(4 points) In order to shift the equilibrium of this reaction to favor the produ
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(4 points) In order to shift the equilibrium of this reaction to favor the products, we had water leave the reaction due to its immiscibility with the ester product. This is not always possible as many esters are solids, requiring organic solvents for the reaction that may be miscible with water. To solve this issue, chemists remove water from a reaction using a piece of glassware called a Dean-Stark trap. Look this piece of equipment up on Wikipedia and explain how it is able to remove water from a reaction. 3.Explanation / Answer
The Dean-Stark trap is used to shift the equilibrium of organic reactions to the product side.
According to Le Châtalier's principle, an equilibrium can be driven toward the products using an excess of one of the reactants, by continuously removing one of the products, or by changing the temperature or the pressure at which the reaction is carried out. Perhaps the most commonly encountered equilibrium reactions are those involving water as a product.
As stated previously, the removal of this water can drive the reaction to completion. A Dean-Stark trap is a specialized piece of glassware used for continuously removing water formed in a chemical reaction.
Reactions such as the conversion of boronic acid to an ester result in the formation of water, which can hydrolyze the ester back to the acid, decreasing the overall yield.
As the reaction progresses, the water produced in the reaction may be continuously removed from the flask with the use of a Dean-Stark trap. In order to do that, first add the reaction components to a flask along with a hydrocarbon such as toluene and heat the mixture. As the reaction progresses, the water is released. Now toluene and water, which boil at 110 and 100 degrees, respectively, form an azeotrope, which boils at 84 degrees. Upon cooling in the condenser, the solvent vapors condense back to liquid, which drips into the collection vessel of the trap, and any overflow is returned to the reaction vessel.
The condensed liquid mixture eventually separates into two immiscible layers, with the denser component on the bottom. This is usually the water layer, which is then drained off. The same process is continued until no more water is produced, which indicates the completion of the reaction.
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