Atmospheric reaction of OH radicals with 1,3-butadiene and 4-hydroxy-2-butenal

The gas-phase reaction of OH radicals with 1,3-butadiene and 4-hydroxy-2-butenal in the presence of NO has been studied in a flow tube operated at 295 +/- 2 K and pressures of 950 mbar of synthetic air or 100 mbar of an O(2)/He mixture. OH radicals were generated using three different experimental approaches, namely, ozonolysis of tetramethylethylene (dark reaction), photolysis of methyl nitrite, or via the reaction of HO(2) with NO (HO(2) from the reaction of H-atoms with O(2)). Products of the reaction of OH radicals with 1,3-butadiene were HCHO (0.64 +/- 0.08), acrolein (0.59 +/- 0.06), 4-hydroxy-2-butenal (0.23 +/- 0.10), furan (0.046 +/- 0.014), and organic nitrates (0.06 +/- 0.02) accounting for more than 90% of the reacted carbon. There was no significant dependence of product yields on experimental conditions which were varied in a wide range. The formation of the 1,4-addition product 4-hydroxy-2-butenal was confirmed unambiguously for the first time. The rate coefficient k(OH + 4-hydroxy-2-butenal) = (5.1 +/- 0.8) x 10(-11) cm(3) molecule(-1) s(-1) was determined using a relative rate technique (p = 100 mbar, T = 295 +/- 2 K). Products of the reaction of OH radicals with 4-hydroxy-2-butenal were glycolaldehyde (0.40 +/- 0.06), glyoxal (0.17 +/- 0.04), trans-butenedial (0.093 +/- 0.033), and organic nitrates (0.043 +/- 0.015) as well as further carbonylic substances remaining unidentified so far. Corresponding reaction mechanisms describing the formation of the detected products are proposed, and the relevance of these data for atmospheric conditions is discussed.     

β-Arylthioalkylation of 2-methoxy-1,3-butadiene

The -arylthioalkylation of 2-methoxy-1,3-butadiene is regiospecific at the alkoxy-substituted C=C bond, giving 6-arylthioalk-1-en-3-ones.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2036–2040, September, 1990.     

Linear codimerization of 2-cyclopropyl-1,3-butadiene with methyl acrylate catalyzed by iron and cobalt complexes

Conclusions The linear codimerization of 2-cyclopropyl-1,3-butadiene with methyl acrylate gave a mixture of methyl esters of 5-cyclopropyl-2Z,5Z- and 2E,5Z-heptadienoic acids.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2364–2366, October, 1984.     

Evidence for a [2+4] cycloaddition in the ion-molecule reaction of ionized 1,3-butadiene with vinyl ethyl (methyl) ether in the gas phase

By use of deuterium labelling it is shown that the radical cation of 1,3-butadiene reacts with vinyl methyl (or ethyl) ether in the gas phase through a [2+4] cycloaddition reaction. This leads to an excited collision complex of ionized 4-methoxy- (or ethoxy) cyclohexene, which expels mthanol (or ethanol) through a 1,3 elimination, as does 4-methoxycyclohexene itself upon electron impact. The spectrum of daughter ions produced by collision induced decomposition of the resulting ion with m/e 80 has been compared with spectra produced by the collision induced decompositions of the m/e 80 ions given by 1,3-cyclohexadiene, 1,4-cyclohexadiene, 1,3,5-hexatriene and the [M–MeOH]\documentclass{article}\pagestyle{empty}\begin{document}$\mathop +\limits_\cdot$\end{document} ion from 4-methoxycyclohexene.     

Structure of tetrahydropyridazines formed from 1-isopropyl-3,4-dimethyl-1,2-diaza-1,3-butadiene and methyl vinyl ketone

In contrast to the cis isomer, trans-1-isopropyl-3,4-dimethyl-1,2-diaza-1,3-butadiene reacts with methyl vinyl ketone to give a mixture of cis and trans isomers of 5-and 6-acetyl-1-isopropyl-3, 4-dimethyl-²-tetrahydropyridazines. The preponderance of the cis isomer in the case of 5-substituted tetrahydropyridazines constitutes evidence for the existence of secondary orbital interactions of the acetyl group of the dienophile with the C=C bond of the diene component.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1684–1686, December, 1978.     

