Showing papers on "Mixed oxide published in 1976"
TL;DR: In this paper, a method of preparation of aerogels of SiO2, Al2O3, TiO2 and mixed oxides has been developed, which does not require the purification of the precipitated metal oxide nor the substitution of an organic solvent for water which is the case when the formation of the initial gel is carried out in water medium.
262 citations
TL;DR: In this paper, the amounts of both the acidic and basic sites of two series of catalysts, TiO2-MoO3 and TiO 2-V2O5, with different compositions were measured by studying the adsorption of the basic and acidic molecules in the gas phase, using both the static and pulse methods.
Abstract: The amounts of both the acidic and basic sites of two series of catalysts, TiO2–MoO3 and TiO2–V2O5, with different compositions were measured by studying the adsorption of the basic and acidic molecules in the gas phase, using both the static and pulse methods. The acidity of TiO2–MoO3 catalysts is very high at Mo=40–60 atom%, though those of the TiO2-rich (Mo 80 atom%) catalysts are fairly low. The acidity of the TiO2–V2O5 increases steadily with the V2O5 content. The basicity of the catalysts is remarkably enhanced by the introduction of a small amount of MoO3 or V2O5. It can be said that the catalysts are basic at Mo<20 atom% or V<10 atom%, while the MoO3-rich or V2O5-rich catalysts are acidic. The vapor-phase oxidation of 1-butene, butadiene,and acetic acid, the dehydration and dehydrogenation of isopropyl alcohol (IRA), and the isomerization of 1-butene were carried out in the presence of an excess of air, and the relationship between the catalytic behavior and the acid-ba...
97 citations
TL;DR: In this article, the oxidation of polycrystalline samples of Fe/Ni alloys at 500°C has been studied by means of Auger electron spectroscopy (AES) and soft X-ray appearance potential spectrographs (APS).
41 citations
Patent•
22 Nov 1976
TL;DR: In this article, the authors describe a catalyst capable of inducing reduction in nitrogen oxide pollutants of exhaust gases from internal combustion engines and industrial plants, which is formed from a mixture of catalytically active aluminum oxides and a mixture with at least two metal oxides, one which is chromium oxide and the other is an oxide of an element of the First Transition Series.
Abstract: A catalyst is described capable of inducing reduction in nitrogen oxide pollutants of exhaust gases from internal combustion engines and industrial plants. The catalyst composition is formed from a mixture of catalytically active aluminum oxides and a mixture of at least two metal oxides, one which is chromium oxide and the other is an oxide of an element of the First Transition Series, impregnated with about 1% by weight of an impregnant comprising a catalytically active noble metal compound. An optional constituent of the catalyst compositions includes 0.5-10% by weight of beryllium, magnesium, calcium, strontium or barium in the mixed oxide composition.
29 citations
CSAV1
TL;DR: In this article, the interaction of propene and H218O in the absence of gaseous oxygen was studied on a Mo−W−Sn−Te−O catalyst prepared for the production of acrylic acid.
Abstract: The interaction of propene and H218O in the absence of gaseous oxygen was studied on a Mo−W−Sn−Te−O catalyst prepared for the production of acrylic acid. The flow reactor working at low pressures was placed close to the ion source of the mass spectrometer. It was found that the formation of an acrolein-lattice oxygen complex is an intermediate step in the formation of acrylic acid. The acrolein type complex reacts further with oxygen from water to give acrylic acid. Evidence was found for the formation of unstable products from water on mixed oxide catalysts of molybdate type.
11 citations
Patent•
13 Apr 1976TL;DR: In this article, a process for selectively ortho-alkylating a phenolic compound which comprises reacting the phenolic compounds with an alkanol in the presence of a copper-zinc-aluminum mixed oxide catalyst is described.
Abstract: A process for selectively ortho-alkylating a phenolic compound which comprises reacting the phenolic compound with an alkanol in the presence of a copper-zinc-aluminum mixed oxide catalyst.
8 citations
TL;DR: The dielectric function and refractive index of an anodically grown mixed oxide on GaSb have been measured ellipsometrically from 1.5 to 6.0 eV as discussed by the authors.
Abstract: The dielectric function and refractive index of an anodically grown mixed oxide on GaSb have been measured ellipsometrically from 1.5 to 6.0 eV. The absorption edge was determined to occur at 4.2 eV, with a weak tail extending to 3.7 eV.
7 citations
Patent•
03 Jul 1976
TL;DR: In this article, the molar ratio of Mn:Pb can be 1000:1 to 1:1000, where pptd is the saturation concn of a mixture of Mn and Pb.
Abstract: Electrochemically and catalytically active substance is produced by introducing O3 into an aq. soln. contg. (CH3COO)2Mn and (CH3COO)2Pb at 70 degrees C or more, whereby a mixed dioxide of Mn and Pb is precipitated. A Mn-Pb dioxide is much more active than the same quantity of physically mixed MnO2 and PbO2. Specifically, the molar ratio Mn:Pb can be 1000:1 to 1:1000. The total concn. of Mn (II) and PB(II) acetates in the aq. soln. is between 2 wt.% and the saturation concn. The O3 concn. is 20% w.r.t. the soln. The pptd. mixed Mn-Pb dioxide is washed and dried at 120 degrees C in the air or at 70 degrees C under vacuum. The mixed oxide can be additionally treated with conc. HNO3, pref. at the boiling temp. The starting soln. may contain up to 1% of an acetate of Na, K, Li, Co, NH4, Ag, Ni, Cu or Cr which promotes the reaction.
