Re: Temp and dioxin question

[ttweed@wildrockies.org (Tony Tweedale)]

billy, accept the upper bound T's carl larkins mentioned, but at the low
end consider that reactions continue to proceed tho at a rapidly
deccelerating rate w/ T drop.  but the electrical charges on molecule
portions can easily overcome most of this energy barrier to fascilitate
PCDD/F formation.  eg, the hydroxyl (-OH, ie an alcohol) in phenols is a
strong electron seeker, as is any Cl atom on the adjacent C (2 & 5
substituted chlrophenols); this really promotes dimerization (linking 2
phenol rings, often w/ an oxygen or two bridging them, ie PDD/F).  in fact,
these 2 or 5 substituted chlorphenols become the 3 & 8 Cl's in the PCDD/F
that have TEq's, the 2,3,7,8 substituted ones.  thus the chlorophenoxy
herbicide 2,4,5-trichloro phenoxy acetic acid (2,4,5-T) can form as much as
1% total PCDD/F (!), and massive TEq's when formulated--it is 2,3,78's
ready made building block.

lignins are complex molecules, sometimes oxygenetaed, that will similarly
have areas that promote dimerization of their rings.  I would imagine going
from 20d C to 150 d C is already really boosting your Rx rates.  If anyone
knows, again I'd be glad to know which APCD promote PCDD/F.  I believe
scrubbers, w/ their long hold times at appropriate T's


Tony Tweedale
Causality is a concept not subject to empirical demonstration.   -David
Hume (1711-'76)