Catalytic wet peroxide oxidation of phenol over AlFe-pillared montmorillonite

Catalytic wet peroxide oxidation of phenol over AlFe-pillared montmorillonite was carried out at room temperature, in a glass batch reactor, under constant airflow at day and UV light, alternatively. At higher concentration of phenol in water solution the efficiency of heterogeneous pillared clay catalyst was significantly lower than the efficiency of homogeneous iron catalyst. This revised version was published online in June 2006 with corrections to the Cover Date.     

Catalytic properties of Ni/ceria-yttria electrode materials for partial oxidation of methane

The catalytic properties of electrode materials Ni/Ce1-xYxO2-δ (x = 0.05, 0.10, 0.15 and 0.20) were investigated for partial oxidation of methane (POM). The CeO2-Y2O3 solid solutions were prepared by co-precipitaion method. The Ni-based catalysts supported on the solid solutions were obtained using the impregnation method. Structural, surface and redox characteristics of the prepared catalysts were systematically examined by means of X-ray diffraction (XRD), N2 adsorption-desorption (Brunauer-Emmet-Teller BET method), H2 temperature-programmed reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS) methods. The results indicated that yttria doped in the ceria system, forming a good solid solution, readily induced more defects and oxygen vacancies that favored the improvement of catalytic activity and coking resistance. In the temperature range of 600-850 ℃, Ni/Ce0.90Y0.10O1.95 catalyst exhibited the best catalytic activity among the four tested catalysts, with the CH4 conversion, CO selectivity and H2 selectivity of 78.8%, 90.6% and 89.8%, respectively, at 850 ℃. And the H2/CO molar ratio in products of Ni/Ce0.90Y0.10O1.95 catalyst was closer to the theoretical value of 2.0. The excellent coking resistant behaviors for all catalysts were clearly manifested by Thermal Analysis.     

Catalytic properties of ferrites in oxidation reactions

Catalytic activities of ferrites MFe₂O₄ (M = Cu, Co, Ni, Mg, and Zn) and M¹ _0.5M² _{0 .5}Fe₂O₄ (M¹ = CU; M² = Co, Zn, and Mg) in oxidation of CO and ethylbenzene were investigated, and their dependences on the cation nature were established. Higher activities were observed for catalysts containing ions with variable valence (Cu, Co, and Ni). A correlation between catalytic and adsorption properties of ferrites was found.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 49–52, January, 1996.     

Cu-Ce/AC吸附-催化剂对所吸附苯酚的催化氧化行为的研究

对活性炭载氧化铜和氧化铈（Cu-Ce/AC）吸附 催化剂在连续吸附-催化氧化苯酚循环过程中的催化氧化活性和失活原因进行了研究。结果表明,Cu-Ce/AC的苯酚吸附性能和催化氧化活性随着吸附 催化氧化循环次数的增加而逐渐降低,经5次循环后,苯酚的初始氧化温度提高约25℃。通过对使用过的Cu Ce/ACs进行XPS、ICP分析, 发现Ce和Cu的流失较小,苯酚残留物覆盖表面Ce和Cu是苯酚催化氧化活性降低的主要原因,残留物主要含有C-O-C和C-OH等官能团。     

Catalytic properties of silica-molybdenum catalysts in propylene oxidation

The activity of silica-molybdenum catalyts in propylene oxidation is shown to be determined by the partially dehydrated silica-molybdenum heteropolyacid stabilized by the SiO₂ surface.

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Catalytic ethoxylation of phenol and phenol derivatives

The kinetics of catalytic mono- and polyethoxylation of phenol, p-cumyl-phenol and p-isooctylphenol have been studied in the presence of strongly basic anion exchanger Wofatit SBW in hydroxy form. The influence of substituents on the rate has been investigated and the mechanism of the reaction is discussed.

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- , - Wofqtit SBW . .

     

Catalytic oxidation of phenol in the presence of iron-containing composites based on silicon and boron nitrides

Sorption and catalytic activities of iron-containing composites based on silicon and boron nitrides in purification of aqueous solutions to remove phenol under ozonation and UV irradiation in the presence of oxalic acid and hydrogen peroxide additives was studied.     

Catalytic properties of spinel-type complex oxides in oxidation reactions

The catalytic activity of M^IM^II ₂O₃ spinel-type complex oxides (M^I = Cu, Ni, Mn, Zn, Mg, Co, M^II = Co, Cr, Al) in the oxidation of CO and ethylbenzene has been investigated. The Co-containing catalysts were more active than the Cr- and Al-containing catalysts. The nature of the cation influenced the catalytic activity. Higher activities were observed for the catalysts containing two transition elements. A correlation between the catalytic and adsorption properties was established.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1730–1732, October, 1994.     

