摘要:
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 μm, 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 μm, (v) coating of the support body with the multimetal oxide particles, (vi) thermal treatment of the coated support body.
摘要:
A process for preparing butadiene from n-butenes, comprising the steps of: absorbing C4 hydrocarbons comprising butadiene and n-butenes, obtained from oxidative dehydrogenation of n-butenes, in an aromatic hydrocarbon solvent as an absorbent and removing uncondensable and low-boiling gas constituents comprising oxygen, low-boiling hydrocarbons, any carbon oxides, aromatic hydrocarbon solvent and any inert gases as gas stream d2, giving an absorbent stream laden with C4 hydrocarbons and the gas stream d2, and then desorbing the C4 hydrocarbons from the laden absorbent stream, giving a C4 product gas stream d1; and at least partly recycling the gas stream d2 as cycle gas stream a2 into the oxidative dehydrogenation zone, wherein the content of aromatic hydrocarbon solvent in the cycle gas stream a2 is limited to less than 1% by volume.