ORGANIC CHEMISTRY II LAB#8

Lab # 8 Princess Norah Bint Abdulrahman University Collage of pharmacy Pharmaceutical Chemistry Department

lipid  Lipids consist of glycerol and fatty acids "tails".  A lot of lipids function as long-term energy storage.  One gram of fat stores more than twice as much energy as one gram of carbohydrates.  Lipids are also an important component of the cell membrane.

lipid  stearic acid: is the saturated fatty acid.  Oliec acid: is the unsaturated fatty acid. CH 3 (CH 2 ) 16 COOH CH 3 (CH 2 ) 7 CH = CH(CH 2 ) 7 COOH

lipid Glycerides (acylglycerols) :  They are esters formed from glycerol and fatty acids.  Glycerol has three hydroxylfunctional groups,which can be esterified with one, two, or three fatty acids to form monoglycerides, diglycerides and triglycerides. Glycerol Acyl glycerol

Saponification - Soaps are formed from the reaction of glycerides with sodium hydroxide. - The product of the reaction is glycerol and salts of fatty acids (soap).

PHYSICAL PROPERTIES

lipid GlycerolOliec acidstearic acid viscous liquidOil State colorlessYellowcolorless color odorlessCharacteristic odor odor 17.8 °C-11 °C69 °C Melting point Glycerol is miscible with water and partially soluble in organic solvents insoluble in water, it is soluble in organic compounds Solubility

Chemical tests

Chemical test general 1\Grease spot test 2\Emulsion of lipid 3\Saponification test Specific 4\Copper acetate test Chemical test

1\ Grease spot test:  To a small amount of lipid add 3ml ether in test tube then pour the mixture in a filter paper.  Result: lipid leave translucent spots (grease spots) on the filter paper.

2\ Emulsion of lipid:  Pour 2ml of ethanol into a test tube. Add one drop of oil to the ethanol in the test tube. Cover the open end of the test tube with your thumb and shake the test tube thoroughly to mix the contents. Pour the mixture into the second test tube containing about 2ml of water.

3\ Saponification test:  Add 1ml of oil to 5ml of NAOH, heat content of the test tube on a water bath the oil will transfer to soap, remove the test tube from the water bath and add 5ml water and mix.

4\ Copper acetate test :  In a test tube add small amount of oil + 3ml of ether + 3ml of copper acetate then shake once. Result:  glycerol : 2 layer “ the above layer is ether and the other layer is copper acetate” (a specific test)

4\ Copper acetate test:  Unsaturated fatty acid (oleic acid): 2 layer “ the upper layer colored green and the lower layer colored blue”  Saturated fatty acid (stearic acid): 2 layer “Appearance of white blue ppt. at the bottom of the upper layer”.

Copper acetate test:

Thank you