Degradation and Shelf Life
The most important chemical reactions of phosphoryl halides is the hydrolysis of the bond between phosphorus and the fluoride. This P-F bond is easily broken by nucleophilic agents, such as water and hydroxide. At high pH, sarin decomposes rapidly to nontoxic phosphonic acid derivatives.
Sarin degrades after a period of several weeks to several months. The shelf life can be shortened by impurities in precursor materials. According to the CIA, some Iraqi sarin had a shelf life of only a few weeks, owing mostly to impure precursors. The persistence of sarin can be extended through the addition of certain oils or petroleum products.
Its otherwise short shelf life can be extended by increasing the purity of the precursor and intermediates and incorporating stabilizers such as tributylamine. In some formulations, tributylamine is replaced by diisopropylcarbodiimide (DIC), allowing sarin to be stored in aluminium casings. In binary chemical weapons, the two precursors are stored separately in the same shell and mixed to form the agent immediately before or when the shell is in flight. This approach has the dual benefit of solving the stability issue and increasing the safety of sarin munitions.
Read more about this topic: Sarin
Famous quotes containing the words shelf life, degradation and, degradation, shelf and/or life:
“The shelf life of the modern hardback writer is somewhere between the milk and the yoghurt.”
—John Mortimer (b. 1923)
“Gradually we come to admit that Shakespeare understands a greater extent and variety of human life than Dante; but that Dante understands deeper degrees of degradation and higher degrees of exaltation.”
—T.S. (Thomas Stearns)
“History is nothing but a procession of false Absolutes, a series of temples raised to pretexts, a degradation of the mind before the Improbable.”
—E.M. Cioran (b. 1911)
“The shelf life of the modern hardback writer is somewhere between the milk and the yoghurt.”
—John Mortimer (b. 1923)
“Greater love hath no man than this, that a man lay down his life for his friends.”
—Bible: New Testament Jesus, in John, 15:13.
In Ulysses, James Joyce wrote, “Greater love than this ... no man hath that a man lay down his wife for his friend.”