Question

1. What is the role of the Dean-Stark apparatus and why is it filled with Toluene up to the top of the apparatus?
2. Should we observe any difference in the reaction rate between teams using the Dean-Stark apparatus and those not using it? Explain your answer.
3. Write a complete table of molar ratio for Acetophenone that is transferred into a metal functional group

Answer 1

Dean-Stark apparatus is it filled with Toluene up to the top because Toluene is a colourless ligth dense organic compound that donot mix with water / inorganic compound. While using Dean-Stark apparatus process of evaporation, condensation and collection may be continued until it ceases to produce additional amounts of water.While to trap other organic volatile compounds to evaporate & trapped in collection flask Toluene is filled on top of other liquid such a way that it will form a liquid seal layer to avoid evaporation of unnecessary organic compound.

Dean-Stark apparatus is used in esterification of butanol with acetic acid catalyzed by sulfuric acid. It is also used in simply removal of moisture from any organic liquid.It is used to find any kind of adultration in fuel done in form of moisture/Water emulsions.

Yes, there will be a difference in the reaction rate between teams using the Dean-Stark apparatus and those not using it.

A reaction equilibrium can be influenced with an excess of reagent or removal of a formed product in order to drive the equilibrium to the product side. Equilibria can be also influenced by temperature or pressure. This underlying principle is called Le Chatelier's principle and states that a change in temperature, pressure, concentration, or volume will cause a readjustment of the reaction to establish a new equilibrium. By adding an excess of reagent, the concentration changes and a new equilibrium establishes, favoring the product side. For instance, driving the equilibrium of a hydrolysis can be easily achieved by adding an excess of water.

Influencing the equilibrium of a reaction where water is formed as a byproduct, like an esterification, is not straightforward and requires special glassware. This special piece of glassware is called a Dean-Stark trap and helps to remove the formed water from the reaction medium. Solvents that form an azeotrope with water, like toluene, are commonly employed. An azeotrope is a point in a distillation where the composition of the liquid phase is equal to the composition of the gas phase. A further separation through a simple distillation past the azeotropic point is not possible. This is an advantage when using the Dean-Stark trap to influence equilibria, because it will ensure the continuous removal of water. Upon heating the reaction mixture, the formed toluene/water azeotrope will distill over, condense in the condenser, and flow into the Dean-Stark trap. Toluene and water will form two separate layers with toluene as the top layer and water as the bottom layer. While toluene can flow back into the reaction flask, water gets trapped as the bottom layer and ultimately removed from the reaction equilibrium thus driving the reaction towards the product side.