Chemical explosives PETN

A shock sensitivity test using a Mklll ballistic mortar (Variable initiator test) has been developed for that purpose 2 0 . One can measure the ease of occurrence of explosions for chemicals with low sensitivity which fall on the boundary of explosives and nonexplosives. The method is place 5g of the test chemical into a 100kg mortar and initiate it with a detonator, which is equivalent to 0.2 - 2.0g of the high explosive PETN. 

ABSTRACT. We describe an apparatus by which the detonation products of an explosive can be identified and whose relative concentrations can be determined quantitatively. These measurements can be made on products that have been formed in less than one microsecond after the passage of the detonation wave. The technique is based on the rapid quenching of chemical reactions by virtue of the free expansion of the products into vacuum. Of course, products that have been formed over a longer period of time and under different pressure/temperature conditions can also be studied. Time resolved molecular-beam mass spectrometry is used, so that whether detonation occurred or not in forming the products can be determined. We describe optical techniques, principally Schlieren photographs, that also confirm detonation. We report measurements made on six standard explosives, PETN, RDX, HMX, HNS, TNT and TATB, and one research explosive, nitric oxide. For none of the standard explosives do we measure product distributions that agree with model predictions based on equilibrium assumptions. A computer model of the free expansion is described briefly and its importance to the interpretation of the data is emphasized. 

PETN, discovered in 1895, is a solid melting at 141°C and is a very powerful explosive. It is very stable both chemically and thermally. 

The chemical structures of some common mifttary explosives are shown in Figure 1. These include the nitrate esters such as nitrocellulose (NC), NG, EGDN, and (PETN) nitroarenes such as trinitrotoluene (TNT, CH3—C6H2(N02)3), picric acid (HO—C5H2(N02)3), and 2,4,6-trinitrophenylmethylnitramine (tetryl) and nitramines such as RDX (C3H6N6O6), HMX (C4H8N8O8), and hexanitrohexa-azaisowurtzitane (CL— 20). Of these, only CL— 20 is new , that is, less than 50 years old [3]. Mixtures of oxidizers and fuels, such as AN and FO (called ANFO), are also secondary explosives. 

Pentaerythritol tetranitrate (PETN) (3) is a powerful explosive which exhibits considerable brisance on detonation (VOD 8310 m/s at = 1.77 g/cm ). It is the most stable and least reactive of the common nitrate ester explosives. The relatively high sensitivity of PETN to friction and impact means that it is usually desensitized with phlegmatizers like wax and the product is used in detonation cord, boosters and as a base charge in detonators. Pentaerythritol tetranitrate can be mixed with synthetic polymers to form plastic bonded explosives (PBXs) like detasheet and Semtex-IA. A cast mixture of PETN and TNT in equal proportions is known as pentolite and has seen wide use as a military explosive and in booster charges. The physical, chemical and explosive properties of PETN commend its use as a high explosive. 

Dynamites were retained for military purposes for some time for use in demolition charges. The disadvantage of these explosives lies in their limited chemical stability. Ultimately, therefore they were replaced by explosives that remain unchanged during storage (aromatic nitro compounds such as TNT, picric acid, and more recently TNT with cyclonite or PETN). 

STD-286B (1 Dec 1967), Method 601.1.1, "Titanous Chloride (0.2N Standard Solution) 20) Frank pristera , 1 Expiosives in Vol 12 of Encyclopedia of Industrial Chemical Analysis, Wiley, NY (1971), pp443—45 (Nitroglycerin and Dynamites, Analysis) 445 (PETN) 445 fit 451 (Ethyleneglycol Nitrates) - 451 (Other organic nitrate esters) 451 (Ammonium Nitrate) 452—60 (Identification of explosives by infrared spectroscopy) 460—62 (Analysis of unknown HE s) 461—67 (Nitrogen content determinations) 467—70 (Other methods for quality control) 470—71 (67 references on analytical procedures)... 

PETN was first prepared in 1894 by nitration of pentaerythritol. Commercial production of PETN could not be achieved until formaldehyde and acetaldehyde required in the synthesis of pentaerythritol became readily available about a decade before World War II. During World War II, RDX was utilized more than PETN because PETN was more sensitive to impact and its chemical stability was poor. Explosive compositions containing 50% PETN and 50% TNT were developed and called Pentrolit or Pentolite . This composition was used for filling hand and anti-tank grenades, and detonators. 

Tetryl. Tetryl or 2,4,6-trinitrophenyl methylnitramine, 3, was frequently used as a base charge in blasting caps, as the booster explosive in high-explosive shells, and as an ingredient of binary explosives. Tetryl is now replaced by PETN or RDX. Tetryl is a very toxic chemical [4-6],... 

---