Acohols and Ethers Flashcards
Why do alcohols have considerably higher boiling points than alkanes of similar molecular mass?
Because of the polar OH group which allows hydrogen bonds to set up between the molecules. Hy bonds require more thermal energy to break then van der waals
Why can small chain alcohols dissolve in water?
Because the energy released when forming hydrogen bonds with water is sufficient to break the hydrogen bonds between the water molecules.
Why do larger chain Alcohols not dissolve in water?
Because the large non-polar hydrocarbon part of the molecule masks the polar hydroxyl group.
How are alcohols prepared?
Hydration of an alkene with concentrated sulphuric acid.(can’t produce methanol)
Nucleophilic substitution of a monohalogenoalkane.
Name 3 types of reaction an alcohol can undertake
With reactive metals to form alkoxides.
Dehydration to form alkenes
Esterification (fast with an acid chloride?)
What is a symmetrical ether?
When both R groups are the same.
How do you name ethers?
Add oxy to the end of the shorter alkane, then put the larger chains name on the end.
How do ether boiling points compare with alcohol boiling points?
Much lower
Why can’t ethers form hydrogen bonds between its molecules?
Because the highly electronegative oxygen atom is not directly bonded to a hydrogen atom.
What can ethers make hydrogen bonds with?
The H in water
What is the effect of chain length on solubility of ethers?
As the chain length increases the solubility decreases
What does the solubility of ethers make them useful for?
Extracting organic molecule from aqueous solutions.
Describe the reactivity of ethers
Volatile and highly flammable. When exposed to air they slowly form peroxides which are unstable and can be explosive.
Why are ethers used as solvents?
They are relatively inert chemically and most organic compounds dissolve in them. Being volatile the solvent is easily removed by distillation.
How are ethers prepared?
Refluxing a halogenoalkane with an alkoxide.
