Abstract:
The invention relates to a method for the oxidative dehydrogenation of n-butenes to form butadiene, said method comprising two or more production steps (i) and at least one regeneration step (ii). In said method: (i) in a production step a starting gas mixture containing n-butene is mixed with a gas containing oxygen and the mixed gas is brought into contact with a multi-metal-oxide catalyst containing at least molybdenum and another metal in a fixed-bed reactor, at a temperature of between 220 and 490 °C. A product gas mixture at least containing butadiene, oxygen and steam is thus obtained at the outlet of the fixed-bed reactor; (ii) in a regeneration step, to regenerate the multi-metal oxide catalyst, a regeneration gas mixture containing oxygen is passed over the catalyst fixed bed at a temperature between 200 and 450 °C and the carbon deposited on the catalyst is burnt off. A regeneration step (ii) is carried out between two production steps (i), the oxygen content of the product gas mixture at the outlet of the fixed-bed reactor is at least 5 vol. % and the duration of a production step (i) is less than 1,000 h.
Abstract:
The invention relates to a method for the oxidative dehydrogenation of n‑butenes to butadiene, comprising two or more production steps (i) and at least one regeneration step (ii), in which (i) in a production step an n‑butene-containing starting gas mixture is mixed with an oxygen-containing gas and is contacted in a fixed-bed reactor at a temperature of 220 to 490°C with a multimetal oxide catalyst arranged in a catalyst fixed bed, which multimetal oxide catalyst contains at least molybdenum, and one further metal, and, before the loss in conversion rate at constant temperature is > 25%, (ii), in a regeneration step the multimetal oxide catalyst is regenerated by passing an oxygen-containing regeneration gas mixture at a temperature of 200 to 450°C over the catalyst fixed bed and burning off the carbon deposited on the catalyst, wherein, between two production steps (i), one regeneration step (ii) is carried out, characterized in that, per regeneration step (ii), 2 to 50% by weight of the carbon deposited on the catalyst is burnt off.
Abstract:
En un proceso para preparar isoprenal y/o prenal mediante la puesta en contacto de una corriente de reactantes gaseosos que comprende isoprenol con un catalizador heterogéneo que contiene plata en presencia de oxígeno molecular para obtener una corriente de producto que contiene isoprenal y/o prenal, donde se mantiene una relación de peso de formaldehído con respecto a isoprenol de menos de 0.04 en la corriente de reactantes. El proceso mantiene una alta conversión y selectividad a lo largo del tiempo y evita el atasco del catalizador y la caída de presión.
Abstract:
Preparing catalytically active composition including a mixture made of a multi element oxide comprising molybdenum and vanadium and at least one oxide of molybdenum, comprises e.g. obtaining a spray-dried powder by spray-drying the aqueous solution comprising multi element oxide or an aqueous suspension, (iii) uniformly mixing the spray-dried powder, at least one powdery oxide of molybdenum and optionally at least one forming agent to obtain a mixture and forming geometrical precursor bodies, and (iv) thermally treating the geometrical precursor bodies. Preparing a catalytically active composition including a mixture made of a multi element oxide comprising molybdenum and vanadium and at least one oxide of molybdenum, comprises (i) preparing an aqueous solution by sources of the elemental constituents of the multi element oxide or an aqueous suspension with the condition that each of the sources passes through the state of an aqueous solution during producing the aqueous suspension, (ii) obtaining a spray-dried powder by spray-drying the aqueous solution or the aqueous suspension, (iii) uniformly mixing the spray-dried powder, at least one powdery oxide of molybdenum and optionally at least one forming agent to obtain a mixture and forming geometrical precursor bodies, and (iv) thermally treating the geometrical precursor bodies. Independent claims are also included for: (1) a catalyst comprising a geometric shaped support body, the catalytically active composition obtained by the above mentioned method, which is applied on the outer surface of the geometric shaped support body, and optionally a binding agent; and (2) heterogeneously catalyzed partial gas phase oxidation of methacrolein to methacrylic acid, using at least one catalyst obtained by the above mentioned method.
Abstract:
Catalyst comprises a support molded body with an active material, which is applied on the support molded body. The active material covering (q) is not > 0.3mg/mm 2>. The active material covering (q) is represented by an equation comprising (q) is equal to (Q/((100-Q)S m)) and Q is the active material of the catalyst in wt.%, and S m is the specific geometric surface area of the support molded body in mm 2>/mg. Independent claims are also included for: (1) preparing the catalyst, comprising coating the support molded body with the active material by mixing many support molded bodies, powdery active material and a liquid binder in a container without saturating the powdered active mass with the liquid binder, where the duration of the coating process is less than 30 minutes; and (2) producing alpha , beta -unsaturated carboxylic acid comprising carrying out gas phase oxidation of alpha , beta -unsaturated aldehyde with molecular oxygen over a fixed catalyst filling, where the fixed catalyst filling comprises a filling of the catalyst.
Abstract:
Procedimiento para producir isocianatos orgánicos con los pasos (a) aportación de una primera cantidad parcial de cloro, en donde el cloro de la primera cantidad parcial presenta un contenido de bromo y yodo libre o enlazado
Abstract:
The invention relates to a process for preparing butadiene from n-butane comprising the steps (A) providing an n-butane-containing feed gas stream, (B) feeding the n-butane-containing feed gas stream into a first dehydrogenation zone and nonoxidatively catalytically dehydrogenating n-butane to 1-butene, 2-butene and optionally butadiene to obtain a first product gas stream comprising n-butane, 1-butene and 2-butene, with or without butadiene and secondary components, (C) feeding the first product gas stream comprising n-butane, 1-butene and 2-butene, with or without butadiene and secondary components, into a second dehydrogenation zone and oxidatively dehydrogenating 1-butene and 2-butene to butadiene to give a second product gas stream comprising butadiene, n-butane and steam, with or without secondary components, (D) recovering butadiene from the second product gas stream.
Abstract:
Novel catalyst beds comprising a physical mixture of catalytically active and catalytically inactive shaped bodies, in which the catalytically inactive shaped bodies have rounded edges on the external rubbing surfaces.