Selective Oxidation Of Alkanes Research Articles

Selective stoichiometric and catalytic oxidation of lower alkanes in the system Co(III)-CF3COOH

It has been found that cobalt(III) trifluoroacetate is capable of oxidizing with a high selectivity (∼90%) methane to methyltrifluoroacetate at 130–180°C and 10–40 atm. In the presence of oxygen the selective oxidation of methane proceeds catalytically with respect to the cobalt salt. Ethane and propane are oxidized with the formation of ethanol and isopropanol trifluoroacetates, respectively (yield ∼80%). The further oxidation of triethanol trifluoroacetate leads to the formation of the ethyleneglycol ester, together with products of the splitting of the C-C bond in the alkyl group of the initial ester. The data obtained lead to the assumption that the reactions of the alkanes and alkyl esters with Co(III) include an electron transfer stage from the RH molecule to the Co(III) ion, with the intermediate formation of the cation radical RH⋅+.

ChemInform Abstract: Selective Air Oxidation of Light Alkanes Catalyzed by Activated Metalloporphyrins. The Search for a Suprabiotic System

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Selective air oxidation of light alkanes catalyzed by activated metalloporphyrins - the search for a suprabiotic system

Halogenated metalloporphyrins have been examined as catalysts for the air oxidation of propane and isobutane at low temperature. Room temperature oxidation of isobutane with air gives > 13,000 turnovers with > 90% selectivity to tert -butyl alcohol.

Surface kinetics of adsorbed intermediates: selective oxidation of C 4C 5 alkanes

An approach to the discussion of the selective behavior of vanadyl pyrophosphate and of 12-molybdovanadophosphoric acid catalysts in C 4–C 5 alkane selective oxidation is given based on a surface dynamic model of the reaction taking into account the kinetics and concentration of adsorbed intermediates after the rate limiting step. The different reaction patterns found using these two catalytic systems are discussed on the basis of this surface kinetic model. Application of the model can be utilized for control and tuning of surface reactions and for a rational approach to surface catalytic design and microstructural engineering.

ChemInform Abstract: Selective Oxidation of Alkanes and Ethers Mediated by Ruthenium(II) Complexes.

AbstractOxidation of dipropyl ether (Ia) or tetrahydrofuran (Ib) with lithium hypochlorite in the presence of a ruthenium(II) catalyst in a biphasic system yields propyl propionate (IIa) or δ‐valerolactone (IIb).

Selective oxidation of alkanes and ethers mediated by ruthenium(II) complexes

Selective hydroxylation (or ketonization) of cyclic alkanes and conversion of ethers to esters and of secondary alcohols to ketones, with significant rates (up to ca. 1 turnover per minute at room temperature), were achieved by using hypochlorite as oxidant and a choice of ruthenium(II) complexes as catalysts, in a biphastic water–dichloromethane system.

Cationic palladium nitro complexes as catalysts for the oxygen-based oxidation of alkenes to ketones, and for the oxydehydrogenation of ketones and aldehydes to the α, β-unsaturated analogues

Cationic palladium nitro complexes permit more rapid and more selective oxidation of alkenes to ketones than existing metal nitro catalysts; they also oxidatively dehydrogenate ketones and aldehydes to the corresponding α, β-unsaturated analogues under extremely mild conditions.

The Selective Partial Oxidation of Alkanes using Zeolite Based Catalysts. Phthalocyanine (PC) “Ship-in-Bottle” Species

Phthalocyaninatoiron (FePc) complexes may be prepared inside the pore structure of large pore zeolites X or Y by a process of sequential introduction of components followed by assembly inside the void space of the zeolite. Such species are capable of performing as catalysts in the oxidation of alkanes using iodosobenzene as the oxygen atom transfer reagent. The fact that such catalysis is constrained to occur inside the size- and shape-selective zeolite crystallites imposes unique selectivities on the distribution of oxidized products. These catalysts prefer to oxidize the smaller of two competitive substrates and to oxidize toward the ends of the long molecular axis of such substrates. In addition. stereoselectivity is apparent in cases of oxidations with diastereotopic C–H bonds. All of the observed selectivities can be explained in terms of the sieving and orienting effects of the zeolite hosts. While selectivities are moderate with the native zeolites, they may be considerably adjusted by simply alter...

