Abstract: ?,?-ethylenically unsaturated aldehydes and/or carboxylic acids are prepared 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. In the process of the present invention, 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.

Abstract: ?,?-ethylenically unsaturated aldehydes and/or carboxylic acids are prepared 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. In the process of the present invention, 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.

Abstract: &agr;,&bgr;-ethylenically unsaturated aldehydes and/or carboxylic acids are prepared 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. In the process of the present invention, 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.

Abstract: Preparation of mixtures of O-phenoxyalkylhydroxylamines Ia and Ib ##STR1## and the corresponding salt mixtures by a) converting mixtures of isomers of O-(2-hydroxyethyl)oximes IIa and IIb ##STR2## with a sulfonyl halide III ##STR3## into a mixture of sulfonates IVa and IVb ##STR4## b) reacting this mixture of IVa and IVb with a phenol HO-Ar (V) to give a mixture of O-phenoxyalkoximes VIa and VIb ##STR5## c) hydrolyzing this mixture in the presence of an acid and, if desired d) liberating the O-phenoxyalkylhydroxylamines Ia and Ib from the resulting salts using a mineral acid.Compounds Ia/Ib and VIa/VIb are important intermediates for crop protection agents.