Postlab Questions 1Is the partition coefficient of caffeine

Post-lab Questions: 1.Is the partition coefficient of caffeine in dichloromethane/water the same at all pH\'s? not, is it higher or lower at acidic pH\'s? (2 )Why was sodium carbonate added to the tea before the extraction? 3. Js neutral caffeine completely nonpolar? Would hexane have worked well as an ction solvent? Uy What is the chemical formula of calcium chloride? Think back to general chemis hat are the likely charges of the calcium and chloride ions? Cac try 2 The partition coefficient kofcompound A in dichloromethane/water is 34. 10.0 g of compound A is dissolved in 2.0 removed by a single extraction with 3.0 L of dichloromethane liters of water. How much o ound A would be A w muchor compoând A would be removed by tiree extractions wit 1.QL each of dichlörometha 10 gof compound A is dissolved in 2.0 liters of water. Ho How much of cor 7. Write a procedure of how you would separate benzoic acid (acidic), decane (neutral), and adenine (basic) using extraction. All three neutral substances dissolve in dichloromethane.

Solution

1) The partion coefficient for caffene in dichloromethane /water is lower at acidic _PH.

2)Caffeine ian an alkaloid which contains four basic nitrogens. Caffeine is extracted more in alkaline medium.It can exists in the nature in the form of salt. To convert it into neutral molecules the Na₂CO₃ is added before extraction..

3)The neutral caffeine is polatr. n-Hexane is less polar. Hence polar solvents like Chloroform/Dichloromethane will be the better solvents for caffeine extraction.

4)Formula of calcium chloride is CaCl2.The chage on Ca is 2+ where as the chage on Cl is -1.

7. The boiling point of decane is 174.9 hence it is non-volatile.

It is Acid + Base + Neutral type of mixture.

a)Mix + Dichloro methane + sat.NahCO3 , shake well in separatory funnel , acid becomes soluble, separate two laters . Aq. layer of bicarbonate + dil. HCl gives the ppt. of acid.

b)Above organic later + Dil HCl, shake in well & separete two layerss. Aqu. later of hdrochloride salt of adenine + aq. dil. NaOH gives adenine high b.p. liquid(Low m.p.solid)

c)The organic layer is removed by rotary evaporation to get non-volatile Decane

This way we can separate Acid +Base + Neutral mixture.