Catalytic properties of manganites in the oxidation of CO and hydrocarbon

Manganites with a spinel structure MMn₂O₄ (M = Co, Cu, Zn, Mo) and M¹ _0.5M² _0.5 Mn₂O₄ (M = Co, Cu, Zn, Mg) have been synthesized and tested in the catalytic oxidation of CO, C₃H₆, and ethylbenzene. The dependence of the catalytic activity of the manganites on the nature of the cation has been established. The spinels containing transition metal ions (Cu, Co) are more active. A relation between catalytic and adsorption properties of manganites has been established. The participation of the lattice oxygen in the oxidation of CO to CO₂ has been found. The mechanism of the oxidation is discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No, 11, pp, 2686–2669. November, 1996.     

Catalytic properties of the carbides of transition metals in oxidation reactions

It was shown that the carbides of transition metals are effective catalysts of oxidation reactions on account of their metal-like nature, combined with their high chemical and thermal stability. The results from systematic investigations into the catalytic characteristics of the carbides in the oxidation of hydrogen, carbon monoxide, and ammonia and in the oxidative coupling of methane (OCM) are examined. The first two reactions are total oxidation processes, and the oxidation of ammonia is a selective oxidation process. The oxidative coupling of methane is a heterogeneous-homogeneous process and represents a prospective method for the direct transformation of methane into higher hydrocarbons. L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Prospekt Nauki, Kiev 252039, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 34, No. 5, pp. 265–281, September–October, 1998.     

Catalytic methylation of phenol

Attempt was made to methylate phenol with methyl formate in the presence of a zeolite-supported palladium and a ruthenium-titanium catalyst.     

Catalytic properties of the vanadium-molybdenum oxide system for acrolein oxidation

The catalytic properties and phase composition of the silica-supported vanadium-molybdenum oxide system have been studied in acrolein oxidation. The active component of the catalyst is the compound VMo₃O_11+x, whose maximum content is observed in the compositions range of 10–15 mol.% V₂O₅ –90–95 mol.% MoO₃.

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, SiO₂. VMo₃O_11+x, 10–15 .% V₂O₅÷90–85 .% MoO₃.

     

Catalytic properties of oxides in vapor phase oxidation of acetone

The temperature dependences of the rate of oxidation of acetone vapors by oxygen on oxide surface catalysts: V₂O₅, Co₃O₄., MoO₃ and TiO₂ (rutile), and the industrial catalyst VKSh were determined. A series of the catalytic activity of the above surface catalysts was established. The relationship between the catalytic properties of the oxides in the oxidation of acetone and their redox and acid-base characteristics was analyzed. The catalytic activity of the oxides in the oxidation reaction of acetone and methanol were compared.Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 24, No. 1, pp. 114–117, January–February, 1988.     

Catalytic properties of the macromolecular polyoxomolybdate cluster in selective oxidation of sulfides

The catalytic properties of the iron-containing Keplerate [H₄Mo₇₂Fe₃₀O₂₅₄(CH₃COO)₁₀-Mo₂O₇(H₂O)H₂Mo₂O₈(H₂O)₃(H₂O)₈₇] • (~80)H₂O (1) in the selective liquid-phase oxidation of thio ethers were studied. Compound 1 shows high catalytic activity and selectivity in the oxidation of organic sulfides to sulfoxides when hydrogen peroxide and tert-butyl hydroperoxide are used as oxidants.     

Catalytic wet peroxide oxidation of phenol over pillared clays containing iron or copper species

The catalytic wet oxidation of phenol by hydrogen peroxide in the presence of oxygen is catalysed, at room temperature, by copper or iron homogeneous species at pH 5 or 3.5, respectively. In such conditions phenol mild oxidation is mainly observed, the total phenol oxidation to CO₂ (TOC abatement) not exceeding 20 %. In similar experimental conditions, Fe, Al or Cu, Al pillared clays (FAZA or CAZA) are much more active, the phenol or the TOC conversion being directly related to the iron or copper content. Moreover, in the presence of iron containing pillared clay (FAZA), the TOC abatement can reach 80 % at 70 °C, with only a H₂O₂ stoichiometric excess equal to 1.5. The low iron leaching (less than 0.2 % of the total amount of iron in the catalyst) observed after a standard experiment (4 h) shows that the FAZA catalyst is highly stable in water media and could be used several consecutive times. These properties could result in the iron species stabilization in the interlamellar space of the pillared clays both by bonding with the Al pillars (60 % of the iron species) or as oxide clusters dispersed between the clay layers.     

