Poly:halogenated dibenzo:dioxin and dibenzofuran cpds. removal from solids - with prods. obtd. in powder or granule from by extn. with inert organic solvent and dehalogenation and redn. with alkali metal

摘要

Dehalogenation and redn. of polyhalogenated dibenzodioxins (IA) and polyhalogenated dibenzofurans (IB) present in powdery and/or granular solids (II) is carried out by reaction with alkali metal, pref. Na. The process comprises: (a) suspending (II) in an inert organic solid (III); (b) continuously extracting (I); (c) removing (II) by filtration and washing with (III); (d) mixing the filtrate and washings and drying by heating and/or chemically; and (e) mixing and reacting the dry organic soln. with the alkali metal (IV). Pref. (II) is milled. (II) is suspended in (III) in a circulating reactor at 10-80 deg.C, with a stirrer operating at 1-5 in/s. Extn. is carried out in the presence of an extn. aid. USE/ADVANTAGE - (I) are destroyed in the liquid phase and any water extd. can be sepd. by azeotropic distn. before dehalogenation or by reaction with excess (IV). The process is suitable for long-term continuous operation and is very safe. It avoids the prodn. of waste gases or waste liquor requiring purificn./or