Two-stage preparation process for α,ß-ethylenically unsaturated carboxylic acids and plant for the purpose

Abstract

The invention relates to a process for preparing α,β-ethylenically unsaturated carboxylic acids by two-stage catalytic gas phase oxidation of alkenes, in which a gas stream (1) containing at least one alkene, in a first reactor (A) in the presence of oxygen, is subjected to a first catalytic oxidation reaction over a first catalyst (K1) in the form of a multimetal oxide of molybdenum to obtain a gas stream (2) containing at least one α,β-ethylenically unsaturated aldehyde, the gas stream (2) containing the at least one α,β-ethylenically unsaturated aldehyde is guided through a connecting conduit (V) into a second reactor (B) and the gas stream (2) containing the at least one α,β-ethylenically unsaturated aldehyde, in the second reactor (B) in the presence of oxygen, is subjected to a second catalytic oxidation reaction over a second catalyst (K2) to obtain a gas stream (3) containing at least one α,β-ethylenically unsaturated carboxylic acid. In the process according to the invention, the gas stream (2) containing the at least one α,β-ethylenically unsaturated aldehyde is guided through an exchangeable structure (S) having high specific surface area which is disposed within the connecting conduit (V). The invention further relates to a corresponding plant.

Dependencies are inferred from the claim text.