1
The Preparation of Uniformly Labeled 14
C-2,7-Dichlorodibenzo-p-dioxin and
14
Downloaded by UNIV OF ALABAMA BIRMINGHAM on January 10, 2013 | http://pubs.acs.org Publication Date: March 1, 1973 | doi: 10.1021/ba-1973-0120.ch001
C-2,3,7,8-Tetrachlorodibenzo-p-dioxin
W E S L E Y W. M U E L D E R and LEWIS A. S H A D O F F Ag-Organics Department and Analytical Laboratories, The Dow Chemical Co., Midland, Mich. 48640
2,7-Dichlorodibenzo-p-dioxin
was prepared
potassium 2,4-dichlorophenate
from
isotopic
uniformly labeled with
Ullman conditions gave a 20.5% yield.
14
C.
Small amounts of
dichlorophenoxy chlorophenol were removed from the product by extraction with sodium hydroxide before purification by fractional sublimation and recrystallization from anisole. Chlorination
of 2,7-dichlorodibenzo-p-dioxin
solution containing trace amounts of FeCl
3
in chloroform and I yielded a 2
mixture of tri-, tetra-, and pentachloro substitution Purification by digestion
products.
in boiling chloroform, fractional
sublimation, and recrystallization from anisole was effective in refining this product to 92% 2,3,7,8-tetrachloro isomer, which also contained 7% of the tri- and 1% of the penta-substituted dibenzo-p-dioxin.
Mass spectroscopy was used
exclusively to monitor the quality of the products during the synthesis.
>T