Silylation effect on the catalytic properties of FeZSM-11 in benzene oxidation to phenol

The outer surface of FeZSM-11 zeolite was selectively silylated without affecting the inner system of its channels. SiO₂ deposition suppressed both the acidity and catalytic activity of the outer surface in mesitylene isomerization. Neither zeolite activity, nor its stability in N₂O benzene oxidation to phenol have changed upon silylation. This fact gives evidence that the latter reaction proceeds primarily within the zeolite channels.     

Catalytic properties of antimony-SBA-15 materials in the benzylation of aromatics reactions

Antimony-containing mesoporous SBA-15 with different Si/Sb ratio has been synthesized using a post-treatment procedure with an aqueous solution of SbCl₃ and characterized by elemental analysis, XRD method, N₂ adsorption measurements (BET and BJH theory) and FTIR spectroscopy. The benzylation of aromatics by benzyl chloride has been investigated over these solids. Indeed, the antimony-containing mesoporous SBA-15 showed both high activity and high selectivity for this reaction. More interesting is the observation that Sb-SBA-15 (35) catalyst is active and selective for large molecules like naphthenic compounds such as 2-methylnaphthalene and it can also be reused in the benzylation of benzene for several times. Kinetics of the benzene benzylation over these catalysts have also been investigated. Published in Russian in Kinetika i Kataliz, 2009, vol. 50, no. 3, pp. 428–433. The article is published in the original.     

Catalytic activities of polymer‐supported metal complexes in oxidation of phenol and epoxidation of cyclohexene

The metal complexes of N, N′‐bis (o‐hydroxy acetophenone) propylene diamine (HPPn) Schiff base were supported on cross‐linked polystyrene beads. The complexation of iron(III), copper(II), and zinc(II) ions on polymer‐anchored HPPn Schiff base was 83.4, 85.7, and 84.5 wt%, respectively, whereas the complexation of these metal ions on unsupported HPPn Schiff base was 82.3, 84.5, and 83.9 wt%. The iron(III) complexes of HPPn Schiff base were octahedral in geometry, whereas copper(II) and zinc(II) ions complexes were square planar and tetrahedral. Complexation of metal ions increased the thermal stability of HPPn Schiff base. Catalytic activity of metal complexes was tested by studying the oxidation of phenol and epoxidation of cyclohexene in the presence of hydrogen peroxide. The polymer‐supported HPPn Schiff base complexes of iron(III) ions showed 73.0 wt% conversion of phenol and 90.6 wt% conversion of cyclohexene at a molar ratio of 1:1:1 of substrate to catalyst and hydrogen peroxide, but unsupported complexes of iron(III) ions showed 63.8 wt% conversion for phenol and 83.2 wt% conversion for cyclohexene. The product selectivity for catechol (CTL) and epoxy cyclohexane (ECH) was 93.1 and 98.3 wt%, respectively with supported HPPn Schiff base complexes of iron(III) ions but was lower with HPPn Schiff base complexes of copper(II) and zinc(II) ions. Activation energy for the epoxidation of cyclohexene and phenol conversion with unsupported HPPn Schiff base complexes of iron(III) ions was 16.6 kJ mol^?1 and 21.2 kJ mol^?1, respectively, but was lower with supported complexes of iron(III) ions. Copyright © 2007 John Wiley & Sons, Ltd.     

Catalytic properties of Ti?Mo oxide catalysts in propylene oxidation

Catalytic properties of Ti–Mo oxide catalysts are shown to be determined to a great extent by the Ti–Mo heteropoly acid anchored to the TiO₂ surface which is formed during the catalyst preparation.

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Catalytic conversion of benzene to phenol

Phenol is very useful intermediate in the manufacture of petrochemicals, drugs, agrochemicals, and plastics. Commercially, phenol is produced by a three-step, high-energy consumption process known as the cumene process. The conversion of a chemical to a value-added product is always economically desirable. More than 90% of phenol consumption in the world is manufactured by the multistep cumene process, in which acetone is coproduced in 1: 1 molar ratio with respect to phenol. However, the drawbacks of the three-step cumene process have spurred the development of more economical routes to decrease energy consumption, avoid the formation of explosive cumene hydroperoxide, and increase the yield. The objective of this article is to highlight benzene-to-phenol conversion technologies with emphasis on direct conversion methods. Gas phase and liquid phase reactions are the two main routes for direct oxidation of benzene to phenol. Indirect methods, such as the cumene process, and direct methods of benzene-to-phenol conversion are discussed in detail. Also discussed is the single-step reaction of benzene to phenol using oxidants such as O₂, N₂O, and H₂O₂. Catalytic conversion of benzene to value-added phenol using a chemically converted graphene-based catalyst, a cost-effective carbon material, is discussed.