Abstract:
The invention relates to a method for producing phthalic anhydride by catalytic gas phase oxidation of o-xylol. According to said method, a gaseous mixture of o-xylol and an oxygen-containing gas is reacted in a primary reactor to give a gaseous intermediate reaction product which contains unreacted o-xylol, phthalic anhydride reaction products with a lower oxidation state and phthalic anhydride, the reaction heat produced in the primary reactor being at least partially carried off by indirect cooling with a heat exchange medium, and introducing the intermediate reaction product to a secondary reactor. The concentration of the unreacted o-xylol in the intermediate reaction product is at least 1% by weight, and the sum of the concentrations of phthalic anhydride of the lower oxidation state in the intermediate reaction product is at least 0.5% by weight. The method according to the invention allows an increase in total yield of phthalic anhydride without any or without substantial decrease in product quality.
Abstract:
Disclosed is a catalyst for gas phase oxidations, comprising an inert carrier and a catalytically active material that is applied thereupon and contains transition metal oxides, or a precatalyst. Said (pre)catalyst is obtained by processing the inert carrier with an aqueous suspension or solution of the transition metal oxides or the precursor compounds thereof. The suspension contains a binder dispersion while the binder is a copolymer of an a-olefin and a vinyl-C 2 -C 4 -carboxylate, the vinyl-C 2 -C 4 -carboxylate content of which amounts to at least 62 mole percent.
Abstract:
The invention relates to a device for the mixing, drying and coating of powdered, granular or moulded bulk material in a fluid bed, in particular, a method for the production of supported catalysts for gas phase oxidations, with a container (10), for holding the bulk goods, whereby a dished recess (17) is provided in a lower region (13) of the container (10), a central tube (27) for the introduction of a gas, whereby the central tube enters in an upper region (12) of the container (10), extending essentially axially downwards into the container (10) and opens out in the recess (17), an essentially annular deflector screen (29), fixed to the central tube (27) in the upper region (12) of the container (10), a guide ring (31), arranged in the lower region (13) of the container (10), which surrounds the central tube (27) over a part of the length thereof essentially concentrically with a separation (L) such that a first passage (34) is formed between the wall of the container (10) at the upper edge of the recess and the lower end (33) of the guide ring (31) and a second outlet (36) is formed between the deflector screen (29) and the upper edge (35) of the guide ring (31) and means for introduction of a fluid into the container (10), such as, for example, nozzles (21). Said device is characterised in that the external wall of the central tube (27) is at least partly provided with a non-stick coating (38). In a preferred embodiment the separation (L) between the wall of the central tube (27) and the wall of the guide ring (27) is greater than the open height (H3) of the first passage (34). The invention further relates to a method for the production of supported catalysts using such a device.
Abstract:
The invention relates to carboxylic acids and/or carboxylic acid hydrides which are produced in high yields by multi-step gas phase oxidation of an aromatic hydrocarbon. A mixture is produced in a first reaction stage containing intermediates with an oxidation stage lying between the aromatic hydrocarbon and the carboxylic acid or the carboxylic acid anhydride. The mixture is separated into intermediates of a low oxidation stage and intermediates of a high oxidation stage and intermediates of a high oxidation stage are oxidated in at least one further reaction stage in the absence of intermediates of a low oxidation stage to form the carboxylic acid and/or the carboxylic acid anhydride.
Abstract:
Method for production of ethylene oxide in a microchannel reactor, wherein an ethylene-containing material stream and an oxygen- or oxygen-source-containing material stream are fed to the microchannel reactor and the reaction to give ethylene oxide takes place in the catalyst-containing microchannel reactor. Alkyl halides are continuously fed to the microchannel reactor at a concentration of 0.3 to 50 ppm by volume with respect to the total volume stream of all material streams fed to the reactor.
Abstract:
In a process for the preparation of acrolein or acrylic acid or a mixture thereof from propane, the propane is subjected, in a first reaction stage, to a partial dehydrogenation under heterogeneous catalysis to give propene, of the components contained in the product gas mixture formed in the first reaction stage other than propene and propane at least a portion of the molecular hydrogen present is then separated off from said mixture and the product gas mixture is then used for the preparation of acrolein and/or acrylic acid by gas-phase catalytic propylene oxidation, molecular nitrogen being present for diluting the reaction gas mixture during the propylene oxidation.
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 μmol/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 μmol/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:
Disclosed is a catalyst for gas phase oxidations, comprising an inert carrier and a catalytically active material that is applied thereupon and contains transition metal oxides, or a precatalyst. Said (pre)catalyst is obtained by processing the inertcarrier with an aqueous suspension or solution of the transition metal oxides or the precursor compounds thereof. The suspension contains a binder dispersion while the binder is a copolymer of an a-olefin and a vinyl-C2-C4-carboxylate, the vinyl-C2-C4-carboxylate content of which amounts to at least 62 mole percent.
Abstract:
La invencion se refiere al uso de mezclas de dioxido de titanio de la forma de anatasa que tienen propiedades fisicas definidas para producir catalizadores, los cuales son particularmente apropiados para la sintesis de anhidrido ftalico. La invencion tambien se refiere a los catalizadores los cuales contienen dioxido de titanio de la forma anatasa que tiene propiedades fisicas definidas.
Abstract:
Un oxido de metal novedoso de la formula general (I) Aga-ccQbMcV12Od ?? e H2O (I) en donde a tiene un valor de 3?? 10, Q es un elemento seleccionado de P, As, Sb y/o Bi, b tiene un valor de 0.2 a 3, M e sun metal, c tiene un valor de 0 a 3, con la condicion de que (a-c)=0.1, d es un numero que se determina mediante la valencia y frecuencia de los elementos en la formula (I) distintos a oxigeno, y e tien un vaor de 0 a