A method is described of producing a catalyst-containing composite oxygen ion membrane and a catalyst-containing composite oxygen ion membrane in which a porous fuel oxidation layer and a dense separation layer and optionally, a porous surface exchange layer are formed on a porous support from mixtures of (Ln.sub.1?xA.sub.x).sub.wCr.sub.1?yB.sub.yO.sub.3?? and a doped zirconia. Adding certain catalyst metals into the fuel oxidation layer not only enhances the initial oxygen flux, but also reduces the degradation rate of the oxygen flux over long-term operation. One of the possible reasons for the improved flux and stability is that the addition of the catalyst metal reduces the chemical reaction between the (Ln.sub.1?xA.sub.x).sub.wCr.sub.1?yB.sub.yO.sub.3?? and the zirconia phases during membrane fabrication and operation, as indicated by the X-ray diffraction results.

A process for producing a catalyst having a heating element that is formed from an electrically conductive metal alloy. In the production process, the catalyst undergoes at least a first heat treatment, during which the catalyst is at least partly heated in defined fashion and cooled in a defined fashion. The steps include heating at least a subregion of the catalyst to a predeterminable temperature of at least 550 degrees celsius, holding the temperature at a constant temperature level for at least two minutes, and cooling the at least one subregion of the catalyst at a temperature transient of at least 500 Kelvin per minute.

A fluorination catalyst such as a chromium oxide-based fluorination catalyst may be activated or reactivated by contacting the catalyst. with a source of reactive fluorine, for example nitrogen trifluoride (NF3) or fluorine (F2). Fluorinated compounds may be prepared by the gas phase reaction of hydrogen fluoride (HF) with various substrates such as chlorinated compounds. A number of metal oxide-based catalysts have been developed for this purpose.

A fluorination catalyst such as a chromium oxide-based fluorination catalyst may be activated or reactivated by contacting the catalyst. with a source of reactive fluorine, for example nitrogen trifluoride (NF3) or fluorine (F2). Fluorinated compounds may be prepared by the gas phase reaction of hydrogen fluoride (HF) with various substrates such as chlorinated compounds. A number of metal oxide-based catalysts have been developed for this purpose.

[Problem] There are provided: a reducing agent in which, in a perovskite oxide, when a combination of metal elements, a composition ratio thereof and the like are set, the amount of carbon dioxide is sufficiently reduced, the efficiency of converting carbon dioxide into valuables containing carbon (that is, a yield of valuables containing carbon) is high, and the efficiency of reduction using hydrogen is high; and a method of producing a gas using such a reducing agent.

[Solution] The reducing agent of the present invention produces valuables containing carbon by reduction of carbon dioxide and is easily reduced using hydrogen. The reducing agent contains an oxygen carrier having a perovskite type crystalline structure represented by a composition formula: ABO.sub.x (x is a real number of 2 to 4) and having oxygen ion conductivity, the A-site element includes at least one of metal elements belonging to Group 1 to Group 3 in the periodic table, the B-site element includes at least one metal element different from the A-site element, and when the electronegativity of the A-site element is A?, the electronegativity of the B-site element is B?, and the temperature at which carbon dioxide is brought into contact with the reducing agent is T(K), relationships of A?<B? and 10.sup.4?[(B??A?)/T]<8.31 are satisfied.

[Problem] There are provided: a reducing agent in which, in a perovskite oxide, when a combination of metal elements, a composition ratio thereof and the like are set, the amount of carbon dioxide is sufficiently reduced, the efficiency of converting carbon dioxide into valuables containing carbon (that is, a yield of valuables containing carbon) is high, and the efficiency of reduction using hydrogen is high; and a method of producing a gas using such a reducing agent.

