Preparation of unsaturated carboxylic acids and unsaturated carboxylic acid esters from alkanes and/or alkenes

摘要

Production of esters of unsaturated carboxylic acids involves passing a first gaseous stream comprising an alkane and molecular oxygen, and a second gaseous stream comprising an alcohol to the reactor. Production of esters of unsaturated carboxylic acids (a1) involves passing a first gaseous stream comprising an alkane and molecular oxygen, and a second gaseous stream comprising an alcohol to the reactor. The reactor containing at least one oxidation catalysts (b1) for the oxidation of the alkane to an ester of its corresponding (a1) with the alcohol. (b1) further comprises a first catalyst for the oxidation of the alkane to its corresponding alkene/unsaturated aldehyde and a second catalyst for the oxidation of the alkene/unsaturated aldehyde in the presence of the alcohol, to an ester of its corresponding (a1). The first catalyst is disposed in a first reaction zone and the second catalyst is disposed in a second reaction zone. The first reaction zone is disposed upstream of the second reaction zone relative to a direction of flow of the first gaseous stream through the reactor. The second gaseous stream is fed to the reactor intermediate the first and second reaction zone. The first reaction zone is operated at 500-1000[deg]C, and the second reaction zone is operated at 100-300 (preferably 200-400)[deg]C, with a first and second reaction zone residence time of not > 100 milliseconds. Independent claims are included for the following: (1) production of esters of (a1) involves reacting an unsaturated aldehyde with an alcohol to form an acetal; and passing a gaseous stream comprising the so-formed acetal and molecular oxygen to a reactor. The reactor containing at least one catalyst for oxidation of the acetal to its corresponding ester. The reactor is operated at 200-500[deg]C, with a reactor residence time of not > 100 milliseconds; and (2) production of (a1) involves passing a gaseous stream comprising an alkane and molecular oxygen to a reactor. The reactor containing at least one oxidation catalysts (b1) for the oxidation of the alkane to its corresponding (a1), the reactor is operated at 500 -1000[deg]C, with a reactor residence time of not > 100 milliseconds.