Showing papers on "Methyl vinyl ketone published in 1972"
TL;DR: In this paper, the effects of the concentration of monomer, the addition of dipyridyl and the coordinating ability of solvent on the molecular weight of the polymer were explained by competitive coordination to the iron complex having a growing polymer chain.
Abstract: Kinetics of polymerization of vinyl compounds (acrylonitrile, methacrylonitrile, acrolein, methyl vinyl ketone, methyl acrylate, alkyl methacrylates, and 2-vinylpyridine) with dialkylbis(dipyridyl)iron(II), FeR2(dipy)2 1 (R=CH3, C2H5, n-C3H7), was studied. By comparison with previous kinetic results in which the decomposition of 1 was followed spectroscopically, a polymerization mechanism including a slow initiation process followed by rapid propagation and unimolecular termination processes was proposed. The effects of the concentration of monomer, the addition of dipyridyl and the coordinating ability of solvent on the molecular weight of the polymer were explained by competitive coordination to the iron complex having a growing polymer chain. Results of copoly-merization experiments were explained in terms of competitive coordination and insertion reactions between the monomers involved. A linear relationship was found between log(1⁄r1) values and the logarithms of stability constants of nickel-olefin ...
28 citations
TL;DR: The structure of tris(methyl vinyl ketone)tungsten has been solved by single-crystal X-ray diffraction methods; its gross geometry is trigonal prismatic as discussed by the authors.
Abstract: The structure of tris(methyl vinyl ketone)tungsten has been solved by single-crystal X-ray diffraction methods; its gross geometry is trigonal prismatic.
15 citations
TL;DR: The titled compounds, 12a, 12 b, 21 a and 21 b, were synthesized by the reaction of the α-sulfonyl carbanion generated from dimethyl sulfone or phenyl methyl sulfone with the bisketal 9 of methyl 7a-methyl-1,5-dioxo-3α,7aβ-hexahydroindan-4α-yl propionate prepared by fermentation of 5 and subsequent oxidation of the product as discussed by the authors.
15 citations
TL;DR: In this article, the reaction between butyne-2 and ground-state oxygen atoms produced by the Hg6(3P1) photosensitized decomposition of N2O has been studied under static conditions at room temperature.
Abstract: The reaction between butyne-2 and ground-state oxygen atoms produced by the Hg6(3P1) photosensitized decomposition of N2O has been studied under static conditions at room temperature. The major products were CO, propylene, ethane, methyl vinyl ketone and a polymer. The results suggest that the initial step involves the formation of a biradical intermediate, which rapidly rearranges into an unsaturated carbonyl compound. Rearrangements involving the internal migration of H atoms and CH3 radicals, and the splitting-off of CH3 radicals occur. The addition product is formed “hot” and undergoes decomposition if not stabilized by collisions. The pressure dependence of the formation of the products enables the lifetime of the initially formed “hot” molecule to be determined.
11 citations
TL;DR: In this paper, the polymerization of vinyl monomers with various xanthates (potassium tert-butyl-xanthate, potassium benzylxanthates, zinc n-Butylxantate, etc.) was carried out at 0°C in dimethylformamide.
Abstract: The polymerization of vinyl monomers with various xanthates (potassium tert-butylxanthate, potassium benzylxanthate, zinc n-butylxanthate, etc.) were carried out at 0°C in dimethylformamide. N-Phenylmaleimide, acrylonitrile, methyl vinyl ketone, and methyl methacrylate were found to undergo polymerization with potassium tert-butylxanthate; however, styrene, methyl acrylate, and acrylamide were not polymerized with this xanthate. In the anionic polymerization of methyl vinyl ketone with potassium tert-butylxanthate, the rate of the polymerization was found to be proportional to the catalyst concentration and to the square of the monomer concentration. The activation energy of methyl vinyl ketone polymerization was 2.9 kcal/mole. In the polymerization, the order of monomer reactivity was as follows: N-phenylmaleimide > methyl vinyl ketone > acrylonitrile > methyl methacrylate. The initiation ability of xanthates increased with increasing basicity of the alkoxide group and with decreasing electronegativity of the metal ion in the series, lithium, sodium, and potassium tert-butylxanthate. The relative effects of the aprotic polar solvents on the reactivity of potassium tert-butylxanthate was also determined as follows: diethylene glycol dimethyl ether > dimethylsulfoxide > hexamethylphosphoramide > dimethylformamide > tetrahydrofuran (for methyl vinyl ketone); dimethyl sulfoxide > hexamethylphosphoramide > dimethylformamide ≅ diethylene glycol dimethyl ether (for acrylonitrile).
