Abstract:
A porous catalyst monolith for the oxidation of SO 2 to SO 3 , composed of alternating layers of linear spaced-apart parallel strands of catalyst material comprising vanadium, at least one alkali metal and sulfate on a silicon dioxide support material, wherein the strands in alternating layers are oriented at an angle to one another, wherein the distance between inner spaced-apart parallel strands is larger than the distance between outer spaced-apart parallel strands in at least a part of the layers of the monolith.
Abstract:
A process for producing ethylene oxide by gas-phase oxidation of ethylene, comprising: directing a feed comprising gaseous ethylene and gaseous oxygen through a packing of individual shaped catalyst bodies, under conditions conducive to obtain a reaction mixture containing at least 2.7 vol.-% of ethylene oxide, wherein each shaped catalyst body comprises silver deposited on a refractory support and is characterized by a content of at least 20 wt.-% of silver, relative to the total weight of the shaped catalyst body; a BET surface area in the range of 1.6 to 3.0 m 2 /g; and a thickness in the range of 0.7 to 2.0 mm, wherein thickness is defined as a distance twice the shortest distance from the geometric surface of the shaped catalyst body to a point inside the structure of the shaped catalyst body for which point the shortest distance is the largest among all points. The process allows for increased activity and/or stability of the catalyst while maintaining or increasing selectivity at high productivity.
Abstract:
The invention relates to a shaped catalyst body for the oxidation of SO 2 into SO 3 , containing vanadium, at least one alkali metal, and sulfate on a silicon dioxide substrate material, wherein the shaped body has the shape of a cylinder having 3 or 4 hollow cylindrical protrusions, obtainable by extruding a catalyst precursor mass, comprising vanadium, at least one alkali metal, and sulfate on a silicon dioxide substrate material, through the opening of an extrusion tool, wherein the opening of the extrusion tool has a cross-section that is formed by 3 or 4 rings, the center points of which lie substantially on a circular line having the diameter y and partially overlap each other, wherein the rings are bounded by an outer line lying on a circle having an outer diameter (x1) and an inner line lying on a circle having an inner diameter (x2).
Abstract:
The present invention relates to a catalyst system for oxidation of o-xylene and/or naphthalene to phthalic anhydride (PA) comprising at least four catalyst zones arranged in succession in the reaction tube wherein the active material of the catalyst in the last catalyst zone towards the reactor outlet has an antimony content (calculated as antimony trioxide) between 0.7 to 3.0 wt.%. The present invention further relates to a process for gas phase oxidation in which a gas stream comprising at least one hydrocarbon and molecular oxygen is passed through a catalyst system which comprises at least four catalyst zones arranged in succession in the reaction tube wherein the active material of the catalyst in the last catalyst zone towards the reactor outlet has an antimony content (calculated as antimony trioxide) between 0.7 to 3.0 wt.%.
Abstract:
An α,β-unsaturated aldehyde and/or an α,β-unsaturated carboxylic acid are prepared by gas phase oxidation of an alkene with molecular oxygen over a fixed catalyst bed comprising a bed of hollow cylindrical shaped catalyst bodies having a multimetal oxide active composition. The fixed catalyst bed comprises at least three successive reaction zones; the highest local temperature in the fixed catalyst bed does not occur in the reaction zone closest to the reactor outlet; the highest local temperature in the fixed catalyst bed does not occur in the reaction zone closest to the reactor inlet; and the value WT = (ED-ID)/2 in the reaction zone in which the highest local temperature in the fixed catalyst bed occurs is lower than in the other reaction zones, in which ED is the external diameter and ID is the internal diameter of the shaped catalyst body. The yield of the products of value is enhanced in this way.
Abstract:
The invention relates to a method for the oxidative dehydrogenation of n‑butenes to butadiene, comprising two or more production steps (i) and at least one regeneration step (ii), in which (i) in a production step an n‑butene-containing starting gas mixture is mixed with an oxygen-containing gas and is contacted in a fixed-bed reactor at a temperature of 220 to 490°C with a multimetal oxide catalyst arranged in a catalyst fixed bed, which multimetal oxide catalyst contains at least molybdenum, and one further metal, and, before the loss in conversion rate at constant temperature is > 25%, (ii), in a regeneration step the multimetal oxide catalyst is regenerated by passing an oxygen-containing regeneration gas mixture at a temperature of 200 to 450°C over the catalyst fixed bed and burning off the carbon deposited on the catalyst, wherein, between two production steps (i), one regeneration step (ii) is carried out, characterized in that, per regeneration step (ii), 2 to 50% by weight of the carbon deposited on the catalyst is burnt off.
Abstract:
The invention relates to a catalyst comprising a catalytically active molybdenum and at least one further metal-containing multimetal oxide of the general formula (I), Mo 12 Bi a Mn b Co c Fe d X 1 e X 2 f O x (I), in which the variables have the following meanings: X 1 = Si and/or AI; X 2 = Li, Na, K, Cs and/or Rb; a = 0.2 to 1; b = 0 to 2; c = 2 to 10; d = 0.5 to 10; e = 0 to 10; f = 0 to 0.5; and x is a number which is determined by the valency and frequency of the elements in (I) that are different from oxygen.