The present invention relates to processes for the preparation of mesoporous zeolites by post-synthetic technologies, the properties of resulting materials, and the use of the resulting materials as catalysts in the refining and petrochemical industry.

The present invention relates to processes for the preparation of mesoporous zeolites by post-synthetic technologies, the properties of resulting materials, and the use of the resulting materials as catalysts in the refining and petrochemical industry.

Provided are: a hydrocarbon adsorbent capable of adsorbing hydrocarbons, storing the adsorbed hydrocarbons up to a relatively high temperature, and desorbing the adsorbed and stored hydrocarbons at a relatively high temperature; an exhaust gas purifying catalyst composition using the same; an exhaust gas purifying catalyst; and a method for treating an exhaust gas. The hydrocarbon adsorbent comprises a zeolite having an MRT-type framework structure. The hydrocarbon adsorbent comprises a small-pore zeolite having a total desorption amount ZD.sub.1 of propylene desorbed at 50° C. or higher and lower than 300° C. being 3.5 mmol/g or less and a total desorption amount ZD.sub.2 of propylene desorbed at 300° C. or higher and 500° C. or lower being 0.5 mmol/g or more, per 1 g by mass of the small-pore zeolite, when adsorbing propylene at 50° C. and then heating from 50° C. to 500° C. under the condition of 10° C./min by a temperature-programmed desorption method.

Provided are: a hydrocarbon adsorbent capable of adsorbing hydrocarbons, storing the adsorbed hydrocarbons up to a relatively high temperature, and desorbing the adsorbed and stored hydrocarbons at a relatively high temperature; an exhaust gas purifying catalyst composition using the same; an exhaust gas purifying catalyst; and a method for treating an exhaust gas. The hydrocarbon adsorbent comprises a zeolite having an MRT-type framework structure. The hydrocarbon adsorbent comprises a small-pore zeolite having a total desorption amount ZD.sub.1 of propylene desorbed at 50° C. or higher and lower than 300° C. being 3.5 mmol/g or less and a total desorption amount ZD.sub.2 of propylene desorbed at 300° C. or higher and 500° C. or lower being 0.5 mmol/g or more, per 1 g by mass of the small-pore zeolite, when adsorbing propylene at 50° C. and then heating from 50° C. to 500° C. under the condition of 10° C./min by a temperature-programmed desorption method.

A method of converting nitrogen oxides in a gas to nitrogen by contacting the nitrogen oxides with a nitrogenous reducing agent in the presence of a zeolite catalyst containing at least one transition metal, wherein the zeolite is a small pore zeolite containing a maximum ring size of eight tetrahedral atoms, wherein the at least one transition metal is selected from the group consisting of Cr, Mn, Fe, Co, Ce, Ni, Cu, Zn, Ga, Mo, Ru, Rh, Pd, Ag, In, Sn, Re, Jr and Pt.

A method of converting nitrogen oxides in a gas to nitrogen by contacting the nitrogen oxides with a nitrogenous reducing agent in the presence of a zeolite catalyst containing at least one transition metal, wherein the zeolite is a small pore zeolite containing a maximum ring size of eight tetrahedral atoms, wherein the at least one transition metal is selected from the group consisting of Cr, Mn, Fe, Co, Ce, Ni, Cu, Zn, Ga, Mo, Ru, Rh, Pd, Ag, In, Sn, Re, Jr and Pt.

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.

A small-pore zeolite that is modified with phosphorus, is excellent in hydrothermal durability, and has an 8-membered oxygen ring structure. The 8-membered oxygen ring structure is CHA, AEI, and AFX. The small-pore zeolite incudes at least an aluminum element, a silica element, a phosphorus element, wherein the phosphorus element is defined by expression (1), and the small-pore zeolite has an 8-membered oxygen ring structure being of CHA, AEI, or AFX. The phosphorus element that modifies the zeolite is unevenly distributed and richly contained on the surface layer side of the zeolite. A method for producing a phosphorus element-containing zeolite.

A small-pore zeolite that is modified with phosphorus, is excellent in hydrothermal durability, and has an 8-membered oxygen ring structure. The 8-membered oxygen ring structure is CHA, AEI, and AFX. The small-pore zeolite incudes at least an aluminum element, a silica element, a phosphorus element, wherein the phosphorus element is defined by expression (1), and the small-pore zeolite has an 8-membered oxygen ring structure being of CHA, AEI, or AFX. The phosphorus element that modifies the zeolite is unevenly distributed and richly contained on the surface layer side of the zeolite. A method for producing a phosphorus element-containing zeolite.

A nano-sized mesoporous zeolite beta composition and processes for the synthesis and use of the nano-sized mesoporous zeolite beta. The nano-sized mesoporous zeolite beta is synthesized using a hydrothermal treatment without drying and calcination of the zeolite prior to or after hydrothermal treatment. A process for hydrocracking a hydrocarbon feedstock using the nano-sized mesoporous zeolite beta is also provided.