Catalytic Disproportionation Of Hydrogen Peroxide Research Articles

“Dark” Singlet Oxygenation of β-Citronellol: A Key Step in the Manufacture of Rose Oxide

We describe the development of a scalable process for the “dark” singlet oxygenation of β-citronellol as a key step in the manufacture of the fragrance compound, rose oxide. This process, based on catalytic disproportionation of hydrogen peroxide into singlet oxygen and water, has been carried out on production scale in 10 m3 reactors.

Catalase and Epoxidation Activity of Manganese Salen Complexes Bearing Two Xanthene Scaffolds

A series of manganese Hangman salen ligand platforms functionalized by tert-butyl groups in the 3 and 3' positions using the Suzuki cross-coupling methodology are presented. The Hangman platforms support multielectron chemistry mediated by proton-coupled electron transfer (PCET), as demonstrated by their ability to promote the catalytic disproportionation of hydrogen peroxide to oxygen and water via a high-valent metal oxo. The addition of the steric groups to the salen macrocycle leads to enhanced catalase activity by circumventing side reactions that sequester the catalyst off pathway. The stereochemistry imposed by the cyclohexanediamine backbone of the salen platform is revealed by the epoxidation of 1,2-dihydronapthalene by a variety of oxidants. Improved enantiomeric excess and catalase activity as compared to sterically unmodified counterparts establishes the efficacy of the tert-butyl groups in promoting PCET catalysis on the Hangman platform.

Lanthanum-doped zinc hydroxycarbonates for the catalytic disproportionation of hydrogen peroxide into singlet oxygen

Lanthanum-containing materials were obtained by coprecipitation of La 3+ and Mg 2+, Ca 2+, or Zn 2+ in the presence of sodium carbonate. All materials were tested in the disproportionation of hydrogen peroxide into singlet molecular oxygen ( 1O 2). Whereas La supported on Mg or Ca hydroxycarbonate showed very low catalytic activity, La-doped zinc hydroxycarbonate was far more active, even without addition of a soluble base. This may be related to the high surface area and small crystal size of the Zn material and the high number of easily accessible basic sites. The catalytic performance of a series of La-containing Zn hydroxycarbonates with varying La/Zn ratios was strongly dependent on the composition; the highest catalytic activity was observed for materials having relatively small amounts of La. Structural characterization of the materials revealed that at low La content, the Zn–La coprecipitate can be considered a Zn hydroxycarbonate (hydrozincite) doped with a small amount of La. At higher La content, distinct La (hydroxy)carbonate phases are formed, which are less active in the disproportionation of H 2O 2. Filtrate tests demonstrated that the La-doped Zn hydroxycarbonate is a truly heterogeneous catalyst, allowing recycling of the catalyst. Finally, this material was used for the selective peroxidation of functionalized alkenes. After reduction of the hydroperoxides, the corresponding allylic alcohols were obtained in good chemical yield (>90%).

Hangman Salen Platforms Containing Two Xanthene Scaffolds

A synthetic strategy for the construction of chiral salen ligands bearing two rigid xanthene spacers functionalized with carboxylic acid and ester groups is presented. Suzuki cross-coupling methodology is used to furnish the appropriately functionalized xanthene spacers to a salicylaldehyde, which is subsequently condensed with (1R,2R)-(-)-1,2-diaminocyclohexane to produce salen ligands featuring an expandable molecular cleft capable of multiple hydrogen-bonding interactions in addition to metallosalen oxidation chemistry. The ability of these "Hangman" platforms to support multielectron chemistry mediated by proton-coupled electron transfer (PCET) is established by their proclivity to promote the catalytic disproportionation of hydrogen peroxide to oxygen and water via a high-valent metal oxo. Within this functionalized Hangman framework, the stereochemistry of the cyclohexyl backbone of the salen platform is revealed in the epoxidation of 1,2-dihydronaphthalene by the metal oxo.

Inorganic compounds and materials as catalysts for oxidations with aqueous hydrogen peroxide

This paper reviews our work on oxidations with aqueous hydrogen peroxide catalyzed by inorganic catalysts devoid of organic ligands. In the first part of the review, the use of the [WZn 3(ZnW 9O 34) 2] 12− “sandwich” polyoxometalate as a multi-purpose oxidation catalyst is described. Attention is paid to practical aspects that are of relevance for large-scale, industrial use of this catalyst, such as catalyst preparation, handling, and recycling. Its activity in cyclooctene epoxidation compared to other W-based catalyst systems has been determined under ceteris paribus conditions. The second part of the review deals with homogeneous and heterogeneous inorganic catalysts for “dark” singlet oxygenation, i.e., singlet oxygenation by catalytic disproportionation of hydrogen peroxide into singlet oxygen and water. The industrial advantages of “dark” singlet oxygenation compared to conventional photo-oxidation are described. It is pointed out that the reaction medium and nature of the catalyst strongly influence the selectivity and scope of the method.

