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Comparison with analogues

The present invention relates to a process of
preparing hydroxylamine hydrochloride.
“Itis known that the hydrochloride of hy
droxylamine maybe obtained in the form of a’ , “more‘or less dilute aqueous solution by the elec
trolytic reduction‘ of nitric acid containing hy
‘l‘drochloric acid. For the preparation of hy
droxylamine hydrochloride in the solid state the _ aqueous solution was ‘hitherto ?rst electrolysed
‘ until it was free from nitric acid and then evap
orated under reduced pressure at a temperature as low as possible. If the nitric acid is not com
pletely removed before the evaporation, it
would, during the concentration, decompose the
hydroxylamine formed. I ’
‘ This known process has the drawback that the
elimination of the last residues of nitric acid is
possible only with sacri?ce of electrolytic efli
ciency‘ and that the‘evaporation is combined with _ losses innyield and with the di?iculty that‘ the
vessels used have small resistance to hot solu
tions’ containing hydrochloric acid. ‘
Now we haveiound that the solubility of the
hydroxylarnine hydrochloride depends to a very
large extent on the concentration of the excess of hydrochloric‘acid‘present; and that this prop
‘erty’may be used for directly, removing the hy
droxylamine hydrochloride in the solid state by salting out the product.‘ Thereby the special ad
’vantage‘ is attained that the entireyprocess con
‘ stitutes a cycle for the circulation of the cath
‘ olyte.’ According to ‘the‘lmeasurements made, the
‘solubility of hydroirylamine hydrochloride at 10°
C. in-the presence of hydrochloric acid; is as fol