Disclosed is a synthesis process of a crystalline material with the CHA structure, which comprises the following steps: i) Preparation of a mixture that comprises one source of water, one source of a tetravalent element Y, one source of an alkaline or alkaline earth cation (A), one source of a trivalent element X, and one organic molecule (OSDA1) with the structure [R.sup.1R.sup.2R.sup.3R.sup.4N.sup.+]Q.sup., being the molar composition: n X.sub.2O.sub.3:YO.sub.2:a A:m OSDA1:z H.sub.2O, ii) crystallisation of the mixture obtained in i) in a reactor, iii) recovery of the crystalline material obtained in ii).

Disclosed is a synthesis process of a crystalline material with the CHA structure, which comprises the following steps: i) Preparation of a mixture that comprises one source of water, one source of a tetravalent element Y, one source of an alkaline or alkaline earth cation (A), one source of a trivalent element X, and one organic molecule (OSDA1) with the structure [R.sup.1R.sup.2R.sup.3R.sup.4N.sup.+]Q.sup., being the molar composition: nX.sub.2O.sub.3:YO.sub.2:aA:mOSDA1:zH.sub.2O, ii) crystallisation of the mixture obtained in i) in a reactor, iii) recovery of the crystalline material obtained in ii).

Systems and methods are provided for selective oxidation of CO and/or C.sub.3 hydrocarbonaceous compounds in a reaction environment including hydrocarbons and/or hydrocarbonaceous components. The selective oxidation can be performed by exposing the CO and/or C.sub.3 hydrocarbonaceous compounds to a catalytic metal that is encapsulated in a small pore zeolite. The small pore zeolite containing the encapsulated metal can have a sufficiently small pore size to reduce or minimize the types of hydrocarbons or hydrocarbonaceous compounds that can interact with the encapsulated metal.

Disclosed are zeolite catalysts having the CHA crystal structure with a low silica to alumina ratio, as well as articles and systems incorporating the catalysts and methods for their preparation and use. The catalysts can be used to reduce NOx from exhaust gas streams, particularly those emanating from gasoline or diesel engines.

The present disclosure recognizes a correlation between zeolitic surface area (ZSA) of a catalyst composition and its catalytic activity. Particularly, the disclosure provides catalyst articles for diesel NO.sub.x abatement, including a substrate and a washcoat layer containing metal-promoted molecular sieves, wherein the zeolitic surface area (ZSA) of the catalyst article is about 100 m.sup.2/g or greater, the volumetric surface area is about 900 m.sup.2/in.sup.3 or greater, and/or the total zeolitic surface area (tZSA) is about 1200 m.sup.2 or greater. The disclosure further relates to methods for evaluating ZSA, volumetric ZSA, and tZSA, e.g., including the steps of coating a catalyst composition comprising metal-promoted molecular sieves onto a substrate; calcining and aging the catalyst composition; determining the ZSA (or volumetric ZSA or tZSA) thereof; and correlating the ZSA (or volumetric ZSA or tZSA) with catalyst composition NO.sub.x abatement activity to determine whether the catalyst composition is suitable for an intended use.

A process the dehydration of methanol to dimethyl ether in the presence of a solid Brnsted acid catalyst selected from aluminosilicate zeolites which have a maximum free sphere diameter of greater than 3.67 Angstroms and heteropolyacids and a promoter selected from methyl formate, dimethyl oxalate and dimethyl malonate and the molar ratio of promoter to methanol is maintained at less than 1.

Provided are a novel synthesis technique for producing pure phase aluminosilicate zeolite and a catalyst comprising the phase pure zeolite in combination with a metal, and methods of using the same.

A method for modifying the surface of a molecular sieve, comprising reacting a molecular sieve with an aminosilane, wherein the reaction is carried out in an aqueous solvent. A modified molecular sieve obtained by the method is also described.

A method of synthesizing chabazite zeolites with controlled aluminum distribution. The method utilizes a source of an organic structure-directing agent, a source of an inorganic structure-directing agent, a source of aluminum and a source of silicon to form a synthesis gel which is subjected to a crystallization process to crystallize a chabazite zeolite with controlled aluminum distribution. A chabazite zeolite structure with controlled aluminum distribution. The structure contains zeolite crystal lattice framework containing silicon, aluminum, and oxygen; and extra-framework positions containing non-divalent chemical species such that each aluminum atom in the zeolite crystal lattice framework is in an isolated configuration. Another variant of this structure wherein a fraction of the aluminum atoms in the zeolite crystal lattice framework positions are not in an isolated configuration and hence oxygen atoms associated with aluminum atoms in the fraction can bind with the non-aluminum cations in the extra-framework positions.

Embodiments of the invention generally provide compositions of crystalline zeolite materials with tailored crystal habits and the methods for forming such crystalline zeolite materials. The methods for forming the crystalline zeolite materials include binding one or more zeolite growth modifiers (ZGMs) to the surface of a zeolite crystal, which results in the modification of crystal growth rates along different crystallographic directions, leading to the formation of zeolites having a tailored crystal habit. The improved properties enabled by the tailored crystal habit include a minimized crystal thickness, a shortened internal diffusion pathlength, and a greater step density as compared to a zeolite having the native crystal habit prepared by traditional processes. The tailored crystal habit provides the crystalline zeolite materials with an aspect ratio of about 4 or greater and crystal surfaces having a step density of about 25 steps/m.sup.2 or greater.