This document discusses various topics related to organic chemistry including ultrasound in organic reactions, supercritical liquids, and uses of enzymes in organic reactions. It provides details on ultrasound and its uses in accelerating and improving various organic reactions such as condensation, oxidation, addition, and substitution reactions. Supercritical fluids are described as substances above their critical point where distinct liquid and gas phases do not exist, allowing for properties that can be tuned between liquid-like and gas-like. Common uses of supercritical fluids discussed include extraction, dry cleaning, chromatography, chemical reactions, and biodiesel production.