Question

Answer the following before coming to lab: 1.) Based on what you saw last week, which enantiomer of tartaric acid would you expect to co- crystallize with (SS)-1,2-diammoniumcyclohexane? 2.) If you had a neutral aqueous solution of triethylamine, would you add acid or base in order to extract it with an organic solvent? 3.) Now, consider a dichloromethane solution of triethylamine. Would you extract with acidic aqueous or basic aqueous solution in order to get the triethylamine out of the organic solution? 4.) The density of dichloromethane, an organic solvent, is 1.325 g/cm? If you mix 50 mL water and 50 mL dichloromethane together in a separatory funnel, which layer would be on top? 5.) The density of diethyl ether, an organic solvent, is 0.706 g/cm? If you mix 50 mL water and 50 mL diethyl ether together in a separatory funnel, which layer would be on top?

Answer 1

1) Based on the R,S nomenclature of tartaric acid it will crystallize with (S,S)-1,2-diammmoniumcyclohexane. (R,R)-form of tartaric acid will crystallize with (S,S)-1,2-diammmoniumcyclohexane.

2) To extract triethylamine from neutral aqueous solution of triethylamine ,we will use base to extract it with an organic layer.

3) From a dichloromethane solution of triethylamine when we want to extract triethylamine out of the organic layer,we will use acid aqueous solution .

4) If we mix 50ml water(1 g/cc ) and 50ml of dichloromethane (density=1.325 g/cc)together in a separatory funnel,aqueous layer will be on the top.   

5)If we mix 50ml water(1 g/cc ) and 50ml of diethylather(density=0.706 g/cc)together in a separatory funnel,aqueous layer will be on the top