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Showing papers on "Methyl vinyl ketone published in 2013"


Journal ArticleDOI
TL;DR: In this article, the photo-oxidation chemistry of isoprene (ISOP; C 5 H 8 ) was studied in a continuous flow chamber under conditions such that the reactions of the O 2 derived peroxyl radicals (RO 2 ) were dominated by the HO 2 pathway.
Abstract: . The photo-oxidation chemistry of isoprene (ISOP; C 5 H 8 ) was studied in a continuous-flow chamber under conditions such that the reactions of the isoprene-derived peroxyl radicals (RO 2 ) were dominated by the hydroperoxyl (HO 2 ) pathway. A proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) with switchable H 3 O + and NO + reagent ions was used for product analysis. The products methyl vinyl ketone (MVK; C 4 H 6 O) and methacrolein (MACR; C 4 H 6 O) were differentiated using NO + reagent ions. The MVK and MACR yields via the HO 2 pathway were (3.8 ± 1.3)% and (2.5 ± 0.9)%, respectively, at +25 °C and 2 pathway implies concomitant production of hydroxyl ((6.3 ± 2.1)%) and hydroperoxyl ((6.3 ± 2.1)%) radicals, meaning a HO x recycling of (12.6 ± 4.2)% given that HO 2 was both a reactant and product. Other isoprene oxidation products, believed to be mostly organic hydroperoxides, also contributed to the ion intensity at the same mass-to-charge ( m/z ) ratios as the MVK and MACR product ions for HO 2 -dominant conditions. These products were selectively removed from the gas phase by placement of a cold trap (−40 °C) inline prior to the PTR-TOF-MS. When incorporated into regional and global chemical transport models, the yields of MVK and MACR and the concomitant HO x recycling reported in this study can improve the accuracy of the simulation of the HO 2 reaction pathway of isoprene, which is believed to be the fate of approximately half of atmospherically produced isoprene-derived peroxy radicals on a global scale.

127 citations


Journal ArticleDOI
TL;DR: This study shows that sulfate radical-induced oxidation in the aqueous particle phase provides a reasonable explanation for the formation of these organosulfates from methacrolein and methyl vinyl ketone.
Abstract: Recent studies show that isoprene-derived organosulfates are an important fraction of ambient secondary organic aerosol (SOA), adding up to 20% to the organic mass. Organosulfates with m/z of 199 and 183 relating to C4 compounds are found in ambient and laboratory generated SOA and a sulfate radical induced oxidation of methacrolein (MACR) and methyl vinyl ketone (MVK) has been shown to be a possible formation mechanism. In the present study, experiments on the sulfate radical-induced oxidation of methacrolein and methyl vinyl ketone were performed in bulk aqueous phase, as well as in an aerosol chamber, and finally compared with ambient PM10 samples collected at a rural East German village during the summer 2008, to investigate their relevance in aqueous phase SOA formation. Samples from aqueous phase experiments and extracts from filters were analysed with UPLC/(−)ESI-IMS-QTOFMS. All the samples showed the abundance of highly oxidised organosulfates with m/z 153, 155, 167, 183 and 199 corresponding to the species found in ambient particle samples. In the bulk phase studies with laser-induced sulfate radical formation, the signal intensities increased with increasing number of laser pulses, indicating the sulfate radical-induced formation of these organosulfates. Additionally, the chamber experiments showed a particle mass growth of about 10 μg m−3 and 4 μg m−3 for experiments on the reactive uptake of MACR and MVK with a sulfate radical precursor (K2S2O8) in the seed particles. Correlations of the C2 to C5 organosulfate species (including the m/z 215, C5H11O7S−), detected in the ambient samples were found to be very strong (r > 0.8), indicating that these compounds are formed from similar mechanisms and under equal environmental conditions. This study shows that sulfate radical-induced oxidation in the aqueous particle phase provides a reasonable explanation for the formation of these organosulfates from methacrolein and methyl vinyl ketone.

94 citations


Journal ArticleDOI
TL;DR: The PdCe(9.6)/ZSM-5 catalyst displayed the highest catalytic efficiency, as a consequence of a higher amount of strong acid sites and a superior PdO-Pd redox cycle in the presence of a CeO(2) additive.

