Abstract: A hydrocarbon adsorbent having high hydrocarbon adsorbing properties even after exposed to a high temperature/high humidity reducing atmosphere, includes a FAU type zeolite having in ESR measurement a spin concentration of a least 1.0×10{circumflex over (?)}19 (spins/g) and a ratio of a peak intensity at a magnetic field of at least 260 mT and at most 270 mT to a peak intensity at a magnetic field of at least 300 mT and at most 320 mT of at least 0.25 and at most 0.50 ? and containing bivalent copper. The hydrocarbon adsorbent may be used for a method for adsorbing hydrocarbons to be exposed to a high temperature/high humidity environment, and may be used particularly for a method for adsorbing hydrocarbons in an exhaust gas of an internal combustion engine, such as an automobile exhaust gas.

Abstract: A composition is provided that has heat resistance sufficient for use as a hydrocarbon adsorbent and desorbs hydrocarbons slowly with respect to an increase in temperature. The composition includes an alkali metal and a zeolite having a YFI structure. A content of the alkali metal is 1 to 40 mass% based on a total mass of the composition, and a content of the zeolite having a YFI structure is 99 to 60 mass% based on the total mass of the composition.

Abstract: A hydrocarbon adsorbent having high hydrocarbon adsorbing properties even after exposed to a high temperature/high humidity reducing atmosphere, includes a FAU type zeolite having in ESR measurement a spin concentration of a least 1.0 × 10^19 (spins/g) and a ratio of a peak intensity at a magnetic field of at least 260 mT and at most 270 mT to a peak intensity at a magnetic field of at least 300 mT and at most 320 mT of at least 0.25 and at most 0.50 Å and containing bivalent copper. The hydrocarbon adsorbent may be used for a method for adsorbing hydrocarbons to be exposed to a high temperature/high humidity environment, and may be used particularly for a method for adsorbing hydrocarbons in an exhaust gas of an internal combustion engine, such as an automobile exhaust gas.

Abstract: To provide a hydrocarbon adsorbent having high hydrocarbon adsorbing properties even after exposed to a high temperature/high humidity reducing atmosphere. A hydrocarbon adsorbent, which includes a FAU type zeolite having a lattice constant of at least 24.29 ? and containing copper. Such a hydrocarbon adsorbent may be used for a method for adsorbing hydrocarbons to be exposed to a high temperature/high humidity environment, and may be used particularly for a method for adsorbing hydrocarbons in an exhaust gas of an internal combustion engine, such as an automobile exhaust gas.

Abstract: A hydrocarbon adsorbent having a high hydrocarbon desorption start temperature and a method for adsorbing hydrocarbons that uses the hydrocarbon adsorbent are provided. The hydrocarbon adsorbent includes an alkali metal and a zeolite having a ring structure that includes at least 10 members is used. In the hydrocarbon adsorbent, a content of the alkali metal is 1 to 40 mass % based on a total mass of the hydrocarbon adsorbent, a content of the zeolite having a ring structure that includes at least 10 members is 99 to 60 mass % based on the total mass of the hydrocarbon adsorbent, and at least a portion of the alkali metal is in a state of being ion-exchangeable.

Abstract: CHA-type zeolite in which the molar ratio of silica to alumina is less than 13, and the content of sodium is 100 ppm or more and 2000 ppm or less is provided. Such a CHA-type zeolite is obtained by a manufacturing method including obtaining a crystallized product by crystallizing a composition which includes a structure-directing agent source containing at least N,N,N-trialkylcyclohexylammonium cation, an alumina source, a silica source, a sodium source, and water and in which the molar ratio of silica to alumina is 20 or less and in which the molar ratio of potassium to sodium is less than 0.05, removing N,N,N-trialkylcyclohexylammonium cation from the crystallized product, and contacting the crystallized product with an ammonium-salt-containing solution having an ammonium concentration of 1 mass percent or more.

Abstract: To provide a hydrocarbon adsorbent having high hydrocarbon adsorbing properties even after exposed to a high temperature/high humidity reducing atmosphere. A hydrocarbon adsorbent, which includes a FAU type zeolite having a lattice constant of at least 24.29 ? and containing copper. Such a hydrocarbon adsorbent may be used for a method for adsorbing hydrocarbons to be exposed to a high temperature/high humidity environment, and may be used particularly for a method for adsorbing hydrocarbons in an exhaust gas of an internal combustion engine, such as an automobile exhaust gas.

Abstract: A process of manufacturing a chabazite-type zeolite is provided having high heat resistance without having a large crystal size. A catalyst is also provided that contains such a chabazite-type zeolite and exhibits high nitrogen oxide reduction properties, and in particular high nitrogen oxide reduction properties in low temperatures below 200° C., even after exposure to high temperature and high humidity. A chabazite-type zeolite is provided having a silica to alumina molar ratio of no less than 15, a silanol group to silicon molar ratio of no more than 1.6×10?2, an average crystal size of 0.5 ?m to less than 1.5 ?m, and a ratio of 50%-volume particle size to 10%-volume particle size of no more than 3.2. The chabazite-type zeolite preferably contains at least one of copper and iron.

Abstract: A process of manufacturing a chabazite-type zeolite is provided having high heat resistance without having a large crystal size. A catalyst is also provided that contains such a chabazite-type zeolite and exhibits high nitrogen oxide reduction properties, and in particular high nitrogen oxide reduction properties in low temperatures below 200° C., even after exposure to high temperature and high humidity. A chabazite-type zeolite is provided having a silica to alumina molar ratio of no less than 15, a silanol group to silicon molar ratio of no more than 1.6×10?2, an average crystal size of 0.5 ?m to less than 1.5 ?m, and a ratio of 50%-volume particle size to 10%-volume particle size of no more than 3.2. The chabazite-type zeolite preferably contains at least one of copper and iron.