3.9 Triglycerides Flashcards
What are triglycerides?
fats and oils derived from plants and animals
What process formed triglycerides?
Condensation of 1,2,3-propan-tri-ol and various carboxylic acids to form tri-esters
Which triglycerides are liquid at RT?
Edible oils
Derived from plants (generally)
Unsaturated triglycerides or fatty acids
Have a lower MP
Which triglycerides are solid at RT?
Edible fats
Derived from animals
Have high MP
Saturated triglycerides or fatty acids
What are fatty acids?
Also known as carboxylic acids
What characteristic are require of fatty acids to form triglycerides?
Even number of carbon between 12 and 20 carbons
NO branching chains
Can be saturated or usaturated
Define saturated
Contains no carbon double-bonds
Define unsaturated
Contains at least one carbon double bond
Define poly-unsaturated
Contains 2 or more carbon double bonds
State and explain MP of saturated fats
High melting point
- They have a regular tetrahedral shapeand therefore are able to pack together efficient increasing the density of the molecule
State and explain MP of unsaturated fats
Lower melting point and liquid at RT
- carbon-carbon double bonds changes the 3D shape to one of irregularity and thus the fatty acids are unable to pack together efficiently thus lower density
How can bromine or iodine be used to determine the degree of unsaturation?
The no. of moles of iodine they turns from brown to colourless per mole of fatty acid will dictate the no. of double bonds present in the particle
What are iodine number and how can they be calculated?
The iodine number is the mass of iodine required to unsaturate 100g of particle
What process will convert unsaturated fats to saturated fats? state conditions and required substances
Hydrogenation requires hydrogen High pressure high heat addition of catalyst
What physical property changes will be experience after hydrogenation?
The MP will increase as saturated fats are density due to more regular shape
What particles are soaps derived from?
Soaps are derived from fats
What is the difference between soaps and synthetic detergents?
Soaps are derived from fats
Synthetic detergents are derived from petroleum compounds (have sulfur)
How are micelles formed?
When triglycerides are hydrolysed in alkaline condition the fatty acid forms the carboxylate anion. The carboxylate anion has both a hydrophilic and hydrophobic end. The hydrophobic ends attract the each other to form a micelle.
Define hydrophilic
Attracted/likes water
Define hydrophobic
Repelled / dislikes water
Describe how micelles can be used to remove grease from clothing
First the carboxylate anions will dissociate from the solid soap and subsequently form micelles.
The hydrophobic centre of the micelle will bond with the non-polar grease using dispersion forces. *agitation
The hydrophilic ends will then bond with water and be washed away removing the grease from clothing