A study of the activity and selectivity of molybdenum crystallographic shear compounds in the oxidation of C 4 hydrocarbons

Oxides which are catalysts in the selective oxidation of olefins are thought to form crystallographic shear (CS) structures. These structures can form as a result of the removal of lattice oxygen which leads to a change from corner to edge sharing of some of the metal-oxygen octahedra. Oxygen removal also results in reduction of some of the metal atoms to form a mixed valence solid. This work was undertaken with the goal of illuminating the role of these reduced molybdenum-oxygen structures in selective oxidation. In particular, several molybdenum CS compounds were studied and compared with MoO{sub 3}.

ChemInform Abstract: Selective Oxidation of Lower Alkanes over Oxide Catalysts

The selective oxidation of alkanes to alkenes, alkadienes, and oxygen-containing products is of great industrial importance. In this review, recent progress in the selective oxidations of C1-C4 alkanes over oxide catalysts has been described.Typical examples reported recently for oxidation of CH4 to C2H6, C2H4, HCHO and CH3OH are summarized in Table 1 and those for C2H6 and C3H8 are in Table 2. The catalytic oxidation of n-butane to maleic anhydride which has been industrialized by using V-P mixed oxide catalysts has been reviewed in more detail. V-P mixed oxide having P/V ratio of 1 - 1.2 have often been claimed as active catalysts. Hovever, by comparing the catalysis of crystalline phases with P/V = 1 (α-, β-VOPO4, etc.), it has been indicated that crystalline (VO) 2P2O7 is the effective phase. Its structural and redox characteristics are discussed based on the recent literature.

ChemInform Abstract: Cyclodextrin‐Palladium Chloride. New Catalytic System for Selective Oxidation of Olefins (I) to Ketones (II).

ChemInformVolume 18, Issue 27 Preparative Organic Chemistry ChemInform Abstract: Cyclodextrin-Palladium Chloride. New Catalytic System for Selective Oxidation of Olefins (I) to Ketones (II). A. HARADA, A. HARADA Pharm. Univ., Kyoto 607, JapanSearch for more papers by this authorY. HU, Y. HU Pharm. Univ., Kyoto 607, JapanSearch for more papers by this authorS. TAKAHASHI, S. TAKAHASHI Pharm. Univ., Kyoto 607, JapanSearch for more papers by this author A. HARADA, A. HARADA Pharm. Univ., Kyoto 607, JapanSearch for more papers by this authorY. HU, Y. HU Pharm. Univ., Kyoto 607, JapanSearch for more papers by this authorS. TAKAHASHI, S. TAKAHASHI Pharm. Univ., Kyoto 607, JapanSearch for more papers by this author First published: July 7, 1987 https://doi.org/10.1002/chin.198727106AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume18, Issue27July 7, 1987 RelatedInformation

Functionalization of paraffinic hydrocarbons by heterogeneous oxidation. I. Control of selectivity in n-butane conversion to maleic anhydride

The selectivity in maleic anhydride formation from n-butane in different reagent conditions and on (VO) 2P 2O 7 catalysts with different rates of oxidation of vanadium was studied and compared with the results obtained (I) in the oxidation of propane and ethane, (II) in the ammoxidation of propane and (III) in the oxidation of n-butane on different vanadium-based catalysts (vanadium-titanium oxide and vanadium-antimony oxide). The results indicate that in the selective oxidation of alkanes not only the first step of activation is important, but also of particular importance is the stability in the reaction conditions of the products formed, which depends either on the oxidizing power of the surface or on the stability of the product formed as regards consecutive oxidation. The other vanadium-based catalysts tested are also able to activate the paraffin, but not to control the oxidation, and only carbon oxides are formed. Similarly, propane and ethane are also activated, but due to the reactivity of the products in consecutive oxidation, only carbon oxides are obtained. On the contrary in the ammoxidation of propane, due to the higher stability of the product, acrylonitrile is formed at the higher temperatures or propylene at the lower temperatures. However ammonia is a strong inhibitor of the activity of the catalyst sites to which the ability of these catalysts in the activation of the paraffinic hydrocarbon was attributed.

