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.

The present invention relates to a process for continuous extraction of an aqueous and/or fat-containing liquid phase F comprising aroma chemicals with a gas G in the liquid or supercritical state.

Processes and apparatuses for compound recovery using supercritical fluid (SCF) are disclosed. An example process involves solvent extraction (including hydrothermal liquefaction and gasification) of a extracted compound using a SCF from a solid or liquid substrate including, but not limited to, microalgae, plant matter, and polymers. The apparatus comprises SCF, an extraction vessel, a pressure exchanger, feedstock, a separate compound, and solid or liquid compound separators.

Certain embodiments described herein are directed to separation systems and methods effective to separate two or more solvents in a solvent mixture. In certain examples, a system effective to separate two or more azeotrope forming solvents is provided. In some embodiments, the system can be effective to remove at least about 95% of one of the solvents from the solvent mixture.

A method of extracting a substance comprising the steps of: placing a substrate on which a substance has been adsorbed into a container; feeding a solvent into the container whilst restricting its exit to achieve a predetermined pressure of the solvent in the container, wherein the solvent has a critical point and the predetermined pressure is above the critical point of the solvent; releasing the solvent and an extract comprising extracted substances into a separator; reducing the temperature and pressure in the separator to remove a gaseous portion of the solvent from the extract; collecting the extract remaining from the separator.