The Vespiary

The Hive => Newbee Forum => Topic started by: auntyjack on November 21, 2003, 02:07:00 PM

Title: Sand as heating medium:WARNING
Post by: auntyjack on November 21, 2003, 02:07:00 PM

swiaj has recently seen a few articles here and on google that recomend using sand as substitute for oil in a heat bath...now swiaj was all ready to run out and buy a big bag of sand when he came across a couple of things on google that say "DON'T USE SAND FOR REACTIONS GREATER THAN 10 ML"...the reason given was that sand of a depth greater than that used in a 10 ml or less reaction will SUPER HEAT at the bottom so if you push your beaker down to far..KABOOM!!!(maybe?)...anyway, it would be interesting to here from anyone who uses sand......have fun...bye for now,
                                                           aunty jack

Title: sand
Post by: unionpacific on November 21, 2003, 02:56:00 PM

why would you push the beaker down into the sand?


sand can be used as a safe heating medium just put a thermometer in the flask on top of the sand, you don't need a huge bag of sand just enough to fill up a sauce pan 3/4

Title: yes but...
Post by: auntyjack on November 21, 2003, 03:48:00 PM

yes...why would you push the beaker down...but still, the idea of super heated anything next to solvents etc scares the shit out of me...i assume that there are a bunch of bees out there quite happily using sand (union pacific)...it is such an apealing substance...but what i'm a bit concerned about is that this super heating business doesn't seem to be common knowledge...real chemists don't use sand much except for these little reactions so there wouldn't be much info from them about the dangers of using too much...see what i mean? it's up to those who don't really know what they're doing to go out and generate the statistics as to who died using how much of what...ok, there is no data so far about problems with sand...but the problem might be hidden...maybe some fires were lit by hot sand before but nobody ever thought to correlate the two...there's a question: could fumes suck into the sand and ignite??? i know this is all miserable stuff but i don't wanna blow up!
bye for now,
            aunty jack

Title: sand vs oil bath
Post by: Oxygen on November 21, 2003, 04:34:00 PM

I've seen a flask break when heated in sand, but a mineral oil bath stirred with a magnetic stirrer and a paperclip works fine.

Title: no warnings needed
Post by: pirat on November 21, 2003, 11:43:00 PM

i ever distill compounds at rel. hight temps with a (steel)sand bath without any problems. the only thing you need is a automatic tempcontroller.

Title: Swim has never had a problem..
Post by: chameyotch on November 22, 2003, 12:00:00 AM

..dreaming of heating numerous nano synths in sand.  Swim dreams of a test tube in a container of sand on a hotplate, and has dreamt of success every time.

Title: apparently chemists of old would use naked...
Post by: auntyjack on November 22, 2003, 02:18:00 PM

Title: Oil is superior in heat distribution to sand...
Post by: paranoid on November 22, 2003, 09:38:00 PM

Oil is superior in heat distribution to sand though, as sand rapidly loses heat in comparison and therefore will be much cooler in the upper layers than the lower.

Title: Sand is pretty safe to use for alot of things...
Post by: Un_Chambered on November 23, 2003, 04:25:00 AM

Sand is pretty safe to use for alot of things bee's dream of(at least no hot splattering oil combined with the flask contents if it cracks :P )and I doubt any deaths can be blamed on using sand instead of oil ;D .If you dampen the sand it will help distribute the heat better but its still not as good as oil.
Swic used to hate using oil baths and avoided it at all costs because some allways managed to spill or splatter and make a mess and/or lots of smoke.He never had a fire but that was his worry.Then one day his brain miraclously decided to work :o  and he learned how to handle oil baths without spilling/splattering or fear of fire.
Peace,chambered

Title: mantle + sand
Post by: methyl_ethyl on November 23, 2003, 10:50:00 AM

I try to use a mantle when I can, however a bath is sometimes needed.  When high constant temps ~ 250C - 300C are needed I have used Corning 710R, although quite expensive, it maintains a very constant high temperature bath IMO.  As Rhodi points out, watch your ass in the lab with this stuff, we had to pay extra for the professional cleaning crew to come in and de silcone-ize our lab after a few days of reckless usage.  ;)

This link

http://www.sas.org/E-Bulletin/2003-04-18/labNotes2/body.html (http://www.sas.org/E-Bulletin/2003-04-18/labNotes2/body.html)

states that  "The safest bath material is sand since it doesn't present a spatter danger, is non-flammable, is non-toxic, is non-conducting and doesn't degrade. It is a great choice when you have an odd-shaped apparatus and don't want to use a fluid. As an added bonus, you can use a heating mantle as your container (don't try that with liquids!). The drawbacks are that sand is not as versatile and doesn't transfer heat as quickly as fluids."

I think I may have to try using sand in a mantle.   :)

Related:

Post 422858 (missing)

(runne: "What to use as a heating (oil) bath.", Newbee Forum)  summarizes above link....

Post 379174 (missing)

(Rhodium: "PEG 400 Oil Bath", Newbee Forum)

Title: try safflower oil
Post by: L_jamf on November 23, 2003, 07:01:00 PM

there's only 2 things better than safflower oil when it comes to non-smoking high-bp oils: avocado oil and something else. i use safflower oil in my baths and a bit of caution and a good hotplate go a long ways to get you consistent temperatures up to about 200°C. if you're going over that, i recommend you get a vacuum pump and fix that right quick.

gl

Title: sand is no problem
Post by: Antibody2 on November 25, 2003, 06:45:00 AM

like someone mentioned above though, keep it shallow as in less than 2.5cm. The problem with using deepers and baths is temperature stratification.

ie. you have 200C at the bottom of the sand bath and 5cm higher it is only 120C so you can literally end up condensing vapours at the top of the flask while charring stuff at the bottom. keep it shallow and it works like a charm

IMHO safflower (or any other of the non burning oils) stinks a whole building at 200C and is a fire hazard besides.

Sand rocks!

Title: Sand is great
Post by: bigdumbnut on December 07, 2003, 02:51:00 AM

SWIB uses sand in a fry cooker. He uses cheap glass, that he treats in a conventinal oven for a few hours, at temps up to 175C. He uses about 3 inches deep and inserts the thermocouple wire for his controller along side the glass near the bottom. He covers the top of the sand with small terrycloth towels. He doesn't experience a stratification problem this way. It doesn't smell, won't catch fire, lasts a long time, and won't splatter from condensation from a condenser using ice water. If he needed a magnetic stirrer he'd probably need to rethink