1. A PROCESS FOR THE PREPARATION OF AN UNSYMMETRICAL HYDRAZINE WHICH COMPRISES PURIFYING A NITROSAMINE BY FRACTIONAL DISTILLATION OF SAME AT A DISTILLATION COLUMN EFFICIENCY OF AT LEAST FOUR THEORETICAL PLATES, AND RECOVERING A PURIFIED NITROSAMINE AS A PRODUCT FRACTION OF SAID DISTILLATION; REACTING THE SAID PURIFIED NITROSAMINE WITH MOLECULAR HYDROGEN, AT A PRESSURE ABOVE ATMOSPHERIC IN THE PRESENCE OF A CATALYTIC MATERIAL HAVING A SURFACE AREA OF AT LEAST ABOUT 15 SQ. M./G. AND COMPRISING, AS THE CATALYST, A GROUP VIII METAL SELECTED FROM THE GROUP CONSISTING OF PALLADIUM, PLATINUM, RHODIUM, NICKEL, COBALT AND IRIDIUM, TO FORM THE CORRESPONDING HYDRAZINE; AND RECOVERING AN UNSYMMETRICAL HYDRAZINE, SO PRODUCED, AS PRODUCT OF THE PROCESS.