Abstract:
This work contains the results of a series of reduction studies
on polyhalogenated aromatic compounds and related ethers using alkali
metals in liquid ammonia.
In general, polychlorobenzenes were reduced to t he parent aromatic
hydrocarbon or to 1 ,4-cyc1ohexadiene, and dipheny1ethers were cleaved to
the aroma tic hydrocarbon and a phenol. Chlorinated dipheny1ethers were
r eductive1y dechlorinated in the process. For example, 4-chlorodipheny1-
ether gave benzene and phenol.
Pentach1orobenzene and certain tetrachlorobenzenes disproportionated
to a fair degree during the reduction process if no added proton source
was present. The disproportionation was attributed to a build-up of
amide ion. Addition of ethanol completely suppressed the formation of
any disproportionation products.
In the reductions of certain dipheny1ethers , the reduction of one
or both of the dipheny1ether rings occurred, along with the normal
cleavage. This was more prevalent when lithium was the metal used .
As a Sidelight, certain chloropheno1s were readily dechlorinated.
In light of these results, the reductive detoxification of the
chlorinated dibenzo-1,4-dioxins seems possible with alkali metals in
l iquid ammonia.
