DeanStarkfällor

A Dean-Stark apparatus, also known as a Dean-Stark trap or Dean-Stark receiver, is a laboratory glassware used in organic chemistry to remove water from a reaction mixture. It is particularly useful in reactions that produce water as a byproduct, such as esterification or acetal formation. The apparatus consists of a graduated collecting tube with a side arm for vapor to enter. A reflux condenser is attached to the top of the collecting tube, and the entire assembly is connected to the reaction flask.

During reflux, the vapor, including water and the solvent, rises into the condenser where it cools and liquefies. The liquid then drips into the collecting tube. Because water is immiscible with many organic solvents commonly used in these reactions, it separates into a distinct layer at the bottom of the collecting tube. The solvent, being less dense, floats on top. The side arm of the collecting tube is positioned at the level of the solvent-solvent interface, allowing the upper solvent layer to continuously overflow and return to the reaction flask. The water, being denser, accumulates at the bottom of the collecting tube, effectively being removed from the reaction system. This removal of water drives the equilibrium of reversible reactions towards product formation, increasing the yield. The volume of water collected can also be used to monitor the progress of the reaction. The apparatus is typically made of glass and comes in various sizes to accommodate different reaction volumes.