46 citations


Journal ArticleDOI
TL;DR: In this article, it was shown that the fast formation of oligomers up to 1800 Da is due to radical oligomerization of methyl vinyl ketone (MVK) in the aqueous phase.
Abstract: . It is now accepted that one of the important pathways of secondary organic aerosol (SOA) formation occurs through aqueous phase chemistry in the atmosphere. However, the chemical mechanisms leading to macromolecules are still not well understood. It was recently shown that oligomer production by OH radical oxidation in the aerosol aqueous phase from α-dicarbonyl precursors, such as methylglyoxal and glyoxal, is irreversible and fast. Methyl vinyl ketone (MVK) was chosen in the present study as it is an α,β-unsaturated carbonyl that can undergo radical oligomerization in the aerosol aqueous phase. We present here experiments on the aqueous phase OH-oxidation of MVK, performed under various conditions. Using NMR and UV absorption spectroscopy, high and ultra-high resolution mass spectrometry, we show that the fast formation of oligomers up to 1800 Da is due to radical oligomerization of MVK, and 13 series of oligomers (out of a total of 26 series) are identified. The influence of atmospherically relevant parameters such as temperature, initial concentrations of MVK and dissolved oxygen are presented and discussed. In agreement with the experimental observations, we propose a chemical mechanism of OH-oxidation of MVK in the aqueous phase that proceeds via radical oligomerization of MVK on the olefin part of the molecule. This mechanism highlights in our experiments the paradoxical role of dissolved O2: while it inhibits oligomerization reactions, it contributes to produce oligomerization initiator radicals, which rapidly consume O2, thus leading to the dominance of oligomerization reactions after several minutes of reaction. These processes, together with the large range of initial concentrations investigated show the fundamental role that radical oligomerization processes likely play in polluted fogs and atmospheric aerosol.

43 citations


Journal ArticleDOI
TL;DR: A palladium(II)-catalyzed highly regioselective tandem reaction of o-alkynylbenzoates with methyl vinyl ketone for the synthesis of isocoumarins was developed.

37 citations


Journal ArticleDOI
TL;DR: In this article, the gas phase conversion of a 1,3-polyol containing primary and secondary OH functions was studied on a series of copper-silica catalysts, and thoroughly characterized by several techniques such as BET surface area, TPR, XRD, N 2 O chemisorption, and UV-vis-DRS.
Abstract: The gas-phase conversion of a 1,3-polyol (1,3-butanediol) containing primary and secondary OH functions was studied on a series of copper-silica catalysts, Z CuSiO 2 (Z = 1–25 wt.% Cu), and thoroughly characterized by several techniques such as BET surface area, TPR, XRD, N 2 O chemisorption, and UV-vis-DRS. The physicochemical properties of the Z CuSiO 2 catalysts depended on whether the metal loading was above or below the copper monolayer surface coverage (Z = 13.5 wt.% Cu). Copper species presenting different degrees of interaction with the silica support were detected. At low Z values Cu 0 dispersion was high ( D ≈ 40%) due to a predominant contribution of nano-sized Cu species (3 nm) which are difficult to reduce, but for Z > 13.5 wt.%, D abruptly dropped to 3–8% because of formation of larger tridimensional Cu clustered species (30 nm) that reduced at lower temperatures because of a decreased copper-silica interaction. On Z CuSiO 2 catalysts, dehydrogenation of the 1,3-butanediol secondary OH function prevailed over that of the primary one and therefore valuable ketones were the main reaction products. Consecutively to dehydrogenation, dehydration and hydrogenation reactions also took place. Products of the tandem reaction were the β-hydroxy ketone (4-hydroxy-2-butanone), the α,β-unsaturated ketone (methyl vinyl ketone) and the saturated ketone (methyl ethyl ketone). A direct 1,3-butanediol dehydration pathway toward methyl ethyl ketone was also found. Reaction pathways were strongly dependent on the Cu loading and therefore on the kind of Cu species (isolated or clustered). When compared at similar conversion levels, selectivity to the dehydrogenation product 4-hydroxy-2-butanone increased with Z suggesting that on large Cu 0 particles 4-hydroxy-2-butanone was released to the gas phase before being converted in consecutive steps. On the contrary, on highly dispersed Cu 0 crystals of low Cu loading catalysts, 1,3-butanediol was readily dehydrated giving the saturated ketone. Kinetically relevant reaction steps of 1,3-butanediol conversion by dehydrogenation and dehydration were promoted on Cu 0 sites. Dehydration of the intermediate 4-hydroxy-2-butanone also occurred on Cu 0 sites. Turnover rates were constant on Cu 0 nano particles and slightly higher on clustered species.

