Abstract: A process for recharging the reaction tubes of a tube bundle reactor with a new fixed catalyst bed, in which a heterogeneously catalyzed partial gas phase oxidation of an organic compound had been performed beforehand in a preceding fixed catalyst bed comprising Mo-comprising multielement oxide active compositions to form a steam-comprising product gas mixture, in which, before the recharge, solid deposit which had been deposited on the tube inner walls and comprises molybdenum oxide and/or molybdenum oxide hydrate is brushed away with the aid of a brush.

Abstract: The invention relates to a process for preparing aromatic amines by hydrogenation of corresponding nitroaromatics by means of hydrogen, and also an apparatus suitable for this purpose. In particular, the invention relates to a process for preparing toluenediamine (TDA) by hydrogenation of dinitrotoluene (DNT).

Abstract: The present invention relates to an apparatus of the loop Venturi reactor type for the continuous reaction of liquids with gases, in particular for hydrogenations, oxidations or acetylations, e.g. for the preparation of toluenediamine by hydrogenation of dinitrotoluene, and a process for the continuous reaction of liquid reactants with gaseous reactants in the apparatus. In the apparatus of the invention, the diversion of an internal circulatory flow in the reactor is effected by means of a diversion pan which is arranged underneath a heat exchanger.

Abstract: The present invention relates to an apparatus of the loop Venturi reactor type for the continuous reaction of liquids with gases, in particular for hydrogenations, oxidations or acetylations, e.g. for the preparation of toluenediamine by hydrogenation of dinitrotoluene, and a process for the continuous reaction of liquid reactants with gaseous reactants in the apparatus. Here, the cooling medium surrounds the tubes of the heat exchanger of the apparatus of the invention whereas the reaction takes place in the tubes.

Abstract: A process for recharging the reaction tubes of a tube bundle reactor with a new fixed catalyst bed, in which a heterogeneously catalyzed partial gas phase oxidation of an organic compound had been performed beforehand in a preceding fixed catalyst bed comprising Mo-comprising multielement oxide active compositions to form a steam-comprising product gas mixture, in which, before the recharge, solid deposit which had been deposited on the tube inner walls and comprises molybdenum oxide and/or molybdenum oxide hydrate is brushed away with the aid of a brush.

Abstract: A process for producing geometric shaped catalyst bodies K whose active material is a multielement oxide of stoichiometry [Bi1WbOx]a[Mo12Z1cZ2dFeeZ3fZ4gZ5hOy]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 d90A2 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·(d90A2)1.5·(a)?1?820. A shaped catalyst body obtained by the process. A catalyst obtained by grinding the shaped catalyst body. A process for heterogeneously catalyzing the partial gas phase oxidation of an alkane, alkanol, alkanal and/or an alkenal of 3 to 6 carbon atoms using the catalyst.

Abstract: A process for preparing aromatic amines by hydrogenation of nitroaromatics in the presence of catalysts, forming a fluid, amine-comprising reaction mixture in a reactor, wherein chromatographic analysis of the reaction mixture is carried out to determine the concentration of nitro and nitroso compounds in the reaction mixture.

Abstract: The present invention relates to a continuous process for preparing at least one aromatic amine by hydrogenation of at least one nitroaromatic by means of hydrogen, where a liquid phase comprising at least the aromatic amine and a gas phase comprising at least hydrogen are present, in the presence of a catalyst suspended in the liquid phase at a temperature of from 50 to 250° C. and a pressure of from 5 to 50 bar, wherein the pressure in the reactor is kept essentially constant by continuous adaptation of the amount of hydrogen fed to the reactor, the total amount of hydrogen fed to the reactor is monitored and the introduction of the at least one nitroaromatic is interrupted if the hydrogen uptake in the reactor is not at least 50 mol % of the amount of hydrogen required for stoichiometric reaction of the at least one nitroaromatic to form the at least one aromatic amine.

