Home – Home – Jornals – Chemistry for Sustainable Development 2005 number 1

An effect of the accelerated electrons generated by the electron accelerator on the composition and indexes of the permolecular structure of brown and mineral coals of a metamorphism series has been studied. It has been demonstrated that the effects of ionizing action are controlled to an essential degree by the irradiation conditions and by the stage of coal metamorphism. Middle rank and high rank mineral coals show stability when exposed to an electron beam: their composition, swelling capacity, and the yield of solubles vary a little upon an irradiation with doses up to 200 Mrad. This may be related to the fact that the derivatives of polycondensed aromatic compounds that make up the mentioned coals may cause the radical and ion-radical reactions to decay inside the organic bulk due to the large electron affinity of these derivatives and trapping the low-velocity electrons. Low-rank coals (brown and mineral) with a great deal of aliphatic chains are rather easily subject to the radiation chemical transformations. When absorbing the small dozes (10-50 Mrad), the destruction processes including partial breaking of the valence cross-linking between macromolecules become dominant which leads to loosening the permolecular structure and to an increased capability of interaction with the molecules of organic solvents. The large radiation dozes (more than 50-100 Mrad) promote preferentially the cross-linking processes and structural regularity.