29 citations


Journal ArticleDOI
TL;DR: In this paper, acid-catalyzed reactions of gas-phase MVK with ammonium sulfate (AS), ammonium bisulfate (ABS), and sulfuric acid (SA) particles were investigated in a flow reaction system at relative humidity (RH) of 40 % and 80 %.
Abstract: Methyl vinyl ketone (MVK) is a key first-generation product from atmospheric isoprene photo-oxidation, especially under high-NOx conditions. In this work, acid-catalyzed reactions of gas-phase MVK with ammonium sulfate (AS), ammonium bisulfate (ABS), and sulfuric acid (SA) particles were investigated in a flow reaction system at relative humidity (RH) of 40 % and 80 %. Ultra-performance liquid chromatography with electrospray ionization time-of-flight mass spectrometry (UPLC/ESI-TOFMS) and gas chromatography-mass spectrometry (GC-MS) are utilized to identify particle-phase products for developing the reaction mechanisms. High-order oligomers such as dimers and tetramers were detected when ABS and SA particles were used, while no oligomeric products were found when AS particles were used. Particle-phase oligomeric products were formed via i) acid-catalyzed aldol reaction with or without dehydration and/or ii) acid-catalyzed hydration followed by oligomerization. Reactions on SA particles yield more abundant and higher-order oligomers up to hexamers than on ABS particles. Moreover, aldol reaction occurred only on SA particles, but hydration followed by oligomerization occurred in both ABS and SA particles. The high RH condition with the same type of acidic particles was found to favor hydration and facilitate the subsequent oligomerization, while the low RH condition with the same type of acidic particles was found to favor aldol reaction with dehydration (aldol condensation). Overall, the findings suggest acidic particles can facilitate the formation of high-order oligomers in the particle phase, with particle acidity and RH as key factors.

25 citations


Journal ArticleDOI
TL;DR: In this paper, a chiral ferrocenophane phosphines featuring only central chirality in good yields were obtained by the reaction of the corresponding chiral alcohol, 1,1′-[(1R)-1-hydroxy-1,3-propanediyl]ferrocene, and diarylphosphines in the presence of chlorotrimethylsilane and sodium iodide.

17 citations


Journal ArticleDOI
TL;DR: Polyhydroxylated pyrrolizidines bearing a methyl group at C-5 have been synthesized by 1,3-dipolar cycloaddition of five membered cyclic nitrones with methyl vinyl ketone followed by a N-O reductive cleavage and in situ intramolecular reductive amination.

13 citations


Journal ArticleDOI
18 Apr 2013-Synlett
TL;DR: An olefin-metathesis catalyst featuring a 1,3-bis(2,6-diisopropylphenyl)-4,5-dihydroimidazol-2-ylidene N-heterocyclic carbene and an ester-chelating carbene ligand was proposed in this paper.
Abstract: An olefin-metathesis catalyst featuring a 1,3-bis(2,6-diisopropylphenyl)-4,5-dihydroimidazol-2-ylidene N-heterocyclic carbene and an ester-chelating carbene ligand efficiently promoted the cross metathesis of olefins with 3-buten-2-one in the presence of copper iodide as cocatalyst. At optimized reaction conditions a 10–20 times lower catalyst loading compared to the state of the art could be achieved.

