I used a soft silicone hose to carry ammonia at ~70 °C. I was surprised to later find the hose had hardened.

A quick materials compatibility search for silicone had given me a lot of info but an "I" (standing for "Insufficient Information") for ammonia. I wrongly assumed it would be OK.

What happened? What was produced? Can ammonia also react with or leach out elements from glassware? Should I throw the hose away? Will it become brittle?

  • 1
    $\begingroup$ Do you mean +70 or -70 ? As if you mean hot ammonia solution, it is quite weird idea what I would avoid at any cost. If you mean freezing cold liquid ammonia, than I bet is just temperature dependent mechanical properties change. You have included too little context to avoid confusion and wrong assumptions of the readers. You prior weak/sctrong acid question is on the way to be closed as not focused, this may be closed from lack of details or clarity. Try to improveit in both ways. The full scenario, its background and detailed observations. $\endgroup$
    – Poutnik
    Commented Nov 14, 2020 at 11:40
  • $\begingroup$ But preliminary guess is NH3 molecule is small, it can diffuse to silicone and chnage its properties. $\endgroup$
    – Poutnik
    Commented Nov 14, 2020 at 11:41
  • $\begingroup$ @Poutnik: Approximately 70C. So it would be NH3 diffusion into the silicone? Is silicone notably inappropriate for this kind of use? Is there any risk of cracking? Do you think the same would happen if the gas had been cooled prior to passing through the tubing? $\endgroup$
    – Hans
    Commented Nov 14, 2020 at 13:14


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