Production of propionic acid (ester), useful e.g. as an intermediate for herbicides, comprises catalytic hydrogenation of acrylic acid (ester), in the presence of a sulfur compound, with temperature control to prevent catalyst poisoning

摘要

Production of propionic acid (and/or its ester) (I), by catalytic hydrogenation of acrylic acid (and/or its ester) (II), in the presence of a catalyst containing at least one Group 8-11 metal and/or its compound. Sulfur-containing compounds are added, with temperature control, to prevent catalyst poisoning. Production of propionic acid (and/or its ester) (I), by catalytic hydrogenation of acrylic acid (and/or its ester) (II) with molecular hydrogen in the gas or liquid phase in the presence of a catalyst containing at least one Group 8-11 metal and/or its compound, includes: (1) addition of sulfur-containing compound(s) (III) to (II); (2) adjustment of (II) to a working pressure P in the vapor phase; (3) adjustment of the temperature of (II) to a value between the b.pt. of (II) and the m.pt. of the highest melting compound (III), under a pressure P; and (4) hydrogenation of the vapor phase directly or after condensation.