!!!Esterification technique help (1 Viewer)

[abc123doremi]

hi in our esterification prac we had to use fused CaCl₂ to dry the organic ester layer
but i don't get how it dries it or what exactly it dries. coz if you put calcium chloride in your organic layer, aren't you contaminating it? even if you distill it, it'll still be there. or is it decanted off?

also when we add sodium carbonate to neutralise remaining acid after the separating funnel procedure, won't that make another salt? or is that dissolved in the aqueous solution and then removed when it's tapped off?

first question is important and i can't find the answer anywhere. please reply

 

[Trebla]

hi in our esterification prac we had to use fused CaCl₂ to dry the organic ester layer
but i don't get how it dries it or what exactly it dries. coz if you put calcium chloride in your organic layer, aren't you contaminating it? even if you distill it, it'll still be there. or is it decanted off?

also when we add sodium carbonate to neutralise remaining acid after the separating funnel procedure, won't that make another salt? or is that dissolved in the aqueous solution and then removed when it's tapped off?

first question is important and i can't find the answer anywhere. please reply

Calcium chloride (anhydrous) is a dehydrating agent. It basically forms what is called a metal complex with water molecules surrounding the calcium ion (since the positively charged calcium ion attracts the electronegative oxygen atoms in the water molecules). Since the calcium ion is covered in water molecules (it literally bonds to them) it is unlikely to react with the ester itself. If you did it properly, you would see that the calcium chloride sticks to the sides of the container (showing that it has binded with water) which allows the mixture to be decanted.

Sodium carbonate reacting with the acid will produce an ionic salt which in turn removes the acid from the organic layer (the layer containing the ester) into the other layer so when it comes to using a separating funnel, the ester layer contains less organic acid reactant and is thus more purified.

 

[abc123doremi]

thanks