Abstract: Process for preparing a vinylidenecarboxylic acid or ester thereof, wherein a reaction gas comprising gaseous formaldehyde, molecular oxygen and an alkycarboxylic acid or ester thereof is brought into contact with a solid catalyst whose active composition comprises a vanadium-phosphorus oxide having an average oxidation state of vanadium of from +4.40 to +5.0 to give a product gas comprising the vinylidenecarboxylic acid or ester thereof.

Abstract: The invention relates to a process for preparing butadiene from n-butenes, which comprises the steps: A) provision of a feed gas stream a comprising n-butenes; B) introduction of the feed gas stream a comprising n-butenes and an oxygen-comprising gas into at least one oxidative dehydrogenation zone and oxidative dehydrogenation of n-butenes to butadiene, giving a product gas stream b comprising butadiene, unreacted n-butenes, water vapor, oxygen, low-boiling hydrocarbons, high-boiling secondary components, possibly carbon oxides and possibly inert gases; Ca) cooling of the product gas stream b by contacting with an organic solvent as coolant, Cb) compression of the product gas stream b in at least one compression stage, giving at least one aqueous condensate stream c1 and a gas stream c2 comprising butadiene, n-butenes, water vapor, oxygen, low-boiling hydrocarbons, possibly carbon oxides and possibly inert gases; D) separation of incondensable and low-boiling gas constituents comprising oxygen, low-boiling

Abstract: The invention relates to a process for preparing butadiene from n-butenes, which comprises the following steps: A) provision of a feed gas stream a comprising n-butenes; B) introduction of the feed gas stream a comprising n-butenes and an oxygen-comprising gas into at least one dehydrogenation zone and oxidative dehydrogenation of n-butenes to butadiene, giving a product gas stream b comprising butadiene, unreacted n-butenes, water vapor, oxygen, low-boiling hydrocarbons, possibly carbon oxides and possibly inert gases; C) cooling and compression of the product gas stream b in at least one cooling stage and at least one compression stage, with the product gas stream b being brought into contact with a circulated coolant to give at least one condensate stream c1 comprising water and a gas stream c2 comprising butadiene, n-butenes, water vapor, oxygen, low-boiling hydrocarbons, possibly carbon oxides and possibly inert gases; D) separation of incondensable and low-boiling gas constituents comprising oxygen,

Abstract: The invention relates to a coated catalyst which comprises (a) a support body, (b) a shell comprising a catalytically active multimetal oxide comprising molybdenum and at least one further metal, where the shell is made up of multimetal oxide particles having a d50 of from 6 to 13 ?m, and can be obtained by (i) production of a multimetal oxide precursor composition comprising molybdenum and at least one further metal, (ii) production of a shaped body from the multimetal oxide precursor composition, (iii) calcination of the shaped body composed of the multimetal oxide precursor composition to produce a multimetal oxide composition, (iv) milling of the shaped body composed of multimetal oxide composition to form multimetal oxide particles having a d50 of from 6 to 13 ?m, (v) coating of the support body with the multimetal oxide particles, (vi) thermal treatment of the coated support body.

Abstract: The invention relates to a catalyst which comprises a catalytically active multimetal oxide which comprises molybdenum and at least one further metal has the general formula (I) Mo12BiaMnbCocFedX1eX2fOx??(I), where the variables have the following meanings: X1=Si and/or Al; X2=Li, Na, K, Cs and/or Rb; a=0.2 to 1; b=0 to 2; c=2 to 10; d=0.5 to 10; e=0 to 10; f=0 to 0.5; and x=is a number determined by the valence and abundance of the elements other than oxygen in (I).

Abstract: The invention relates to a process for the oxidative dehydrogenation of n-butenes to butadiene, which comprises at least two production steps (i) and at least one regeneration step (ii), in which (i) in one production step, a starting gas mixture comprising n-butenes is mixed with an oxygen-comprising gas and brought into contact with a multimetal oxide catalyst which comprises at least molybdenum and a further metal and is arranged in a fixed catalyst bed in a fixed-bed reactor, and (ii) in a regeneration step, the multimetal oxide catalyst is regenerated by passing an oxygen-comprising regeneration gas mixture over the fixed catalyst bed and burning off the carbon deposited on the catalyst, where a regeneration step (ii) is carried out between two production steps (i), wherein the at least two production steps (i) are carried out at a temperature of at least 350° C. and the at least one regeneration step (ii) is carried out at a temperature which is not more than 50° C.

Abstract: The invention relates to a catalyst, in particular a coated catalyst, for the oxidative dehydrogenation of n-butenes to butadiene, its use and also a process for the oxidative dehydrogenation of n-butenes to butadiene.

Abstract: The invention relates to a process for the oxidative dehydrogenation of n-butenes to butadiene, which comprises two or more production steps (i) and at least one regeneration step (ii), in which (i) in one production step, a starting gas mixture comprising n-butenes is mixed with an oxygen-comprising gas and brought into contact with a multimetal oxide catalyst which comprises at least molybdenum and a further metal and is arranged in a fixed catalyst bed in a fixed-bed reactor at a temperature of from 220 to 490° C., and, before the relative decrease in conversion at constant temperature is >25%, (ii) in a regeneration step, the multimetal oxide catalyst is regenerated by passing an oxygen-comprising regeneration gas mixture at a temperature of from 200 to 450° C.