Process for the preparation of a nitrogen-containing Compound, comprising the Steps of: a) bringing N 2 , optionally NH 3 and optionally a recycle stream together with a carbon- and hydrogen-containing Compound or a carbon-containing Compound and H2 to form a reaction mixture, whereby the ammonia in the reaction mixture, if present, originates for at least 30 wt.% from the recycle stream; b) bringing the reaction mixture in contact with a catalyst at a temperature lying between 200°C and 800°C and at a space velocity lying between 10 2 and 10 6 ml/(g.h), said catalyst containing a metal M1 on a support, M1 being chosen from the group consisting of metals in group 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 of the IUPAC Periodic Table of Elements or mixtures thereof, whereby the nitrogen- containing Compound is formed; c) optionally separating, subsequent to step b), a portion of between 1 and 99 vol.% off from the reaction mixture, said portion being the recycle stream.