methods of increasing the solubility of a base in supercritical carbon dioxide include forming a complex of a lewis acid and the base , and dissolving the complex in supercritical carbon dioxide . the lewis acid is soluble in supercritical carbon dioxide , and the base is substantially insoluble in supercritical carbon dioxide . methods for increasing the solubility of water in supercritical carbon dioxide include dissolving an acid or a base in supercritical carbon dioxide to form a solution and dissolving water in the solution . the acid or the base is formulated to interact with water to solubilize the water in the supercritical carbon dioxide . some compositions include supercritical carbon dioxide , a hydrolysable metallic compound , and at least one of an acid and a base . some compositions include an alkoxide and at least one of an acid and a base .