5 citations
TL;DR: In this article, the Wittig reaction was used to obtain cyclohexene derivatives of trans-Δ2-Anhydromevalonic acid (XVII) by starting from (4-tetrahydro-2-pyranyloxy)-2-butanone.
Abstract: trans-Δ2-Anhydromevalonic acid (XVII) was prepared by a Wittig reaction, starting from (4-tetrahydro-2-pyranyloxy)-2-butanone. On the other hand, the corresponding 4-acetoxy-2-butanone gave, under similar conditions, the cyclohexene derivative V, explainable by a twofold Michael addition of the Wittig reagent to methyl vinyl ketone, followed by an intramolecular alcol condensation.
5 citations
TL;DR: In this paper, the graft copolymerization reaction of methyl vinyl ketone from several solvents with fibrous cotton cellulose, preirradiated to a dosage of 5.2 × 1019 eV/g with γ-radiation from 60Co, was investigated.
Abstract: The graft copolymerization reaction of methyl vinyl ketone from several solvents with fibrous cotton cellulose, preirradiated to a dosage of 5.2 × 1019 eV/g with γ-radiation from 60Co, was investigated. Solvents included water, methanol, N,N-dimethyl formamide, and several combinations of these solvents. From water a maximum yield of copolymer product was obtained after 2 hr at 25°C. The addition of methanol to aqueous solutions of methyl vinyl ketone, in all concentrations, inhibited the graft copolymerization reaction. The addition of a small amount of N,N-dimethylformamide to aqueous solutions of the monomer increased the rate of the copolymerization reaction; however, the addition of large amounts of N,N-dimethylformamide to these solutions also inhibited the reaction. From solutions of methanol or N,N-dimethylformamide and monomer, little or no copolymerization of monomer with irradiated cellulose occurred. The copolymer products exhibited a strong infrared absorption band at 5.85 μ which is characteristic of the CO group of the grafted poly(methyl vinyl ketone). Fibrous copolymer yarns exhibited increased yarn number and decreased breaking strength and average stiffness, as compared with unmodified cotton yarns.
3 citations
2 citations
TL;DR: The reduction of the latter with lithium aluminum hydride gave the hydroxymethyl derivatives of dihydropyrans, while ammonolysis gave amides of 2-ethoxy-Δ5-dihydropyran-2-carboxylic acids as mentioned in this paper.
Abstract: Acrolein and methyl vinyl ketone undergo diene condensation with ethyl α-ethoxyacrylate to give the corresponding 2-ethoxy-2-carbethoxy-Δ5-dihydropyrans in 50–60% yields. The reduction of the latter with lithium aluminum hydride gave the hydroxymethyl derivatives of dihydropyrans, while ammonolysis gave amides of 2-ethoxy-Δ5-dihydropyran-2-carboxylic acids.
1 citations
TL;DR: In this paper, the isomeric composition of 2-pyrazolines obtained by the condensation of croton aldehyde and methyl vinyl ketone with C1-C4 monoalkyl hydrazines has been studied by the GLC method.
Abstract: The isomeric composition of the 2-pyrazolines obtained by the condensation of croton aldehyde and methyl vinyl ketone with C1–C4 monoalkyl hydrazines has been studied by the GLC method. It has been shown that in the reaction of croton aldehyde with isopropyl hydrazine, isobutyl hydrazine, and, to a smaller extent, with methyl hydrazine, in addition to the 1-alkyl-5-methyl-2-pyrazolines the 1, 3-isomers are formed. In other cases, only one pyrazoline, corresponding to the structure of the carbonyl compound, is formed. Eight previously-unknown dialkyl-2-pyrazolines are described.