Process for the continuous preparation of n-butyraldehyde by selective hydrogenation of crotonaldehyde in liquid phase in the presence of a palladium alumina catalyst

摘要

For continuous preparation of n-butyraldehyde by selective hydrogenation of crotonaldehyde, the hydrogenation is carried out in liquid phase in the presence of a supported palladium/alumina catalyst containing the palladium in a surface zone of the support particles of 0.05 to 0.2 mm in thickness. The palladium content of this catalyst is 0.1 to 0.6% by weight. The alumina support, at a specific pore volume of 0.4 to 0.6 cm<3>/g, comprises pores having a diameter of > 7.5 nm and an inner surface area of 130 to 160 m<2>/g. The hydrogenation is carried out at absolute pressures of 5 to 50 bar and temperatures of 20 to 100 DEG C. n-Butyraldehyde is obtained in high purity without any troublesome byproducts.