ESTERS Flashcards
How are esters formed? (1)
carboxylic acids react with alcohols in a process called esterification in the presence of a strong acid catalyst.
what is the group of esters? (1)
-COO-
What is esterification also? (1)
a condensation reaction because it releases water
why can compounds dissolve in esters? (1)
because esters are polar liquids so lots of polar organic compounds will dissolve in them.
what is hydrolysis? (1)
hydrolysis is when a substance is split by water.
why is an acid or alkali used instead of water? (1)
because using water cane produce a slow reaction so an acid or an alkali is used to speed it up.
what are the two types of hydrolysis of waters? (2)
-acid hydrolysis
-base hydrolysis
what occurs in acid hydrolysis? (1)
splits the ester into an acid and an alcohol, you have to reflux the ester with a dilute acid such as hydrochloric or sulphuric
what occurs in base hydrolysis? (1)
involves refluxing the ester with a dilute alkali such as sodium hydroxide, you get a carboxylate ion and an alcohol
what are fatty acids? (1)
fatty acids are long chain carboxylic acids
what fats are animal fats usually? (1)
animal fats have mainly saturated hydrocarbon chains, they fit nearly together, increasing the van der waals forces between them, they need higher temperature to melt them so there solid at room temperature.
what fats are vegetable oils usually? (1)
vegetable oils have unsaturated hydrocarbon chains- the double bonds mean that the chains are bent and don’t pack together well, decreasing the van der waals forces so they easily melt and are liquid at room temperature.
what happens if you hydrolyse vegetable oils and animal fats? (1)
if hydrolyse vegetable fats and animal fats with sodium hydroxide you produce the sodium salt, soap.
what is biodiesel? (1)
biodiesel is a mixture of methyl esters of fatty acids.
how is biodiesel produced? (1)
by reacting vegetable oils with methanol using potassium hydroxide as a catalyst.
