This document discusses different types of chemical explosives, including PETN, RDX, lead azide, and rocket propellants. PETN, or pentaerythritol tetra nitrate, is a primary high explosive used as a booster or bursting charge. RDX, or cyclonite, is one of the most powerful explosives known and can be prepared through various methods. Lead azide decomposes exothermically when struck. Rocket propellants are either solid composites made of oxidizers and fuels bound together, or homogeneous single-, double-, or triple-base mixtures where ingredients have multiple roles as fuels, oxidizers and binders.

1. Chemical explosives
An explosive may be defined as a material, which under the influence of
thermal or mechanical shock, decomposes rapidly and spontaneously
with the evolution of great amount of heat and large volume of gases.
Classification: There are three fundamental types of explosive-
mechanical, atomic and chemical. We are, however, mainly concerned
here with chemical explosives. The chemical explosives are of two types:
(i) Detonating or high explosive (ii) Deflagrating or low explosives.
The high explosives are further divided into two classes: (a) Primary or
initiating explosives (b) Secondary high explosive

2. Chemical explosives
PETN or Penthrit: Pentaerythritol tetra nitrate [C(CH2ONO2)4] is one of the
most brisant and sensitive military high explosive. For use as a booster
explosive, a bursting charge or a plastic demolition explosive, it is
desensitized by admixture with TNT (the mixture is called pentrolite) or by
the addition of wax. PETN is prepared by the nitration of pentaerythritol
with strong 96% HNO3 at about 5oC.
The decomposition of PETN probably take place in the following
way: C(CH2ONO2)4---- 4H2O + 3CO2+ 2CO+ 2N2

3. Chemical explosives
RDX or CYCLONITE: RDX or cylconite is sym-trimethylene trinitramine
[(CH2)3N3(NO2)3]. It is one of the most powerful explosives known at
present time. It can be prepare by following methods:
a. Hale method: A British chemist G. C. Hale (1925) prepared RDX by
destructive nitration of hexamethylene tetramine with conc. HNO3
(CH2)6N4 + 3HNO3 -------- C3H6O6N6 + 3HCHO + NH3
b.Ebele-Schlessler-Ross method: This method consists in addition of
paraformaldehyde and amonium nitrate to acetic anhydride at 70oC.
3HCHO + 3NH4NO3 + 6 (CH3CO)2O ------ [(CH2)3N3(NO2)3] +12CH3COOH
RDX is used in a mixture with TNT and aluminum, known as torpex, for
mines, depth charges, and torpedo warheads. It is also used as an
ingredient for explosive for shells and bomb and it is desensitized by wax
or oily material

4. Chemical explosives
Lead Azide: Lead azide can be prepared by treating sodium azide
(prepared from sodium amide and nitrous oxide) with lead acetate or lead
nitrite.
NaNH2 + N2O – NaN3 + H2O
NaN3 + Pb(CH3COO)2---Pb(N3)2 + 2CH3COONa
Lead azide decompose exothermically on being struck in the following
manner
Pb(N3)2 ……. Pb + 3N2 + 0.6 Kcals

5. Chemical explosives
Rocket propellant is the reaction mass of a rocket. This reaction mass is
ejected at the highest achievable velocity from a rocket engine to produce
thrust. The energy required can either come from the propellants themselves,
as with a chemical rocket, or from an external source, as with ion engines.
Solid propellants come in two main types. "Composites" are composed mostly
of a mixture of granules of solid oxidizer, such as ammonium
nitrate, ammonium dinitramide, ammonium perchlorate, or potassium
nitrate in a polymer binding agent, with flakes or powders of energetic fuel
compounds (examples: RDX, HMX, aluminium, beryllium). Plasticizers,
stabilizers, and/or burn rate modifiers (iron oxide, copper oxide) can also be
added.
Single-, double-, or triple-bases (depending on the number of primary
ingredients) are homogeneous mixtures of one to three primary ingredients.
These primary ingredients must include fuel and oxidizer and often also
include binders and plasticizers. All components are macroscopically
indistinguishable and often blended as liquids and cured in a single batch.
Ingredients can often have multiple roles. For example, RDX is both a fuel and
oxidizer while nitrocellulose is a fuel, oxidizer, and structural polymer.