Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
 Pages:  1  2  
Author: Subject: Boiling Stones?
Varmint
National Hazard
****




Posts: 264
Registered: 30-5-2013
Location: Near Atlanta, GA
Member Is Offline

Mood: No Mood

[*] posted on 29-8-2013 at 07:25


Which is why I mentioned it.

DAS
View user's profile View All Posts By User
subsecret
National Hazard
****




Posts: 426
Registered: 8-6-2013
Location: NW SC, USA
Member Is Offline

Mood: Human Sadness - Julian Casablancas & the Voidz

[*] posted on 30-8-2013 at 12:02


Sorry, IrC. Thanks for the reminder.

On another note, I purchased a pumice scouring block at Lowe's. It's much more difficult to crush this block into small pieces, as it hitting or crushing it simply crushes the air pockets. Boiling stones made from this material (as previously identified) work well.




Fear is what you get when caution wasn't enough.
View user's profile View All Posts By User
Magpie
lab constructor
*****




Posts: 5939
Registered: 1-11-2003
Location: USA
Member Is Offline

Mood: Chemistry: the subtle science.

[*] posted on 30-8-2013 at 12:38


I also use little pieces of a broken clay pot.

I'm interested in the silicon carbide boiling stones commercially available. It's not that I need them for boiling stones: I need porous silicon carbide for use as a catalyst support.

Are the silicon carbide boiling stones porous? Or do they just rely on sharp edges for use as boiling stones?




The single most important condition for a successful synthesis is good mixing - Nicodem
View user's profile View All Posts By User
testimento
National Hazard
****




Posts: 351
Registered: 10-6-2013
Member Is Offline

Mood: No Mood

[*] posted on 15-2-2014 at 20:14


What boiling stone material would be ideal for concentrating sulfuric acid? I tried borosilicate glass shards, silica sand and curshed porcelain fuse shells, but it just kept bumping. Havent tried silica gel yet.
View user's profile View All Posts By User
BromicAcid
International Hazard
*****




Posts: 3049
Registered: 13-7-2003
Location: Wisconsin
Member Is Offline

Mood: Legitimate

[*] posted on 16-2-2014 at 07:08


Because concentrated sulfuric acid is so dense and thick boiling stones do not do the trick. Old school capillary N2 action would likely be the best.



Shamelessly plugging my attempts at writing fiction: http://www.robvincent.org
View user's profile Visit user's homepage View All Posts By User
Oscilllator
International Hazard
*****




Posts: 659
Registered: 8-10-2012
Location: The aqueous layer
Member Is Offline

Mood: No Mood

[*] posted on 16-2-2014 at 19:26


Quote: Originally posted by testimento  
What boiling stone material would be ideal for concentrating sulfuric acid? I tried borosilicate glass shards, silica sand and curshed porcelain fuse shells, but it just kept bumping. Havent tried silica gel yet.

I have used coke (as mentioned previously on this thread) to prevent the bumping of sulfuric acid. In my case it completely eliminated the bumping :)




View user's profile View All Posts By User
ZIGZIGLAR
Hazard to Self
**




Posts: 79
Registered: 3-2-2014
Member Is Offline

Mood: No Mood

[*] posted on 16-2-2014 at 20:38


Can't you reuse ptfe boiling chips? I use these as they offer the flexibility of working well under vacuum, as I don't have a nitrogen or argon line ...

I've used capillary bleed tubes with success too. You can easily make them yourself by just buying 6mm OD borosilicate tube and holding the tip with needle tip plyers, heating the end up really hot, then stretching it out until you have a thin tip, then just break/cut the end bit off. The 6mm OD will slide comfortably through any gland designed for thermometers. If oxidation is a concern, then you're probably using a nitrogen bleed already, I imagine.
View user's profile View All Posts By User
Refinery
National Hazard
****




Posts: 370
Registered: 17-2-2014
Member Is Offline

Mood: Still

[*] posted on 17-2-2014 at 07:34


Quote: Originally posted by Oscilllator  
I have used coke (as mentioned previously on this thread) to prevent the bumping of sulfuric acid. In my case it completely eliminated the bumping :)


Can you say, is graphite essentially a pure carbon and would it be suitable for the purpose? I have a similar problem and only place I can get coke is from industrial supply and they sell it only in 40kg bags. :)

And don't you get fine particles into the sulfuric acid, turning it like black goo? What do you use to filter the carbon off?