Synergism between Molybdenum and Lanthanum in the Disproportionation of Hydrogen Peroxide into Singlet Oxygen

The catalytic disproportionation of hydrogen peroxide into singlet molecular oxygen was studied using the combined action of lanthanum(III) and molybdenum(VI). A synergistic effect was observed between both metals, resulting in a strong acceleration of the H2O2 disproportionation. An optimum in the catalytic activity was found at La/Mo and La/NaOH molar ratios of 4/1 and 1/3, respectively.

Molybdate-exchanged layered double hydroxides for the catalytic disproportionation of hydrogen peroxide into singlet oxygen: Evaluation and improvements of 1O 2 generation by combined chemiluminescence and trapping experiments

The generation of singlet molecular oxygen ( 1O 2) from H 2O 2 catalyzed by molybdate-exchanged layered double hydroxides (Mo-LDHs) was studied by chemiluminescence (CL) and chemical trapping (CT) experiments. In the first part, the utility of chemiluminescence spectroscopy to quantify the amount of 1O 2 produced in heterogeneous media was evaluated by comparison with 1O 2 yields determined in homogeneous solutions of sodium molybdate. On the other hand, the 1O 2 yields determined by CL spectroscopy were compared with those obtained via chemical trapping of 1O 2 with β-citronellol as an olefinic substrate. Advantages and limitations of CL spectroscopy for the determination of 1O 2 yields in heterogeneous media are discussed. CL spectroscopy allows the rapid screening of heterogeneous catalysts for the generation of 1O 2. On the other hand, the spectroscopic technique only yields the total amount of 1O 2 and provides no information on the availability of the produced 1O 2 for reaction with olefinic substrates. In the second part, CL and CT experiments were used to determine optimized conditions for the generation of 1O 2 from Mo-LDHs. Compositional parameters of the catalyst and reaction conditions were varied. A Mo-LDH catalyst possessing a low Mg/Al molar ratio and a low Mo loading was identified as the optimum catalyst in terms of activity and efficiency. Methanol and N, N-dimethylformamide are the optimum solvents.

Meso-tetraaryl cofacial bisporphyrins delivered by Suzuki cross-coupling.

The Suzuki cross-coupling methodology provides a facile synthetic approach for the modular preparation of meso-tetraaryl cofacial bisporphyrins anchored by xanthene and dibenzofuran. This synthetic method furnishes cofacial bisporphyrin templates with enhanced steric and electronic protection from mu-oxo formation and oxidative degradation. The ability of these platforms to support multielectron oxidation chemistry mediated by proton-coupled electron transfer (PCET) is demonstrated by their reactivity for the catalytic disproportionation of hydrogen peroxide to oxygen and water.

Structure and Raman spectra of transient species in the catalytic disproportionation of hydrogen peroxide by molybdate ions

AbstractThe Raman spectra of the transient peroxo species [MoO4]2−, [MoO3(O2)]2−, [MoO2(O2)2]2−, [MoO(O2)3]2− and [Mo(O2)4]2− appearing during the catalytic disproportionation of hydrogen peroxide, were recorded and characterized in solutions corresponding to concentrations varying from 0 to 8.5 M H2O2. These spectra were assigned with the help of quantum chemical normal mode analyses using configuration interaction (CISD) and the B3LYP approximation. It turns out that by increasing the number of peroxo groups around the molybdenum atom the stability of the molecule and its oxidizing power are increased. Copyright © 2002 John Wiley & Sons, Ltd.

Dissociative cycloelimination, a new selenium based pericyclic reaction.

The stereospecific oxidation of hydrazine into cis-diimide and the catalytic disproportionation of hydrogen peroxide effected by selenoxides are suggested to involve a dissociative cycloelimination from an intermediary selenurane.

The [Mn2(2-OHsalpn)2]2-,1-,0 System: An Efficient Functional Model for the Reactivity and Inactivation of the Manganese Catalases

The complexes [Mn(2-OH(X-sal)pn)]2n- (where X = 5-OCH3, H, 5-Cl, 3,5-diCl, or 5-NO2 and where n = 0 or 2) are shown to be excellent hydrogen peroxide disproportionation catalysts in acetonitrile. When carried out in an open vessel, the reaction can occur for over 5000 turnovers without an indication of catalyst decomposition. The disproportionation reaction cycles between the [MnIII(2-OH(X-sal)pn)]2 and the [MnII(2-OH(X-sal)pn)]22- oxidation levels. All derivatives show saturation kinetics with the highest kcat (21.9 ± 0.2 s-1) observed for the [MnIII(2-OH(5-Clsal)pn)]2 dimer and the optimal kcat/KM (990 ± 60 s-1·M-1) observed for the [MnIII(2-OHsalpn)]2. The first step of the reaction is proposed to be the binding of peroxide to the [MnIII(2-OH(X-sal)pn)]2 through an alkoxide shift to form a ternary intermediate {[MnIII(2-OH(X-sal)pn)]2(H2O2)}. We propose that the turnover-limiting step is the oxidation of peroxide from this intermediate. The binding efficiency of the peroxide is dependent on the phenyl-ring substitution with the derivatives donating the most electrons having the highest affinity for the substrate. Studies with isotopically labeled H2O2 indicate that protons are important in the turnover-limiting step of the reaction and that the O−O bond is not cleaved during peroxide oxidation. In a closed vessel, the product dioxygen will oxidize [MnII(2-OH(5-NO2sal)pn)]22- to [MnII/III(2-OH(5-NO2sal)pn)2]-, and this species can then be stoichiometrically oxidized by hydrogen peroxide to give [MnIII/IV(2-OH(5-NO2sal)pn)2(μ2-O)2]-. This di-μ2-oxobridged species is catalytically incompetent; however, addition of hydroxylamine hydrochloride restores catalytic activity. The relationship of this catalytic disproportionation of hydrogen peroxide and inactivation of the catalyst will be used to define a model for similar reactions observed for the Lactobacillus plantarum Mn catalase.

