From: Maringanti Krishnamacharyulu (maringanti9$##$yahoo.com)
Date: Wed Mar 05 2003 - 20:20:20 EST
Dear Members:
Instances of violent explosions are well known, when THF is treated with KOH. Industrially, the recycling of THF stored in containers for a long time (without inhibitor) is carryied out in a couple of stages. First stage involves treatment of THF with KOH. The second stage involves distilling the thf through a column of molecular sieves. This seems to be rather UNSAFE but, people do follow this procedure in India,as it is a cost effective way to recycle THF.
As we all know, explosions with THF can be due to two reasons.
1. Formation of peroxides, and accumulation of the same. (These perexides sometimes detonate, when treated with KOH, or when allowed to get concentrated while distilling THF.
2. THF forms an explosive mixture with Air.
The original question talks about the danger of explosion when THF is chilled. I beleive that this could be because of the second reason. If a THF solution is chilled carelessly, there is a chance that siezable quantities of AIR can get condensed along with THF during the process. This essentially forms a dangerous mixture. (2-12% v/v mixtures of THF with air are potentially explosive.) Coupled with a low flash point, (-21 deg. Celsius), this could be the reason. Also, THF can Flash back!!!.. If there is remote source of ignition, that could be the Major reason for explosion. In the absence of it, I feel it could be owing to the formation of Explosive mixture with air.
Krishna
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