Showing papers on "Methyl vinyl ketone published in 2018"
TL;DR: First strong indications for the crucial role of halogen bonding in this kind of catalyses are presented, including the solvolysis of benzhydryl chloride and the Diels-Alder reaction of cyclopentadiene with methyl vinyl ketone.
Abstract: Hypervalent iodine(III) derivatives are known as versatile reagents in organic synthesis, but there is only one previous report on their use as Lewis acidic organocatalysts. Herein, we present first strong indications for the crucial role of halogen bonding in this kind of catalyses. To this end, the solvolysis of benzhydryl chloride and the Diels-Alder reaction of cyclopentadiene with methyl vinyl ketone served as benchmark reactions for halide abstraction and the activation of neutral compounds. Iodolium compounds (cyclic diaryl iodonium species) were used as activators or catalysts, and we were able to markedly reduce or completely switch off their activity by sterically blocking one or two of their electrophilic axes. Compared with previously established bidentate cationic halogen bond donors, the monodentate organoiodine derivatives used herein are at least similarly active (in the Diels-Alder reaction) or even decidedly more active (in benzhydryl chloride solvolysis).
141 citations
TL;DR: The initial laboratory synthesis and direct detection of MVK-OO is reported through reaction of a photolytically generated, resonance-stabilized monoiodoalkene radical with O2, and the rate of appearance of OH products agrees with the unimolecular decay rate predicted using statistical theory with tunneling.
Abstract: The reaction of ozone with isoprene, one of the most abundant volatile organic compounds in the atmosphere, produces three distinct carbonyl oxide species (RR′COO) known as Criegee intermediates: formaldehyde oxide (CH2OO), methyl vinyl ketone oxide (MVK-OO), and methacrolein oxide (MACR-OO). The nature of the substituents (R,R′ = H, CH3, CH═CH2) and conformations of the Criegee intermediates control their subsequent chemistry in the atmosphere. In particular, unimolecular decay of MVK-OO is predicted to be the major source of hydroxyl radicals (OH) in isoprene ozonolysis. This study reports the initial laboratory synthesis and direct detection of MVK-OO through reaction of a photolytically generated, resonance-stabilized monoiodoalkene radical with O2. MVK-OO is characterized utilizing infrared (IR) action spectroscopy, in which IR activation of MVK-OO with two quanta of CH stretch at ca. 6000 cm–1 is coupled with ultraviolet detection of the resultant OH products. MVK-OO is identified by comparison of t...
92 citations
TL;DR: UV-visible spectroscopy on the first π* ← π transition is shown by a combination of experiment and theory to provide a sensitive method for detection of the MVK-oxide Criegee intermediate that will enable further studies of its photochemistry and unimolecular and bimolecular reaction dynamics.
Abstract: Ozonolysis of isoprene, one of the most abundant volatile organic compounds in the atmosphere, proceeds through methyl vinyl ketone oxide (MVK-oxide), methacrolein oxide, and formaldehyde oxide (CH2OO) Criegee intermediates. The present study focuses on MVK-oxide, a four-carbon unsaturated carbonyl oxide intermediate, using vacuum ultraviolet photoionization at 118 nm and UV-visible induced depletion of the m/z = 86 mass channel to characterize its first π* ← π electronic transition. The electronic spectrum is broad and unstructured with its peak at 388 nm (3.2 eV). The MVK-oxide spectrum is shifted to a significantly longer wavelength than CH2OO and alkyl-substituted Criegee intermediates studied previously due to extended conjugation across the vinyl and carbonyl oxide groups. Electronic excitation results in rapid dissociation at λ ≤ 430 nm to methyl vinyl ketone and O 1D products, the latter detected by 2 + 1 resonance enhanced multiphoton ionization using velocity map imaging. Complementary electronic structure calculations (CASPT2(12,10)/AVDZ) predict two π* ← π transitions with significant oscillator strength for each of the four conformers of MVK-oxide with vertical excitation energies (and corresponding wavelengths) in the 3.1-3.6 eV (350-400 nm) and 4.5-5.5 eV (220-280 nm) regions. The computed electronic absorption profile of MVK-oxide, based on a Wigner distribution of ground state configurations and summed over the four conformers, is predicted to peak at 397 nm. UV-visible spectroscopy on the first π* ← π transition is shown by a combination of experiment and theory to provide a sensitive method for detection of the MVK-oxide Criegee intermediate that will enable further studies of its photochemistry and unimolecular and bimolecular reaction dynamics.
40 citations
TL;DR: In this paper, the authors describe the preparation of ten amino acid ionic liquids (AAILs) formed from ammonium salts as cations, derivatives of glycerol, and natural amino acids as anions.
