Presentation on theme: "Lipids Oil, greasy organic substances found in living organisms Insoluble in water (because water is very polar) Soluble in organic solvents (benzene,"— Presentation transcript:
Lipids Oil, greasy organic substances found in living organisms Insoluble in water (because water is very polar) Soluble in organic solvents (benzene, chloroform (trichloromethane), diethylether (ethoxy ethane)). No common chemical structure
Classes of Lipids Fats and oils – obtained from natural sources; important source of energy Phospholipids – water insoluble components which biological membranes are constructed. Glycolipids – lipids attached to a sugar; energy storage and cell recognition Steriods – chemical messengers
Fats and Oils Esters of glycerol and predominantly long- chain fatty acids (carboxylic acids)
Fats and oils are esters of glycerol and predominantly long chain fatty acids.
Ester Functional Group Long Chain Fatty Acids
General formula of a triacylglycerol. Fats and oils are called triacylglycerols or triglycerides since each molecule is derived from one molecule of glycerol and three molecules of fatty acid. Typical triacylglycerol: contains 3 fatty acids.
Triglycerides Vary in 3 ways… 1) length of fatty acid chain can contain between 4 and 20 carbons, but carbon number is almost always even 2) Can be saturated or unsaturated 3) May contain three different fatty acids
The human body can produce all but two fatty acids: Linoleic, alpha-Linolenic (Omega 3 and Omega 6) These must be supplied in the diet. Impaired growth and reproduction Eczema and dermatitis.
Fats are solid at room temperature. Fats contain a higher proportion of saturated fatty acids. Oils are liquid at room temperature. Oils contain higher amounts of unsaturated fatty acids. Polyunsaturated means that the molecules of a particular product each contain several double bonds. Monounsaturated and polyunsaturated fats are better for humans than saturated.
Soap is made by hydrolyzing fats or oils with aqueous NaOH or KOH. This is called saponification.
Saponification When a triglyceride is reacted with KOH (potassium hydroxide) or NaOH (sodium hydroxide or lye) a soap is formed and glycerol. Triglycerides are esters. The base hydrolyzes the ester into soap and glycerol. This is known as saponification. If the soap is a sodium salt, it is a “hard soap”. If the soap is a potassium salt, it is a “soft soap”.
Example of a “hard soap” :
Soaps Very long chain One end is polar and the other is nonpolar Polar end orients itself toward polar water Nonpolar ends orient them selves toward one another and trap grease and oil
Lipid formations Liposome is spherical and contains a lipid bilayer (2 layers) Micelle is also spherical, but contains a lipid monolayer (1 layer) Can also have a bilayer sheet.
Heavy Metal Ions Emulsify means combining two liquids together which normally don't mix easily. Iron (III), calcium and magnesium create an insoluble salt which does not have the same emulsification properties as soap made with potassium and sodium. Addition of phosphate solves this problem but causes another pollution problem, eutrophication. Eutrophication – fish and other organisms are killed due to insufficient oxygen
LAS, ABS, SDS LAS - Linear alkyl sulfonates – sodium salt of an alkylbenzenesulfonate. – Biodegradable – Non-branched side chain – Soft detergent, less foam ABS - Alkylbenzene sulfonates – Not biodegradable – Branched side chain – Hard detergent, no longer used in US SDS – a sodium alkyl sulfates – Sodium dodecyl sulfate – Very common detergent (major ingredient in carpet shampoos)
Reflux Continual boiling of a solution in a vial or flask Solvent is continually returned to the reaction vessel from a condenser atop the vial or flask Ethanol has a low boiling point and would easily evaporate from the reaction flask without a condensor A common technique for carrying out organic reactions Reaction mixture can be heated to boiling without solvent loss.
Reflux Equipment Wikipedia Heating Mantel
What you’re doing… Day 1: Synthesize soap via reflux and then cooling! Day 2: Testing various properties of your soap – Tube #1 = DI water (negative control), Tube #2 = your Soap, Tube #3 = Detergent (positive control) – Tests Emulsification Heavy metals Acidity Unsaturations
Acidification of a soap molecule (test for unsaturations)
Bromination Addition of Bromine across double bonds. Test for unsaturations Yellow/Orange to Clear