 VC insertion of Cp2Zr{C(O)Me}+ is favored over 2,1 insertion by steric factors. The molecular structure of 1a was determined by X-ray crystallography.

Reaction of Vinyl Chloride with Cationic Palladium Acyl Complexes

Vinyl chloride (VC) reacts with the cationic Pd complexes [L2Pd(Me)(CO)][B(C6F5)4] (3a−d; L2 = Me2bipy, tBu2bipy, dppp, dmpe) and [L2Pd{C(O)Me}(CO)][B(C6F5)4] (4a−d) by 2,1-insertion of L2Pd{C(O)Me}(VC)+ intermediates to yield the O-chelated products [L2Pd{CHClCH2C(O)Me}][B(C6F5)4] (5a−d). 5a−d were characterized by NMR spectroscopy, and the molecular structures of 5a and 5b·CH2Cl2 were determined by X-ray crystallography. The VC 2,1-insertion regiochemistry is favored in part because the alternative L2Pd{CH2CHClC(O)Me}+ 1,2-insertion products would be destabilized by placement of the electron-withdrawing Cl and acyl substituents on the same carbon. In contrast to analogous nonhalogenated L2Pd{CHRCHR‘C(O)Me}+ species, 5a,c do not further react with CO, due to the stability of the chelate ring and the low migratory aptitude of the −CHClCH2C(O)Me group.

Reaction of vinyl chloride with late transition metal olefin polymerization catalysts.

The reactions of vinyl chloride (VC) with representative late metal, single-site olefin dimerization and polymerization catalysts have been investigated. VC coordinates more weakly than ethylene or propylene to the simple catalyst (Me(2)bipy)PdMe(+) (Me(2)bipy = 4,4'-Me(2)-2,2'-bipyridine). Insertion rates of (Me(2)bipy)Pd(Me)(olefin)(+) species vary in the order VC > ethylene > propylene. The VC complexes (Me(2)bipy)Pd(Me)(VC)(+) and (alpha-diimine)Pd(Me)(VC)(+) (alpha-diimine = (2,6-(i)Pr(2)[bond]C(6)H(3))N[double bond]CMeCMe[double bond]N(2,6-(i)Pr(2)[bond]C(6)H(3))) undergo net 1,2 VC insertion and beta-Cl elimination to yield Pd[bond]Cl species and propylene. Analogous chemistry occurs for (pyridine-bisimine)MCl(2)/MAO catalysts (M = Fe, Co; pyridine-bisimine = 2,6-[(2,6-(i)Pr(2)[bond]C(6)H(3))N[double bond]CMe](2)-pyridine) and for neutral (sal)Ni(Ph)PPh(3) and (P[bond]O)Ni(Ph)PPh(3) catalysts (sal = 2-[C(H)[double bond]N(2,6-(i)Pr(2)-C(6)H(3))]-6-Ph-phenoxide; P[bond]O = [Ph(2)PC(SO(3)Na)[double bond]C(p-tol)O]), although the initial metal alkyl VC adducts were not detected in these cases. These results show that the L(n)MCH(2)CHClR species formed by VC insertion into the active species of late metal olefin polymerization catalysts undergo rapid beta-Cl elimination which precludes VC polymerization. Termination of chain growth by beta-Cl elimination is the most significant obstacle to metal-catalyzed insertion polymerization of VC.

Reaction of vinyl chloride with group 4 metal olefin polymerization catalysts.