Abstract: A process for producing a ringlike oxidic shaped body by mechanically compacting a pulverulent aggregate introduced into the fill chamber of a die, wherein the outer face of the resulting compact corresponds to that of a frustocone.

Abstract: The invention relates to a process for preparing aromatic amines by hydrogenation of corresponding nitroaromatics by means of hydrogen, and also an apparatus suitable for this purpose. In particular, the invention relates to a process for preparing toluenediamine (TDA) by hydrogenation of dinitrotoluene (DNT).

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: Precipitations of nitrohydroxyaromatic salts out of the nitrated crude products obtained in the nitration of aromatic compounds after alkaline scrubbing, for example mononitrotoluenes, are prevented by contacting the nitrated crude products with an acidic ion exchanger. The nitrated crude products are preferably selected from a feedstream to a distillation column, a bottoms circulation stream of a distillation column and a feedstream to a vaporizer.

Abstract: The invention relates to a process for the continuous preparation of toluenediamine by liquid-phase hydrogenation of dinitrotoluene by means of hydrogen in the presence of a suspended, nickel-comprising catalyst in a reactor with a product isolation unit downstream of the reactor to give a product output from the reactor comprising a liquid phase comprising toluenediamine and dinitrotoluene, in which the nickel-comprising catalyst is suspended, wherein the concentration of dinitrotoluene in the liquid phase of the product output from the reactor in the region between the reactor and the downstream product isolation unit is set to a value in the range from 1 to 200 ppm by weight, based on the total weight of the liquid phase of the product output from the reactor.

Abstract: A process for preparing shaped catalyst bodies whose active composition is a multielement oxide, in which a finely divided precursor mixture with addition of graphite having a specific particle size is shaped to the desired geometry and then treated thermally.

Abstract: A process for producing geometric shaped catalyst bodies K whose active material is a multielement oxide which comprises the element Mo, the elements Bi and/or V and one or more of the elements Co, Ni, Fe, Cu and alkali metals, in which sources of the different elements are used to obtain a finely divided mixture which is coarsened to a powder by press agglomeration, the coarsened powder is used to form, by press agglomeration, shaped bodies V which are separated into undamaged shaped bodies V+ and into damaged shaped bodies V?, the undamaged shaped bodies V+ are converted by thermal treatment to the shaped catalyst bodies K, and the damaged shaped bodies V? are comminuted and recycled into the obtaining of the finely divided mixture.

Abstract: A process for charging a reactor with a fixed catalyst bed which comprises at least one annular shaped support catalyst body K, in which, before the charging, fragments formed in the preparation of the shaped catalyst bodies K are removed by screening.

Abstract: A process for producing a ringlike oxidic shaped body by mechanically compacting a pulverulent aggregate introduced into the fill chamber of a die, wherein the outer face of the resulting compact corresponds to that of a frustocone.

Abstract: A process for preparing (meth)acrolein by heterogeneously catalyzed gas phase partial oxidation of a precursor compound, in which the reaction gas mixture which comprises at least 3% by volume of precursor compound is passed through a fresh fixed catalyst bed whose active material is a multielement oxide which comprises the elements Mo, Fe and Bi and at least one of the elements Ni and Co, and the fixed catalyst bed is loaded with at least 40 l (STP)/l·h of precursor compound, and the precursor compound is converted to an extent of at least 90 mol %, wherein, over the first 8000 operating hours, during X=10 to 500 operating hours, the highest temperature of the reaction gas mixture in the fixed catalyst bed is 400 to 450° C. and, during the remaining 8000?X operating hours, is 300 to <400° C., and the loading of the fixed catalyst bed with organic precursor compound, averaged over the time, for the X=10 to 500 operating hours is greater than for the 8000?X operating hours.

Abstract: A process for preparing a coated catalyst in which a finely divided mixture of a multielement oxide comprising the elements Mo and V and a molybdenum oxide or a molybdenum oxide former is applied to the surface of a support body as an active composition.

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.