Ralph

I looked at the Dow data. The inhibitor depletion graph hits 0 ppm
inhibitor in about 105 days. Your sample is around 1600 days in your
storage. I would not consider this "normal" storage as the term is used in
the Dow document.

Your faculty could test the material for performance or run a peroxide test
on it. I suspect that the monomer concentration is fairly low.

Ultimately, this should be disposed of. You could put some ferrous sulfate
in the bottle which will kill any peroxides present, so it will not need to
be handled as highly reactive.

Have fun

nl

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-----Original Message-----
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**med.cornell.edu] On Behalf Of
Stuart, Ralph
Sent: Monday, June 27, 2016 6:48 AM
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
Subject: [DCHAS-L] "Normal storage periods"

I am investigating whether a container of inhibited Dicyclopentadiene that
is lightly used should be retained for future use. The Dow guidance document
on the subject says:
"Considering the inhibitor depletion of 4-TBC in DCPD Resin Grade (see
figure-5) and the fact that no polymer was formed during laboratory testing,
it was concluded that for normal storage periods a dose of 50 ppm will
provide sufficient guard against gum and peroxide formation and product
degradation."
Their graph shows degradation of the inhibitor over a storage period of 70
days.
https://urldefense.proofpoint.com/v2/url?u=http-3A__msdssearch.dow.com_Publi
shedLiteratureDOWCOM_dh-5F0957_0901b803809577d1.pdf-3Ffilepath-3Daromatics_p
dfs_noreg_778-2D04301.pdf-26fromPage-3DGetDoc&d=DQIFAg&c=lb62iw4YL4RFalcE2hQ
UQealT9-RXrryqt9KZX2qu2s&r=meWM1Buqv4IQ27AlK1OJRjcQl09S1Zta6YXKalY_Io0&m=Ck2
7htc85TRXjLKtcdUuqnJyTky1v4vfykG9JqNPQUA&s=Pf7oI2AAScAx2SoaudNnnAJyMiY150NrP
8qPE6Ec7ZU&e=

The question is whether for 95% Dicyclopentadiene, more than 5 years falls
into the category of "normal storage period"?

Thanks for any thoughts on this.

- Ralph

Ralph Stuart, CIH, CCHO
Chemical Hygiene Officer
Keene State College

ralph.stuart**At_Symbol_Here**keene.edu

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