摘要 |
Hydroxylamine sulphate is produced by reduction, in aqueous sulphuric acid solution, of nitric oxide by hydrogen, with a Pt metal containing catalyst. The reaction temperature (35-85 DEG C.) is chosen in relation to the molar ratio (0.3-1.5) of sulphuric acid to hydroxylamine sulphate plus ammonium sulphate (by-product), using a lower temperature for a lower ration and a higher temperature for a higher ratio. The process may be multi-stage, with a lower ration and temperature in each succeeding stage. The reaction may be continuous and each stage take place in a separate vessel, or may be discontinuous and in a single vessel with the temperature adjusted as the molar ratio alters with time as the reaction proceeds. According to an example, 75 DEG C. corresponded to a molar ratio of 1.5, 65 DEG C. to 0.7, 55 DEG C. to 0.4 and 45 DEG C. to 0.3. |