酸化物触媒を用いる低級アルカンの選択的酸化反応

The selective oxidation of alkanes to alkenes, alkadienes, and oxygen-containing products is of great industrial importance. In this review, recent progress in the selective oxidations of C1-C4 alkanes over oxide catalysts has been described.Typical examples reported recently for oxidation of CH4 to C2H6, C2H4, HCHO and CH3OH are summarized in Table 1 and those for C2H6 and C3H8 are in Table 2. The catalytic oxidation of n-butane to maleic anhydride which has been industrialized by using V-P mixed oxide catalysts has been reviewed in more detail. V-P mixed oxide having P/V ratio of 1 - 1.2 have often been claimed as active catalysts. Hovever, by comparing the catalysis of crystalline phases with P/V = 1 (α-, β-VOPO4, etc.), it has been indicated that crystalline (VO) 2P2O7 is the effective phase. Its structural and redox characteristics are discussed based on the recent literature.

ChemInform Abstract: Identification of Active Oxide Ions in a Bismuth Molybdate Selective Oxidation Catalyst.

Direct structural identification of catalytically active oxide ions for selective olefin oxidation has been achieved using in situ Raman spectroscopy. Spectroscopic examination of Bi2MoO6 reduced with select probe molecules such as but-1-ene, propene, methanol and ammonia, when reoxidized with oxygen-18, establishes the existence of the multifunctional nature of catalyst active site for propene oxidation and ammoxidation, wherein α-H abstraction occurs by oxide ions bridging bismuth and molybdenum atoms (Bi—O—Mo), and oxygen or NH insertion into the π-allylic intermediate occurs at centres associated with molybdenum. Sites for O2 chemisorption, reduction and dissociation are likely to be associated with the directed lone pairs of electrons of the Bi—O—Bi species in the structure. Pulse kinetic experiments reveal that diffusion of the oxide ions through the bulk of the catalyst is the rate-limiting step in catalyst reoxidation. This process is rapid when an oxide ion of only one functional type, i.e.α-H abstraction or oxygen insertion, is removed. The process becomes less facile when oxide ions associated with both α-H abstraction and oxygen insertion are removed from the catalyst. The relative rates reflect the extent of active-site reconstruction achieved by diffusion of oxide ions from the bulk to the surface of the catalyst.

Selectivity and activity factors in bismuth-molybdate oxidation catalysts

Selective catalytic oxidation and ammoxidation of olefins to the corresponding diolefins, unsaturated aldehydes, acids and nitriles accounts for about one-fourth of the industrial chemicals produced by allylic oxidation processes. Selectivity and activity in these processes is achieved by means of catalysts in which key catalytic functions are optimized in a single phase of a multi-phase mixed metal oxide. Such catalysts contain active sites capable of olefin chemisorption, ammonia activation, alpha hydrogen abstraction to generate an allylic intermediate, oxygen and NH insertion into the allylic intermediate, lattice oxygen migration from the bulk to the surface active sites, and dioxygen reduction and incorporation of oxide ions into anion vacancies of the catalyst structure. Bismuth molybdates are one such class of materials which contain all of the key catalytic features to affect selective olefin oxidation and ammoxidation of olefins. The design of effective catalysts is based on a molecular level understanding of surface atomic composition, phase composition of the bulk, oxidation states of the materials and defect structure of the solid phases.

Identification of active oxide ions in a bismuth molybdate selective oxidation catalyst

