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:
Procedimiento para la obtención de anhídrido de ácido ftálico, en el que se conduce una corriente gaseosa, que comprende un hidrocarburo aromático seleccionado entre o-xileno y/o naftalina, y un gas que contiene oxígeno molecular, a temperatura elevada a través de un lecho de un primer catalizador, y un lecho de un segundo catalizador dispuesto en el sentido de circulación de la corriente gaseosa, con la corriente respecto al primer catalizador, con actividad más elevada que el primer catalizador, conteniendo la masa con actividad catalítica del primer catalizador, al menos óxido de vanadio, dióxido de titanio y óxido de antimonio, y ascendiendo la proporción de vanadio, calculado como V2O5, respecto a antimonio, calculado como Sb2O3, a 3, 5:1 4, 5:1, preferentemente 3, 8:1 a 4, 5:1, en el primer catalizador.
Abstract:
A catalyst for gas-phase oxidations which comprises an inert support and a catalytically active composition comprising transition metal oxides applied thereto, or a precatalyst, is described. The (pre)catalyst is obtained by treating the inert support with an aqueous suspension or solution of the transition metal oxides or their precursor compounds, where the suspension contains a binder dispersion and the binder is a copolymer of an alpha-olefin and a vinyl-C 2 -C 4 -carboxylate whose vinyl C 2 -C 4 -carboxylate content is at least 62 mol %.
Abstract:
A catalyst for gas-phase oxidations which comprises an inert support and a catalytically active composition comprising transition metal oxides applied thereto, or a precatalyst, is described. The (pre)catalyst is obtained by treating the inert support with an aqueous suspension or solution of the transition metal oxides or their precursor compounds, where the suspension contains a binder dispersion and the binder is a copolymer of an alpha-olefin and a vinyl-C 2 -C 4 -carboxylate whose vinyl C 2 -C 4 -carboxylate content is at least 62 mol %.
Abstract:
A description is given of a process for preparing aldehydes, carboxylic acids and/or carboxylic anhydrides, in particular phthalic anhydride, in which a gaseous stream comprising an aromatic hydrocarbon and molecular oxygen is passed at elevated temperature over a bed of a first catalyst and a bed which is made up of a second catalyst having a higher activity than the first catalyst and is located downstream of the first catalyst in the flow direction of the gaseous stream, wherein the catalytically active composition of the first catalyst comprises at least vanadium oxide, titanium dioxide and antimony oxide and the ratio of vanadium, calculated as V 2 O 5 , to antimony, calculated as Sb 2 O 3 , in the first catalyst is from 3.5:1 to 5:1. The source of antimony oxide used for the first catalyst is preferably particulate antimony trioxide having a mean particle size of from 0.5 to 5 mum. The process allows the desired oxidation products to be obtained in high yield over longer periods of time.
Abstract:
Un oxido de multimetal de la formula 1 Aga-cQbMcV2Od * e H2O en donde a es de 0.3 a 1.9, Q es un elemento seleccionado de entre P, As, Sb y/o Bi, es de 0 a 0.3, M es un metal seleccionado de entre Nb, Ce, w, Mn, Ta, Pd, Pt, Ru y/o Rh, c es de 0.001 a 0.5, con la condicion de que (a-c) ( 0.1, d es un numero que se determina por la valencia y abundancia de los elementos distintos a oxigeno en la formula 1 y e es de 0 a 20, y tambien precatalizadores y catalizadores producidos de los mismos, para la oxidacion parcial de hidrocarburos aromaticos se describen.
Abstract:
A catalyst is described which has a catalytically active composition which contains a phase A and a phase B in the form of three-dimensional delimited regions, wherein phase A is a silver-vanadium oxide bronze and phase B a mixed oxide phase based on titanium dioxide and vanadium pentoxide. The catalyst serves to prepare aldehydes, carboxylic acids and/or carboxylic anhydrides from aromatic or heteroaromatic hydrocarbons by gas phase oxidation.
Abstract:
In the preparation of a catalyst for gas phase oxidations, particles for an inert support are weighed into a fluid bed with a total mass (MTrager). A fluid is prepared as an aqueous solution or suspension of a catalytically-active material, or source, preferably TiO 2 and/or V 2O 5, with a content (BSusp) of bonding agents. The inert support particles are fluidized by a gas flow with a controlled temperature (TGas) and flow (QGas). The suspension is sprayed on to the fluidized inert support at a given dosage rate (QSusp). The values are selected to give ranges of 3000=QGas[m3/h]=9000, 1000=QSusp[g/min]=3500, 2=BSusp[wt.%]=18.60=MTrager[kg]=240, 75=TGas[[deg]C]=120. The ranges are such that, for a parameter (K) where K=0.020QGas-0.055QSusp+7.500BSusp-0.667MTrager+2.069TGas-7, the relationship 127.5=K=202 is satisfied.