Patent GB-737529-A (GB)
Title: Improvements in the production of highly chlorinated dioxanes
IPC: C07D319/12
Filed: 1953-08-07
Abstract: The invention comprises chlorinated 1 : 4-dioxanes with at least 3 chlorine atoms, containing an odd plural number of chlorine atoms, and octachloro-1 : 4-dioxane.  It also comprises a process for the production of chlorinated 1 : 4-dioxanes which consists in subjecting a 1 : 4-dioxane in the liquid phase at temperatures between 10 DEG and 80 DEG  C. so long to the action of chlorine that a substantial part of the chlorination products contains at least 3 chlorine atoms for each molecule of the chlorinated 1 : 4-dioxane.  As the starting material may be used 1 : 4-dioxane itself or its derivatives containing 1 or 2 substituents, which are preferably saturated or aromatic radicals such as ethyl and its homologues, cyclohexyl, phenyl, tolyl or benzyl, or other substituents such as alkoxy, aryloxy groups and heterocyclic ring systems.  During the chlorination at 15 DEG  to 30 DEG  C., for example, crystals form and redissolve in two stages (or can be isolated, being tetra- and hexachlorodioxanes respectively) and then a third crystalline product separates. From the liquid products there can be separated, e.g. by fractional distillation, tri-, tetra and octachlordioxanes and two hexa- and two heptachloro-dioxanes.  During the reaction irradiation with sunlight or artificial light may be effected, and there may be present peroxides particularly from the dioxane itself, or other peroxides, iodine, bromine, metals such as iron or aluminium or chlorination catalysts, e.g. PCl3, AsCl3, SbCl3, SnCl4, FeCl3 or CuCl. Reduced, atmospheric or increased reaction pressures can be employed.  In examples (1) 1 : 4-dioxane in carbon tetrachloride is treated at 20 DEG  C. with chlorine, the crystals of tetrachloro-dioxane which first deposit being redissolved on further treatment.  When chlorination is complete the carbon tetrachloride is removed, the product is cooled to -20 DEG  C. and the precipitated hexachloro-dioxane (m.p. 94 DEG  C.) is removed. Fractional distillation of the remaining liquid yields tetra-, penta-, hexa-, hepta- and octachlorodioxanes; (2) 1 : 4-dioxane in carbon tetrachloride is chlorinated at 10 DEG  to 15 DEG  C. to give tri- and tetrachlorodioxanes; (3) 1 : 4-dioxane is chlorinated at 20 DEG C., deposited crystals of tetrachlorodioxane being separated, and the chlorination continued.  Fractional distillation of the product gives hexa- and heptachloro-dioxanes; (4) 1 : 4-dioxane is chlorinated at 20 DEG  C., deposited 2 : 5-dichloro-dioxane being redissolved on further treatment.  Further crystals (tetrachlorodioxane) then deposit and chlorination is stopped when these begin to redissolve. Fractionation of the separated oil yields hexachlorodioxane (m.p. 92 DEG  C.); (5) 1 : 4-dioxane is chlorinated at 30 DEG  C. for 140 hours giving solid hepta-chlorodioxane (m.p. 56 DEG  C.) and a liquid, which on further chlorination and fractionation gives octachloro-dioxane; (6) 1 : 4-dioxane is chlorinated with the temperature rising from 10 DEG  to 40 DEG  C. during the reaction; the product after 140 hours being heptachlorodioxane; (7) 1 : 4-dioxane is chlorinated at 50 DEG  C. until the reaction comes to a standstill.  Heptachlorodioxane (m.p. 56 DEG  C.) is filtered off and the liquid further chlorinated at 50 DEG  C. to give as product hepta-chlorodioxane (m.p. 123 DEG  C.); (8) 2 : 3-diphenyl 1 : 4-dioxane in carbon tetrachloride is treated at 20 DEG  C. with chlorine to give a mixture of di-, tri- and tetrachlorodiphenyl-1 : 4-dioxanes; (9) chlorine is introduced above the surface of 1 : 4-dioxane at 20 DEG  C. in a vessel with internal and external cooling and when the reaction becomes slower the temperature is raised in steps of 0 DEG  to 50 DEG  C., the product being heptachlorodioxane; (10) 1 : 4-dioxane freed of its usual peroxide content is mixed with benzoyl peroxide and chlorinated at 150 DEG  C. and then at 25 DEG  and 35 DEG  C., to give a product similar to that of example (9).  Instead of adding peroxide the normal peroxide content of the dioxane may be increased by previously passing oxygen through it.