10 citations


Journal ArticleDOI
TL;DR: This work measures the absolute photoionization cross-section of the vinyl radical between 8.1 and 11.0 eV, which is ∼1.7 times smaller than a previous determination of this value.
Abstract: This work measures the absolute photoionization cross-section of the vinyl radical (σ vinyl(E)) between 8.1 and 11.0 eV. Two different methods were used to obtain absolute cross-section measurements: 193 nm photodissociation of methyl vinyl ketone (MVK) and 248 nm photodissociation of vinyl iodide (VI). The values of the photoionization cross-section for the vinyl radical using MVK, σ vinyl(10.224 eV) = (6.1 ± 1.4) Mb and σ vinyl(10.424 eV) = (8.3 ± 1.9) Mb, and using VI, σ vinyl(10.013 eV) = (4.7 ± 1.1) Mb, σ vinyl(10.513 eV) = (9.0 ± 2.1) Mb, and σ vinyl(10.813 eV) = (12.1 ± 2.9) Mb, define a photoionization cross-section that is ∼1.7 times smaller than a previous determination of this value.

Journal ArticleDOI
TL;DR: Salt effects on the Diels-Alder reaction of cyclopentadiene with methyl vinyl ketone are investigated using reference interaction site model self-consistent field (RISM-SCF) theory and the endo-trans structure shows the lowest energy in both water and LiCl solution.
Abstract: Salt effects on the Diels-Alder reaction of cyclopentadiene with methyl vinyl ketone are investigated using reference interaction site model self-consistent field (RISM-SCF) theory. The rate of the reaction is accelerated by adding LiCl to the water solvent. The structures of four transition states, endo-cis, endo-trans, exo-cis, exo-trans, were found by geometry optimization of the cyclopentadiene and methyl vinyl ketone complexes. The endo-trans structure shows the lowest energy in both water and LiCl solution. The activation barrier of the reaction in LiCl solution is lower than that in water, and the difference is in good agreement with that from experiments. The decrease in the activation barrier arises from destabilization of the reactant species. The salt effect of LiCl makes all species concerning the reaction unstable by the hydrophobic effect; however, the increased hydrophobic effect in the TS complexes is suppressed by making the hydrogen bond, which is stronger compared with the reactant methyl vinyl ketone.

Journal ArticleDOI
TL;DR: In this article, the authors measured the yields of methacrolein (MAC) and methyl vinyl ketone (MVK) from the OH-initiated oxidation of isoprene under NO x -free conditions at 303, 323 and 343 K and 1m in a quartz reaction chamber coupled to a mass spectrometer.

Journal ArticleDOI
TL;DR: In this article, the authors performed a systematic study on reactions of selenium dichloride and dibromide with unsaturated compounds, and found that selenion dihalides react with divinyl sulfide and divinyl selenide with formation of the corresponding Markovnikov adducts, 2,6-dihalo-1,4-thiaselenanes and -diselenane.
Abstract: We perform systematic studies on reactions of selenium dichloride and dibromide with unsaturated compounds [2–5]. Selenium dihalides were found to react with divinyl sulfide and divinyl selenide with formation of the corresponding Markovnikov adducts, 2,6-dihalo-1,4-thiaselenanes and -diselenanes, whose subsequent rearrangement yields thermodynamically more stable 1,3-thiaselenolanes and -diselenolanes [2]. Unlike vinyl sulfides, the double C=C bond in vinyl sulfones is deactivated toward electrophilic addition due to strong electron-withdrawing effect of the sulfonyl group. Reactions of selenium dihalides with divinyl sulfone are slower than with divinyl sulfide, and selenium adds to both βand α-position of the double bond with formation of fourand five-membered heterocycles [3].