Direct structural identification of catalytically active oxide ions for selective olefin oxidation has been achieved using in situ Raman spectroscopy. Spectroscopic examination of Bi2MoO6 reduced with select probe molecules such as but-1-ene, propene, methanol and ammonia, when reoxidized with oxygen-18, establishes the existence of the multifunctional nature of catalyst active site for propene oxidation and ammoxidation, wherein α-H abstraction occurs by oxide ions bridging bismuth and molybdenum atoms (Bi—O—Mo), and oxygen or NH insertion into the π-allylic intermediate occurs at centres associated with molybdenum. Sites for O2 chemisorption, reduction and dissociation are likely to be associated with the directed lone pairs of electrons of the Bi—O—Bi species in the structure. Pulse kinetic experiments reveal that diffusion of the oxide ions through the bulk of the catalyst is the rate-limiting step in catalyst reoxidation. This process is rapid when an oxide ion of only one functional type, i.e.α-H abstraction or oxygen insertion, is removed. The process becomes less facile when oxide ions associated with both α-H abstraction and oxygen insertion are removed from the catalyst. The relative rates reflect the extent of active-site reconstruction achieved by diffusion of oxide ions from the bulk to the surface of the catalyst.

Activation of molecular oxygen and selective oxidation of olefins catalyzed by group VIII transition metal complexes

Abstract

The functions of redox couples in catalysts for the selective oxidation of olefins

Data obtained from the oxidation-reduction reactions of some metal cations in aqueous solutions, Me n+ I + Me z+ II → Me (n + 1)+ I + Me (z−1)+ II can give valuable indications that such redox couples also operate in metal oxide catalysts such as Bi 2MoO 6 and Fe 2(MoO 4) 3 and in multicomponent molybdate catalysts such as Fe-Bi molybdates and Co-Fe-Bi molybdates.

Selective Oxidation of Alkanes and Ethers with Iodine Tris(trifluoroacetate)

Angewandte Chemie International Edition in EnglishVolume 15, Issue 7 p. 436-436 Communication Selective Oxidation of Alkanes and Ethers with Iodine Tris(trifluoroacetate)† Priv.-Doz. Dr. Joachim Buddrus, Priv.-Doz. Dr. Joachim Buddrus Institut für Spektrochemie und Angewandte Spektroskopie, Postfach 778, 4600 Dortmund 1 (Germany)Search for more papers by this authorDipl.-Chem. Horst Plettenberg, Corresponding Author Dipl.-Chem. Horst Plettenberg Institut für Spektrochemie und Angewandte Spektroskopie, Postfach 778, 4600 Dortmund 1 (Germany)Institut für Spektrochemie und Angewandte Spektroskopie, Postfach 778, 4600 Dortmund 1 (Germany)Search for more papers by this author Priv.-Doz. Dr. Joachim Buddrus, Priv.-Doz. Dr. Joachim Buddrus Institut für Spektrochemie und Angewandte Spektroskopie, Postfach 778, 4600 Dortmund 1 (Germany)Search for more papers by this authorDipl.-Chem. Horst Plettenberg, Corresponding Author Dipl.-Chem. Horst Plettenberg Institut für Spektrochemie und Angewandte Spektroskopie, Postfach 778, 4600 Dortmund 1 (Germany)Institut für Spektrochemie und Angewandte Spektroskopie, Postfach 778, 4600 Dortmund 1 (Germany)Search for more papers by this author First published: July 1976 https://doi.org/10.1002/anie.197604361Citations: 28 † This work was supported by the Deutsche Forschungsgemeinschaft. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume15, Issue7July 1976Pages 436-436 RelatedInformation

Quantum-chemical calculations of π-allyl complexes of Co, Ni, Fe and Mg as intermediates in the selective oxidation of propylene

Quantum-chemical calculations of the charge distribution and electronic configuration of π-allyl complexes of Co, Ni, Fe and Mg in the presence of an octahedral arrangement of oxygen ions, as apparently exists as an initial intermediate in the selective oxidation of propylene, show that in these Co 2+, Ni 2+ Fe 2+ and Mo 6+ complexes there is a considerable shift of the π-allyl electrons to the metal with the positive charge appearing at the allyl ligand, whilst in the case of the Mg 2+ complex the allyl ligand remains neutral indicating a very weak bonding arrangement. Measurements of the catalytic activity of isostructural molybdates of Co 2+, Ni 2+ and Mg 2+ show that in the presence of the first two molybdates propylene is selectively oxidized whereas the Mg 2+ molybdate is completely inactive. From this it may be concluded that the ability of a given cation to bind the π-allyl ligand is a necessary condition for the activity of a particular molybdate in the selective oxidation of olefins.