The reactions of three types of group 4 metal olefin polymerization catalysts, (C(5)R(5))(2)ZrX(2)/activator, (C(5)Me(5))TiX(3)/MAO (MAO = methylalumoxane), and (C(5)Me(4)SiMe(2)N(t)Bu)MX(2)/activator (M = Ti, Zr), with vinyl chloride (VC) and VC/propylene mixtures have been investigated. Two general pathways are observed: (i) radical polymerization of VC initiated by radicals derived from the catalyst and (ii) net 1,2 VC insertion into L(n)MR(+) species followed by beta-Cl elimination. rac-(EBI)ZrMe(mu-Me)B(C(6)F(5))(3) (EBI = 1,2-ethylenebis(indenyl)) reacts with 2 equiv of VC to yield oligopropylene, rac-(EBI)ZrCl(2), and B(C(6)F(5))(3). This reaction proceeds by net 1,2 VC insertion into rac-(EBI)ZrMe(+) followed by fast beta-Cl elimination to yield [rac-(EBI)ZrCl][MeB(C(6)F(5))(3)] and propylene. Methylation of rac-(EBI)ZrCl(+) by MeB(C(6)F(5))(3)(-) enables a second VC insertion/beta-Cl elimination to occur. The evolved propylene is oligomerized by rac-(EBI)ZrR(+) as it is formed. At high Al/Zr ratios, rac-(EBI)ZrMe(2)/MAO catalytically converts VC to oligopropylene by 1,2 VC insertion into rac-(EBI)ZrMe(+), beta-Cl elimination, and realkylation of rac-(EBI)ZrCl(+) by MAO; this process is stoichiometric in Al-Me groups. The evolved propylene is oligomerized by rac-(EBI)ZrR(+). Oligopropylene end group analysis shows that the predominant chain transfer mechanism is VC insertion/beta-Cl elimination/realkylation. In the presence of trace levels of O(2), rac-(EBI)ZrMe(2)/MAO polymerizes VC to poly(vinyl chloride) (PVC) by a radical mechanism initiated by radicals generated by autoxidation of Zr-R and/or Al-R species. CpTiX(3)/MAO (Cp = C(5)Me(5); X = OMe, Cl) initiates radical polymerization of VC in CH(2)Cl(2) solvent at low Al/Ti ratios under anaerobic conditions; in this case, the source of initiating radicals is unknown. Radical VC polymerization can be identified by the presence of terminal and internal allylic chloride units and other "radical defects" in the PVC which arise from the characteristic chemistry of PCH(2)CHCl(*) macroradicals. However, this test must be used with caution, since the defect units can be consumed by postpolymerization reactions with MAO. (C(5)Me(4)SiMe(2)N(t)Bu)MMe(2)/[Ph(3)C]][B(C(6)F(5))(4)] catalysts (M = Ti, Zr) react with VC by net 1,2 insertion/beta-Cl elimination, yielding [(C(5)Me(4)SiMe(2)N(t)Bu)MCl][B(C(6)F(5))(4)] species which can be trapped as (C(5)Me(4)SiMe(2)N(t)Bu)MCl(2) by addition of a chloride source. The reaction of rac-(EBI)ZrMe(2)/MAO or [(C(5)Me(4)SiMe(2)N(t)Bu)ZrMe][B(C(6)F(5))(4)] with propylene/VC mixtures yields polypropylene containing both allylic and vinylidene unsaturated chain ends rather than strictly vinylidene chain ends, as observed in propylene homopolymerization. These results show that the VC insertion of L(n)M(CH(2)CHMe)(n)R(+) species is also followed by beta-Cl elimination, which terminates chain growth and precludes propylene/VC copolymerization. Termination of chain growth by beta-Cl elimination is the most significant obstacle to metal-catalyzed insertion polymerization/copolymerization of VC.

Reaction of Vinyl Chloride with a Prototypical Metallocene Catalyst: Stoichiometric Insertion and β-Cl Elimination Reactions with rac-(EBI)ZrMe+ and Catalytic Dechlorination/Oligomerization to Oligopropylene by rac-(EBI)ZrMe2/MAO

Reaction of Vinyl Chloride with a Prototypical Metallocene Catalyst: Stoichiometric Insertion and β-Cl Elimination Reactions with <i>r</i><i>ac</i>-(EBI)ZrMe⁺ and Catalytic Dechlorination/Oligomerization to Oligopropylene by <i>r</i><i>ac</i>-(EBI)ZrMe₂/MAO

