engleski

[14C] -UL-Chlorothalonil: a Study of the Catalytic Chlorination of [14C] -UL-1, 3-Dicyanobenzene

[‘ 4C]-UL-2, 4, 5, 6-tetrachloro- 1, 3-dicyanobenzene (chlorothalonil, 2) was prepared by catalytic chlorination of [‘ %I-UL-dicyanobenzene (1) on activated carbon, in a tubular reactor at a controlled temperature and in a stream of chlorine. Optimization of the ratio between the catalyst (activated carbon, 30-60 mesh) and the inert support (glass beads, silicagel 0.2-0.5 mm) as well as the geometry of the column reactor, the temperature of the preheated chlorine and the reaction temperature was studied in ca 90 “ cold” experiments. At 300°C gas temperature, 300°C reactor temperature, 5 mL/min flow rate of chlorine, and a catalyst : silicagel support: 1 ratio (1: 7 : 0.25) the reactor design produces [“ ‘ Cl-UL 2 in over 90% chemical yield and ca 95% purity (GLC). On purification by column chromatography on silicagel, with toluene-n-hexane (2: 3, v/v) as eluant, 99.6% pure ‘ T-UL 2 (sp. act. 9.2 MBq/mmol, 0.242 mCi/mmol)is obtained.

catalytic chlorination ; dicyanobenzene ; 14C

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