An exhaust gas-purifying catalyst includes a support and a catalytic metal as one or more precious metals supported by the support. The support includes a composite oxide having a composition represented by a general formula AB.sub.C.sub.O.sub.3, wherein A represents one or more elements selected from the group consisting of lanthanum, neodymium, and yttrium, B represents iron or a combination of iron and aluminum, C represents one or more elements selected from the group consisting of iridium, ruthenium, tantalum, niobium, molybdenum, and tungsten, and each represents a numerical value within a range of more than 0 and less than 1, and and satisfy relational formulae of > and +1.

An apparatus for producing a mixed solution, comprising a mixing vessel for preparing an aqueous mixed solution containing a dicarboxylic acid and an Nb compound and a filter for the aqueous mixed solution connected to the mixing vessel via a pipe, the mixing vessel being anticorrosive and equipped with a stirring unit, a heating unit and a cooling unit for the aqueous mixed solution, wherein the aqueous mixed solution prepared in the mixing vessel is fed to the filter via the pipe and filtered in the filter under increased pressure.

An apparatus for producing a mixed solution, comprising a mixing vessel for preparing an aqueous mixed solution containing a dicarboxylic acid and an Nb compound and a filter for the aqueous mixed solution connected to the mixing vessel via a pipe, the mixing vessel being anticorrosive and equipped with a stirring unit, a heating unit and a cooling unit for the aqueous mixed solution, wherein the aqueous mixed solution prepared in the mixing vessel is fed to the filter via the pipe and filtered in the filter under increased pressure.

Provided are a catalyst whereby isobutylene can be produced at high yield in a lower-temperature environment, and a method for producing isobutylene using the catalyst. The catalyst for producing isobutylene is an oxide including at least one element selected from molybdenum and tungsten, and at least one element selected from tantalum, niobium, and titanium.

Provided are a catalyst whereby isobutylene can be produced at high yield in a lower-temperature environment, and a method for producing isobutylene using the catalyst. The catalyst for producing isobutylene is an oxide including at least one element selected from molybdenum and tungsten, and at least one element selected from tantalum, niobium, and titanium.

A catalyst for preparing aviation fuel from synthetic oil obtained by Fischer-Tropsch process, including: between 20 and 50 percent by weight of an amorphous aluminum silicate, between 5 and 20 percent by weight of alumina, between 20 and 60 percent by weight of a hydrothermally modified zeolite, between 0.5 and 1.0 percent by weight of a Sesbania powder, between 0.5 and 5 percent by weight of nickel oxide, and between 5 and 15 percent by weight of molybdenum oxide. The invention also provides a method for preparing the catalyst.

A catalyst for preparing aviation fuel from synthetic oil obtained by Fischer-Tropsch process, including: between 20 and 50 percent by weight of an amorphous aluminum silicate, between 5 and 20 percent by weight of alumina, between 20 and 60 percent by weight of a hydrothermally modified zeolite, between 0.5 and 1.0 percent by weight of a Sesbania powder, between 0.5 and 5 percent by weight of nickel oxide, and between 5 and 15 percent by weight of molybdenum oxide. The invention also provides a method for preparing the catalyst.

The present invention relates to a method for producing an unsaturated carboxylic acid using a catalyst having both a high catalytic performance and a high mechanical strength, and in the method, a supported catalyst obtained by feeding a liquid binder component and a catalytic active component containing molybdenum and vanadium and/or a precursor thereof into a rolling granulator and conducting granulation at a relative centrifugal acceleration of 0.5 G or more and 30 G or less is used.

The present invention relates to a method for producing an unsaturated carboxylic acid using a catalyst having both a high catalytic performance and a high mechanical strength, and in the method, a supported catalyst obtained by feeding a liquid binder component and a catalytic active component containing molybdenum and vanadium and/or a precursor thereof into a rolling granulator and conducting granulation at a relative centrifugal acceleration of 0.5 G or more and 30 G or less is used.

The present invention relates to a method of preparing butadiene. More particularly, the present invention relates to a method of preparing butadiene by feeding butene and oxygen into a reactor containing a composite metal oxide catalyst and performing oxidative dehydrogenation, wherein a mole ratio of the oxygen to the butene is 1.8 to 2.2. In accordance with the present invention, a method of preparing butadiene to secure long-term operation stability by maintaining the intensity of a catalyst despite oxidative dehydrogenation and not to decrease selectivity due to less side reaction is provided.