Production of hydroxyl ammonium salts

Claim 1

IN A PROCESS FOR THE PRODUCTION OF A HYDROXYLAMMONIUM SALT BY CATALYTIC KHYDROGENATION OF NITRIC OXIDE IN AN AQUEOUS SOLUTION OF A STRONG MINERAL ACID WHEREIN A PLATINUM CATALYST IS SUSPENDED IN A SOLUTION CONSISTING ESSENTIALLY OF WATER AND A STRONG MINERAL ACID, A MIXTURE OF HYDROGEN AND NITRIC OXIDE IS INTRODUCED INTO THE SUSPENSION TO FORM SAID HYDROXYLAMMONIUM SALT, THE RESULTANT SOLUTION OF THE HYDROXYLAMMONIUM SALT IS SEPARATED FROM SAID CATALYST, AND THE CATALYST IS THEN SUSPENDED IN A FRESH SOLUTION CONSISTING ESSENTIALLY OF WATER AND A STRONG MINERAL ACID WITH REPEATED INTRODUCTION OF HYDROGEN AND NITRIC OXIDE TO FORM ADDITIONAL HYDROXYLAMMONIUM SALT, THE IMPROVEMENT FOR PROLONGING THE ACTIVITY OF THE CATALYST WHICH COMPRIESE: REPEATEDLY TREATING THE CATALYST SUSPENSION AT ANY STAGE OF THE PROCESS WITH NITRIC OXIDE, AFTER FIRST AT LEAST PARTLY DISPLACING THE GAS MIXTURE OF NITRIC OXIDE AND HYDROGEN WITH AT LEAST ONE GAS SELECTED FROM THE GROUP CONSISTING OF LNITROGEN, CARBON DIOXIDE AND NITRIC OXIDE, SAID REPEATED TREATMENT OF THE CATALYST SUSPENSION WITH NITRIC OXIDE BEING CARRIED OUT SUCH THAT THE SUPERNATANT GAS MIXTURE CONTAINS AN AMOUNT OF AT LEAST 10% BY VOLUME OF NITRIC OXIDE AFTER ANY RESIDUAL HYDROGEN HAS BEEN USED UP BY REACTION WITH NITRIC OXIDE.