# What's the purpose of an ice bath when preparing a nitration mix from KNO3?

Most preparations for nitrocellulose from $$\ce{(KNO3 + H2SO4)}$$ mixture require the use of an ice bath during the process of dissolving $$\ce{KNO3}$$ into $$\ce{H2SO4}$$. Last time I did this I omitted this step and the nitrocellulose turned out to be of very low quality, but there's a number of other possible causes I can think of. Therefore, for the sake of troubleshooting I have this question: What is the purpose of an ice bath during this step? Is it to just limit the fuming, or does omitting it lead to decomposition of $$\ce{HNO3}$$ significant enough to impact the yield? I did not see any brown $$\ce{NO2}$$ fumes coming out, just the typical white mist of acid.

• What generally can happen if you run an (exothermic) reaction at a higher starting temperature? – Karl Jan 3 '20 at 11:11
• It is an exothermic reaction and generates a lot of heat. – Nilay Ghosh Jan 3 '20 at 11:32
• It's not very exothermic, I imagine I'd have to dump all KNO3 at once to see it runaway. So it's just an additional safety measure? – Francis L. Jan 3 '20 at 11:51
• Its certainly also a safety measure. You are aware that there are three different basic types of nitrocellulose (mono, di, trinitrate) ? – Karl Jan 3 '20 at 14:45