The Kinetics of the Reaction between the Ethylene Halohydrins and Hydroxyl Ion in Water and Mixed Solvents<sup>1a</sup>

McCabe, C. L.; Warner, John C.

doi:10.1021/ja01192a018

Cited by 14 publications

(5 citation statements)

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“…3). Because HCl is not consumed, the pH of the anolyte becomes acidic over the course of the electrolysis (pH 1.1) (7) The final step involves addition of hydroxide (OH -), which then reacts with ethylene chlorohydrin to yield the desired ethylene oxide and regenerate Cl - (28). The hydrogen evolution reaction (fig.…”

mentioning

confidence: 99%

“…Experiments were first carried out at 300 mA/cm 2 . On the basis of prior studies (28), in this process Clis oxidized to Cl 2 at the Pt anode (Eq. 1; e is the charge on the electron), which disproportionates in the aqueous environment to form hypochlorous and hydrochloric acid (HOCl and HCl, respectively) (Eq.…”

mentioning

confidence: 99%

“…The final step involves addition of hydroxide (OH -), which then reacts with ethylene chlorohydrin to yield the desired ethylene oxide and regenerate Cl - (28). The hydrogen evolution reaction (fig.…”

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confidence: 99%

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Chloride-mediated selective electrosynthesis of ethylene and propylene oxides at high current density

Leow

Lum

Ozden

et al. 2020

Science

284

229

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Chemicals manufacturing consumes large amounts of energy and is responsible for a substantial portion of global carbon emissions. Electrochemical systems that produce the desired compounds by using renewable electricity offer a route to lower carbon emissions in the chemicals sector. Ethylene oxide is among the world’s most abundantly produced commodity chemicals because of its importance in the plastics industry, notably for manufacturing polyesters and polyethylene terephthalates. We applied an extended heterogeneous:homogeneous interface, using chloride as a redox mediator at the anode, to facilitate the selective partial oxidation of ethylene to ethylene oxide. We achieved current densities of 1 ampere per square centimeter, Faradaic efficiencies of ~70%, and product specificities of ~97%. When run at 300 milliamperes per square centimeter for 100 hours, the system maintained a 71(±1)% Faradaic efficiency throughout.

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confidence: 99%

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Chloride-mediated selective electrosynthesis of ethylene and propylene oxides at high current density

Leow

Lum

Ozden

et al. 2020

Science

284

229

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“…Extensive studies have been made [487][488][489][490][491][492] of the hydrolysis of ethylene halohydrins, CH 2 OHCH 2 X, and of ethylene oxide, CH 2 OCH 2 . It is thought that the first-order racemizations in aqueous or alcoholic solutions may arise from the rapid formation of the disolvated carbonium ion, aided by the dissociation of the ion pair in these polar solvents and by the high concentration of hydroxylic reagent present.…”

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Solvent Influence on Rates and Mechanisms

Amis

Hinton

1973

Solvent Effects on Chemical Phenomena

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“…These data indicate that the leaving group effect is only partially expressed in k, (the first-order rate constant for inactivation, obtained under conditions of saturating inactivator) but may or may not be fully expressed in kJKI (the second-order rate constant for inactivation, obtained under conditions in which most of the enzyme has no bound form of the inactivator), depending on the peptidyl halomethane-enzyme pair. The maximal Cl/F leaving group effect for conversion of the enzyme-bound tetrahedral intermediate to the epoxy ether is assumed to be about 700, since ring closure of the 2-chloroethoxide anion to form ethylene oxide is 700 times faster than ring closure of the 2-fluoroethoxide anion (McCabe & Warner, 1948;Knipe, 1973 …”

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Three-Dimensional Structure of Chymotrypsin Inactivated with (2S)-N-Acetyl-L-alanyl-L-phenylalanyl .alpha.-chloroethane: Implications for the Mechanism of Inactivation of Serine Proteases by Chloroketones

Kreutter

Steinmetz²,

Liang³

et al. 1994

Biochemistry

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The reaction of enantiomerically pure (2S)-N-acetyl-L-alanyl-L-phenylalanyl alpha-chloroethane with gamma-chymotrypsin was studied as a probe of the mechanism of inactivation of serine proteases by peptidyl chloroalkanes. It was determined crystallographically that the peptidyl chloroethane alkylates His57 with retention of configuration at the chiral center, indicating a double displacement mechanism. We think it likely that a Ser195-epoxy ether adduct is an intermediate on the inactivation pathway, although other possibilities have not been disproven. Kinetic data reported by others [Angliker et al. (1988) Biochem. J. 256, 481-486] indicate that the epoxy ether intermediate is not an irreversibly inactivated form of enzyme [a conclusion confirmed experimentally (Prorok et al. (1994) Biochemistry 33, 9784-9790)] and that both ring closure of the tetrahedral intermediate to form the epoxy ether and ring opening by His57 partially limit the first-order rate constant for inactivation, ki. The peptidyl chloroethyl derivative adopts a very different active site conformation from that assumed by serine proteases inactivated by peptidyl chloromethanes. Positioning the chloroethyl derivative into the conformation adopted by chloromethyl derivatives would cause the extra methyl group to make a bad van der Waals contact with the inactivator P2 carbonyl carbon, thereby preventing the formation of the invariant hydrogen bond between the inactivator P1 amide nitrogen and the carbonyl group of Ser214. We conclude that the unusual conformation displayed by the chloroethyl derivative is caused by steric hindrance between the extra methyl group and the rest of the inactivator chain.

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The Kinetics of the Reaction between the Ethylene Halohydrins and Hydroxyl Ion in Water and Mixed Solvents^1a

Cited by 14 publications

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Chloride-mediated selective electrosynthesis of ethylene and propylene oxides at high current density

Chloride-mediated selective electrosynthesis of ethylene and propylene oxides at high current density

Solvent Influence on Rates and Mechanisms

Three-Dimensional Structure of Chymotrypsin Inactivated with (2S)-N-Acetyl-L-alanyl-L-phenylalanyl .alpha.-chloroethane: Implications for the Mechanism of Inactivation of Serine Proteases by Chloroketones

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The Kinetics of the Reaction between the Ethylene Halohydrins and Hydroxyl Ion in Water and Mixed Solvents1a

Cited by 14 publications

References 0 publications

Chloride-mediated selective electrosynthesis of ethylene and propylene oxides at high current density

Chloride-mediated selective electrosynthesis of ethylene and propylene oxides at high current density

Solvent Influence on Rates and Mechanisms

Three-Dimensional Structure of Chymotrypsin Inactivated with (2S)-N-Acetyl-L-alanyl-L-phenylalanyl .alpha.-chloroethane: Implications for the Mechanism of Inactivation of Serine Proteases by Chloroketones

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The Kinetics of the Reaction between the Ethylene Halohydrins and Hydroxyl Ion in Water and Mixed Solvents^1a