Sciencemadness Discussion Board

safe storage of PCl5

chemrox - 4-7-2012 at 12:25

I transferred my PCl5 to a Teflon bottle after it ate up the bottle cap. Now the Teflon bottle is starting to deform. The bottom sort of drops in the middle; the opposite of any new bottle that has a slight upward bow. What can I store this stuff in (after I distill it)?

Endimion17 - 4-7-2012 at 14:11

Seal it into an ampoule, glass tubing or a test tube. That's how it's supposed to be stored, and that's how it is being shipped from the companies that produce it.

DJF90 - 4-7-2012 at 14:38

I agree and disagree with Endimion, in that the best way to store it is sealed in glass, but I have 2x250g from aldrich. However, the contents have significantly eaten the caps.

woelen - 5-7-2012 at 02:16

I store my PCl5 in Schott Duran media bottles with teflon-lined caps (search for GL 45 media bottles, with the red caps or blue caps with a red rim). These bottles and especially these caps are expensive. I had good luck to find a set of second hand bottles and caps. Have a look at the wiki page for bromine:

http://en.wikipedia.org/wiki/Bromine

This shows some of my bromine, stored in such a bottle with a suitable cap.

My PCl5 is stored in a similar bottle, one of 250 ml, with the same type of cap.

woelen - 15-3-2016 at 02:55

Even the Schott Duran bottle with teflon lined GL45 cap did not keep well. Last weekend I saw that the bottle was very frosty on the outside and when I opened it, I was greeted by a huge cloud of HCl (the bottle was pressurized) and the teflon liner was completely rotten away and there was a burst in the red screw cap. The PCl5 inside the bottle still was good (dry, pale green/yellow and after a little poking in it with a glass rod I obtained a free flowing powder). I ampouled the whole lot into eight 20 ml ampoules, each ampoule holding between 25 and 30 grams of PCl5.

I also had a small 50 ml bottle with GL25 cap and teflon liner, holding 25 to 30 grams of PCl5. When I opened this bottle, there also was a big cloud of HCl. The screw cap had partly become liquid on the inside and dirty brown drops of liquid were in the PCl5 and along the glass walls of the little bottle. Approximately 30 seconds after I opened the bottle, the screw cap suddenly made a loud POP noise and it ejected a huge amount of brown mud (looked like diarrhea). I dumped the whole lot (bottle with dirty PCl5 and the totally wrecked cap) in a big bucket of water, allowed the PCl5 to dissolve with a hissing noise, and then dumped the bottle and cap in the waste bin and flushed the dissolved PCl5 down the drain (it is neutralized to harmless H3PO4 and dilute HCl). My entire lab was filled with dense clouds of HCl, I really had to leave the room for a while (after putting the window open and switching mechanical ventilation to max speed).

PCl5 cannot be stored for extended periods of time (years) in anything else than completely sealed glass ampoules or glass tubes!!

I have a similar problem with my POCl3 and NbCl5. I also have to ampoule these chemicals. The POCl5 already has dirty drops of liquefied remnants of the cap in it. I will have to distill this liquid before ampouling. I only have 90 ml of POCl3, so ampouling that is an easy job.

I already ampouled my SOCl2, my 20 ml of PBr3 (I have made that myself) and PCl3 (appr. 75 ml). I will not do experiments anymore with these chemicals, I just keep them around in their ampoules and maybe in the future I will pick up again with them. For now I simply quit using them. Too extreme for a home lab. Storing bromine is a child's play, compared to storing acid chlorides and acid bromides like PCl5, POCl3, SOCl2.


[Edited on 15-3-16 by woelen]

PTFE Caps

Deathunter88 - 15-3-2016 at 06:29

The problem with a lot of chemicals is that they attack the cap of the container they are stored in. Bromine and PCl5 are all examples of such chemicals. It has always been recommended that these be ampouled for long term storage. However, this may be time consuming and inefficient for chemicals used frequently. Here in China there are these caps made of pure PTFE that fit the standard GL45 bottles. Perhaps these can be used as an alternative to ampouling? I wanted to ask on here because #1 they are expensive (8 dollars each) so I want to make sure they are effective and #2 I wanted to just let the community know that these things exist. I have attached 2 photos of these I got from the seller.

Screen Shot 2016-03-15 at 10.25.09 PM.png - 608kB Screen Shot 2016-03-15 at 10.25.02 PM.png - 705kB

woelen - 15-3-2016 at 07:39

PTFE is somewhat porous, so I think that these are not the ultimate solution. The cap itself probably will good longer, but the bottle slowly will leak and on the bottle and around it, things will be covered with some "frost", due to escaping HCl or Br2 (depending on what is stored). I think that these bottles will be nice for a working stock, but long-term storage must be done in ampoules or glass tubes (e.g. sealed test tubes).

chemrox - 15-3-2016 at 11:08

I have around 500 ml. Storing in test tubes seems a rather tedious adventure and what is your technique for sealing them if one wanted to go that route? I can seal the ends of glass tubing but a little daunted by larger diameter items and headspace involved.

