606. Kinetics of the reaction of bromine with olefins in aqueous solution

Atkinson, J. R.; Bell, R. P.

doi:10.1039/jr9630003260

Cited by 30 publications

(37 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A similar situation holds for the values of kz and k; measured by Bell and students (194,195) for bromination in aqueous solution. Early studies by Robertson and co-workers (193) established that, for bromine addition to substituted ethylenes in acetic acid, both k, and k3 increase with increasing electron-donating ability of the substituent.…”

Section: B Addition To Acetylenessupporting

confidence: 68%

“…Thus, if only an A d~3 mechanism were involved, the rate of mixed adduct formation, (194,195) have determined k,, kj, and the dibromide to bromohydrin ratio for bromination of a variety of olefins in aqueous solution and conclude that an A d~3 mechanism is not the dominant mode of addition for the more reactive olefins, but may be so for diethyl fumarate and less reactive olefins, as Kanyaev (200) has suggested. In principle, these mechanisms might be distinguished from kinetic and product studies in hydroxylic solvents.…”

Section: B Addition To Acetylenesmentioning

confidence: 98%

See 1 more Smart Citation

The Stereochemistry of Electrophilic Additions to Olefins and Acetylenes

Fahey

1968

Topics in Stereochemistry

View full text Add to dashboard Cite

Section: B Addition To Acetylenessupporting

confidence: 68%

Section: B Addition To Acetylenesmentioning

confidence: 98%

The Stereochemistry of Electrophilic Additions to Olefins and Acetylenes

Fahey

1968

Topics in Stereochemistry

View full text Add to dashboard Cite

“…However, we find that the dimethoxy con~pound 2 (R = Me) also reacts only slowly with bromine. Clearly then, the oxygens of 2 and 4 substantially reduce the reactivity of their double bonds, compared to what is normal for an alkene (24,25). Presunlably this is due to the combined inductive effects of all three oxygens.…”

Section: Discussionmentioning

confidence: 93%

On the reaction of furan with bromine in aqueous solution. Observation of the slow hydration of malealdehyde

Tee¹,

Swedlund²

1983

Can. J. Chem.

View full text Add to dashboard Cite

Thc rate of rcaction of furan with brominc in aqueous solution has bcen measurcd and thc ratc constant obtaincd by Williamson and Collcr is confirmed. Howcvcr. it is now found that thc rcaction of brominc with furan in watcr has two distinct stages: attack of brominc leading to the formation of malealdehyde 3 and hydration of 3 to a 2: 1 mixture of thc geometrical isomers of its cyclic hydrate 4. This second, slower process is observable by stopped-flow uv spectrophoton~etry occurring aftcr the consumption of bromine. The observed kinetics are vcry similar to thosc rcccntly found for thc analogous hydration of phthalaldchydc by McDonald and Martin.OSWALD S. TEE et B. E. SWEDLUND. Can. J. Chem. 61, 2171Chem. 61, (1983.On a mesuri la vitesse de la rCaction du furanne avec Ic brome en solution aqueusc et on a confirm6 la constantc de vitesse obtenue par Williamson et Coller. Cependant on trouve maintenant que la rCaction du brome avec le furanne dans I'cau a deux Ctapes distinctes: I'attaque du brome qui conduit B la formation du malCaldChyde 3 et I'hydratation du composC 3 qui conduit ? I un mClange 2: 1 des isomkres gComCtriques de son hydrate cyclique 4. Cc sccond processus. le plus lent, peut Ctre obscrvd par la spectrophotomdtrie uv a flux stoppd que I'on utilise apres la disparition du brome. Les cindtiqucs observees sont scmblables h cclles trouvCes rCcemment pour I'hydratation analogue du phthalaldehyde par McDonald ct Martin.[Traduit par le journal]The halogenation of furans is complex with the nature of products varying widely with the substrate, reagent, solvent, and reaction conditions (1 -4). However, two broad classes of reaction may be recognized, viz. addition and substitution, with the former often leading to ring-opening (1 -4).Bromination of furan in CCI, gives a mixture of 2-bromoand 2,5-dibromofuran (5). Using ' Hmr spectroscopy, Baciocchi et nl. (6) observed the formation of 1,4-and 1,2-dibromo adducts from furan and bromine in the nonnucleophilic solvent carbon disulphide, at low temperature. With time, and on warming, the adducts underwent elimination to 2-bromofuran (6). In hydroxylic solvents the reaction of furan (1) follows a different course. With bromine (or chlorine) in an alcohol solvent at low temperatures, reaction leads to the formation of a that bromination of methyl furoate in 50% aqueous acetic acid gives the substitution product, eq. [3], the same product as can be obtained under other reaction conditions (12).We have begun to study the bromination of furans systematically to try to ascertain why some derivatives undergo addition, whereas others show substitution. Our initial approach to this problem was to study the effect of substituents and solvents upon the rate of br~mination.',~ To anchor a correlation of results for aqueous solution a reliable value for furan was required.' During measurement of this value we found that another, slower process is observable, which is the subject of the present paper. Results Kinetic studies 1 2We first measured the second-order rate c...

show abstract

“…Bromine may form polybromides Br3-and Brs-. High bromide ion concentrations catalyze the addition of molecular bromine to olefins by formation of tribromide ion (28). Bromine may also hydrolyze to form hypobromous acid at high pH (38).…”

Section: Br Br (Dibromide)mentioning

confidence: 99%

“…The yield of bromohydrin from Eq. [2] and [6] is above 90% at bromide ion concentrations less than 0.1M (28). Bromohydrin can be quantitatively converted to oxide because the rate difference between oxide and glycol formation is large (35).…”

Section: Br Br (Dibromide)mentioning

confidence: 99%

Mass Transfer Requirements for Alternating Polarity, Alternating Voltage Synthesis

Lisius

Hart

1991

J. Electrochem. Soc.

View full text Add to dashboard Cite

Operation of electrosynthesis reactors with 60 Hz transmission power modulates the electrode potential as a sine wave with no dc offset voltage. Alternating polarity alternating voltage (APAV) describes the synthesis because an electrode changes polarity every half cycle. In APAV electrosynthesis, products from electrode reactions must be removed from the electrode to prevent back reaction and loss of net current efficiency before the next half-cycle. An experimental study was made of the bromine current efficiency in the indirect electrosynthesis of alkene oxides. Reduction of soluble electrogenerated bromine at polarity reversal decreased the current efficiency for the production of bromine. High mass transfer, rapid homogeneous reaction, and low current density conditions produced high bromine current efficiencies. Bromine current efficiency was correlated as a function of three dimensionless numbers incorporating the homogeneous reaction rate constant, mass transfer coefficient, frequency, average current density, and exchange current density. A mass transfer criterion predicted process conditions required to produce bromine at 95% current efficiency. The correlations were applied to determine the suitability of a candidate chemical pathway for APAV electrosynthesis. Electrogenerated species in direct and indirect syntheses can be produced at 95% current efficiency with km/(D~) ~ above 5.6. Electrogenerated species in indirect syntheses with rapid homogeneous reactions can be produced at 50 to 95% current efficiency with 0.

show abstract

606. Kinetics of the reaction of bromine with olefins in aqueous solution

Cited by 30 publications

References 0 publications

The Stereochemistry of Electrophilic Additions to Olefins and Acetylenes

The Stereochemistry of Electrophilic Additions to Olefins and Acetylenes

On the reaction of furan with bromine in aqueous solution. Observation of the slow hydration of malealdehyde

Mass Transfer Requirements for Alternating Polarity, Alternating Voltage Synthesis

Contact Info

Product

Resources

About