Patent ID: 7115775
Filing Date: 2006-10-03
Classification: B01J,C07C,G01N

Abstract:
1. A process for preparing α, β-ethylenically unsaturated aldehydes and/or carboxylic acids by means of a two-stage catalytic gas-phase oxidation in which a gas mixture comprising at least an alkane or alkene having from three to six carbon atoms and oxygen is subjected to a catalytic oxidation reaction in the first stage ( 1 ), oxygen is added to the gases produced in the first stage ( 1 ) and the resulting mixture is introduced into the second stage ( 2 ) in which it is subjected to a further catalytic oxidation reaction, wherein a signal which correlates with the oxygen content of the reaction gases before and/or after the addition of oxygen between the first and second stages ( 1 , 2 ) is generated and the oxygen addition is regulated as a function of the signal.