[Edited on 17-2-2014 by Refinery]
View user's profile View All Posts By User
organicchemist25
Hazard to Others
***




Posts: 121
Registered: 12-2-2014
Member Is Offline

Mood: No Mood

[*] posted on 17-2-2014 at 10:59


When I first started using boiling chips I used broken up pieces of a spark plug. They worked fine. I eventually just bought two big containers of boiling chips. They are relatively inexpensive.
View user's profile View All Posts By User
Oscilllator
International Hazard
*****




Posts: 659
Registered: 8-10-2012
Location: The aqueous layer
Member Is Offline

Mood: No Mood

[*] posted on 17-2-2014 at 15:42


Quote: Originally posted by Refinery  
Quote: Originally posted by Oscilllator  
I have used coke (as mentioned previously on this thread) to prevent the bumping of sulfuric acid. In my case it completely eliminated the bumping :)


Can you say, is graphite essentially a pure carbon and would it be suitable for the purpose? I have a similar problem and only place I can get coke is from industrial supply and they sell it only in 40kg bags. :)

And don't you get fine particles into the sulfuric acid, turning it like black goo? What do you use to filter the carbon off?

[Edited on 17-2-2014 by Refinery]

The main property of the coke that makes it a good material for boiling chips is its extremely high porosity. Graphite is not porous, so i dont know if graphite would be suitable for boiling chips but its worth a try. Coke is quite hard so it does not disintegrate into a black goo and because I used chunks with a diameter of 5+mm, I can just decant the sulfuric acid off the coke.
Even though it comes in 40kg sacks, its probably worth getting one (or more!) to power a forge like the one I have. I have been able to do many high temperature experiments with my forge (like casting copper) so it's well worth the money.




View user's profile View All Posts By User
packetforger
Harmless
*




Posts: 48
Registered: 21-2-2014
Member Is Offline

Mood: Condensing

[*] posted on 21-2-2014 at 05:40


We mainly use small pieces of pumice in the lab, however smashed up flowerpots is a viable alternative according to the manual that came with a chemistry set I bought as a child.

Pieces of plates/pottery are good too, but I suspect the reason we use pumice in the college is due to the fact it is very porous, giving rise to many nucleation sites for bubble formation to prevent the forming of hotspots and the like (instead, you get many small bubbles).

Pumice is widely available as it is used for scraping dead skin off, just buy a lump of it and hit it with a hammer to make the small pieces. Perhaps washing it may be a good idea as it might be contaminated with some antiseptic or something (I doubt it, but better safe than sorry...)

[Edited on 21-2-2014 by packetforger]
View user's profile Visit user's homepage View All Posts By User
bfesser
Resident Wikipedian
*****




Posts: 2114
Registered: 29-1-2008
Member Is Offline

Mood: No Mood

[*] posted on 21-2-2014 at 06:16


Pumice and most ceramics will scratch the hell out of your glassware. Better to stick with boiling sticks or proper boiling stones.



View user's profile View All Posts By User
ZIGZIGLAR
Hazard to Self
**




Posts: 79
Registered: 3-2-2014
Member Is Offline

Mood: No Mood

[*] posted on 21-2-2014 at 15:17


Why doesn't anyone use capillary bleed tubes these days? They add the flexibility of being viable during vacuum distillation and can also be used to introduce N2 for sensitive reactions or boiling of highly flammable solvents ...
View user's profile View All Posts By User
Oxirane
Hazard to Self
**




Posts: 92
Registered: 19-9-2014
Member Is Offline

Mood: No Mood

[*] posted on 11-10-2014 at 14:09


Have you any experience on silica gel except for the one poster on the first page? I found two types of gel, the clear one for smaller pores and larger, opaque ones as cat litter. Tried to vac distill pure some DMSO, but it started to bump so badly the whole distillation setup was gonna jump off the table and I was afraid it could strike so hard to implode the vacuum so I immediately cut it off.
View user's profile View All Posts By User
S.C. Wack
bibliomaster
*****




Posts: 2169
Registered: 7-5-2004
Location: Cornworld, Central USA
Member Is Offline

Mood: Enhanced

[*] posted on 11-10-2014 at 15:45


A problem with silica gel is that it's only so inert, but it's unsurprising that your boiling stones failed in vacuum distillation of DMSO.

I'm also a fan of the off-topic use of pulled capillaries through the thermometer hole for vacuum distillation, and have heard that a proper capillary pulls negligible air through it, but haven't tested this with even a balloon. A fine capillary end on a stout tube can usually withstand an amazing bumping ordeal.

[Edited on 11-10-2014 by S.C. Wack]




"You're going to be all right, kid...Everything's under control." Yossarian, to Snowden
View user's profile Visit user's homepage View All Posts By User
Dr.Bob
International Hazard
*****




Posts: 2200
Registered: 26-1-2011
Location: USA - NC
Member Is Offline

Mood: No Mood

[*] posted on 11-10-2014 at 19:15


Pumice is likely softer than most boiling stones. I have a bottle of them, and I think they are made of alumina, which is quite hard and will scratch most things well. They specifically state that they are high porosity, I think that is key, magpie, so the SiC ones are likely the same highly porous material.

