Microkinetic analysis of ring opening and decarboxylation of γ-valerolactone over silica alumina

Bond, Jesse Q.; Jungong, Christian S.; Chatzidimitriou, Anargyros

doi:10.1016/j.jcat.2016.10.021

Cited by 39 publications

(26 citation statements)

References 65 publications

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“…This apparent ambiguity can only be explained taking into account an equilibrium between PEAs and GVL in favor of GVL under the conditions. This assumption is supported by recent studies of Bond et al 58 and Wong et al 61 Finally, a commercial Pt on carbon catalyst was tested, and the results are worse in comparison to those of the 2.0Pt/ ZSM-5(11), cf. Fig.…”

Section: Effect Of Pt Loading and Acid Site Densitysupporting

confidence: 54%

“…This indicates that not only PEAs to GVL, but also HPA to GVL reactions over the acidic zeolite should be thermodynamically favorable in our conditions. In fact, this assumption is supported by the kinetic observations of Bond et al 58 and Abdelrahman et al 68 studying the microkinetics of GVL ring opening over silicaalumina and LA hydrogenation to GVL over Ru/C, respectively. This equilibrium between GVL and HPA and PEAs has also been emphasized by Wong et al 61 using aqueous-acidic solution extending the reaction time to 48 h resulted in a further increase of PA yield to 75% at the expense of the GVL yield, dropping to 23%.…”

Section: Catalyst Stability and Reusabilitymentioning

confidence: 67%

“…The GVL conversion rate of the three Pt catalysts, as calculated from the data of Fig. S7 † assuming a pseudo-zero order reaction (taking the slope of the first 3 points) for GVL conversion in accord to the kinetic model of Bond et al, 58 are plotted against the Pt surface area in Fig. 2.…”

Section: Effect Of Pt Loading and Acid Site Densitymentioning

confidence: 99%

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Pentanoic acid from γ-valerolactone and formic acid using bifunctional catalysis

et al. 2020

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Section: Effect Of Pt Loading and Acid Site Densitysupporting

confidence: 54%

Section: Catalyst Stability and Reusabilitymentioning

confidence: 67%

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Pentanoic acid from γ-valerolactone and formic acid using bifunctional catalysis

et al. 2020

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“…Adsorbates in TON exhibit the largest loss in entropy upon adsorption, while FAU results in the smallest entropic losses. If the molecules were to behave as immobile adsorbates on the surface, the entropy lost upon adsorption (Δ S ads ) can be approximated to be equal to three degrees of translational freedom, 3 , 35 , 36 which can be calculated from statistical mechanics using the Sackur–Tetrode equation 37 where S Ar,298K 0 is the entropy of Ar in the gas phase at 298 K and 1.0 bar, 154.8 J mol –1 K –1 ; R is the universal gas constant, m the molecular weight of the molecule of interest, m Ar that for Argon, and T the temperature at which the entropy is calculated. Alternatively, for the case of a mobile adsorbate, the entropy of adsorption can be approximated to be equal to one degree of translational freedom (S trans /3, eq 4 ).…”

Section: Resultsmentioning

confidence: 99%

A Universal Descriptor for the Entropy of Adsorbed Molecules in Confined Spaces

Dauenhauer

Abdelrahman

2018

ACS Cent. Sci.

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Confinement of hydrocarbons in nanoscale pockets and pores provides tunable capability for controlling molecules in catalysts, sorbents, and membranes for reaction and separation applications. While computation of the enthalpic interactions of hydrocarbons in confined spaces has improved, understanding and predicting the entropy of confined molecules remains a challenge. Here we show, using a set of nine aluminosilicate zeolite frameworks with broad variation in pore and cavity structure, that the entropy of adsorption can be predicted as a linear combination of rotational and translational entropy. The extent of entropy lost upon adsorption is predicted using only a single material descriptor, the occupiable volume (Vocc). Predictive capability of confined molecular entropy permits an understanding of the relation with adsorption enthalpy, the ability to computationally screen microporous materials, and an understanding of the role of confinement on the kinetics of molecules in confined spaces.

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“…Therefore, disruption or removal of the lactone has been associated with drastic reduction or loss of toxicity [223]. This ring is readily opened under extreme pH values (<3 or >10), but can either retrieve its original structure once the pH returns to milder values or be permanently modified if the ring opening is followed by a decarboxylation reaction [224]. The lactone can also be disrupted by different enzymes of various origins, including laccases, peroxidases, reductases, and oxidases [223].…”

Section: Decontaminationmentioning

confidence: 99%

Aflatoxins: Producing-Molds, Structure, Health Issues and Incidence in Southeast Asian and Sub-Saharan African Countries

Benkerroum

2020

IJERPH

193

112

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This review aims to update the main aspects of aflatoxin production, occurrence and incidence in selected countries, and associated aflatoxicosis outbreaks. Means to reduce aflatoxin incidence in crops were also presented, with an emphasis on the environmentally-friendly technology using atoxigenic strains of Aspergillus flavus. Aflatoxins are unavoidable widespread natural contaminants of foods and feeds with serious impacts on health, agricultural and livestock productivity, and food safety. They are secondary metabolites produced by Aspergillus species distributed on three main sections of the genus (section Flavi, section Ochraceorosei, and section Nidulantes). Poor economic status of a country exacerbates the risk and the extent of crop contamination due to faulty storage conditions that are usually suitable for mold growth and mycotoxin production: temperature of 22 to 29 °C and water activity of 0.90 to 0.99. This situation paralleled the prevalence of high liver cancer and the occasional acute aflatoxicosis episodes that have been associated with these regions. Risk assessment studies revealed that Southeast Asian (SEA) and Sub-Saharan African (SSA) countries remain at high risk and that, apart from the regulatory standards revision to be more restrictive, other actions to prevent or decontaminate crops are to be taken for adequate public health protection. Indeed, a review of publications on the incidence of aflatoxins in selected foods and feeds from countries whose crops are classically known for their highest contamination with aflatoxins, reveals that despite the intensive efforts made to reduce such an incidence, there has been no clear tendency, with the possible exception of South Africa, towards sustained improvements. Nonetheless, a global risk assessment of the new situation regarding crop contamination with aflatoxins by international organizations with the required expertise is suggested to appraise where we stand presently.

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Microkinetic analysis of ring opening and decarboxylation of γ-valerolactone over silica alumina

Cited by 39 publications

References 65 publications

Pentanoic acid from γ-valerolactone and formic acid using bifunctional catalysis

Pentanoic acid from γ-valerolactone and formic acid using bifunctional catalysis

A Universal Descriptor for the Entropy of Adsorbed Molecules in Confined Spaces

Aflatoxins: Producing-Molds, Structure, Health Issues and Incidence in Southeast Asian and Sub-Saharan African Countries

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