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woelen
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Suitable test tubes for use with 48% HF
I just ordered some 48% HF and I am intending to do some small scale experiments with this. It apparently is capable of forming very interesting
fluoroanions with many elements in high oxidation states. E.g. with permanganates it can form fluoromanganates. I want to experiment with such high
oxidation state fluoro anions.
I know of the dangers of HF and I will take good safety measures, such as working outside and not handling tubes with my hands (I use clamps on long
sticks). The only issue I have is that HF attacks glass and it does so very quickly at concentrations around 50%.
I would like to do experiments with it in transparent tubes. What kind of tubes can I use for this? I have seen cheap "chemistry sets" for kids, which
contain little plastic "test tubes". Are these suitable for this kind of experiments, or are they eaten by HF in minutes. Any other suggestions for
suitable transparent tubes?
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Adas
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Polypropylene is quite resistant plastic. You can give it a try. 
Rest In Pieces!
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D-glucose
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What type of plastic are they? Then look up the appropriate chemical resistance sheet: http://www.borealisgroup.com/pdf/chemical-resistance/chemtab...
http://www.borealisgroup.com/pdf/chemical-resistance/chemica...
there's more but i can't see the test tube being made out of anything else in a cheap set.
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kristofvagyok
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Last time when I worked with cc. HF I made some HBF4 on a half liter scale. Easy reaction but highly exothermic.
I have done it in a simple PP bottle and I had no problem, except that when the reaction reached 80 Celsius the bottle softened a bit 
Try PE of PP, they will survive the acid even at elevated temperatures, but not sure that will they survive the permanganate...
I have a blog where I post my pictures from my work: http://labphoto.tumblr.com/
-Pictures from chemistry, check it out(:
"You can’t become a chemist and expect to live forever." |
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plante1999
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Polypropylene is the way I use to go, however Teflon is better when HF and heat is needed.
I never asked for this.
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Hexavalent
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Yes, but Teflon is opaque, making it undesirable for many test-tube reactions as woelen mentioned.
"Success is going from failure to failure without loss of enthusiasm." Winston Churchill
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Eddygp
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PP should be OK.
there may be bugs in gfind
[ˌɛdidʒiˈpiː] IPA pronunciation for my Username |
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Manifest
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Be careful working with that stuff.
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blogfast25
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The chemical resistances of PP and PE are very similar, also with respect to HF. Bu PE softens thermally way below PP. With PP you can at least use a
steambath, PE just becomes rubber at that temperature.
Both have the disadvantage of being somewhat opaque.
I'm wondering about clear PS? You might want to try these chemset tubes or some clear plastic tubes for candy, it might well work...
[Edited on 19-1-2013 by blogfast25]
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bfesser
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There is commercially available labware available made from perfluorinated polymers other than <a href="http://en.wikipedia.org/wiki/PTFE"
target="_blank">PTFE</a> <img src="../scipics/_wiki.png" />; examples: <a href="http://en.wikipedia.org/wiki/Perfluoroalkoxy"
target="_blank">PFA</a> <img src="../scipics/_wiki.png" />, <a href="http://en.wikipedia.org/wiki/ETFE"
target="_blank">ETFE</a> <img src="../scipics/_wiki.png" />, and <a
href="http://en.wikipedia.org/wiki/Fluorinated_ethylene_propylene" target="_blank">FEP</a> <img src="../scipics/_wiki.png" />. FEP is
fairly transparent, and containers made of it are <a
href="http://www.ebay.com/itm/BOTTLE-Teflon-FEP-500-mL-Nalgene-16A-500A-New-Fluoropolymer-Container-/330858105851" target="_blank">readily
available</a> <img src="../scipics/_ext.png" />. Prohibitively expensive <a
href="http://www.ebay.com/itm/NEW-Nalgene-Nalge-Nunc-1630-0032-Lab-Bottle-Teflon-PFA-Narrow-Mouth-1000ml-/360550664744" target="_blank">PFA
example</a> <img src="../scipics/_ext.png" />.
If memory serves, <a href="http://en.wikipedia.org/wiki/High-density_polyethylene" target="_blank">HDPE</a> <img
src="../scipics/_wiki.png" /> is sometimes used to store HF(aq)—no idea about heating, and don't take my word for it! Most manufacturers
and distributors of polymer labware have compatibility charts or data available.
[Edited on 7/9/13 by bfesser]
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blogfast25
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Teflon's MP is about 327 C (Wiki), so fairly respectable re. PE (about 100 C) and PP (about 160 C).
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woelen
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Based on all your responses I decided to buy polypropylene en polyethylene materials for storage and experimenting with HF.
I ordered all of the following for experimenting. I do not want to pour any 48% HF, I just want to use a small PE pipette and disperse the material in
the test tubes. I also ordered some beakers and other plasticware, so that I can make some larger scale things as well (e.g. making HBF4 from HF and
H3BO3).
50 ml beaker
100 ml beaker
PE disposable pipettes
10 pcs test tubes
10 ml measuring cylinder
25 ml measuring cylinder
The HF comes in a 1000 ml bottle, but I intend to store 70 to 80 ml of 48% HF in a little bottle and use that for experimenting, combined with the
plastic pipettes, shown above. This allows me to steer away from pouring 48% HF from bottle to test tube, I use the pipettes from this little bottle:
Bottle for storing work solution of HF
If something is missing from this list or something is wrong/unsafe, then please let me know. These are my first steps in HF-chemistry and I want it
to be as safe and non-destructive as possible.
This same seller also has fully transparent polystyrene test tubes, but I read that polystyrene is attacked by HF fairly quickly, so this does not
seem like a good choice. I think I have to live with the somewhat limited transparency of polypropylene, but the material looks sufficiently
transparent to be useful.
