DCHAS-L Archives, Jun 27 2016 - Re: [DCHAS-L] "Normal storage periods"

Dicyclopentadiene is an industrial byproduct of steam cracking, so it's dirt cheap. $25 for 100 grams from Aldrich. So there's no compelling reason to hold onto an excessive extra amount.

You usually find this in organometallic labs that use the cyclopentadienyl (Cp) ligand; DCPD undergoes a reversible Diels-Alder reaction upon heating to yield CpH (b.p. 46 =B0C) which is distilled off as it forms. Most of these groups would only need maybe tens of grams quantities at a time, so if you have multiple research groups working with the Cp ligand they should consider sharing a bottle between them rather than each group having their own even though it's "cheap" (in the up-front cost).

I recall that a few decades back, there was some excitement in industry that they could unload what was essentially an industrial waste by using olefin metathesis to ring-opening polymerize the DCP. The only problem was that the resulting plastic still had an odor to it, and the only use it found commercially was in outdoor applications such as snowmobile hoods. A quick Wikipedia glance suggests they haven't gone too much further with it (and also demonstrates the shortcomings of Wikipedia): https://en.wikipedia.org/wiki/Polydicyclopentadiene This article gives a little more info on current application: http://pslc.ws/macrog/pdcpd.htm and this one has some more detail on where the field is trying to head: http://www.jeccomposites.com/news/composites-news/polydicyclopentadiene-winning-over-construction-professionals

Rob Toreki

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On Jun 27, 2016, at 9:47 AM, "Stuart, Ralph" <Ralph.Stuart**At_Symbol_Here**keene.edu> wrote:

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_PublishedLiteratureDOWCOM_dh-5F0957_0901b803809577d1.pdf-3Ffilepath-3Daromatics_pdfs_noreg_778-2D04301.pdf-26fromPage-3DGetDoc&d=DQIFAg&c=lb62iw4YL4RFalcE2hQUQealT9-RXrryqt9KZX2qu2s&r=meWM1Buqv4IQ27AlK1OJRjcQl09S1Zta6YXKalY_Io0&m=Ck27htc85TRXjLKtcdUuqnJyTky1v4vfykG9JqNPQUA&s=Pf7oI2AAScAx2SoaudNnnAJyMiY150NrP8qPE6Ec7ZU&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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