The Role of Oxygen in the Polymerization of Vinyl Chloride

Abstract Vinyl chloride (VC) as well as other vinyl monomers interact with oxygen of the air to give peroxide compounds. It is known that the course of this reaction has some influence on the production process of polyvinyl chloride (PVC) as well as on the properties of the polymer. The whole problem of VC autoxidation in connection with the polymerization of this monomer was discussed in the sixties in Russian [l]. No new review of the publications concerning autoxidation of VC is available. In a recent interesting review [2] devoted to the formation and degradation of polymeric peroxides, only a small part of the literature about peroxides based on VC was mentioned, and important aspects of the VC autoxidation problem were not touched upon. In this review, an attempt is undertaken to represent comprehensive information about the reaction of VC with oxygen, chemical structure and reactions of the oxidation products, the role of small amounts of oxygen in VC polymerization, and the dependence of PVC properties on the presence of oxygen in the polymerization mixture. Pathways for the prevention of the negative effect of oxygen during polymerization are also discussed. In this review, we do not enter into the field of VC polymerization initiated by systems containing oxygen and reducers such as trialkylbor and other metallorganic compounds. The role of oxygen in the destruction processes occurring after the polymer has been formed is also not discussed.

Copolymerization of vinyl chloride with 1‐olefins. III. An investigation of the copolymerization reaction of vinyl chloride with 1‐butene and 1‐pentene

AbstractSeries of suspension copolymerization of vinyl chloride with various contents of 1‐butene and 1‐pentene (5–30 mass%) were carried out under the same reaction conditions. By applying a method which utilizes periodic sampling of heterogeneous reaction mixture from the reactor during the reaction and a gas chromatographic determination of unreacted vinyl chloride in the sample, the conversion curves of vinyl chloride were determined and the initial reaction rates were compared.

The copolymerization of vinyl chloride with 1-olefins. II. An investigation of the copolymerization reaction of vinyl chloride and propene

The conversion curve of the copolymerization of vinyl chloride with propene and the conversion curves of both monomers were determined, their initial reaction rates compared, and the copolymerization parameters determined by a method which utilizes periodical sampling of a heterogeneous reaction mixture from the reactor during the reaction and gas-chromatographic determination of unreacted monomers contained in the sample. The agreement between the final conversion values determined chromatographically and gravimetrically was evaluated by using results of a series of copolymerizations of vinyl chloride containing various amounts of propene in the initial monomeric mixture (5–30 wt %) carried out under the same conditions.

Reaction of vinyl chloride with bromoform and related compounds in the presence of coordination initiators based on Fe(CO)5

1. The telomerization of vinyl chloride (VC) with bromoform, with initiation by coordination initiators based on Fe(CO)5, proceeds with a greater conversion of the telogen and an increased yield of lower telomers when compared with initiation by benzoyl peroxide. Together with the CHBr2 (CH2CHCl)nBr (n=1−3) telomers, a small amount of 1,3-dibromo-1,3-dichloropropane is formed. 2. Under the reaction conditions, the CHBr2CH2CHClBr telomer is capable of reacting with VC, with cleavage of the C-Br bonds of both the CHBr2 and CHClBr groups. 3. We were able to add 1,1,3-tribromopropane and 1,3-dibromo-1-chloropropane to VC by initiation with Fe(CO)5 + DMF.

Reaction of vinyl chloride with difluorosilylene by cocondensation

Reaction of vinyl chloride with difluorosilylene by cocondensation

Re-examination of the vinyl chloride–phosphorus trichloride–oxygen reaction: an example of direct formation of a phosphate derivative from an olefin

Contrary to previous reports, the reaction of vinyl chloride with phosphorus trichloride and oxygen gives as the main products a 1·7 : 1 mixture of Cl2P(:O)·O·CHCl·CH2Cl and Cl2P(:O)·CHCl·CH2Cl; the former has been incorrectly assigned the structure Cl2P(:O)·CH2·CHCl2.

Thermal addition of hydride chlorosilanes to alkenylchlorosilanes

1. A study of the high-boiling byproducts of the thermal condensation reaction of vinyl chloride with trichlorosilane showed that the formation of vinyltrichlorosilane was accompanied by its reaction with the trichlorosilane. 2. The reaction mentioned takes place in a quartz reactor according to a condensation mechanism with the formation of bis(trichlorosilyl)ethylene, and in a steel reactor an addition reaction takes place with the formation of bis(trichlorosilyl)ethane.