Abstract: This invention relates to a process, comprising reacting ethylene and oxygen or a source of oxygen in the presence of a catalyst in a reactor to form a product comprising ethylene oxide, wherein the catalyst contains silver or silver compound and a support and the catalyst is in the form of particulate solids having a mean particle diameter from 1 to 1000 ?m and wherein the molar ratio of oxygen to ethylene is from 1:4 to 10:1.

Abstract: What is described is a process for starting up a gas phase oxidation reactor for oxidation of o-xylene to phthalic anhydride, said reactor comprising at least one catalyst layer and being temperature-controllable by means of a heat carrier medium, wherein a) the catalyst layer is interrupted by a moderator layer which is less catalytically active than the catalyst layer or is catalytically inactive, b) a gas stream is passed through the reactor with an initial loading of o-xylene and at an initial temperature of the heat transfer medium, c) the loading of the gas stream is increased to a target loading and, in parallel, the temperature of the heat transfer medium is lowered to an operating temperature. The introduction of the moderator layer allows the loading to be increased more rapidly and the startup time to be shortened.

Abstract: What is described is a method for starting a gas phase oxidation reactor that contains a bed of a first catalyst whose active material comprises a catalytically active silver-vanadium oxide bronze, and at least one bed of a second catalyst whose catalytically active material comprises vanadium pentoxide and titanium dioxide, and whose temperature is controllable by means of a heat transfer medium. In the operating state, a gas stream which comprises a loading cop of a hydrocarbon and molecular oxygen is passed through the reactor over the bed of the first and second catalyst at a temperature Top of the heat transfer medium. For the startup, a) a gas stream is passed through the reactor with a starting loading c0 which is less than cop, and at a starting temperature T0 of the heat transfer medium which is less than Top, and b) the temperature of the heat transfer medium is brought to Top and the loading of the gas stream to cop.

Abstract: Catalytic titanium dioxide mixtures comprising: a first anatase titanium dioxide having a BET surface area greater than 15 m2/g and a hydrogen uptake for the reduction of Ti4+ to Ti3+ of from 5 to 20 ?mol/m2; and a second anatase titanium dioxide having a BET surface area less than or equal to 15 m2/g and a hydrogen uptake for the reduction of Ti4+ to Ti3+ of from 0.6 to 7 ?mol/m2, processes for preparing catalysts containing the same, catalysts containing active compositions including such titanium dioxide mixtures on support materials, and catalyst systems using the same.

Abstract: Catalyst systems for preparing phthalic anhydride by means of gas-phase oxidation of o-xylene and/or naphthalene, and a process for preparing phthalic anhydride using the catalyst systems

Abstract: Catalyst systems for preparing phthalic anhydride by means of gas-phase oxidation of o-xylene and/or naphthalene, and a process for preparing phthalic anhydride using the catalyst systems.

Abstract: A process for producing geometric shaped catalyst bodies K whose active material is a multielement oxide of stoichiometry [Bi1WbOx]a[Mo12Z1cZ2dFeeZ3fZ4gZ5nOy]1, in which a finely divided oxide Bi1WbOx with the particle size d50A1 and, formed from element sources, a finely divided intimate mixture of stoichiometry Mo12Z1cZ2dFeeZ3fZ4gZ5h with the particle size d50A2 are mixed in a ratio of a:1, this mixture is used to form shaped bodies and these are treated thermally, where (d50A1)0.7•(d90A1)1.5•(a)?1?820.

Abstract: A process for producing geometric shaped catalyst bodies K whose active material is a multielement oxide of stoichiometry [BiaZ1bOx]p[BicMo12FedZ2eZ3fZ4gZ5hZ6iOy]1, in which a finely divided oxide BiaZ1bOx and, formed from element sources, a finely divided mixture of stoichiometry BicMo12FedZ2eZ3fZ4gZ5hZ6i are mixed in a ratio of p:1, this mixture is used to form shaped bodies and these are treated thermally, where 0<c?0.8.

Abstract: The present invention relates to a process for gas-phase oxidation, in which a gaseous stream comprising an aromatic hydrocarbon and molecular oxygen is passed through two or more catalyst zones. Furthermore, the present invention relates to a catalyst system for gas-phase reaction using a preliminary zone.

Abstract: Catalyst systems for preparing carboxylic acids and/or anhydrides, the catalyst system comprising a reaction zone and a layered catalyst, the reaction zone comprises a gas inlet region and a gas outlet region, the layered catalyst comprises an active composition and one or more middle layers, one or more first layers disposed on a side of the one or more middle layers toward the gas inlet region, and one or more second layers on a side of the one or more middle layers toward the gas outlet region, wherein the active composition content of one or more of the middle catalyst layers, based on total mass of the layered catalyst, is lower than the active composition content of the one or more first catalyst layers and is lower than one or more second catalyst layers; and processes for gas phase oxidation employing a layered catalyst of the present invention.

Abstract: A process is described for converting a precatalyst which comprises an inert support, an organic carbon source and a multimetal oxide comprising silver and vanadium to a gas phase oxidation catalyst which comprises the inert support and a catalytically active silver vanadium oxide bronze, by treating the precatalyst thermally at a temperature of at least 350° C. in a gas atmosphere which comprises less than 10% by volume of oxygen, wherein, before the thermal treatment, the amount of the carbon source in the precatalyst is adjusted to a value below a critical amount The carbon content is reduced by burning-off at a temperature of from 80 to 200° C. in an oxygenous atmosphere with decomposition of a portion of the carbon source. The catalysts obtained serve for the gas phase partial oxidation of aromatic hydrocarbons to aldehydes, carboxylic acids and/or carboxylic anhydrides.

