1. Extraction
Extraction is a general theory for the recovery of a substance from a mixture by bringing it into contact with a solvent which preferentially dissolves the desired material. In organic chemistry, the reaction product is frequently obtained as a solution in water along with other organic and inorganic byproducts.

2. Let’s get started
To begin this lesson, click on the web address below and view this first 12 pages.
Return to this powerpoint after viewing the first 12 pages.

3. Let’s do the math By definition, the distribution coefficient is:
concentration in the organic layer
concentration in the water layer
Let us consider compound A:
10g of compound A will dissolve in 100ml ethyl ether (an organic compound)
2g of compound A will dissolve in 100ml of water
Calculate the KD for compound A
KD=

4. Determining the KD
concentration in the organic layer = 10g/100ml concentration in the water layer 2g/100ml KD= 5 If you are given a solution of 1g of compound A dissolved in 100ml of water, how much could you extract if you did three extractions using 25ml of ethyl ether with each extraction?
KD=

5. Set up the problem
Solve for X by cross multiplying two times. Go to the next page to see the value for X.

6. X = 0.556g
This means that 0.556g of compound A has now moved to the ethyl ether layer.
How much compound A remains in the water?
1g – 0.556g = 0.444g of compound A in the water.
Now set up the problem for the next extraction:

7. 2nd Extraction
Cross multiply twice and solve for X.

8. X=0.247g
This means that more grams of compound A have moved from the water layer to the ethyl ether.
How much compound A remains in the water?
0.444g-0.247g = 0.197g of compound A are still in the water.
Set up the problem for the third extraction.

9. 3rd Extraction
Solve for X and you should obtain X = 0.109g of compound A.
What is the total amount of compound A extracted?
0.556g g g = 0.912g extracted in the ethyl ether.
1g – 0.912g = 0.88g of compound A remaining in the water.

10. Try another problem? 15g of compound J dissolves in 100ml of benzene.
5g of compound J dissolves in water.
You are given a solution with 2g of compound J dissolved in 100ml of water. If you do two extractions with 50ml of benzene in each extraction, how many grams of compound A can you extract from the water?

11. Solve for KD and 1st extraction

12. 2nd extraction and final answer