Experimental and computational studies on solvent effects in reactions of peracid–aldehyde adducts

Lehtinen, Christel; Nevalainen, Vesa; Brunow, Gösta

doi:10.1016/s0040-4020(01)00397-0

Cited by 35 publications

(21 citation statements)

References 12 publications

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“…The migration ratios obtained in heptane are consistent with the general migratory aptitude for BV oxidation 9a. c Selectivity shifts during the BV oxidation of aldehydes in different solvents were investigated by Lehtinen et al 13. Specifically, solvents capable of forming hydrogen bonds, such as methanol and 1‐propanol, were shown to favor the migration of hydrogen over branched alkyl groups, while the migration of branched alkyl groups was preferentially observed in non‐hydrogen‐bonding solvents, such as toluene and CH 2 Cl 2 .…”

Section: Methodssupporting

confidence: 73%

Acid‐catalyzed Oxidation of Levulinate Derivatives to Succinates under Mild Conditions

2015

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Levulinate derivatives are an attractive platform for the production of renewable chemicals. Here we report on the oxidation of methyl levulinate into dimethyl succinate with peroxides under mild conditions using Brønsted and Lewis acid catalysts. Selectivities to succinate and acetate derivatives of approximately 60 and 40 %, respectively, were obtained with strong Brønsted acids in methanol. Although the molecular structure (i.e., carbon-chain length and branching around the C=O group) and the oxidant type affect the product distribution, solvent choice has the strongest impact on changing the location of oxygen insertion into the carbon backbone. Specifically, switching the solvent from methanol to heptane resulted in a decrease in the succinate/acetate ratio from 1.6 to 0.3. In contrast to Brønsted acids, we demonstrate that the nature of the metal cation is responsible for changing the reaction selectivity of water-tolerant Lewis acidic triflate salts.The conversion of renewable resources into commodity and specialty chemicals through chemical or biological routes has attracted considerable attention. [1] Thermocatalytic routes offer an attractive alternative to biological routes, with less stringent requirements for temperature and pH control, as well as potentially less energy-intensive product separation and purification processes. [1a, 2] Succinic acid (SA) has been identified as one of the top 12 building blocks from biomass by the US Department of Energy. [3] The market for SA is expected to exceed $ 1.1 billion in revenue by 2020. [4] Succinates, formed from the esterification of SA with monoalcohols, are important plasticizers, lubricants, and chemical intermediates. [5] A thermocatalytic route to produce SA and other succinate derivatives from renewable resources is highly desirable.Levulinic acid (LA) is a key platform molecule that can be readily produced from lignocellulosic carbohydrates. [6] Upon scale up, the estimated LA price is expected to decrease to less than $ 1 kg À1 from the current commercial price of approximately $ 3.5 kg À1 . [7] The carbonyl group in LA and its esters can be oxidized to produce SA and its esters, respectively; however, linear aliphatic ketones are generally difficult to oxidize selectively. Consequently, only a few studies, mostly using vanadium-, ruthenium-, and manganese-based catalysts, have been reported on the oxidation of LA derivatives. [8] These catalytic systems suffer from several challenges, including necessitating high reaction temperatures, using toxic reagents, or releasing a stoichiometric amount of CO 2 . Recently, Podolean et al. demonstrated that Ru-based magnetic nanoparticles are efficient catalysts for the oxidation of LA into SA under 10 bar of O 2 at 150 8C. [1b] The authors hypothesized that strong Brønsted acid sites are responsible for catalyzing the oxidation of the LA carbon backbone via a Baeyer-Villiger (BV) mechanism. Unfortunately, no systematic studies on the role of Brønsted acids in the BV oxidation of LA into SA were report...

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Section: Methodssupporting

confidence: 73%

Acid‐catalyzed Oxidation of Levulinate Derivatives to Succinates under Mild Conditions

2015

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“…www.chemeurj.org only by the entropy effect, but also critically by the solvent effect, which has been known to greatly influence the migration aptitude of the B-V reaction of some substrates. [18,71] In fact, both the catalytic efficiency and the asymmetric induction in our phosphoric acid catalyzed B-V oxidation of 2 a using aqueous H 2 O 2 were found to be strongly dependent on the nature of solvents used. [42] …”

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confidence: 82%

Mechanistic Investigation of Chiral Phosphoric Acid Catalyzed Asymmetric Baeyer–Villiger Reaction of 3‐Substituted Cyclobutanones with H₂O₂ as the Oxidant