If anyone wants a small amount, I am happy to provide a little for free. Magpie, if you think Al2O3 might work, let me know and I will send you some to test.

View user's profile View All Posts By User
Amos
International Hazard
*****




Posts: 1247
Registered: 25-3-2014
Location: Yes
Member Is Offline

Mood: No

[*] posted on 11-10-2014 at 20:25


I chiefly use pieces of quartz salvaged from geodes; they're free and easy to obtain and they get the job done really well.



View user's profile View All Posts By User
Little_Ghost_again
International Hazard
*****




Posts: 985
Registered: 16-9-2014
Member Is Offline

Mood: Baffled

[*] posted on 12-10-2014 at 02:05


I use the broken ceramic tubes from the tri pod triangles, a very small bit does the job perfect!
View user's profile View All Posts By User
Refinery
National Hazard
****




Posts: 370
Registered: 17-2-2014
Member Is Offline

Mood: Still

[*] posted on 10-7-2020 at 12:56


I'm pretty much betting between these three options:

1) Bleeder tube (with forced air if system is open)
2) Activated carbon granules
3) Calcium sulfate chips (prepared as gypsum, spread onto plastic/glass/al foil, chipped when dried for 24h)
View user's profile View All Posts By User
Mateo_swe
Hazard to Others
***




Posts: 166
Registered: 24-8-2019
Location: Within EU
Member Is Offline


[*] posted on 11-7-2020 at 03:07


I been looking for some reusable boiling chips and it seems they are not cheap nowadays.
500g of PTFE boiling chips would cost me almost 90 Euros on ebay.

So what is usable instead of the PTFE boiling chips?
I read broken glass pieces, small ceramic pieces or a crushed clay pots for flowers would work.
Some said crushed dinner plates works but can only be used once, it that true?
I guess i can crush some old dinner plates or flower pots and put in a jar to use when needed and if they only can be used once its ok as they cost almost nothing.
Are any of the cheap alternatives better than the others?

[Edited on 2020-7-11 by Mateo_swe]
View user's profile View All Posts By User
pneumatician
Hazard to Others
***




Posts: 218
Registered: 27-5-2013
Location: Catalonia
Member Is Offline

Mood: Anar fent.

[*] posted on 1-9-2020 at 14:37


glass balls? I use it and work 100% easy to clean, well, sometimes hard to clean but if too hard I send to Hell :)

very cheap for 1kg, a lot of balls!!!

used in rectification columns!

https://duckduckgo.com/?q=Solid+Soda+Glass+Balls+columns+lab...

[Edited on 1-9-2020 by pneumatician]
View user's profile View All Posts By User
teodor
National Hazard
****




Posts: 259
Registered: 28-6-2019
Location: Heerenveen
Member Is Offline


[*] posted on 2-9-2020 at 02:27


Once I took a thick ceramic plate, smashed it with a hammer, selected pieces of proper size. They where glazed but after few boiling of acids they become completely unglazed as well as free from metal contaminations. They serve me well. I didn't get good results with glass balls - they just don't prevent bamping (in most cases). Unglazed porcelain has pores which are essential for smooth boiling.

[Edited on 2-9-2020 by teodor]

[Edited on 2-9-2020 by teodor]
View user's profile View All Posts By User
unionised
International Hazard
*****




Posts: 4402
Registered: 1-11-2003
Location: UK
Member Is Offline

Mood: No Mood

[*] posted on 2-9-2020 at 04:03


I'm fairly sure that the reason people took to using capillary leaks for vacuum distillations i that boiling chips simply don't work properly.

For solvent recovery from non aggressive solutions I use a matchstick with a bit of wire wrapped round it so it sinks.
For acids I use silica gel.

I found that broken glass, while generally available in chem. labs, isn't very effective.
View user's profile View All Posts By User
pneumatician
Hazard to Others
***




Posts: 218
Registered: 27-5-2013
Location: Catalonia
Member Is Offline

Mood: Anar fent.

[*] posted on 2-9-2020 at 08:59


maybe you not use enought balls or too big. Sometimes I get a bloob but so neutralized... it's interesting to see :)

glazed ceramic is with lead so if you remove it is in your solvent.
View user's profile View All Posts By User
teodor
National Hazard
****




Posts: 259
Registered: 28-6-2019
Location: Heerenveen
Member Is Offline


[*] posted on 2-9-2020 at 10:03


I've made some illustration what I mean by "glazed ceramic".
I was mistaken, the glaze is still there. But after smashing there are chips which contain it only on very small surface that it is almost unnoticeable, probably I just selected most unglazed over the time. These on picture where already used 5-15 times. I don't see any signs on wearing.
The glass balls I compare them to is of 1.5-3 mm in diameter.

chips.jpg - 32kB
View user's profile View All Posts By User
 Pages:  1  2  

  Go To Top