Kinetic medium effects. II. Hydrolysis of esters in electrolyte solutions

McTigue, PT; Watkins, AR

doi:10.1071/ch9651943

Cited by 4 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, it would be imprudent to claim that mechanistic information can be deduced from the observed salt effect. The theories proposed separately by McTigue (42,43) and Bunnett (44) could be used to measure the effect of hydration on the activities of the species present in hydrolytic reactions. However, McTigue's observations could have been explained simply by the change in yB.…”

Section: Resultsmentioning

confidence: 99%

Hydrolysis oftert-Butyl Methyl Ether (MTBE) in Dilute Aqueous Acid

O’Reilly

Moir

Taylor

et al. 2001

Environ. Sci. Technol.

View full text Add to dashboard Cite

tert-Butyl methyl ether (MTBE) is generally considered to be resistant to chemical transformation in aqueous solution. This lack of reactivity has led to concerns of the long-term impacts of MTBE in groundwater. Although hydrolysis in the presence of strong acids has been recognized as a mechanism for MTBE transformation, it has been discounted as a significant reaction under environmental conditions. In this study, we have examined the fate of MTBE and other ether oxygenates under moderately acidic conditions (> or=pH 1). The results demonstrate that MTBE is sensitive to acid-catalyzed hydrolysis reaction that generates tert-butyl alcohol (TBA) and methanol as products. The reaction is first-order with respect to the concentration of MTBE and hydronium ion with a second-order rate constant of about 0.9 x 10(-2) M(-1) h(-1) at 26 degrees C. Commercially available acidic ion-exchange resins were also shown to catalyze the hydrolysis of MTBE at near neutral pH. Pseudo-first-order rate constants were observed to be as high as 0.03 h(-1) at 25 degrees C and 0.12 h(-1) at 35 degrees C. These findings are discussed in terms of their possible implications for the treatment and environmental fate of MTBE and other gasoline oxygenates.

show abstract

Section: Resultsmentioning

confidence: 99%

Hydrolysis oftert-Butyl Methyl Ether (MTBE) in Dilute Aqueous Acid

O’Reilly

Moir

Taylor

et al. 2001

Environ. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…As regards the catalytical activity of excess protons analogous effects are found (4,5). Trautmann and Ambard (4), for instance, studied the HT catalyzed hydrolysis of sacharose.…”

Section: Introductionmentioning

confidence: 99%

The influence of neutral salts on the easily polarizable hydrogen bond of H₅O₂⁺ groupings in acid solutions

Schiöberg¹,

Zuńdel²

1976

Can. J. Chem.

View full text Add to dashboard Cite

DAG SCHIOBERG and GEORG ZUNDEL. Can. J. Chem. 54. 2193 (1976). The influence of neutral salts on the easily polarizable hydrogen bond of H502T groupings in aqueous acid solutions is studied, using ir spectroscopy. The absorbance of the ir continuum. caused by the polarizable hydrogen bond in the H5Q2+ groupings, usually decreases with increasing neutral salt concentration. This is explained by the polarization of the hydrogen bonds caused by local fields due to the neutral salt ions. The H+ becomes more or less trapped a t one of the H 2 0 of the H50,+. The prominence of this effect increases with increasing cation field, i.e., from Cs+ to Li+, and is more pronounced with bivalent than with monovalent cations. The opposite effect is observed with tetraethylammonium chloride. The symmetry of H5Q2T groups is less strongly disturbed in the presence of neutral salts with ions with very large radii. i.e., small electrical fields, than in pure acid solutions. Considering the torsional vibration of the water molecules, it is finally shown that the hydrate structure network around the H50zA becomes disintegrated due to the presence of neutral salts.It is known from electrochemical investigations that the activity coefficient of the excess proton usually increases strongly due to the addition of neutral salts to acid solutions. The opposite is true with the addition of tetraethylammonium salt. Furthermore, the addition of neutral salt decreases the excess proton conductivity. All these observations are discussed on the basis of the ir spectroscopic results.DAG SCHIOBERG et GEORG ZUNDEL. Can. J. Chem. 54, 2193 (1976). On Ctudie, grgce 2 la spectroscopie infrarouge, l'influence des sels neutres sur les liaisons hydrogkne facilement polarisables des groupe H5Q2+ dans des solutions aqueuses d'acide. L'absorption du continuum ir, causke par les liaisons hydrogkne polarisables dans les groupes H502fr diminue generalement avec une a~~gmentation dans la concentration d'un sel neutre. On explique ce resultat par une polarisation des liaisons hydrogkne causee par les champs locaux dus aux sels d'ions neutres. Les ions H + deviennent plus ou moins coinces par une des molkules d'eau du HjOL-L'importance de cet effet augmente avec une augmentation du champ du cation, i.e. partir de Cs-jusqu'a LiT, et est plus prononce avec les cations biqu'avec les cations monovalents. On observe I'effet inverse avec le chlorure de tetraethylarnmonium. La symetrie des groupes H502-est moins fortement influencee en presence de sels neutres d'ions de rayons trks larges, i.e. des petits effets Clectriques, que dans des solutions d'acides purs. Considerant la vibration torsionnelle des mol~cules d'eau, on montre finalement que le riseau structural de l'hydrate autour du H 5 0 2 + se desintkgre en presence de sels neutres. I1 est connu. partir d'etudes electrochimiques, que le coefficient d'activiti du proton en excks augmente genkralement d'une facon importante par l'addition de sels neutres des solutipns acides. L'inverse est vrai pour l'addition du sel...

show abstract

On the Interpretation of Reaction Rates in Concentrated Acid Solutions

Yagil

1971

Israel Journal of Chemistry

View full text Add to dashboard Cite

The model of Bascombe and Bell for the indicator acidity of concentrated acid solutions is applied to the analysis of acid catalyzed reactions. A number of well studied reactions are shown to obey the relationship: where Cw is the molar concentration of water not bound to proton (or to hydroxyl OH−). Values of Cw for use in the above correlation are calculated, assuming the existence of the proton in the form suggested by Eigen, H3O(H2 O)3+. The volume fractions of nonbound water are also calculated, this quantity giving even better correlation in some cases. Values of n are obtained which agree, after subtraction of water molecules given up by the proton, with the number of water molecules which can be expected to participate in the formation of the transition state of these reactions.

show abstract

Kinetic medium effects. II. Hydrolysis of esters in electrolyte solutions

Cited by 4 publications

References 0 publications

Hydrolysis oftert-Butyl Methyl Ether (MTBE) in Dilute Aqueous Acid

Hydrolysis oftert-Butyl Methyl Ether (MTBE) in Dilute Aqueous Acid

The influence of neutral salts on the easily polarizable hydrogen bond of H₅O₂⁺ groupings in acid solutions

On the Interpretation of Reaction Rates in Concentrated Acid Solutions

Contact Info

Product

Resources

About

Kinetic medium effects. II. Hydrolysis of esters in electrolyte solutions

Cited by 4 publications

References 0 publications

Hydrolysis oftert-Butyl Methyl Ether (MTBE) in Dilute Aqueous Acid

Hydrolysis oftert-Butyl Methyl Ether (MTBE) in Dilute Aqueous Acid

The influence of neutral salts on the easily polarizable hydrogen bond of H5O2+ groupings in acid solutions

On the Interpretation of Reaction Rates in Concentrated Acid Solutions

Contact Info

Product

Resources

About

The influence of neutral salts on the easily polarizable hydrogen bond of H₅O₂⁺ groupings in acid solutions