Sealing PHOSGENE 1

[israelkk]

Can Teflon (PTFE) be used for sealing PHOSGENE (i hope the spelling is correct)?

Can anyone recommend a suitable rubber compound that can do the job too?

 

[MortenA]

Ask the manufactor (of either compound). As far as i remember phosgen is extreamely toxic so they should know this. And if they dont then you should only use replies here as indicative (or directional if you prefere)

Best regards

Morten

 

[imok2]

Try this:

http://www.accessconnect.com/loctite_threadlocker_.htm

 

[NGiLuzzu]

Israelkk,

PHOSGENE (Formula: CCl₂O; Density: 3.4 kg/m³; Molecular Weight: 98.92; CAS Registry Number: 75-44-5), also called "Carbonyl chloride" or "Chloroformyl chloride", is a very dangerous and toxic gas: it was also used for chemical attacks during the I^st World War!

For the relevant "safety card", see:

http://www.ilo.org/public/english/protection/safework/cis/products/icsc/dtasht/_icsc00/icsc0007.htm

The problem of sealing and "fugitive" emissions is very critical when dealing with such a fluid... so I agree with MortenA: take this only as indicative, the issue is worth of more study!

Anyway, regarding the compatibility of PTFE, a catalogue of a sealing materials' Manufacturer (Angst+Pfister), for example, tells me that it is good with liquid phosgene (i.e. below 8°C at ambient pressure); Cloroprene (Neoprene) and fluorinate rubber (Viton^TM) also show a good behaviour.

Phosgene gas is not mentioned... may be because the prefer to be directly consulted in such delicate cases.

Hope this helps, 'NGL

 

[ArcticDesigner]

Teflon is excellent for sealing Phosgene. I have worked in the engineering department of several plants that produced Phosgene. As long as Phosgene is dry it can be contained in carbon steel. When moisture combines with Phosgene Hydrochloric Acid HCl is produced which is very corrosive. Wet Phosgene usually will usually require a high nickel content metals such as Hastelloy for piping. For piping flanges use Hastelloy/Teflon filled spiral wound gaskets for normally dry Phosegene. Valve seats and seals can be glass or graphite filled Teflon. Phosgene is very simular to Chlorine. In fact Phosgene is made by reacting Chlorine with Carbon Monoxide. For more information see

http://www.phosgenepanel.org/

 

[ArcticDesigner]

I forgot to respond to your question about a suitable rubber compound for Phosgene. "Kalrez" made by Du pont or "Chemraz" made by Greene-Tweed.

http://www.dupont-dow.com/Header/index.asp

http://www.gtweed.com/GTIntro.htm

 

[NGiLuzzu]

ArcticDesigner,
please take a look at Thread798-95255: chemical process Engineers seem to disagree with your judgement about PTFE in this service... I'm a bit confused ;-)

Bye, 'NGL