Abstract: In the present work, we describe the preparation of ten amino acid ionic liquids (AAILs) formed from ammonium salts as cations, derivatives of glycerol, and natural amino acids as anions. All of them are viscous oils, colorless or pale yellow, and hygroscopic at room temperature. They have appreciable solubility in many protic and aprotic polar solvents. The AAILs were used as catalysts in a Morita–Baylis–Hillman (MBH) reaction. The ionic liquids derivative from L-proline and L-histidine demonstrated the ability to catalyze the reaction between methyl vinyl ketone and aromatic aldehydes differently substituted in the absence of an additional co-catalyst under organic solvent-free conditions. The AAIL derivatives from L-valine, L-leucine, and L-tyrosine catalyzed the MBH reaction only in the presence of imidazole. The MBH adducts were obtained in moderate to good yields. Although the catalytic site in the ILs was in its enantiomerically pure form, all the MBH adducts were obtained in their racemic form.
19 citations
TL;DR: In this paper, it was shown that C2−C4 organosulfur compounds, as well as their oligomers, can form in the aqueous phase from reactions of unsaturated carbonyl compounds, i.e., methacrolein (MACR) and methyl vinyl ketone (MVK), with the bisulfite anion (HSO3−) in the presence of Fe3+.
Abstract: Organosulfur compounds, particularly organosulfates, are considered as important tracers of secondary organic aerosol formation. However, the mechanistic pathways for the formation of these compounds in the atmosphere are still not well understood. In this study, we show for the first time that C2–C4 organosulfur compounds, as well as their oligomers, can form in the aqueous phase from reactions of unsaturated carbonyl compounds, i.e., methacrolein (MACR) and methyl vinyl ketone (MVK), with the bisulfite anion (HSO3–) in the presence of Fe3+. The mechanism for product formation in the presence of Fe3+ involves sulfite and sulfate ion radicals. As shown here, the formation of specific organosulfur compounds depends on the concentrations of MVK and MACR and the solution pH. Our findings provide new insights into pathways for forming organosulfur compounds in the atmosphere and the role that transition metal ions, such as Fe3+, play in catalyzing these reactions.
18 citations
TL;DR: Adduct formation is observed for both reactions and is attributed to the formation of a secondary ozonides (1,2,4-trioxolanes), supported by master equation calculations of the kinetics and the agreement between measured and calculated adiabatic ionization energies.
Abstract: Methyl vinyl ketone (MVK) and methacrolein (MACR) are important intermediate products in atmospheric degradation of volatile organic compounds, especially of isoprene. This work investigates the reactions of the smallest Criegee intermediate, CH2OO, with its co-products from isoprene ozonolysis, MVK and MACR, using multiplexed photoionization mass spectrometry (MPIMS), with either tunable synchrotron radiation from the Advanced Light Source or Lyman-α (10.2 eV) radiation for photoionization. CH2OO was produced via pulsed laser photolysis of CH2I2 in the presence of excess O2. Time-resolved measurements of reactant disappearance and of product formation were performed to monitor reaction progress; first order rate coefficients were obtained from exponential fits to the CH2OO decays. The bimolecular reaction rate coefficients at 300 K and 4 Torr are k(CH2OO + MVK) = (5.0 ± 0.4) × 10−13 cm3 s−1 and k(CH2OO + MACR) = (4.4 ± 1.0) × 10−13 cm3 s−1, where the stated ±2σ uncertainties are statistical uncertainties. Adduct formation is observed for both reactions and is attributed to the formation of a secondary ozonides (1,2,4-trioxolanes), supported by master equation calculations of the kinetics and the agreement between measured and calculated adiabatic ionization energies. Kinetics measurements were also performed for a possible bimolecular CH2OO + CO reaction and for the reaction of CH2OO with CF3CHCH2 at 300 K and 4 Torr. For CH2OO + CO, no reaction is observed and an upper limit is determined: k(CH2OO + CO) < 2 × 10−16 cm3 s−1. For CH2OO + CF3CHCH2, an upper limit of k(CH2OO + CF3CHCH2) < 2 × 10−14 cm3 s−1 is obtained.
15 citations
TL;DR: In this paper, a mechanistic cycle has been proposed for the Fe−NHC mediated Michael addition reaction, where the presence of l -proline as chiral auxiliary under ambient conditions was detected.
15 citations
TL;DR: The reactions of the zirconium MOF with the Michael acceptors acrylonitrile, acrylic acid, methyl acrylate and methyl vinyl ketone led to post-synthetic modification of the MOF through C-N bond formation without loss of crystallinity.
