Abstract: A method for the start-up of a process for the epoxidation of ethylene comprising: initiating an epoxidation reaction by reacting a feed gas composition containing ethylene, and oxygen, in the presence of an epoxidation catalyst at a temperature of about 180° C. to about 210° C.; adding to the feed gas composition about 0.05 ppm to about 2 ppm of moderator; increasing the first temperature to a second temperature of about 240° C. to about 250° C., over a time period of about 12 hours to about 60 hours; and maintaining the second temperature for a time period of about 50 hours to about 150 hours.

Abstract: A charging device for a tubular reactor has metering chambers which can be filled with filling material, such as, for example, catalytically coated carrier material, it being possible for a respective tube of the tubular reactor to be filled via a feed device which adjoins the metering chamber. The metering chamber has a sloping surface and an opposing surface for supporting the filling material, which run at an angle to one another.

Abstract: A process for regenerating a hydrogenation catalyst which has been used in a gas-phase hydrogenation, which comprises stripping at from 50 to 300° C. with a substance or a substance mixture which under the process conditions has no oxidizing action and is present in the gaseous state is described.

Abstract: The present invention relates to the use of a catalyst comprising at least one first catalyst zone located towards the gas inlet, a second catalyst zone located closer to the gas outlet and a third catalyst zone located even closer to or at the gas outlet for the preparation of phthalic anhydride by gas-phase oxidation of o-xylene and/or naphthalene, with the catalyst zones preferably each having an active composition comprising TiO2, characterized in that the catalyst activity of the first catalyst zone is higher than the catalyst activity of the second catalyst zone. Furthermore, a preferred process for the preparation of phthalic anhydride is described.

Abstract: The present invention relates to processes for improving or optimizing a catalyst for the preparation of phthalic anhydride by gas-phase oxidation of o-xylene and/or naphthalene, which comprises the following steps: a) provision of a starting catalyst (C) comprising at least one first catalyst zone located towards the gas inlet and a second catalyst zone located closer to the gas outlet, with the catalyst zones preferably each having an active composition comprising TiO2; b) replacement of part of the first catalyst zone by an upstream zone of a catalyst having a higher activity than the first catalyst zone in order to provide an improved catalyst. Furthermore, an improved catalyst obtainable by this process is described.

Abstract: The present invention relates to processes for improving or optimizing a catalyst for the preparation of phthalic anhydride by gas-phase oxidation of o-xylene and/or napthalene, which comprises the following steps: a) provision of a starting catalyst (C) comprising at least one first catalyst zone located towards the gas inlet and a second catalyst zone located closer to the gas outlet, with the catalyst zones preferably each having an active composition comprising TiO2; b) replacement of part of the first catalyst zone by an upstream zone of a catalyst having a higher activity than the first catalyst zone in order to provide an improved catalyst. Furthermore, an improved catalyst obtainable by this process is described.

Abstract: The present invention relates to the use of a catalyst comprising at least one first catalyst zone located towards the gas inlet, a second catalyst zone located closer to the gas outlet and a third catalyst zone located even closer to or at the gas outlet for the preparation of phthalic anhydride by gas-phase oxidation of o-xylene and/or naphthalene, with the catalyst zones preferably each having an active composition comprising TiO2, characterized in that the catalyst activity of the first catalyst zone is higher than the catalyst activity of the second catalyst zone. Furthermore, a preferred process for the preparation of phthalic anhydride is described.

Abstract: The invention relates to a process for preparing nitrogen-containing catalysts, comprising: a) preparation of an oxidic species comprising the following components: at least one metal M selected from groups Ib to VIIb and VIII of the Periodic Table of the Elements, it being possible for the same metal to be present in different oxidation states; if appropriate one or more promoters P selected from groups Ib to VIIb and VIII of the Periodic Table of the Elements, the lanthanides, and from groups IIIa to VIa of the Periodic Table of the Elements, excluding oxygen and sulfur; if appropriate one or more elements R selected from hydrogen, alkali metals and alkaline earth metals; if appropriate one or more elements Q selected from chloride and sulfate; oxygen, the molar proportion of oxygen being determined by the valency and frequency of the elements in the oxidic species other than other oxygen; b) reaction of the oxidic species with an amine component selected from ammonia, primary and secondary amines and

Abstract: A charging device for a tubular reactor has metering chambers which can be filled with filling material, such as, for example, catalytically coated carrier material, it being possible for a respective tube of the tubular reactor to be filled via a feed device which adjoins the metering chamber. The metering chamber has a sloping surface and an opposing surface for supporting the filling material, which run at an angle to one another.

Abstract: A process for regenerating a hydrogenation catalyst which has been used in a gas-phase hydrogenation, which comprises stripping at from 50 to 300° C. with a substance or a substance mixture which under the process conditions has no oxidizing action and is present in the gaseous state is described.