The invention relates to a process for the production of an alkenylaromatic compound comprising the step of: contacting a hydrocarbon stream including an alkylaromatic compound with water vapor in the presence of a dehydrogenation catalyst, suitable for the dehydrogenation of the alkylaromatic compound, in one or more consecutive reactors,
wherein the weight ratio between the water vapor and the hydrocarbon (water/hydrocarbon ratio) is from 0.4 to 1.5, wherein the dehydrogenation catalyst comprises three or more of teeth and a body, such that the cross-section of the dehydrogenation catalyst is a toothed-wheel shape, and wherein the dehydrogenation catalyst comprises, based on the total weight of the dehydrogenation catalyst components as oxides, from 30 to 90 weight percent (wt. %) of iron calculated as Fe.sub.2O.sub.3, from 1 to 50 wt. % of potassium calculated as K.sub.2O, from 1 to 50 wt. % of cerium calculated as CeO.sub.2, and from 0.01 to 1 wt. % of yttrium calculated as Y.sub.2O.sub.3. Further the invention relates to a dehydrogenation catalyst comprising: from 30 to 90 weight percent (wt. %) of iron calculated as Fe.sub.2O.sub.3, from 1 to 50 wt. % of potassium calculated as K.sub.2O, from 1 to 50 wt. % of cerium calculated as CeO.sub.2, and from 0.01 to 1 wt. % of yttrium calculated as Y.sub.2O.sub.3,
wherein the wt. % is based on the total weight of the dehydrogenation catalyst components as oxides, wherein the dehydrogenation catalyst comprises at least three teeth and a body, such that the cross-section of the dehydrogenation catalyst is a toothed-wheel shape, and a process of synthesizing such a catalyst.

The invention relates to a process for the production of an alkenylaromatic compound comprising the step of: contacting a hydrocarbon stream including an alkylaromatic compound with water vapor in the presence of a dehydrogenation catalyst, suitable for the dehydrogenation of the alkylaromatic compound, in one or more consecutive reactors,
wherein the weight ratio between the water vapor and the hydrocarbon (water/hydrocarbon ratio) is from 0.4 to 1.5, wherein the dehydrogenation catalyst comprises three or more of teeth and a body, such that the cross-section of the dehydrogenation catalyst is a toothed-wheel shape, and wherein the dehydrogenation catalyst comprises, based on the total weight of the dehydrogenation catalyst components as oxides, from 30 to 90 weight percent (wt. %) of iron calculated as Fe.sub.2O.sub.3, from 1 to 50 wt. % of potassium calculated as K.sub.2O, from 1 to 50 wt. % of cerium calculated as CeO.sub.2, and from 0.01 to 1 wt. % of yttrium calculated as Y.sub.2O.sub.3. Further the invention relates to a dehydrogenation catalyst comprising: from 30 to 90 weight percent (wt. %) of iron calculated as Fe.sub.2O.sub.3, from 1 to 50 wt. % of potassium calculated as K.sub.2O, from 1 to 50 wt. % of cerium calculated as CeO.sub.2, and from 0.01 to 1 wt. % of yttrium calculated as Y.sub.2O.sub.3,
wherein the wt. % is based on the total weight of the dehydrogenation catalyst components as oxides, wherein the dehydrogenation catalyst comprises at least three teeth and a body, such that the cross-section of the dehydrogenation catalyst is a toothed-wheel shape, and a process of synthesizing such a catalyst.

An embodiment of the present specification provides a method for preparing a catalyst for preparing a carbon nanotube, comprising: (a) dissolving a main catalyst precursor, a support precursor, a cocatalyst precursor and a precipitation inhibitor in a solvent to prepare a precursor solution; and (b) pyrolyzing the precursor solution by spraying the precursor solution into a reactor, wherein a mole fraction of the precipitation inhibitor to the cocatalyst precursor is 0.1 to 1.5.

A catalyst for production of carboxylic acid ester, containing: catalyst metal particles; and a support supporting the catalyst metal particles, wherein a bulk density of the catalyst for production of carboxylic acid ester is 0.50 g/cm.sup.3 or more and 1.50 g/cm.sup.3 or less, when a particle diameter, at which a cumulative frequency is x % in a particle diameter distribution based on a volume of the catalyst for production of carboxylic acid ester, is defined as D.sub.x, D.sub.10/D.sub.50?0.2 and D.sub.90/D.sub.50?2.5 are satisfied, and when a half-width of the particle diameter distribution is defined as W, W/D.sub.50?1.5 is satisfied.

A catalyst for production of carboxylic acid ester, containing: catalyst metal particles; and a support supporting the catalyst metal particles, wherein a bulk density of the catalyst for production of carboxylic acid ester is 0.50 g/cm.sup.3 or more and 1.50 g/cm.sup.3 or less, when a particle diameter, at which a cumulative frequency is x % in a particle diameter distribution based on a volume of the catalyst for production of carboxylic acid ester, is defined as D.sub.x, D.sub.10/D.sub.50?0.2 and D.sub.90/D.sub.50?2.5 are satisfied, and when a half-width of the particle diameter distribution is defined as W, W/D.sub.50?1.5 is satisfied.

The present invention relates to a method for preparing a catalyst which can produce carbon nanotubes having a higher bulk density by supporting a catalyst component under pressurized conditions, and to a method for producing carbon nanotubes using the catalyst so produced.

The present invention relates to a method for preparing a catalyst which can produce carbon nanotubes having a higher bulk density by supporting a catalyst component under pressurized conditions, and to a method for producing carbon nanotubes using the catalyst so produced.

The present invention relates to a process for preparing fluid catalytic cracking (FCC) catalysts having porosity and accessibility controlled by the activity of water-soluble porogens. The catalyst produced can be used as an additive for fluid cracking, as additives for SOx and NOx reduction, as a combustion promoter and reduction of sulfur in cracked naphtha. It can also be used in hydrocracking, as a support for hydrotreating catalysts, catalytic pyrolysis of post-consumer polymers (rubber tires, plastic films, and so on) and pyrolysis of biomass.

The present invention relates to a process for preparing fluid catalytic cracking (FCC) catalysts having porosity and accessibility controlled by the activity of water-soluble porogens. The catalyst produced can be used as an additive for fluid cracking, as additives for SOx and NOx reduction, as a combustion promoter and reduction of sulfur in cracked naphtha. It can also be used in hydrocracking, as a support for hydrotreating catalysts, catalytic pyrolysis of post-consumer polymers (rubber tires, plastic films, and so on) and pyrolysis of biomass.

An embodiment of the present specification provides a method for preparing a catalyst for preparing a carbon nanotube, comprising: (a) dissolving a main catalyst precursor, a support precursor, a cocatalyst precursor and a precipitation inhibitor in a solvent to prepare a precursor solution; and (b) pyrolyzing the precursor solution by spraying the precursor solution into a reactor, wherein a mole fraction of the precipitation inhibitor to the cocatalyst precursor is 0.1 to 1.5.