PEROXIDES IN BUTADIENE: ASTM D5799
EXPLANATION
Due to inherent danger of peroxides in butadiene, specification limits are usually set for their presence. Butadiene polyperoxide is a very dangerous product of the reaction between butadiene and oxygen that can occur. The peroxide has been reported to be the cause of some violent explosions in vessels that are used to store butadiene. This test method will provide values that can be used to determine the peroxide content of a sample of commercial butadiene. This test method covers the concentration range of 1 to 10 ppm by mass as available oxygen.
TEST SUMMARY
A known mass of the butadiene sample is placed in a flask and evaporated. The residue is then refluxed with acetic acid and sodium iodide reagents. The peroxides react to liberate iodine which is titrated with standard sodium thiosulfate solution using visual end point detection. Interfering traces of iron are complexed with sodium fluoride.
TEST PRECISION
Repeatability: 1.4 ppmw
Reproducibility: 3.4 ppmw
As no reliable source of butadiene polyperoxide is available, the actual bias of this test method is unknown; but published data reports that this test method determines 90 % of the polyperoxide.
