Glyceryl Trinitrate is prepared by nitration of glycerin (glycerol). In the process, glycerin is slowly tipped into a mix of concentrated nitric and sulfuric acids. The solution is slowly mixed. The temperature should never exceed 30 C otherwise there is a risk of explosion.

Glycerol		Glyceryl Trinitrate

 

The industrial manufacturing process uses a 50:50 mixture of fuming sulphuric acid and red fuming nitric acid. This produces nitronium ions, which attack glycerin at its negatively charged oxygen atoms. The functional group NO2 is thus added, adding extra oxygen atoms to the flammable substance glycerin.The reaction is exothermic. However, if the mixture becomes too hot, it explodes. Thus, the acid mixture is added slowly to the reaction vessel containing the glycerin. The reaction vessel itself is cooled with ice-cold water or some other coolant mixture at about 0 C . The vessel itself has an emergency trap door at its bottom, which hangs over a large pool of very cold water. If sensors in the mixture detect the temperature rising too rapidly, then the whole mixture can be dumped into the ice-cold water, which prevents an explosion if done in time.