MnO2 as a catalyst for H2O2 decomposition. Dem. 646

Alyea, Hubert N.

doi:10.1021/ed046pa496.2

Cited by 6 publications

(10 citation statements)

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“…It is not easy to make a live demonstration showing the influence of the number of active sites on the catalytic reaction rate during lectures in an ordinary lecture hall. There are several examples of heterogeneous catalytic reactions that are simple enough for such classroom demonstrations, i.e., catalytic oxidation of alcohols, ammonia, , acetone, and sulfur dioxide; reduction of alcohols; , and variations on the decomposition of hydrogen peroxide, such as H 2 O 2 decomposition catalyzed by manganese dioxide, transition metals, or Cr 2 O 7 2– adsorbed on solids . Those experiments allow demonstration of the heterogeneous catalysis phenomenon but are not suitable for quantitative analysis of the influence of the number of active sites (which is directly proportional to the specific surface area) on the reaction rate.…”

Section: Introductionmentioning

confidence: 99%

“…The choice of the decomposition of hydrogen peroxide as a model reaction was dictated by the simplicity of the reaction setup, harmless gaseous product of the reaction, and a common, inexpensive substrate. There are two best-known approaches for demonstrations of hydrogen peroxide decomposition: (1) the reaction catalyzed by potassium iodide solution in the presence of a detergent, called “Elephant’s Toothpaste”, − and (2) the reaction catalyzed by solid manganese oxide, called “Genie in the Bottle” or “Aladdin’s Lamp”. ,, Recently, the influence of the specific surface area of the catalyst was reported in the second case, but only in the context of lowering the rate of the reaction using MnO 2 with a larger particle size (44 μm) for safety purposes without the possibility of systematic quantitative analysis. The approach proposed herein is a blend of the above two methods.…”

Section: Introductionmentioning

confidence: 99%

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Demonstration of the Influence of Specific Surface Area on Reaction Rate in Heterogeneous Catalysis

et al. 2021

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Heterogeneous catalysis plays an important role in many chemical reactions, especially those applied in industrial processes, and therefore, its theoretical foundations are introduced not only to students majoring in chemical engineering or catalysis but also as part of general chemistry courses. The consideration of catalytic activity of various solids and mechanisms of catalytic reactions requires the introduction of the concept of an active site, which together with the catalyst specific surface area are discussed as key parameters controlling the reaction rate. There are many known demonstrations of heterogeneous catalysis phenomena that can be performed live in a lecture hall, but all of them focus only on the general idea of catalytic processes and are not suitable for quantitative analysis. Therefore, herein we present a simple demonstration of the influence of the specific surface area of a catalyst on the rate of a catalytic reaction. This demonstration is based on a model reaction of hydrogen peroxide decomposition catalyzed by cobalt spinel (Co3O4) calcined at various temperatures. The differences in reaction rates can be monitored visually, and the obtained data can be used directly for a simple kinetic analysis, including comparison of numerical values of the reaction rate constants.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Demonstration of the Influence of Specific Surface Area on Reaction Rate in Heterogeneous Catalysis

et al. 2021

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“…Therefore, it appeared plausible that high HMF feed concentrations and subsequent conversion result in H 2 O 2 stress and acidic environment that hinder FDCA production. Since MnO 2 decomposes H 2 O 2 42 and CaCO 3 neutralizes acidic products, 1 we tested whether addition of MnO 2 and CaCO 3 to the culture could improve FDCA production. We separately cultured the HG and OG strains using 100 mM HMF feed, with MnO 2 (0.5 mg/mL) or CaCO 3 (30 mg/mL) supplement alone or in combination.…”

Section: ■ Resultsmentioning

confidence: 99%

Engineering Stable Pseudomonas putida S12 by CRISPR for 2,5-Furandicarboxylic Acid (FDCA) Production

Pham

Chen

et al. 2020

ACS Synth. Biol.

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FDCA (2,5-furandicarboxylic acid) can be enzymatically converted from HMF (5-hydroxymethylfurfural). Pseudomonas putida S12 is promising for FDCA production, but generating stable P. putida S12 is difficult due to its polyploidy and lack of genome engineering tools. Here we showed that coupling CRISPR and λ-Red recombineering enabled one-step gene integration with high efficiency and frequency, and simultaneously replaced endogenous genes in all chromosomes. Using this approach, we generated two stable P. putida S12 strains expressing HMF/furfural oxidoreductase (HMFH) and HMF oxidase (HMFO), both being able to convert 50 mM HMF to ≈42−43 mM FDCA in 24 h. Cosupplementation of MnO 2 and CaCO 3 to the medium drastically improved the cell tolerance to HMF and enhanced FDCA production. Cointegrating HMFH and HMFT1 (HMF transporter) genes further improved FDCA production, enabling the cells to convert 250 mM HMF to 196 mM (30.6 g/L) FDCA in 24 h. This study implicates the potentials of CRISPR for generating stable P. putida S12 strains for FDCA production.

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“…When 3% H 2 O 2 is applied to Mn oxides, it results in the effervescence of O 2 according to the reaction in [Eq. 10], (Figure 5), whereby, Mn oxide functions as a catalyst for the decomposition of (Alyea, 1969). This reaction does not induce a soil color change.…”

Section: Rapid Fes Oxidation and Color Change Following Exposure To O 2 Or H 2 O 2 Applicationmentioning

confidence: 99%

Iron monosulfide identification: Field techniques to provide evidence of reducing conditions in soils

Duball

Vaughan

Berkowitz

et al. 2020

Soil Science Soc of Amer J

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The accurate and timely identification of soil morphological indicators of anaerobic conditions is critical for the proper documentation of hydric soils and prolonged soil saturation. Iron monosulfide (FeS) forms under anaerobic conditions following complexation of Fe and reduced S to form insoluble, black to very dark gray (value ≤ 4, chroma ≤ 1) concentrations and/or soil coatings. These features are observable as soft masses or pore linings or are dispersed throughout the soil matrix in the form of concentrated zones of FeS. Variation in soil and environmental conditions result in a wide range of FeS expression from <1 to 100% coverage of the soil matrix. We seek to explain the environmental conditions required for FeS formation and describe diagnostic methods to document FeS in a field setting. Field identification of FeS can be performed through an oxidized color change test (either ambient air or the application of 3% H 2 O 2 ) and via the evolution of H 2 S after the application of 1 M HCl. The use of Indicator of Reduction in Soil (IRIS) devices provides additional supporting evidence of S reducing conditions in soils and thus environmental conditions conducive to FeS formation when other necessary constituents are present. The concepts and techniques outlined in this review can serve as useful resources to inform our understanding of belowground redox chemistry and facilitate the accurate identification of FeS in wet soil environments.

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MnO2 as a catalyst for H2O2 decomposition. Dem. 646

Abstract: 21. Metals of Groups IV-VIII D. Group VII (Manganese)

Cited by 6 publications

References 0 publications

Demonstration of the Influence of Specific Surface Area on Reaction Rate in Heterogeneous Catalysis

Demonstration of the Influence of Specific Surface Area on Reaction Rate in Heterogeneous Catalysis

Engineering Stable Pseudomonas putida S12 by CRISPR for 2,5-Furandicarboxylic Acid (FDCA) Production

Iron monosulfide identification: Field techniques to provide evidence of reducing conditions in soils

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