Identification of the precursor of singlet oxygen (1O2, 1Δg) involved in the disproportionation of hydrogen peroxide catalyzed by calcium hydroxide

Catalytic disproportionation of hydrogen peroxide by calcium hydroxide generates singlet molecular oxygen 1O2 (1Δg) through the diperoxohydrate peroxide CaO2·2H2O2 with a 50% yield based on the calcium peroxide.

90Mo NMR and kinetic studies of peroxomolybdic intermediates involved in the catalytic disproportionation of hydrogen peroxide by molybdate ions

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXT90Mo NMR and kinetic studies of peroxomolybdic intermediates involved in the catalytic disproportionation of hydrogen peroxide by molybdate ionsV. Nardello, J. Marko, G. Vermeersch, and J. M. AubryCite this: Inorg. Chem. 1995, 34, 20, 4950–4957Publication Date (Print):September 1, 1995Publication History Published online1 May 2002Published inissue 1 September 1995https://doi.org/10.1021/ic00124a007RIGHTS & PERMISSIONSArticle Views907Altmetric-Citations109LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (987 KB) Get e-AlertsSupporting Info (3)»Supporting Information Supporting Information Get e-Alerts

High-valent dinuclear manganese complexes as functional models of the catalase-like activity in the oxygen evolving complex

While this reaction is catalyzed by the Mn catalase enzyme through a lowvalent Mn(II,II)/Mn(III,III) cycle, the catalase-like activity of the OEC is believed to proceed through a high-valent Mn(IIl,III)/Mn(IV,IV) cycle, most likely involving two of the four Mn ions in the site. This high-valent activity is mimicked by the Mn schiff base complex [M~I~~(SALPN)(O)]~.[ 1 ] The rate of reactivity of this model complex shows striking dependence upon a number of factors, including protonation state, the presence of acid or base sources in solution, electron-donating and withdrawing substituents on the ligand system, and the solvent. The mechanistic details of the catalytic disproportionation of hydrogen peroxide by this complex, as well as its formation by reaction of Mn(III) complexes with hydrogen peroxide, are being studied by comparison of the reaction kinetics under conditions which probe the effects of the perturbations listed above. Addition of a base source is shown to significantly accelerate the catalytic reaction, and numerous solvents have been shown to substantially inhibit this reaction. More subtle perturbations, such as addition of Cl, N@, and 0CH3 groups to the phenolate rings of the SALPN ligand, and addition of substoichiometric sources of protons will also be presented. The results of these studies are correlated to the electrochemistry and UVNIS spectroscopy of these complexes with different electron-withdrawing and -donating groups, different protonation states of the 0x0 bridges, and different solvents in order to determine the origin of these effects on the reaction kinetics. Additionally, we compare the reactivity of the oneelectron reduced Mn(III)Mn(IV) bis oxo-bridged dimer [2 ] in order to determine its competency as an intermediate in the catalytic disproportionation of hydrogen peroxide.

Catalytic disproportionation of hydrogen peroxide by manganese complex [Mn(IV)(.mu.2-O)(SALPN)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCatalytic disproportionation of hydrogen peroxide by manganese complex [Mn(IV)(.mu.2-O)(SALPN)]2Erlund J. Larson and Vincent L. PecoraroCite this: J. Am. Chem. Soc. 1991, 113, 20, 7809–7810Publication Date (Print):September 1, 1991Publication History Published online1 May 2002Published inissue 1 September 1991https://doi.org/10.1021/ja00020a079RIGHTS & PERMISSIONSArticle Views613Altmetric-Citations92LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (277 KB) Get e-Alerts Get e-Alerts

An EPR study on the formation of the superoxide radical ion on monoclinic zirconia

Zirconium oxide is capable of forming and stabilizing the Superoxide radical ion O 2 − at its surface according to various routes. These include both an electron transfer from the solid to molecular oxygen and the capture of superoxide ions formed along a different surface process like the catalytic disproportionation of hydrogen peroxide. The EPR spectrum is characterized by an anisotropic g tensor with g zz = 2.0336, g yy = 2.0096 and g xx = 2.0034. A less abundant species is sometimes observed with g zz = 2.0255. The superoxide formation from molecular oxygen is favored by partial rehydration of the surface.