[Solution] The reducing agent of the present invention produces valuables containing carbon by reduction of carbon dioxide and is easily reduced using hydrogen. The reducing agent contains an oxygen carrier having a perovskite type crystalline structure represented by a composition formula: ABO.sub.x (x is a real number of 2 to 4) and having oxygen ion conductivity, the A-site element includes at least one of metal elements belonging to Group 1 to Group 3 in the periodic table, the B-site element includes at least one metal element different from the A-site element, and when the electronegativity of the A-site element is A?, the electronegativity of the B-site element is B?, and the temperature at which carbon dioxide is brought into contact with the reducing agent is T(K), relationships of A?<B? and 10.sup.4?[(B??A?)/T]<8.31 are satisfied.

A process is described for increasing the hydrogen content of a synthesis gas mixture comprising hydrogen, carbon oxides and steam, comprising the steps of: passing the synthesis gas mixture at an inlet temperature in the range 170-500 C. over a water-gas shift catalyst to form a hydrogen-enriched shifted gas mixture, wherein the water-gas shift catalyst is in the form of a cylindrical pellet having a length C and diameter D, wherein the surface of the cylindrical pellet has two or more flutes running along its length, said cylinder having no through-holes and domed ends of lengths A and B such that (A+B+C)/D is in the range 0.25 to 0.25, and (A+B)/C is in the range 0.03 to 0.30.

In the production of hydrogen peroxide, when ketone forms are increased upon conversion from higher alcohol components in organic solvents, such increased levels of ketone forms reduce the water content in a working solution and lead to deterioration of catalytic activity. Moreover, increased levels of ketone forms reduce the solubility of anthrahydroquinone compounds and may cause an obstacle to stable and safe operation in the production of hydrogen peroxide due to crystallization and deposition of the anthrahydroquinone compounds. The object of the present invention is to provide a process in which polar solvent-derived altered substances (ketone forms) in a working solution provided for use in the production of hydrogen peroxide via the anthraquinone process are regenerated into the original alcohol components to thereby improve the production efficiency of hydrogen peroxide. From a working solution which has been used for many years, organic solvent components containing ketone forms are separated by distillation and hydrogenated in the presence of a metal catalyst to regenerate the organic solvent components into the original alcohol components, whereby hydrogen peroxide can be produced more efficiently.

The present invention provides a process for preparing 2,3,3,3-tetrafluoropropene from 1,1,1,2,3-pentachloropropane and/or 1,1,2,2,3-pentachloropropane, comprising the following steps: (a) catalytic reaction of 1,1,1,2,3-pentachloropropane and/or 1,1,2,2,3-pentachloropropane with HF into a reaction mixture comprising HCl, 2-chloro-3,3,3-trifluoropropene, 2,3,3,3-tetrafluoropropene, unreacted HF, and optionally 1,1,1,2,2-pentafluoropropane; (b) separating the reaction mixture into a first stream comprising HCl and 2,3,3,3-tetrafluoropropene and a second stream comprising HF, 2-chloro-3,3,3-trifluoropropene and optionally 1,1,1,2,2-pentafluoropropane; (c) catalytic reaction of the second stream into a reaction mixture comprising 2,3,3,3-tetrafluoropropene, HCl, unreacted 2-chloro-3,3,3-trifluoropropene, unreacted HF and optionally 1,1,1,2,2-pentafluoropropane and (d) feeding the reaction mixture of step (c) directly without separation to step (a).

Provided are particle size-controlled, chromium oxide particles or composite particles of iron oxide-chromium alloy and chromium oxide; a preparation method thereof; and use thereof, in which the chromium oxide particles or the composite particles of iron oxide-chromium alloy and chromium oxide having a desired particle size are prepared in a simpler and more efficient manner by using porous carbon material particles having a large pore volume as a sacrificial template. When the chromium oxide particles or the composite particles of iron oxide-chromium alloy and chromium oxide thus obtained are applied to gas-phase and liquid-phase catalytic reactions, they are advantageous in terms of diffusion of reactants due to particle uniformity, high-temperature stability may be obtained, and excellent reaction results may be obtained under severe reaction environment.