Dimethyl ether
The functional group of an ether is an atom of oxygen bonded to two carbon atoms. In dimethyl ether,two sp3 hybrid orbitals of oxygen form sigma bond to the two carbon atoms.
The other two sp3 hybrid orbitals of oxygen atom each contain an unshared pair of electrons. The C–O–C bond angle in dimethyl ether is 110.3°, a value close to the tetrahedral angle of 109.5°. In still other ethers, the ether oxygen is bonded to sp2 hybridized carbons. In ethoxy ethene(ethyl vinyl ether), for example the ether oxygen is bonded to one sp3 and one sp2 hybridized carbon.
Williamson Ether synthesis
General methods of preparation of ethers:
Sulfuric acid process (or) synthesis of ethers from alcohols:
This method is used to make sterically hindered symmetrical ethers.
Williamson's method:
The williamson ether synthesis proceeds via an SN2 mechanism, in which an alkoxide ion displaces a halogen ion.
By heating haloalkenes with dry silver oxide:
Halo alkanes when heated with Ag2O give ether. By this method, both simple as well as mixed ethers can be prepared.
Reaction with acids
Chemical properties of ether:
Ethers are quite stable compounds. These are not easily attacked by alkalis, dilute mineral acids, active metals, reducing
agents or oxidizing agents under ordinary conditions.
Reaction with acids:
Being Lewis bases, ethers form complexes with Lewis acids such as BF3, AlCl3, FeCl3, etc. These
complexes are called etherates.
Similarly, diethyl ether reacts with Grignard reagent forming Grignard reagent etherate. Due to the formation of the etherate,
Grignard reagents dissolve in ether. That is why Grignard reagents are usually prepared in ethers. However, they cannot be
prepared in benzene, because benzene has no lone pair of electrons and therefore, cannot form complexes with them.
Zeisel's method
Zeisel's method used for the detection and estimation of alkoxy group in a compound.
Action of hydriodic acid:
With cold HI:
With hot HI:
The silver iodide thus formed in the above reaction can be detected and estimated by Zeisel's method.
Reaction with carbon monoxide:
Ethers used as anesthesia.
Uses:
- Used in ether extractions for purification of organic substances.
- Used as a refrigerant.
- Used as an anesthetic.
- Used as a solvent.
- Used as substitute for petrol with ethanol.
- Used in the preparation of Grignard reagent.