Wang

et al. 2010

Chemistry A European J

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The mechanism of the chiral phosphoric acid catalyzed Baeyer-Villiger (B-V) reaction of cyclobutanones with hydrogen peroxide was investigated by using a combination of experimental and theoretical methods. Of the two pathways that have been proposed for the present reaction, the pathway involving a peroxyphosphate intermediate is not viable. The reaction progress kinetic analysis indicates that the reaction is partially inhibited by the gamma-lactone product. Initial rate measurements suggest that the reaction follows Michaelis-Menten-type kinetics consistent with a bifunctional mechanism in which the catalyst is actively involved in both carbonyl addition and the subsequent rearrangement steps through hydrogen-bonding interactions with the reactants or the intermediate. High-level quantum chemical calculations strongly support a two-step concerted mechanism in which the phosphoric acid activates the reactants or the intermediate in a synergistic manner through partial proton transfer. The catalyst simultaneously acts as a general acid, by increasing the electrophilicity of the carbonyl carbon, increases the nucleophilicity of hydrogen peroxide as a Lewis base in the addition step, and facilitates the dissociation of the OH group from the Criegee intermediate in the rearrangement step. The overall reaction is highly exothermic, and the rearrangement of the Criegee intermediate is the rate-determining step. The observed reactivity of this catalytic B-V reaction also results, in part, from the ring strain in cyclobutanones. The sense of chiral induction is rationalized by the analysis of the relative energies of the competing diastereomeric transition states, in which the steric repulsion between the 3-substituent of the cyclobutanone and the 3- and 3'-substituents of the catalyst, as well as the entropy and solvent effects, are found to be critically important.

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“…GC-MS analysis of the reaction mixture shows an aldehyde conversion of 35% and a selectivity of 85% towards the carboxylic acid comparable to previously published catalysed autoxidation. 5,6 The byproducts were identified, i.e. 3-heptylformate, 3-heptanol and are compatible with a Criegee intermediate.…”

Section: Uncatalysed Autoxidation Of 2-ethylhexanalmentioning

confidence: 99%

“…The migration of the hydride from the aldehyde moiety to the nearest peroxide oxygen gives two carboxylic acids whereas the migration of the alkyl group from the aldehyde gives an equimolar mixture of carboxylic acid and formate. 5,6 The ratio of hydride to alkyl migration was found to depend critically on the structure of aldehydes, temperature, solvent, ….…”

Section: Introductionmentioning

confidence: 99%

Insights in the aerobic oxidation of aldehydes

et al. 2013

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The hydroformylation of olefins (oxo synthesis) is the most important process for the production of higher aldehydes (.C 4 ). The liquid phase oxidation of the latter to carboxylic acids by molecular oxygen or air has been known for more than 150 years and is an industrially important process. However, in the recent literature, several different oxidizing reagents and catalytic processes have been reported for this oxidation but most of them have limitations as they use environmentally unacceptable reagents or unnecessarily sophisticated conditions. Herein, we re-evaluated the air oxidation of aldehydes. We show that under mild conditions (air or oxygen and non-optimized stirring), reactions are transfer limited and thus catalyst has no effect on reaction rate. Using efficient stirring (self-suction turbine), uncatalysed air oxidation of 0.8 M aldehyde is possible in 50 min at room temperature whereas less than 10 min was necessary with 10 ppm Mn(II). Thus, recommendations for avoiding common pitfalls that may rise during the evaluation of new catalysts are made.

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Experimental and computational studies on solvent effects in reactions of peracid–aldehyde adducts

Cited by 35 publications

References 12 publications

Acid‐catalyzed Oxidation of Levulinate Derivatives to Succinates under Mild Conditions

Acid‐catalyzed Oxidation of Levulinate Derivatives to Succinates under Mild Conditions

Mechanistic Investigation of Chiral Phosphoric Acid Catalyzed Asymmetric Baeyer–Villiger Reaction of 3‐Substituted Cyclobutanones with H₂O₂ as the Oxidant

Insights in the aerobic oxidation of aldehydes

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Experimental and computational studies on solvent effects in reactions of peracid–aldehyde adducts

Cited by 35 publications

References 12 publications

Acid‐catalyzed Oxidation of Levulinate Derivatives to Succinates under Mild Conditions

Acid‐catalyzed Oxidation of Levulinate Derivatives to Succinates under Mild Conditions

Mechanistic Investigation of Chiral Phosphoric Acid Catalyzed Asymmetric Baeyer–Villiger Reaction of 3‐Substituted Cyclobutanones with H2O2 as the Oxidant

Insights in the aerobic oxidation of aldehydes

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Mechanistic Investigation of Chiral Phosphoric Acid Catalyzed Asymmetric Baeyer–Villiger Reaction of 3‐Substituted Cyclobutanones with H₂O₂ as the Oxidant