摘要:
A catalyst material for preparing nanotubes, especially carbon nanotubes, said material being in the form of solid particles, said particles including a porous substrate supporting two superposed catalytic layers, a first layer, directly positioned on the substrate, including at least one transition metal from column VIB of the Periodic Table, preferably molybdenum, and a second catalytic layer, positioned on the first layer, comprising iron. Also, a process for preparing same and to a process for the synthesis of nanotubes using this catalyst material.
摘要:
This invention relates to a solid divided composition comprising grains whose mean size is greater than 25 μm and less than 2.5 mm, wherein each grain is provided with a solid porous core and a homogeneous continuous metal layer consisting of at least one type of transition non-oxidised metal and extending along a gangue coating the core in such a way that pores are inaccessible. A method for the production of said composition and for the use thereof in the form of a solid catalyst is also disclosed.
摘要:
The invention relates to a continuous process for the manufacture of acetic acid and/or methyl acetate, characterized in that, during the continuous operation of the installation for a continuous industrial process, called the initial process, for the carbonylation of methanol or a carbonylatable derivative of methanol such as dimethyl ether, methyl halides or methyl acetate, in the homogeneous liquid phase and under carbon monoxide pressure, in the presence of a catalyst system comprising a rhodium-based homogeneous catalyst and a halogenated promoter, and in the presence of a concentration of water greater than or equal to 14% in the reaction medium, the composition of said homogeneous catalyst is modified gradually by adding an iridium compound over time.This process makes it possible on the one hand to modify the composition of the catalyst system so as to change from a homogeneous catalyst based on rhodium alone to a catalyst based on rhodium and iridium, or even iridium alone, without stopping the installation, and on the other hand to reduce the water content of the reaction medium once the iridium additions have been effected.
摘要:
The invention relates to a process for the preparation of acetic acid and/or methyl acetate in the liquid phase by the carbonylation of methanol and/or the isomerization of methyl formate in the presence of water, a solvent, a homogeneous catalyst system comprising iridium and a halogen-containing promoter, and carbon monoxide, wherein said catalyst system also comprises platinum.
摘要:
This invention relates to a solid divided composition comprising grains whose mean size is greater than 25 μm and less than 2.5 mm, wherein each grain is provided with a solid porous core and a homogeneous continuous metal layer consisting of at least one type of transition non-oxidised metal and extending along a gangue coating the core in such a way that pores are inaccessible. A method for the production of said composition and for the use thereof in the form of a solid catalyst is also disclosed.
摘要:
The invention relates to a method for selectively producing nanotubes made of carbon ordered by decomposing a gaseous carbon source in contact with at least one solid catalyst in the form of catalyst grains which are made of an alumina porous support provided with a metallic ferrous non-oxidised deposit and whose mean grain-size ranges from 25 μm to 2.5 mm and on which said metallic ferrous deposit covers more than 75% of the surface of the microscopic alumina support and is embodied in the form of at least one cluster formed by a plurality of metallic agglutinated bulbs.