The entire order cost me around GBP 20 (including shipping), but I think it is a good investment and together with gloves, goggles and good
ventilation I think that this set allows relatively safe experimenting with HF.
[Edited on 20-1-13 by woelen]
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plante1999
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Take note that polypropylene/teflon equipment, when normally used is not corrodable, do not break from thermal shock/mechanical stress, which is very
interesting in an home lab, as glassware tend to break easily when abused. This make plastic wear a very good investment.
Talking of plastic wear, few day ago I saw Viton gloves on ebay. Such glove would be the holy grail of chemical safety.
I never asked for this.
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12AX7
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Just to modify that, however, PP has a glass transition temperature around room temperature, so you might be able to bend and stretch slightly warm
material, but it might break and tear at lower temperatures.
Tim
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BromicAcid
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At my place of employment they often use PTFE/PFA NMR tube liners for fluorinated compounds. The little liners fit right into the NMR tubes and
render them impervious to the attack of the fluorine species. Unfortunately when I was just searching for "PTFE test tube liners" the only results I
got involved liners for caps for test tubes. Such a thing may exist but I have yet to find it. Additionally for smaller scale work I have used 1/2"
PTFE tubing (the clear style) and snipped off sections and sealed the ends by heating and crimping with pliers. This makes little disposable test
tubes. I also have very good experience with the Nalgene FEP bottles, such a bottle contained a strong fluorinating reagent in dichloromethane for a
year without escaping! The dichloromethane alone posed a challenge but with the fluorinating agent it made a blistery molten mess of most other
bottles.
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woelen
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I have found Nalgene bottles as well, but these are too expensive for me. E.g. a 125 ml Nalgene FEP bottle has a price of EUR 60 or so (appr. $80).
This is four times the price I paid for the 48% HF and three times the price of all items I just ordered (see my previous post above) for
experimenting.
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blogfast25
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Quote: Originally posted by 12AX7  | Just to modify that, however, PP has a glass transition temperature around room temperature, so you might be able to bend and stretch slightly warm
material, but it might break and tear at lower temperatures.
Tim |
Glass transition (GT)? Normal isotactic PP (excluding atactic PP) is crystalline, although commercial grades often contain small amounts of ethylene
propylene copolymer (EPR or EPDM) to increase impact resistance (typically car bumpers e.g.). If it's opaque it probably contains some amorphous
impact modifier.
Commercial PP labware has some flexibility, even in the cold because the GT of the amorphous phase is well below 0 C.
Trust me, I was a rubber technologist for 10 boring years ;-)
[Edited on 20-1-2013 by blogfast25]
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Random
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Be sure to stock up on some calcium gluconate before handling it.
| Quote: |
Because of the ability of hydrofluoric acid to penetrate tissue, poisoning can occur readily through exposure of skin or eyes, or when inhaled or
swallowed.
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[Edited on 20-1-2013 by Random]
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12AX7
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Right, not glass, a ductile-brittle transition. I've seen it in consumer packaging before; lab bottles may be different as you note.
Rubber is an interesting subject! (...*Cough*?  )
Tim
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blogfast25
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Not after about 3 years!
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Darkblade48
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I was thinking the exact same thing --- better to have some way to treat HF burns, just in case. Better safe than sorry, as the saying goes.
I've never had to work with HF before, so I cannot offer any helpful advice on the the proper type of plasticware to use, unfortunately.
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bfesser
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Found the specific compatibility table I had in mind when I made my earlier post:
https://static.thermoscientific.com/images/D20481~.pdf
Out of personal curiosity, and possible benefit to others; I'm <a href="viewthread.php?tid=19098&page=23#pid272260">requesting the two
articles</a> regarding the treatment of HF burns with <a href="http://en.wikipedia.org/wiki/Calcium_gluconate" target="_blank">calcium
gluconate</a><img src="../scipics/_wiki.png" />, which are cited in the Wikipedia article.
[Edited on 7/9/13 by bfesser]
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woelen
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What's specific of calcium gluconate? Can calcium chloride or calcium nitrate not be used? I have both and could make some concentrated solution of
these into a gel. I could not find calcium gluconate gel on eBay, but I could find the pure chemical (500 grams, way too much for me). It is strange
that HF can be purchased from eBay, but that the antidote gel is not easily available.
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BromicAcid
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Perhaps some of it would be that if you used calcium nitrate you would neutralize your HF to nitric acid and calcium fluoride. However I was told
that calcium gluconate along with the gel medium permeate into the skin deeper to allow for a more intensive administration rather that a simple
reaction at the surface. Looking at the structure it doesn't seem that lipophilic with all of those hydroxyl groups on there but that is what I have
been told.
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Random
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| Quote: Originally posted by woelen | | What's specific of calcium gluconate? Can calcium chloride or calcium nitrate not be used? I have both and could make some concentrated solution of
these into a gel. I could not find calcium gluconate gel on eBay, but I could find the pure chemical (500 grams, way too much for me). It is strange
that HF can be purchased from eBay, but that the antidote gel is not easily available. |
I have read somewhere that calcium chloride could be injected directly but I guess that's only in extreme cases. From what I heard guys usually soak
themselves in calcium gluconate gel for few days if something goes wrong. Better safe than sorry with HF. Maybe it gets absorbed more slowly and
continuous? I don't know, but it is commonly used.
Also the mechanism of action if I remember correctly is that it supplies body with calcium, because flouride ions react with blood calcium ions, make
them insoluble and heart basically stops. You basically want to prevent hypocalcemia if I'm correct.
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