Evidently the PCl5 softened the bottle but is sitting in there OK. HCl frost continues..

[Edited on 15-3-2016 by chemrox]

Herr Haber - 15-3-2016 at 12:35

Quote: Originally posted by Deathunter88  
The problem with a lot of chemicals is that they attack the cap of the container they are stored in. Bromine and PCl5 are all examples of such chemicals. It has always been recommended that these be ampouled for long term storage. However, this may be time consuming and inefficient for chemicals used frequently. Here in China there are these caps made of pure PTFE that fit the standard GL45 bottles. Perhaps these can be used as an alternative to ampouling? I wanted to ask on here because #1 they are expensive (8 dollars each) so I want to make sure they are effective and #2 I wanted to just let the community know that these things exist. I have attached 2 photos of these I got from the seller.



I'd say it's a good price. At least Worth trying compared to what Duran has to offer.
I tried Duran Premium Caps for 90%+ nitric acid and even though they do the job (being a fluoropolymer) the inner seal still looks attacked by the acid.
Pressure buildup in the bottle made some condensate appear on the screw of the bottle but the caps themselves seemed unharmed by this.

I once had a red Duran cap with the PTFE seal completely destroyed (except the PTFE seal...) because I had left the pouring ring and the ring wasnt even.
Meaning: it still had bits from the mould it was made in. Therefore, even with a PTFE seal the vapors managed to get on the screw (as mentioned with the Premium Caps) and eat away the red cap itself.

Teachings from this:
- If it's corrosive and going to build any pressure: remove the pouring ring!
- If you'll be needing a pouring ring, get a scalpel aswell.
- There's no such thing as a perfect cap :-/

When I mentioned this to a biologist friend who happens to also work with corrosives she shrugged and said: "The first thing I do is remove the pouring ring since I'll be pipetting what I need from the bottle".
And since this is exactly the way I do things, I took it as an advice.

woelen - 15-3-2016 at 14:14

Ampouling 500 ml of powder/liquid in test tubes indeed is very tedious and also quite a lot of hassle. Ampouling PCl5 in test tubes will not be easy and will produce a lot of fumes.

I use real ampoules, which can be sealed much more easily and one ampoule can hold appr. 22 ml of volume, which is between 25 and 30 grams of PCl5 per ampoule. But even with these ampoules, it is quite tedious. I had to make 8 ampoules. But my stock of NbCl5 is larger, I expect I need to make appr. 20 ampoules of NbCl5 and I need to make 5 ampoules of POCl3. A lot of tedious work with nasty HCl fumes around. A typical job, which needs good weather.
Quote: Originally posted by chemrox  
I have around 500 ml. Storing in test tubes seems a rather tedious adventure and what is your technique for sealing them if one wanted to go that route? I can seal the ends of glass tubing but a little daunted by larger diameter items and headspace involved.

Evidently the PCl5 softened the bottle but is sitting in there OK. HCl frost continues..

[Edited on 15-3-2016 by chemrox]

JJay - 15-3-2016 at 16:02

I wonder if I should ampule my POCl3... I have 30 mL in a small amber bottle. I don't see any degradation on the cap, but the tamper-proof plastic wrap does show some cloudiness.

chemplayer.. - 16-3-2016 at 03:46

We've got experience with PCl3 and acetyl / propionyl chloride. They are a pain in the ass to store! We're not tried the 'red cap' GL45 lids but the regular ones will work for the acyl chlorides provided that you line the thread with teflon tape. We also keep them in the freezer so that they're less volatile and the cool environment is dryer and they tend to decompose less quickly. Even so the shelf life is a few months before you start to get considerable degradation. (The freezer is probably not very happy either, but don't worry there's no food in it!)

PCl3 is a different story of nastiness. The speed at which it reacts with the moisture in the air forming HCl and generating a pressure build-up in the storage container is scary.

We've found though that an old school glass bottle with a ground glass stopper (and some hi vac grease on the stopper) does work. If the bottle neck and stopper are quite small, you can pipette out the liquid without introducing much moist air in, and then immediately close the bottle again. This then goes into a plastic bag which is tied over the top of the glass stopper, keeping it in.

We know it works because any HCl released would generate condensation inside the plastic bag (and there's virtually none). Likewise the reagent is still good and going strong after 9 months.

If we got some PCl5 we'd try out an old school ground glass medicine bottle in the same way, but with a question of whether it would work given the likely greater displacement of air in accessing the contents.