3 citations
TL;DR: In this article, the synthesis methods for mixed oxide catalysts are classified based on solid-solid reactions, gas-solid reaction, liquid-solid reactivity, and liquid-decomposition.
Abstract: Publisher Summary This chapter discusses the synthesis methods for mixed oxide catalysts Methods of preparing mixed oxides could be classified based on solid–solid reactions, gas–solid reactions, liquid–solid reactions, and others Solid–solid reaction method consists of carefully mixing simple oxides or oxide precursors in proportions corresponding to the mixed oxides required The mixture is ground either dry or in the presence of water A succession of calcination and grinding operations produces the mixed oxide sought after This method requires temperatures higher than 1000°C to be used It results in dense and relatively undivided products, and so it is not very frequently used in catalysis Examples of preparing mixed oxides by a gas–solid reaction have to do only with research projects, except for applications in electronics This method may also involve the thermal decomposition of mixed alkoxides or mixed chlorides Liquid–solid reactions are the main way of producing mixed oxides and mixed-oxide base catalysts They all attempt, by either a physical or a chemical method, to produce a precursor that is an intermediate solid compound having the composition sought after in the end catalyst
3 citations
Patent•
09 Nov 1976TL;DR: In this paper, the authors describe catalysts which may be used in the purification of air and other gaseous media, in particular in the decomposition of one or more of the oxides of nitrogen comprising a mixed oxide of iron and cobalt selected from the group consisting of (a) Co x II FE 1-x II Fe 2 III O 4 where x normally has values of o≦x≦1 and (b) Co II Co.sub.sub.(x-1) III Fe.
Abstract: This invention relates to catalysts which may be used in the purification of air and other gaseous media. More particularly, the invention relates to catalysts which may be used in the decomposition of one or more of the oxides of nitrogen comprising a mixed oxide of iron and cobalt selected from the group consisting of (a) Co x II FE 1-x II Fe 2 III O 4 where x normally has values of o≦x≦1 and (b) Co II Co.sub.(x-1) III Fe.sub.(3-x) III O 4 where x normally has values 1≦x≦3.
3 citations
Patent•
14 Dec 1976
01 Jan 1976
TL;DR: In this paper, the authors studied how the hydrogen reduction of nickel ferrites at 1000/sup 0/C is affected by the presence of 3.5 cation mole % aluminum in solid solution.
Abstract: When oxide ceramics are used in a hydrogen environment at elevated temperatures they will be reduced at a rate which can depend on a variety of parameters. The presence of minor amounts of alloying elements, e.g., can significantly alter the reduction rate. Since practical oxide ceramics generally contain mixed oxides of two or more metals, an understanding of the reduction behavior of mixed oxides, as well as an understanding of the effects of minor alloying elements in this, is important as a guide to extending the usefulness of oxide ceramics, and may serve to help in selecting raw materials that contain elements beneficial in improving resistance to reduction. In this paper, how the hydrogen reduction of nickel ferrites at 1000/sup 0/C is affected by the presence of 3.5 cation mole % aluminum in solid solution is studied.
TL;DR: The characteristics of Fe-Bi-P mixed oxide catalysts of different compositions for reduction by propylene or ammonia and the ammoxidation activities of propylene were studied using a McBain type thermobalance and the pulse reaction technique respectively.
Abstract: The characteristics of Fe-Bi-P mixed oxide catalysts of different compositions for reduction by propylene or ammonia and the ammoxidation activities of propylene were studied using a McBain type thermobalance and the pulse reaction technique respectively. By comparing the dependency of the reduction characteristics and catalytic activity with oxide composition and also the reduction rates and reoxidation rates of the reduced catalyst it was concluded that the ammoxidation of propylene on Fe-Bi-P mixed oxide catalyst proceeds through alternate repetition of reduction by propylene and reoxidation by oxygen, and that abstraction of allylic hydrogen from adsorbed C3H6 is the rate determining step.
Patent•
18 Mar 1976
TL;DR: In this paper, a dark coating on the surface of a heating element with an insulating layer for electron tube cathodes, in which a metal oxide suspension is applied to the surface and the metal oxide is then reduced to a dark metal by high temp. thermal treatment in a H2 atmos.
Abstract: In the prodn. of a dark coating on the surface of a heating element with an insulating layer for electron tube cathodes, in which a metal oxide suspension is applied to the surface of the insulating layer and the metal oxide is then reduced to a dark metal by high temp. thermal treatment in a H2 atmos., the suspension used is alkali-free to a high degree, esp. with a purity of 2 x 10-4 g alkali ions/g. Dark coatings with good adhesion and high insulation props. are obtd. The heating element with the dark coating is dipped in a silicic ester hydrolysed with water and acid, esp. Si(OEt)4 or Si(OMe)4, and then heated to 100-1000 degrees C in air, vacuo or a H2 atmos. The metal, e.g. Fe, Ni, Co, Cr and esp. Mo, is pptd. from its salt with an Al salt from aq. soln. with NH4OH, then calcined in air to the mixed oxide and reduced in H2 to a black powder, before or after coating on the heating coil. Alternatively, an alkali-free suspension is prepd. by dissolving salts or oxides of Fe, Ni, Co, Cr, Mo or esp. H2WO4 in a melt of an Al salt, esp. Al2(NO3)3.9H2O, calcined in air to the mixed oxide and reduced in H2. The insulating layer to which the dark coating is applied consists of Al2O3.