Catalytic hydroprocessing of polychlorinated derivatives of aromatic compounds.
Special Symposium - Environmental Protection & Sustainability
Environmental Protection & Sustainability (EPS - Poster)
Keywords: Polychlorinated biphenyls, hydrogenation,reduction,palladium catalyst,processing of wastes
Polychlorinated derivatives of aromatic compounds as well as biphenyls, are highly toxic products. The combustion of these compounds results in formation of secondary pollutants, e.g. polychlorinated dibenzofurans and dibenzodioxis. Polychlorinated biphenyls were used as dielectric in condensers and transformers. According to the Stockholm convention of transfrontier pollutants of air these compounds belong to stable organic pollutants. Also the problem is to clean up the equipment from the leavings of polychlorinated wastes.
To solve this problem we investigated the reaction of reducing of polychlorinated derivatives of aromatic compounds with hydrogen in sodium hydroxide solution on Pd catalyst at 80-150 oC and under overpressure of 0,6-2 MPa. We have studied conditions of formation of carbohydrates from polychlorinated derivatives of aromatic compounds with the conversion of 100%. The leavings of polychlorinated derivatives of aromatic compounds which can remain in various equipment (e.g. transformers and condensers) can be washed out by sodium hydroxide solution until the purity of 50 ppm.
In this report we represent results of investigation of conversion of 1,2-dichlorobenzene and 1,3-dichlorobenzene. Experiments were carried out on Pd supported carbonic carrier in laboratory autoclave. The volume of the autoclave is 500 ml and it is provided with mixer, electric heater and bubbling system for hydrogen feeding.
The experimental data obtained showed that growth of conversion can be observed up to content of Pd 2%. Further increase of content of Pd do not gives rise to increment of conversion of 1,2-dichlorobenzene and 1,3-dichlorobenzene.
The rate of reaction slightly decreases with the concentration of sodium hydroxide 13 %. Increasing of concentration of sodium hydroxide more then 13%, results in increasing of the desalting effect. Because of that phenomenon fractional conversion decreases.
Conversion of the reactants directly proportional depends on pressure and has a classical temperature dependence.
This investigation is an important stage of creation of new non-polluting technology of processing of polychlorinated derivatives of aromatic compounds.
Presented Monday 17, 13:30 to 15:00, in session Environmental Protection & Sustainability (EPS - Poster) S-7P.
