Oxygen balance
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Oxygen balance (OB, OB%, or Ω) is an expression that is used to indicate the degree to which an explosive can be oxidized,[1] to determine if an explosive molecule contains enough oxygen to fully oxidize the other atoms in the explosive. For example, fully oxidized carbon forms carbon dioxide, hydrogen forms water, sulfur forms sulfur dioxide, and metals form metal oxides. A molecule is said to have a positive oxygen balance if it contains more oxygen than is needed and a negative oxygen balance if it contains less oxygen than is needed.[2]
An explosive with a negative oxygen balance will lead to
Calculating oxygen balance
The procedure for calculating oxygen balance in terms of 100 grams of the explosive material is to determine the number of moles of oxygen that are excess or deficient for 100 grams of the compound.
X = number of atoms of carbon, Y = number of atoms of hydrogen, Z = number of atoms of oxygen, and M = number of atoms of metal (metallic oxide produced).
In the case of
Molecular weight = 227.1
X = 7 (number of carbon atoms)
Y = 5 (number of hydrogen atoms)
Z = 6 (number of oxygen atoms)
Therefore,
- OB% = −73.97% for TNT
Examples of materials with negative oxygen balance are e.g.
Oxygen balance and power
Because sensitivity, brisance, and strength are properties resulting from a complex explosive chemical reaction, a simple relationship such as oxygen balance cannot be depended upon to yield universally consistent results. When using oxygen balance to predict properties of one explosive relative to another, it is to be expected that one with an oxygen balance closer to zero will be the more brisant, powerful, and sensitive; however, many exceptions to this rule do exist.[citation needed]
One area in which oxygen balance can be applied is in the processing of mixtures of explosives. The family of explosives called
References
- ^ "The Oxygen Balance for Thermal Hazards Assessment". iomosaic.com. Retrieved 2022-10-11.
- ISBN 978-3-527-31656-4.
- ISBN 978-0-85177-329-2.
- ^ U.S. Explosive Ordnance, Bureau of Ordnance. Washington, D.C.: U.S. Department of the Navy. 1947. p. 580.
- ^ a b Barron, Andrew. Chemistry of the Main Group Elements.