Abstract: The reactions of the zirconium MOF [Zr6O4(OH)4(bdc-NH2)6] (UiO-66-NH2, bdc-NH2 = 2-amino-1,4-benzenedicarboxylate) with the Michael acceptors acrylonitrile (CH2[double bond, length as m-dash]CHCN), acrylic acid (CH2[double bond, length as m-dash]CHCO2H), methyl acrylate (CH2[double bond, length as m-dash]CHCO2Me) and methyl vinyl ketone (CH2[double bond, length as m-dash]CHC(O)Me) led to post-synthetic modification of the MOF through C-N bond formation without loss of crystallinity. The reactions with acrylonitrile and acrylic acid go to completion, yielding [Zr6O4(OH)4(bdc-NHCH2CH2CN)6] (UiO-66-AN, 1) and [Zr6O4(OH)4(bdc-NHCH2CH2CO2H)6] (UiO-66-AA, 2) respectively, whereas those with methyl acrylate and methyl vinyl ketone are incomplete, yielding [Zr6O4(OH)4(bdc-NH2)0.66(bdc-NHCH2CH2CO2Me)5.34] (UiO-66-MA, 3) and [Zr6O4(OH)4(bdc-NH2)2.76(bdc-NHCH2CH2C(O)Me)3.24] (UiO-66-MVK, 4), respectively. The acrylonitrile-modified MOF UiO-66-AN undergoes further reaction with sodium azide in the presence of zinc(ii) chloride in n-butanol to form the tetrazolate-modified MOF [Zr6O4(OH)4(bdc-NHCH2CH2CN)4.74(bdc-NHCH2CH2CN4H)1.26] (UiO-66-TZ, 5).
15 citations
13 Jun 2018
TL;DR: In this article, the ground state rearrangement and decomposition of methyl vinyl ketone and methacrolein were investigated using quantum chemical calculations and RRKM theory/master equation simul...
Abstract: The ground-state rearrangement and decomposition of methyl vinyl ketone (MVK) and methacrolein (MACR) has been investigated using quantum chemical calculations and RRKM theory/master equation simul...
7 citations
TL;DR: This aza-Michael addition/cyclization domino reaction by the 5'-hydrazino G4·K+ hydrogel has promise for environmental remediation of toxic α,β-unsaturated carbonyls from water and the atmosphere.
6 citations
TL;DR: According to the total gastrointestinal transit time estimated by Belzer, the estimate distribution of STX released in the different organs indicated that the performance is obtained with the drug – carrier-system containing equal ratios of polymer and 10 wt% of STx (STX-10/PAA-50).
Abstract: A series of poly(acrylic acid)/poly(methyl vinyl ketone) (PAA/PMVK) blends with different compositions were prepared by the solvent casting method. The miscibility of this pair of polymers was inve...
TL;DR: Several iron oxides nanoparticles have been assessed as catalysts in the 1,4-addition of a cyclic β-ketoester onto methyl vinyl ketone under neat conditions.
TL;DR: In this paper, it was found that the intramolecular cyclization of the 1: 2 reaction product with mesityl oxide, trimethylsilyl bis(2-methyl-4- oxopentan-2-yl)phosphinate, yields, after hydrolysis, a phosphorinane with exocyclic carbonyl and hydroxyl groups.
Abstract: Bis(trimethylsilyl) hypophosphite reacts with unsaturated ketones (methyl vinyl ketone and mesityl oxide) to give, depending on the reaction conditions, 1: 1 or 1: 2 adducts after hydrolysis. It was found that the intramolecular cyclization of the 1: 2 reaction product with mesityl oxide, trimethylsilyl bis(2-methyl-4- oxopentan-2-yl)phosphinate, yields, after hydrolysis, a phosphorinane with exocyclic carbonyl and hydroxyl groups.
TL;DR: A mild and efficient protocol for the synthesis of chromanols has been elaborated via an arginine-mediated cascade cyclisation reaction between salicylaldehyde and methyl vinyl ketone in water, affording the chromanol adducts in very good yields.
TL;DR: In this article, the Michael type addition of pyrroles and indoles bearing strongly electron-withdrawing N-protecting groups (e.g., arylsulfonyl-, benzoyl-) to methyl vinyl ketone have not been previously reported.
Abstract: The Michael type addition of pyrroles and indoles bearing strongly electron-withdrawing N-protecting groups (e.g., arylsulfonyl-, benzoyl-) to methyl vinyl ketone have not been previously reported. We find that such alkylative processes can be effected in low to moderate yields using bismuth triflate as catalyst in conjunction with microwave irradiation.
01 Jan 2018
Patent•
23 Mar 2018
TL;DR: In this article, a film is used for covering the surface of a battery body, and is prepared from the following components: fatty acid methyl ester sulfonate, sodium tripolyphosphate, polyisobutene, bis-thiodipropionate, methanol polyoxyethylene ether phosphate, vinyl trimethoxy silane, benzoyl peroxide, ethyl acetoacetate, methyl vinyl ketone and propylene glycol methyl ether acetate.
Abstract: The invention discloses a film applied to lithium ion batteries. The film is used for covering the surface of a battery body, and is prepared from the following components: fatty acid methyl ester sulfonate, sodium tripolyphosphate, polyisobutene, bis-thiodipropionate, methanol polyoxyethylene ether phosphate, vinyl trimethoxy silane, benzoyl peroxide, ethyl acetoacetate, methyl vinyl ketone and propylene glycol methyl ether acetate. The film has double properties of insulation and heat conduction; after the film coveres on the surface of the battery body, the safety performance of the batterycan be effectively improved.