Formation of Hydrocarbons from Acid-Clay Suspensions by Gamma Irradiation

摘要

The adsorption of certain organic compounds by clays gives rise to the transformation of the adsorbate through the action of the clays. This phenomenon can be enhanced using ionizing radiation. In this context, these kinds of reactions play an important role in many natural and industrial processes. For example, in oil and gas exploration, the source and trap of petroleum hydrocarbons is frequently clay-rich rocks. Clay-water-based muds are also seen as environmentally friendly alternatives to toxic oil-based fluids. The principal processes that occur in sediments are usually held to be of bacterial action and thermal transformation, which may include thermally induced catalytic alteration of the organic debris. On the other hand, radioactive materials are widely distributed throughout Earth. They were more abundant in the past, but are present in petroleum reservoirs. Their presence induced radioactive bombardment, which may have altered these sediments. This important subject has not been extensively studied. The aim of this work is to study the behavior of fatty acids-like behenic acid-and dicarboxylic acids-like fumaric acid-as model compounds, which are adsorbed in a clay mineral (Na-montmorillonite) and exposed to gamma radiation. The results show that the radiation-induced decomposition of the clay-acid system goes along a definitive path (oxidation), rather than following several modes of simultaneous decomposition, as happens in radiolysis without clay or by heating the system. The main radiolytic products for fatty acids are their corresponding hydrocarbons, with one C-atom less than the original acid.