Topic
Methyl vinyl ketone
About: Methyl vinyl ketone is a research topic. Over the lifetime, 1510 publications have been published within this topic receiving 26839 citations. The topic is also known as: 3-buten-2-one & gamma-oxo-alpha-butylene.
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TL;DR: In this article, the [4 + 2]-cycloaddition of N-(5-nitrofuranyl)morpholine with methyl vinyl ketone affords a mixture of three phenols derived from a Diels−Alder reaction followed by nitro group ejection and subsequent aromatization.
Abstract: 5-Amino-2-furancarboxylic acid methyl ester undergoes a facile Diels−Alder cycloaddition with a variety of dienophiles to afford ring-opened cycloadducts that are readily dehydrated using BF3· OEt2 to give polysubstituted anilines. In each case, the cycloaddition proceeds with high regioselectivity, with the electron-withdrawing group being located ortho to the amino group. The most favorable FMO interaction is between the HOMO of the furanamine and the LUMO of the dienophile. The atomic coefficient at the ester carbon of the furan is larger than that at the amino center, and this nicely accommodates the observed regioselectivity. The [4 + 2]-cycloaddition of N-(5-nitrofuranyl)morpholine with methyl vinyl ketone affords a mixture of three phenols. One of the phenols is derived from a Diels−Alder reaction followed by nitro group ejection and subsequent aromatization. The remaining two phenols are the result of cleavage of the initially formed oxabicyclic intermediate with concomitant migration of the nitro...
8 citations
TL;DR: In this paper , the absolute photodissociation cross sections of methyl vinyl ketone oxide (MVKO) and methacrolein oxide (MACRO) were determined by measuring their laser depletion fraction at 352 nm, which was deduced from their time-resolved UV-visible absorption spectra.
Abstract: Methyl vinyl ketone oxide (MVKO) and methacrolein oxide (MACRO) are resonance-stabilized Criegee intermediates which are formed in the ozonolysis reaction of isoprene, the most abundant unsaturated hydrocarbon in the atmosphere. The absolute photodissociation cross sections of MVKO and MACRO were determined by measuring their laser depletion fraction at 352 nm, which was deduced from their time-resolved UV-visible absorption spectra. After calibrating the 352 nm laser fluence with the photodissociation of NO2, for which the absorption cross section and photodissociation quantum yield are well known, the photodissociation cross sections of thermalized (299 K) MVKO and MACRO at 352 nm were determined to be (3.02 ± 0.60) × 10-17 cm2 and (1.53 ± 0.29) × 10-17 cm2, respectively. Using their reported spectra and photodissociation quantum yields, their peak absorption cross sections were deduced to be (3.70 ± 0.74) × 10-17 cm2 (at 371 nm, MVKO) and (3.04 ± 0.58) × 10-17 cm2 (at 397 nm, MACRO). These values agree fairly with our theoretical predictions and are substantially larger than those of smaller, alkyl-substituted Criegee intermediates (CH2OO, syn-CH3CHOO, (CH3)2COO), revealing the effect of extended conjugation. With their cross sections, we also quantified the synthesis yields of MVKO and MACRO in the present experiment to be 0.22 ± 0.10 (at 299 K and 30-700 torr) and 0.043 ± 0.019 (at 299 K and 500 torr), respectively, relative to their photolyzed precursors. The lower yield of MACRO can be related to the high endothermicity of its formation channel.
8 citations
TL;DR: In this article, the authors studied the mechanism of the initial reaction of methyl vinyl ketone (MVK) by SO3− radical and the subsequent sulfonate formation processes using DFT calculation.
8 citations
TL;DR: The subtle balance between the different pathways (additions versus abstractions) serves to give an understanding of the pressure dependence of the rate constants of these tropospheric oxidation processes.
Abstract: High-level electronic structure calculations were carried out for the study of the reaction pathways in the OH-initiated oxidations of methyl vinyl ketone (MVK) and methacrolein (MACR). For the two conformers of MVK (called synperiplanar and antiperiplanar), the addition channels of OH to the terminal and central carbon atom of the double bond dominate the overall rate constant, whereas the abstraction of the methyl hydrogen atoms has no significant kinetic role. In the case of MACR, only the antiperiplanar conformer is important in its reactivity. In addition, the lower Gibbs free energy barrier for MACR corresponds to the aldehydic hydrogen abstraction reaction, which will be somewhat more favorable than the addition processes. The subtle balance between the different pathways (additions versus abstractions) serves to give an understanding of the pressure dependence of the rate constants of these tropospheric oxidation processes.
8 citations
TL;DR: In this paper, a method for the synthesis of α, β-unsaturated compounds was developed by using methanol as a methylenylating agent, which was applied to the conversion of acetone to methyl vinyl ketone and that of methyl propionate to methyl methacrylate.
Abstract: A novel method for the synthesis of α, β-unsaturated compounds was developed by using methanol as a methylenylating agent. Methyl or methylene group at α-position of saturated ketones, esters or nitriles is converted into vinyl group by the addition of methanol over metal ion containing magnesium oxide catalysts, M-MgO [M=Cr(III), Fe(III), Al(III), Mn(II), Ni(II), Cu(II)]. The most promising application of this method is demonstrated by the selective synthesis of acrylonitrile from acetonitrile and methanol over Cr-MgO catalyst. Selectivity to acrylonitrile of more than 95% is attained at 10% conversion of acetonitrile and no deactivation of the catalyst is observed. The method was also applied to the conversion of acetone to methyl vinyl ketone and that of methyl propionate to methyl methacrylate. It was found that the step determining the rate of reaction was the abstraction of α-hydrogen from substrates by surface basic sites. Reaction mechanism and role of added metal ion are discussed.
8 citations