75749-92-7Relevant academic research and scientific papers
Intermediacy of ion neutral complexes in the fragmentation of short-chain dialkyl sulfides
Filsak,Budzikiewicz
, p. 601 - 610 (2007/10/03)
The main fragmentation processes after electron ionization of butyl methyl and butyl ethyl sulfides are rationalized by the intermediacy of the ion neutral complex [RSH · methylcyclopropane](+·) as demonstrated by extensive labeling and collision activation studies.
The 2-butyl cation in trifluoroacetic acid. A hydrogen-bridged carbonium ion
Dannenberg,Goldberg,Barton,Dill,Weinwurzel,Longas
, p. 7764 - 7768 (2007/10/02)
The solvolyses of CH3CH2CH(OTs)CH3, CH3CH2CD(OTs)CD3 (III) and CD3CD2CH(OTs)CH3 (XIII) have been studied in CF3COOH and CF3COOD. The product distributions and solvolysis rates are consistent with the intermediacy of a hydrogen-bridged 2-butyl cation. The ratio of the solvolysis rates of III to XIII is 1.1-1.2 which is consistent with anchimeric assistance by a β-H on C3. The rate of additions of CF3COOH to 2-butene is less than half as fast as the trifluoroacetolysis, thereby eliminating 2-butene as an intermediate in the reaction. The steady-state concentration of 2-butene is shown to be proportional to added [CF3COONa], indicating that the trifluoroacetate anion, often used as a buffer, is a strong enough base to direct the reaction toward elimination products.
The Thermal Ring Opening of 3,3-Disubstituted Cyclobutenes
Curry, Michael J.,Stevens, Ian D. R.
, p. 1391 - 1398 (2007/10/02)
The rates of the thermal unimolecular isomerisation of 3-t-butyl-3-methylcyclobutene and 3-methyl-3-phenylcyclobutene have been measured in the gas phase over the temperature ranges 158-190 deg C and 120-180 deg C, respectively.They are correlated by the Arrhenius expressions k = 1014.08 +/- 0.30exp(-150.8 +/- 2.5/RT) s-1 and k = 1012.50 +/- 0.12exp(-126.15 +/- 0.95/RT) s-1, respectively.The ratio of Z- to E-isomer of the butadienes formed has been measured both for these two and for the 3-methyl-3-R-cyclobutenes, where R = isopropyl, n-propyl, cyclopropyl, pentadeuterioethyl, 4-methoxyphenyl, 3-methoxyphenyl, and 4-cyanophenyl.In each case the proportion of Z-isomer formed is much larger than would be predicted on steric grounds.For the aryl compounds an attractive interaction during the formation of the Z-diene is proposed to account for its excess formation.For the alkyl substituents, a repulsive electronic interaction between the group and the developing remote double bond should be larger for methyl than for the other alkyl groups, accounting for the observed product ratios.The rates of isomerization of the 3-aryl-3-methylcyclobutenes at 161 deg C correlate with the LUMO of the aromatic ring.The conclusions are shown to apply to results which have been reported by other authors.
DEHYDRATION OF ALCOHOLS ON ALUMINA-12
KNOEZINGER H,SCHEGLILA A
, p. 252 - 263 (2007/10/05)
Primary kinetic isotope effects of the dehydration from the gas phase of tertiary, secondary and iso-butanol on alumina have been easured between 120 and 230 C. The deuteration on the hydroxyl group does not give rise to an isotope effect, whereas substitution of the !-proton by deuterium produces an appreciable effect. Below 200 C primary, secondary, and tertiary alcohols are dehydrated via reaction intermediates over alumina which presumably contain a certain degree of ionic contributions. With increasing temperature these ionic contributions are favored.