Polymerization and copolymerization of 2-phthalimidomethyll 1,3-butadiene. II. Kinetic study of the polymerization of 1,3-butadiene and of the copolymerization of 1,3-butadiene with 2-phthalimidomethyl 1,3-butadiene initiated by bis-(η3-allyl nickel trifluoroacetate)

The kinetics of the polymerization of 1,3-butadiene initiated by bis(η³-allyl nickel trifluoroacetate) prepared in benzene was studied in methylene chloride at 40°C. The reaction is first order with respect to the monomer, second order with respect to the catalyst in contrast to the case in which solvent is benzene. We have shown that the presence of a polar molecule (fe, N-methyl phthalimide) decreases the overall rate of polymerization. The apparent reactivity ratios for the system 2-phthalimidomethyl 1,3-butadiene (1)-1,3-butadiene (2) are r₁ = 0.65 ± 0.006 and r₂ = 0.48 ± 0.015.     

The cycloaddition of the 1,3-butadiene radical cation with acrolein and methyl vinyl ketone

The 1,3-butadiene radical cation reacts with acrolein and methyl vinyl ketone to produce ‘stable’ adducts. The nature of the reaction and the structures of the adducts were investigated by collisional activation decomposition (CAD) combined with tandem mass spectrometry (MS/MS), and also by Fourier transform mass spectrometry. The CAD spectra of gas-phase adducts were compared with those of suitable model compounds. On that basis, it was determined that the 1,3-butadiene radical cation undergoes a cycloaddition with these α,β-unsaturated carbonyl compounds. The butadiene radical cation serves as the ‘ene’, and the acrolein and methyl vinyl ketone react as dienes, forming cycloadducts having 2-ethenyl-2,3-dihydropyran radical cation structures.     

2-Phenylsulfinylmethyl-1,3-butadiene in the thermal Diels-Alder reaction

Russian Chemical Bulletin -     

Preparation and reaction of 2-aryl-3-silyl-1,3-butadiene

[reaction: see text] A conjugated pi-electron compound, 2-aryl-3-silyl-1,3-butadiene, was easily prepared from 1-benzyloxy-3-silyl-2-propyne, bis(iodozincio)methane, and an aryl halide in the presence of nickel catalyst. A subsequent cross-coupling reaction of the product with another aryl halide gave an unsymmetrical 2,3-diaryl-1,3-butadiene efficiently.     

Triplet states in 1,3-butadiene

The electron impact excitation spectrum 0f 1,3-butadiene has been studied at 20, 35 and 55 eV impact energies and scattering angles of 10° to 80°. Two low lying states are observed with maxima at 3.2 and 4.9 eV, and are identified as the ³B_u state and ³A_g state respectively     

Monomer-isomerization oligomerization of 2-ethyl-1,3-butadiene by acid catalysts

The cationic oligomerization of 2-ethyl-1,3-butadiene (2EBD) by a superacid (CF₃SO₃H) and a superacid derivative (CH₃COClO₄) accompanied monomer isomerization to 3-methyl-1,3-pentadiene (3MPD) before propagation to yield oligomers of the isomerized monomer as main products in benzene at 50°C. Detection of 3MPD in the reaction mixture and ¹H-NMR structural analysis of the produced oligomers confirmed the occurrence of this “monomer-isomerization oligomerization.” On the other hand, in the presence of a metal halide catalyst (BF₃OEt₂) 2EBD reacted without isomerization and yielded oligomers that were different from those produced by the foregoing superacid catalysts. Monomer isomerization was suppressed in a polar solvent [(CH₂Cl)₂] or at lower temperatures. The mechanism of the oligomerization with monomer isomerization was discussed.     

Aminobutadienes. V. Polymers of 1-phthalimido-1,3-butadiene and 1-succinimido-1,3-butadiene

The radical polymerizations of 1-phthalimido-1,3-butadiene (1-PB) and 1-succinimido-1,3-butadiene (1-SB) were carried out in bulk and in solution. The polymers obtained had reduced viscosities in the ranges of 1.0–4.0 (1-PB) and 0.2–0.6 (1-SB). Both polymers had a similar softening point of 190–200°C. The radical polymerization of 1-phthalimido-1,3-butadiene clearly showed a tendency to give crosslinked polymer. Steric arguments about these polymer structures as a result of the infrared and ozonolysis data led to the conclusion that these polymers contained approximately 20% of the 3,4 form but no 1,2 configuration, and, therefore, that the 1,4 addition was preferred.