Process for producing free hydroxylamine aqueous solution

摘要

This invention provides a highly pure and highly concentrated free hydroxylamine aqueous solution substantially not containing any salt or organic substance.This invention is a process for obtaining a free hydroxylamine aqueous solution, comprising the steps of letting an aqueous solution or slurry containing hydroxylammonium sulfate and an alkali react with each other, to obtain an aqueous solution or slurry containing free hydroxylamine and dissolved or partially precipitated sulfates; mixing the obtained reaction solution and a lower alcohol, to precipitate solid sulfates; separating a solution containing the lower alcohol and some of water by distillation from the aqueous solution remaining after separating and removing the solid sulfates; and obtaining a free hydroxylamine aqueous solution from the remaining solution by distillation.