Fetching of ota solutions in sulfuric concentrated acid medium; said solutions, preparation onta

The present invention relates to: - a method of obtaining solutions containing 1,2,4-triazol-5-one (3) (OTA) in concentrated sulfuric acid; said method using 3-amino-1,2,4-triazole (1) (ATA) as a precursor of the OTA (3); - said solutions, and - a process for preparing the 3-nitro-1,2,4-triazol-5-one (4) (ONTA) from such solutions.