The manufacture of pentaerythritol tetranitrate

Of the various methods of manufacturing PETN, the most widely used involves pouring pentaeiythritol into nitric acid ( /= 1.50-1.52) at a temperature not exceedbg 25°C. PETN is scarcely soluble in nitric acid. The product which is precipitated towards the end of the nitration, is filtered, washed with water and recrystallized from acetone. 

Specific gravity Roth [41] Friedrich [40] LaflBtte and Parisot [42]8 T. Urbaiiski and Galas [34]  

Certain workers (e.g. Stettbacher [44]) have suggested precipitating PETN from nitric acid by adding sulphuric acid at 20°C, filtering the product only after thii operation. This method is not to be recommended, since sulphuric acid causes the precipitation of certain impurities dissolved in nitric acid, so that the slight increase in yield is offset by the diminished purity of the product. 

Another method suggested, by T. Urbahski [45] consists in diluting the acid remaining after the nitration with water. If the final concentration of acid is 30-50% HNO3, complete precipitation of PETN occurs, while the impurities remain in the solution. Howev, the method can only be used if pentaerythritol of the highest purity is available as the raw material. In practice, two methods are in use (1) 

Pentaerythritol destined for the preparation of PETN must be exceptionally pure. In Germany, nitrating grade pentaerythritol ( grade M ) had to conform to the following technical specification  

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Refs 1) Anon, Process for the Manufacture of Pentaerythritol Tetranitrate Monoacrylate and Petrin Acrylate Propellants , Rohm Haas Co, Redstone Are, Ala (12 March 1956) 2) R.F. 

Uses. In the manufacture of pentaerythritol tetranitrate alkyd resins in surface-coating compositions pentaerythritol triacrylate and protective coatings insecticides pharmaceuticals... 

Pentaerythritol is used as a raw material for the explosive known as pentaerythritol tetranitrate (PETN). The most important end-use of pentaerythritol is in the manufacture of alkyd resins, in competition with glycerol. Due to its higher alcohol functionality, pentaerythritol gives alkyds somewhat better properties over glycerol. Other important end-uses include pentaerythritol resin esters used as floor-polish, fire-retardant, high pressure lubricants. Pentaerythritol is also used to produce chlorinated polyethers by the following reactions ... 

Lott et al. [106] report on the successful differentiation between different sources of pentaerythritol tetranitrate (PETN), RDX, cyclotetramethylene tetra-nitramine (HMX), and AN. The effect of using different raw materials and different manufacturing processes on the isotopic composition of the product was evaluated. The batch-to-batch and lot-to-lot variations of these explosives were also assessed. 

Secondary explosives, or high explosives, are generally less sensitive to heat and shock than primary explosives and are therefore safer to manufacture, transport, and handle. Most secondary explosives will simply burn rather than explode when ignited in air, and most can be detonated only by the nearby explosion of a primary initiator. Among the most common secondary explosives are nitroglycerin, trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), and RDX. 

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