METHOD FOR PREPARING HYDROXYLAMINE AQUEOUS SOLUTION Russian patent published in 2005 - IPC

FIELD: chemical technology.

SUBSTANCE: invention relates to a method for preparing hydroxylamine aqueous solutions, to methods for its preparing by neutralization of its salts and the following isolation of indicated solutions. Method for preparing hydroxylamine an aqueous solution is carried out by neutralization of hydroxyl ammonium with a base in aqueous medium followed by isolation of hydroxylamine aqueous solution. Firstly, equipment used for carrying out the process is treated with 1-3% aqueous solution of alkyl-substituted phosphonic acid and/or its salt for 0.5-1 h. Alkyl-substituted phosphonic acid and/or its salts taken in the amount 0.01-0.1% of hydroxyl ammonium sulfate mass is added to the parent hydroxyl ammonium sulfate solution feeding to neutralization stage, and alkyl-substituted phenol taken in the amount 0.01-0.3% of hydroxylamine mass is added to the flow feeding to the isolation stage. Oxyethylidene diphosphonic acid (1-hydroxyethane-1,1-diphosphonic acid) and/or its salts, for example, sodium salt is used preferably as alkyl-substituted phosphonic acid. Sodium sulfate precipitate removing from neutralization stage is washed out with water and prepared liquid phase is returned to flow feeding to neutralization stage. Method can be carried out in equipment made of stainless. As result of carrying out the method colorless and stable in storage hydroxylamine an aqueous solution is prepared being without using the additional addition of stabilizing agents. Analysis showed absence of ions SO₄ ^2-. Atomic-absorption analysis showed that mass part of iron ions is 1.2 x 10^-6% that allows using the end product in electronic industry.

EFFECT: improved method for preparing.

3 cl, 7 ex