Journal ArticleDOI
TL;DR: In this paper, the aqueous phase reactions of methyl vinyl ketone and methacrolein with bisulfite anions lead to the formation of primary and secondary organic hydroxysulfonates which currently are not included in the atmospheric chemistry modelling, but can be relevant in mechanisms explaining the formation and growth of the secondary organic aerosols from atmospheric carbonyls.
Abstract: Methacrolein and methyl vinyl ketone are highly reactive carbonyls that play a pivotal role in the formation of secondary organic aerosols in the Earth’s atmosphere. Both carbonyls are the major products of isoprene oxidation. We show that among the atmospheric sinks of methacrolein and methyl vinyl ketone, the aqueous-phase addition of bisulfite anions to their molecules can be relevant under polluted conditions with the increased presence of sulfur dioxide. We demonstrate that aqueous-phase reactions of methyl vinyl ketone and methacrolein with bisulfite anions lead to the formation of primary and secondary organic hydroxysulfonates which currently are not included in the atmospheric chemistry modelling, but can be relevant in mechanisms explaining the formation and growth of the secondary organic aerosols from atmospheric carbonyls. The rate constants for all aqueous-phase reactions involved were determined. The primary addition of bisulfite anions to methacrolein was found significantly faster than that to methyl vinyl ketone, with rate constants kMAC1f = 8 and kMVK1f = 0.18 mol –1 dm s at room temperatures, respectively. The rate constant for the bisulfite addition to methacrolein was ten times faster than reported in the literature. The kinetic and mass spectrometric analyses revealed that in both cases, the dominating product was the C4 alpha-hydroxysulfonate (a primary adduct), while the C4 alpha-hydroxy disulfonate (a secondary adduct or diadduct) was produced only in trace quantities. The primary addition of bisufite anions to methacrolein and methyl vinyl ketone should be considered in atmospheric studies relevant to areas with enhanced presence of sulfur dioxide providing sufficiently high concentrations of bisulfite ions in atmospheric waters.

Journal ArticleDOI
TL;DR: In this paper, the reaction of methyl phlomisoate with styrene results in a mixture of 15,16-distyryl, 16-styryl-, and 16-(1-phenylvinyl)-derivatives of furanolabdanoid.
Abstract: Reactions of methyl phlomisoate with methyl acrylate, phenyl acrylate, methyl vinyl ketone, phenyl vinyl ketone, or N-substituted acrylamides catalyzed by Pd(OAc)2 in the presence of Cu(OAc)2, p-benzoquinone in the mixture of propionic acid and acetonitrile proceed regio- and stereoselectively with the formation of (E)-16-vinyl labdatrienoates. The oxidative coupling under these conditions of the methyl phlomisoate with styrene results in a mixture of 15,16-distyryl-, 16-styryl-, and 16-(1-phenylvinyl)-derivatives of furanolabdanoid.

Journal ArticleDOI
TL;DR: In this paper, X-ray photoelectron spectroscopy (XPS) showed that the active catalyst components can be in a partially oxidized state, particularly after storing the catalysts in air.
Abstract: The oxidation of 1,3-butadiene over the Pd/C and Pd-Te/C heterogeneous catalysts occurs in organic solvents containing water at a temperature of 100°C and an oxygen partial pressure of $$P_{\left[ {O_2 } \right]} = 4$$ atm. Crotonaldehyde dominates among the three major products of oxidation over the Pd catalyst. The introduction of Te into the catalyst increases the methyl vinyl ketone yield, the furan yield being the lowest in all cases. X-ray photoelectron spectroscopy (XPS) showed that the active catalyst components can be in a partially oxidized state, particularly after storing the catalysts in air. Additional hydrogen treatment results in almost complete reduction of the active components to metals and enhances the catalytic activity. It is supposed that the oxidation of 1,3-butadiene over the Pd-Te catalysts proceeds via the activation of dioxygen over the Pd0 sites, with oxidized Pd and Te participating in subsequent chemical transformations.

Patent
25 Dec 2013
TL;DR: In this article, a synthesis method of 8-bromine-4-carboxyl quinoline was proposed, which comprises the following steps of (1) allowing bromoaniline to react with methyl vinyl ketone to form 8-brromine 4 carboxyldioxioxioxine under the catalysis of ferric trichloride, and (2) oxidizing 8-binomial quinine 4 methyl quinyl quine with selenium dioxide in an organic solvent to form eight-bromaquinoline-4 methyl
Abstract: The invention discloses a synthesis method of 8-bromine-4-carboxyl quinoline, which comprises the following steps of (1) allowing bromoaniline to react with methyl vinyl ketone to form 8-bromine-4-methyl quinoline under the catalysis of ferric trichloride, (2) oxidizing 8-bromine-4-methyl quinoline with selenium dioxide in an organic solvent to form 8-bromoquinoline-4-methanal, and (3) oxidizing 8-bromoquinoline-4-methanal with hydrogen peroxide in an acid medium to form 8-bromine-4-carboxyl quinoline. The method takes cheaper bromoaniline as a raw material, and is simple in synthesis step, high in synthesis yield and high in selectivity.