Dr.Bob - 16-3-2016 at 03:55

I have worked with many of those, especially POCl3 and thionyl chloride. Aldrich used to use a glass bottle with a hard reddish fluropolymer cap, those did well, but they have a few others ones now, seems different one each bottle, sometimes different from year to year. Most do OK, as some of our bottles are several years old, and they seem to have kept well. But I did find an empty bottle of bromine (not Aldrich) recently, cleaning out a corrosives cabinet, where the cap had cracked and leaked for a while, brominating the cabinet quite well (rusty and nasty goo from metal shelf). I would try to use a narrow mouth bottle, if possible, then the cap has a smaller surface area. The media bottles can work, but the lid has a very large area to leak/diffuse through. But if you find the old Aldrich bromine type bottles with a narrow mouth and a reddish cap, keep them, they do very well and handle most anything I have ever seen.

DJF90 - 16-3-2016 at 05:28

Quote: Originally posted by Dr.Bob  

But if you find the old Aldrich bromine type bottles with a narrow mouth and a reddish cap, keep them, they do very well and handle most anything I have ever seen.


The 100 mL CDCl3 bottles that come from most suppliers (e.g. Aldrich, Cambridge Isotope Labs) have narrow necks and PTFE lined caps. Maybe they'd be suitable?

woelen - 16-3-2016 at 05:39

CDCl3 does not sound like a corrosive thing (probably comparable to CHCl3 which is not really corrosive) and I do not expect bottles for storing a relatively non-corrosive (although volatile) compound to be suitable for long-term storage of PCl5, NbCl5, POCl3, SOCl2 and so on.

Dr.Bob - 16-3-2016 at 09:19

The Cambridge 100 ml bottles are very good, qorpak bottles, with green PTFE caps. And Alfa Aesar sells bromine in that exact bottle, so I know it handles it pretty well. They should handle most other chemicals OK, but the worst corrosives can even corrode or leak through those caps. They are just trying to keep the CDCl3 clean and from absorbing stuff from the cap and liner, I suspect. It will leach stuff from many other caps I have seen, especially polypropylene caps or liners.

woelen - 16-3-2016 at 11:26

I just ampouled my PCl3 now (in 8 ampoules, each holding well over 10 ml). Ampouling the PCl5 was much more unpleasant than ampouling the PCl3. PCl5 is MUCH harder on the nose and upper throat than PCl3 I can say now. Probably this is due to formation of H3PO4, which is non-volatile, while being quite a strong acid and hence it remains in the tissue. PCl3 forms H3PO3 and this only is a weak acid. The accompanying HCl quickly disappears and only stings when inhaled and immediately after.

My next project will be distilling my now brown POCl3 and then ampouling that as well. Finally my NbCl5 must be ampouled. Then I finally will have no issues anymore with storage of these nasties.

Magpie - 16-3-2016 at 13:29

Six months ago I made 39g of PCl5. I placed this in a 100ml wide-mouth Qorpak bottle with the green thermoplastic lid and ptfe liner. I then dipped the lid in molten paraffin. At this time I don't see any evidence of a breach. But I can't see the inner surface of the lid or threads so can't tell their status.

[Edited on 16-3-2016 by Magpie]

[Edited on 16-3-2016 by Magpie]

Herr Haber - 16-3-2016 at 13:35

Woelen, get a gas mask !
I suppose that you have a suitable working environment, certainly better than mine but a gas mask is a very useful piece of Equipment.
Depending on the cartridge you have it can protect you against almost any chemicals you are likely to use (military grade filters). Otherwise, it's a perfect protection for the eyes and face. And if you're "just going to load lead azide" Inside something, there are cheaper filters that will stop particles.
The choice of filter is really important.
Israelis and UK gas masks are great. Russian... not so much, not even the newest ones.

mr.crow - 16-3-2016 at 19:50

According to len1's book the phosphorus halides have delayed toxicity like phosgene, yuck

My technique is to put bottles of nasty HCl releasing stuff into a tupperware box with a rubber seal. Snapware is a good brand (from Amazon). Put an open container of NaOH into the plastic box to absorb all moisture and HCL fumes. It seems to work very well.

woelen - 16-3-2016 at 23:59

@Herr Haber: I have a work place with very good ventilation and a good air-flow, but unfortunately it is not like a fume hood. It is an open work bench with air suction above it and a large open window close to the work bench. It works fine in almost all cases, but indeed with PCl5 it is not sufficient. I have more PCl5 to ampoule. This will be done outside.
Buying a gas mask is not an option for me. In NL it is considered quite suspicious if you buy a gas mask. I do not know of any source for a professional mask with suitable filters. Asking for such a thing certainly will raise quite some flags, people will think that I am preparing something not good at all. So, working outside is my only option now, until I make a real fumehood.

chemrox - 17-3-2016 at 16:59

@woelen- so what? Buy it on ebay or amazon. Or are there reasons you might be seen with it a lot?
And: "fuck 'em if they can't take a joke.." @ mr. crow: good idea about the tupperware etc.

[Edited on 18-3-2016 by chemrox]