Abstract: The present invention relates to a catalyst system for preparing carboxylic acids and/or carboxylic anhydrides which has at least three catalyst layers arranged one on top of the other in the reaction tube, with the proviso that the most inactive catalyst layer is preceded in the upstream direction by a more active catalyst layer. The invention further relates to a process for gas phase oxidation in which a gaseous stream which comprises one hydrocarbon and molecular oxygen is passed through a plurality of catalyst layers, the least active catalyst layer being upstream of a more active catalyst layer.

Abstract: Processes for preparing ethylene oxide, the process comprising: (a) providing a catalyst-comprising microchannel reactor; (b) feeding (i) an ethylene-comprising stream and (ii) a stream comprising oxygen, an oxygen source or both, into the microchannel reactor; and (c) continuously feeding one or more components selected from the group consisting of alkyl halides, nitrogen-comprising compounds, and mixtures thereof into the microchannel reactor in a concentration of from 0.3 to 50 ppm by volume, each based on the total volume flow of all streams introduced into the reactor.

Abstract: A process is described for producing a catalyst for gas-phase oxidations, in which a suspension of TiO2 and V2O5 particles is applied to a fluidized inert support, wherein at least 90% by volume of the V2O5 particles have a diameter of 20 ?m or less and at least 95% by volume of the V2O5 particles have a diameter of 30 ?m or less. The defined particle size distribution of the V2O5 allows a high coating efficiency.

Abstract: A process is described for preparing phthalic anhydride by catalytic gas phase oxidation of o-xylene. In, in a main reactor, a gaseous mixture of o-xylene and an oxygenous gas is passed through at least two reaction zones whose temperature can be controlled independently, and converted to a gaseous intermediate reaction product which comprises unconverted o-xylene, phthalic anhydride underoxidation products and phthalic anhydride, and the intermediate reaction product is introduced into a postreactor, wherein the temperature of the reaction zones in the main reactor is regulated in such a way that the concentration of unconverted o-xylene in the intermediate reaction product is at least 0.5% by weight. The process allows an increase in the overall yield of phthalic anhydride without or without significant deterioration in the product quality.

Abstract: The present invention relates to a catalyst system for preparing carboxylic acids and/or carboxylic anhydrides which has at least four catalyst layers arranged one on top of another in the reaction tube, the ratio of the bed lengths of the more selective catalyst layers to the bed lengths of the more active catalyst layers being between 1.4 and 2. The present invention further relates to a process for gas phase oxidation in which a gaseous stream which comprises a hydrocarbon and molecular oxygen is passed through a plurality of catalyst layers, the ratio of the bed lengths of the more selective catalyst layers to the bed lengths of the more active catalyst layers being between 1.4 and 2.

Abstract: A process is described for preparing phthalic anhydride by catalytic gas phase oxidation of o-xylene, in which a gaseous mixture of o-xylene and an oxygenous gas is converted in a main reactor to a gaseous intermediate reaction product which comprises unconverted o-xylene, phthalic anhydride underoxidation products and phthalic anhydride, the heat of reaction which arises in the main reactor being removed at least partly by indirect cooling with a heat carrier medium, and the intermediate reaction product being introduced into a postreactor. The concentration of unconverted o-xylene in the intermediate reaction product is at least 1% by weight, and the sum of the concentrations of phthalic anhydride underoxidation products in the intermediate reaction product is at least 0.5% by weight. The process allows an increase in the overall yield of phthalic anhydride without or without significant deterioration in the product quality.

Abstract: Supported catalysts comprising a support having a mean diameter of ?78 ?m, a vanadium oxide, an antimony oxide, one or more alkali metal or alkaline earth metal oxides, and one or more oxides of tungsten, molybdenum, titanium, iron, cobalt, nickel, manganese, potassium, copper or mixtures thereof; processes for preparing said catalysts; and processes for preparing an aromatic or heteroaromatic nitrile in the presence of such a supported catalyst.

Abstract: Methods comprising: providing an oxidation catalyst bed; and starting up the oxidation catalyst at a temperature of 360° C. to 400° C. with an amount of air of 1.0 to 3.5 standard m3/h and a hydrocarbon loading of 20 to 65 g/standard m3, such that a hot spot having a temperature of 390° C. to <450° C. is formed in the first 7-20% of the catalyst bed.

Abstract: A multimetal oxide of the formula I, Aga-cQbMcV2Od*e H2O,??I where a is from 0.3 to 1.9, Q is an element selected from among P, As, Sb and/or Bi, is from 0 to 0.3, M is a metal selected from among Nb, Ce, W, Mn, Ta, Pd, Pt, Ru and/or Rh, c is from 0.001 to 0.5, with the proviso that (a-c)?0.1, d is a number which is determined by the valence and abundance of the elements other than oxygen in the formula I and e is from 0 to 20, and also precatalysts and catalysts produced therefrom for the partial oxidation of aromatic hydrocarbons are described.