The present disclosure provides a modified catalyst, and preparation method and a method for producing aromatic hydrocarbons by aromatization of olefins using the modified catalyst. The modified catalyst comprises an acidic molecular sieve and an olefin aromatization active metal component, the total acid amount of the catalyst as measured by NH3-TPD method is not higher than 0.35mmo1/g, and ratio of the strong acid to weak acid is within a range of 0.8-1.2.

The present disclosure provides a modified catalyst, and preparation method and a method for producing aromatic hydrocarbons by aromatization of olefins using the modified catalyst. The modified catalyst comprises an acidic molecular sieve and an olefin aromatization active metal component, the total acid amount of the catalyst as measured by NH3-TPD method is not higher than 0.35mmo1/g, and ratio of the strong acid to weak acid is within a range of 0.8-1.2.

Described are compositions and methods for inhibiting polymerization of a monomer (e.g., styrene) composition a quinone methide polymerization retarder and an ammonium salt. In a mixture, the ammonium salt improves the efficacy of the quinone methide polymerization retarder and provides greater antipolymerant activity. In turn, the mixture reduces or prevents apparatus fouling and improves the purity of monomer streams.

Described are compositions and methods for inhibiting polymerization of a monomer (e.g., styrene) composition a quinone methide polymerization retarder and an ammonium salt. In a mixture, the ammonium salt improves the efficacy of the quinone methide polymerization retarder and provides greater antipolymerant activity. In turn, the mixture reduces or prevents apparatus fouling and improves the purity of monomer streams.

A catalyst support comprising at least 95% silicon carbide, having surface areas of ≤10 m.sup.2/g and pore volumes of ≤1 cc/g. A method of producing a catalyst support, the method including mixing SiC particles of 0.1-20 microns, SiO.sub.2 and carbonaceous materials to form an extrusion, under inert atmospheres, heating the extrusion at temperatures of greater than 1400° C., and removing residual carbon from the heated support under temperatures below 1000° C. A catalyst on a carrier, comprising a carrier support having at least about 95% SiC, with a silver solution impregnated thereon comprising silver oxide, ethylenediamine, oxalic acid, monoethanolamine and cesium hydroxide. A process for oxidation reactions (e.g., for the production of ethylene oxide, or oxidation reactions using propane or methane), or for endothermic reactions (e.g., dehydrogenation of paraffins, of ethyl benzene, or cracking and hydrocracking hydrocarbons).

A catalyst support comprising at least 95% silicon carbide, having surface areas of ≤10 m.sup.2/g and pore volumes of ≤1 cc/g. A method of producing a catalyst support, the method including mixing SiC particles of 0.1-20 microns, SiO.sub.2 and carbonaceous materials to form an extrusion, under inert atmospheres, heating the extrusion at temperatures of greater than 1400° C., and removing residual carbon from the heated support under temperatures below 1000° C. A catalyst on a carrier, comprising a carrier support having at least about 95% SiC, with a silver solution impregnated thereon comprising silver oxide, ethylenediamine, oxalic acid, monoethanolamine and cesium hydroxide. A process for oxidation reactions (e.g., for the production of ethylene oxide, or oxidation reactions using propane or methane), or for endothermic reactions (e.g., dehydrogenation of paraffins, of ethyl benzene, or cracking and hydrocracking hydrocarbons).

A catalyst support comprising at least 95% silicon carbide, having surface areas of ≤10 m.sup.2/g and pore volumes of ≤1 cc/g. A method of producing a catalyst support, the method including mixing SiC particles of 0.1-20 microns, SiO.sub.2 and carbonaceous materials to form an extrusion, under inert atmospheres, heating the extrusion at temperatures of greater than 1400° C., and removing residual carbon from the heated support under temperatures below 1000° C. A catalyst on a carrier, comprising a carrier support having at least about 95% SiC, with a silver solution impregnated thereon comprising silver oxide, ethylenediamine, oxalic acid, monoethanolamine and cesium hydroxide. A process for oxidation reactions (e.g., for the production of ethylene oxide, or oxidation reactions using propane or methane), or for endothermic reactions (e.g., dehydrogenation of paraffins, of ethyl benzene, or cracking and hydrocracking hydrocarbons).

A catalyst support comprising at least 95% silicon carbide, having surface areas of ≤10 m.sup.2/g and pore volumes of ≤1 cc/g. A method of producing a catalyst support, the method including mixing SiC particles of 0.1-20 microns, SiO.sub.2 and carbonaceous materials to form an extrusion, under inert atmospheres, heating the extrusion at temperatures of greater than 1400° C., and removing residual carbon from the heated support under temperatures below 1000° C. A catalyst on a carrier, comprising a carrier support having at least about 95% SiC, with a silver solution impregnated thereon comprising silver oxide, ethylenediamine, oxalic acid, monoethanolamine and cesium hydroxide. A process for oxidation reactions (e.g., for the production of ethylene oxide, or oxidation reactions using propane or methane), or for endothermic reactions (e.g., dehydrogenation of paraffins, of ethyl benzene, or cracking and hydrocracking hydrocarbons).

The invention provides methods, catalysts and systems for producing styrene from DME and toluene. Zeolite catalysts comprising potassium, rubidium or cesium and containing at least 0.1 wt % B are described. Methods of making the catalysts are also described.

The invention provides methods, catalysts and systems for producing styrene from DME and toluene. Zeolite catalysts comprising potassium, rubidium or cesium and containing at least 0.1 wt % B are described. Methods of making the catalysts are also described.