PURPOSE: To efficiently recover an expensive platinum group metal compound as an insoluble material by adding a specific amount of hydroxide of an alkali (earth) metal to a reaction liquid when carbamic acid esters are produced from specific raw materials using a platinum group metal compound as a catalyst.
CONSTITUTION: When carbamic acid esters useful as precursors for agriculture or isocyanate are synthesized from (A) carbon monoxide and (B) compound having amino group, compound having nitro group and organic compound containing hydroxyl group, using a transition metal compound belonging to a platinum group of VIII group of periodic table and carrier as a catalyst 11 in the presence of a non-metal halide while additionally adding water or water and oxygen to reaction system, an expensive platinum group metal eluted into reaction liquid and/or compound thereof is efficiently and simply recovered by adding 0.0001-1wt.% hydroxide, carbonate, hydrogen carbonate or oxide of hydroxide or alkaline earth metal to the reaction liquid.
YAMADA RIKUO
MURAKAMI KAZUMI
