[Dano41]

I am  a beekeeper and am making a device for sublimating oxalic acid.There is a commercial device called a Sublimox in which the a stainless steel bowl is held at a temperature of 300c.The oxalic, one or two grams is tipped into the bowl from a cap which seals the bowl the oxalic immediately starts coming out a small pipe which is attached to the bowl and is completed in thirty seconds.Will it send formic into the hive or because it sublimates so quickly will this not happen.Any help would be greatly appreciated.

[AWK]

http://www.chemicalforums.com/index.php?topic=79788.0

300 C is to high temperature. It decomposes at 190 completely.

[Dano41]

Thank you for your very quick reply.I read that post but I am still not 100% clear of the answer.At 190c you say it decomposes completely so are you saying that when the 2 grams sublimate in the 30 seconds that there is no residue remaining to turn to formic even if the bowl is at a much higher temperature than 190c.
 1) The water of hydration leaves at 101.5° C (214.7° F) The water boils off leaving anhydrous oxalic acid crystals.
2) At 157° C (314.6° F) the oxalic acid starts to sublime (goes directly from solid to gas)
3) At 189° C (372.2° F) the oxalic acid which has not yet sublimed decomposes to formic acid and carbon monoxide.

[AWK]

Over temperature of decomposition always you obtain, at least partially CO₂ + HCOOH
or at higher temperature CO + CO₂ +H₂O.  Below temperature of sublimation, oxalic acid immediately crystallizes. Formic acid is much more volatile when formed.

You probably need fumigation with formic acid?
Commercial device is probably correctly designed for your purpose.

[kamiyu]

I think for sublimation to work (I am working on OLED which requires materials to be of ultra-pure qaulity, something in the 99.9999%), train sublimation is required.

Simply put, if one uses a very high temperature and the impurity also sublimes, then what is the use of this setup?

That said, you mentioned the oxalic acid sublimes at 159oC, then i think it is a good to just keep that temperature

In the lab, one can just use an oil bath with temperature control.

Outside the lab, one may use a heating jacket.

Hope this helps