Journal ArticleDOI
TL;DR: In this paper, the efficiency of poly(N-vinylimidazole) as the basic recyclable catalyst for the addition of CH-acids to acrylonitrile, methyl acrylate, methyl vinyl ketone and methyl vinyl sulfone in water at ambient temperature was studied.
Abstract: Efficiency of poly(N-vinylimidazole) as the basic recyclable catalyst for the Michael addition of CH-acids to acrylonitrile, methyl acrylate, methyl vinyl ketone and methyl vinyl sulfone in water at ambient temperature was studied. In these reactions, formation of both 1: 1 and 1: 2 adducts is possible.


Journal ArticleDOI
TL;DR: In this paper, primary or secondary amines are added to acrylates, acrylonitrile, or methyl vinyl ketone in the presence of FeCl3 supported on the title silicate to give the corresponding alkylated amines.
Abstract: Primary or secondary amines are added to acrylates, acrylonitrile, or methyl vinyl ketone in the presence of FeCl3 supported on the title silicate to give the corresponding alkylated amines.

Journal ArticleDOI
TL;DR: In this paper, it was shown that the Michael-type adducts with cyclohexanone or methyl vinyl ketone at C-3 exist as a mixture of open-chain and cyclic tautomers in CDCl3 solutions.
Abstract: It is shown that the Michael-type adducts with cyclohexanone or methyl vinyl ketone at C-3 exist as a mixture of open-chain and cyclic tautomers in CDCl3 solutions, whereas adducts with cyclopentanones at C-3 exist only in the open-chain form.

Patent
30 Aug 2013
TL;DR: In this paper, a synthesis method of 8-bromine-4-carboxyl quinoline was proposed, which comprises the following steps of (1) allowing bromoaniline to react with methyl vinyl ketone to form 8-brromine 4 carboxyldioxioxioxine under the catalysis of ferric trichloride, and (2) oxidizing 8-binomial quinine 4 methyl quinyl quine with selenium dioxide in an organic solvent to form eight-bromaquinoline-4 methyl
Abstract: The invention discloses a synthesis method of 8-bromine-4-carboxyl quinoline, which comprises the following steps of (1) allowing bromoaniline to react with methyl vinyl ketone to form 8-bromine-4-methyl quinoline under the catalysis of ferric trichloride, (2) oxidizing 8-bromine-4-methyl quinoline with selenium dioxide in an organic solvent to form 8-bromoquinoline-4-methanal, and (3) oxidizing 8-bromoquinoline-4-methanal with hydrogen peroxide in an acid medium to form 8-bromine-4-carboxyl quinoline. The method takes cheaper bromoaniline as a raw material, and is simple in synthesis step, high in synthesis yield and high in selectivity.

Journal ArticleDOI
TL;DR: In this paper, the authors report two domino reactions between salicyl N-thiophosphoryl imines and methyl vinyl ketone catalyzed by bifunctional phosphine catalysts and DBU.
Abstract: We report two domino reactions between salicyl N-thiophosphoryl imines and methyl vinyl ketone catalyzed by bifunctional phosphine catalysts and DBU. These reactions provide two simple and efficient methods to construct chromans and chromens under mild conditions, respectively.

Journal ArticleDOI
TL;DR: In this paper, the combination of methyl 3,7-dioxo-2-diazo-4-octenoate from the zinc triflate catalyzed Mukaiyama-Michael reaction was achieved in an efficient one-pot multi-component transformation by sequential addition of the reagents.
Abstract: The combination of methyl 3,7-dioxo-2-diazo-4-octenoate from the zinc triflate catalyzed Mukaiyama–Michael reaction of methyl 3-tert-butylsilyloxy-2-diazobutenoate and 4-methoxy-3-buten-2-one with Michael acceptors (methyl vinyl ketone, N-phenylmaleimide, β-nitrovinylarenes) in the presence of a catalytic amount of base provides convenient access to highly substituted resorcinol derivatives. This transformation is achieved in an efficient one-pot multi-component transformation by the sequential addition of the reagents.