Verfahren zur Herstellung von Ammoniumnitrilosulfonat.

摘要

Ammonium nitrilosulphonate, which may be converted to ammonium sulphamate by hydrolysis, is obtained as a byproduct in the manufacture of ammonium hydroxylamine disulphonate by reacting sulphur dioxide with an aqueous solution of ammonium nitrite and ammonium bisulphite, or any other compound, e.g. ammonium hydroxide, yielding ammonium bisulphite with sulphur dioxide, by maintaining the pH- value of the reaction mixture initially between 5 and 7 and separating the precipitated ammonium nitrilosulphonate before the pH is reduced below this range. Sulphur dioxide-containing gas is supplied, in amount regulated to maintain the pH of the reaction liquor at 5.5-6, at 3 to packed reactor 1 countercurrent to ammonium nitrite and hydroxide solution introduced at 2. The liquor is drained to tank 6 and recycled through pump 8, cooler 10, and pipe 9 to reactor 1. Part of the recycled liquor is drained off through pump 12 to filter 13 to separate precipitated ammonium nitrilosulphonate. The filtrate passes to reactor 17 and passes therethrough, from distributor ring 16, countercurrent to sulphur dioxide-containing gas entering at 19 in amount regulated to give a pH of 3.5 in the resulting ammonium hydroxylamine disulphonate solution which is recovered and air blown to remove excess SO2. Reactor 17 has packed pipes 18 surrounded by a refrigerant jacket.