Sciencemadness Discussion Board

PP cone lined or PTFE cap for HCl

Mr. Rogers - 30-10-2017 at 20:36

I have 1L of 37% HCl in a plastic bottle that I want to transfer to several small glass bottles. I have polypropylene cone-lined Bakelite caps and also caps lined with Teflon disks with silicone backings.

Which would be the better choice for storing the HCl if I intend to use it very slowly and sparingly?

LearnedAmateur - 31-10-2017 at 03:51

They should all be fairly resistant to chemical attack - I know polypropylene and Teflon easily handle HCl, even H2SO4. Bakelite is the part I'm concerned about, I can't seem to find any information on its compatibilities but it has been stated that it is 'chemical resistant' ambiguously. Addition polymers, as these all are, are generally good at handling reagents. The ones to avoid are polyesters like PET since they can hydrolyse.

Are your Teflon lined caps like these, I.E a 'spongy' disc? If so, they will be fine, I've got these on a lot of my bottles containing hazardous reagents and they're untouched. Since your HCl isn't concentrated enough to be fuming, I'd be less worried about the caps deteriorating.

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