According to one or more embodiments described herein, a process for producing propylene, the process comprising at least partially metathesizing a first portion of a first stream to form a first metathesis-reaction product, at least partially cracking the first metathesis-reaction product to form a cracking-reaction product, the cracking reaction product comprising propylene and ethylene, at least partially separating ethylene from at least the cracking reaction product to form a first recycle stream, combining the first recycle stream with a second portion of the first stream to a form a mixed stream, and at least partially metathesizing the mixed stream to from a second metathesis-reaction product. In embodiments, the second metathesis-reaction product may comprise propylene, the first stream may comprise butene, and the first recycle stream may comprise ethylene.

A process is described for the preparation of an inorganic material with a hierarchical porosity in the micropore and mesopore domains. The material has at least two elementary spherical particles having a maximum diameter of 200 microns. The process comprises: a) preparing a solution containing zeolitic nanocrystals with a maximum nanometric dimension equal to 60 nm based on silicon and/or precursor elements of proto-zeolitic entities based on silicon; b) mixing, in solution, metallic particles or at least one metallic precursor of metallic particles, a surfactant and the solution obtained in accordance with a) such that the ratio of the volumes of inorganic and organic materials, V.sub.inorganic/V.sub.organic, is 0.29 to 0.50; c) aerosol atomization of the solution obtained in b) resulting in formation of spherical particles; d) drying the particles; g) eliminating any remaining precursor elements of proto-zeolitic entities based on silicon and the surfactant.

A cold start catalyst is disclosed. The cold start catalyst comprises a zeolite catalyst and a supported platinum group metal catalyst. The zeolite catalyst comprises a base metal, a noble metal, and a zeolite. The supported platinum group metal catalyst comprises one or more platinum group metals and one or more inorganic oxide carriers. The invention also includes an exhaust system comprising the cold start catalyst. The cold start catalyst and the process result in improved NO.sub.x storage and NO.sub.x conversion, improved hydrocarbon storage and conversion, and improved CO oxidation through the cold start period.

Embodiments of processes for producing propylene utilize a dual catalyst system comprising a mesoporous silica catalyst impregnated with metal oxide and a mordenite framework inverted (MFI) structured silica catalyst downstream of the mesoporous silica catalyst, where the mesoporous silica catalyst includes a pore size distribution of at least 2.5 nm to 40 nm and a total pore volume of at least 0.600 cm.sup.3/g, and the MFI structured silica catalyst has a total acidity of 0.001 mmol/g to 0.1 mmol/g. The propylene is produced from the butene stream via metathesis by contacting the mesoporous silica catalyst and subsequent cracking by contacting the MFI structured silica catalyst.

The present invention provides an adsorbent catalytic nanoparticle including a mesoporous silica nanoparticle having at least one adsorbent functional group bound thereto. The adsorbent catalytic nanoparticle also includes at least one catalytic material. In various embodiments, the present invention provides methods of using and making the adsorbent catalytic nanoparticles. In some examples, the adsorbent catalytic nanoparticles can be used to selectively remove fatty acids from feedstocks for biodiesel, and to hydrotreat the separated fatty acids.

According to one embodiment described in this disclosure, a process for producing propylene may comprise at least partially metathesizing a first stream comprising at least about 10 wt. % butene to form a metathesis-reaction product, at least partially cracking the metathesis-reaction product to form a cracking-reaction product comprising propylene, and at least partially separating propylene from the cracking-reaction product to form a product stream comprising at least about 80 wt. % propylene.

According to one or more embodiments described herein, a process for producing propylene, the process comprising at least partially metathesizing a first portion of a first stream to form a first metathesis-reaction product, at least partially cracking the first metathesis-reaction product to form a cracking-reaction product, the cracking reaction product comprising propylene and ethylene, at least partially separating ethylene from at least the cracking reaction product to form a first recycle stream, combining the first recycle stream with a second portion of the first stream to a form a mixed stream, and at least partially metathesizing the mixed stream to from a second metathesis-reaction product. In embodiments, the second metathesis-reaction product may comprise propylene, the first stream may comprise butene, and the first recycle stream may comprise ethylene.

Embodiments of a metathesis process for producing propylene comprise providing a metathesis catalyst comprising an amorphous mesoporous silica foam impregnated with metal oxides, where the metathesis catalyst has a pore size distribution of at least 3 nm to 40 nm and a total pore volume of at least 0.700 cm.sup.3/g. The process further involves producing a product stream comprising propylene by contacting a feed stream comprising butene with the metathesis catalyst.

Embodiments of processes for producing propylene utilize a dual catalyst system comprising a mesoporous silica catalyst impregnated with metal oxide and a mordenite framework inverted (MFI) structured silica catalyst downstream of the mesoporous silica catalyst, where the mesoporous silica catalyst includes a pore size distribution of at least 2.5 nm to 40 nm and a total pore volume of at least 0.600 cm.sup.3/g, and the MFI structured silica catalyst has a total acidity of 0.001 mmol/g to 0.1 mmol/g. The propylene is produced from the butene stream via metathesis by contacting the mesoporous silica catalyst and subsequent cracking by contacting the MFI structured silica catalyst.

A catalyst composition for isomerization of paraffins includes at least one metal, at least one heteropoly acid and a support material. Further provided are a process for preparation of the catalyst composition and a process for isomerization of paraffins using the catalytic composition.