Methyl Vinyl Ether

 Methyl Vinyl Ether

The simplest unsaturated ether is methyl vinyl ether, which is prepared industrially by passing acetylene into methanol at 160-200oC in presence of 1-2 per cent potassium methoxide, and under pressure sufficient to prevent boiling:

C2H2   +   CH3OH       CH3OCH=CH2

The acetylene is diluted with nitrogen to prevent explosions. Methyl vinyl ether is a very reactive gas, b.p. 5-6oC. It is hydrolysed rapidly by dilute acid at room temperature to give methanol and acetaldehyde (cf. the ethers), but is stable in alkaline

CH3OCH=CH2   +   H2O     (H+)     CH3OH   +   CH3CHO

Solution. It undergoes many addition reactions at the double bond, e.g.,

CH2=CHOCH3   +   HCl    (0oC)     CH3CHClーOーCH3
CH2=CHOCH3   +   CH3OH    (2.5oc + trace of HCl) ⟶    CH3CH(OCH3)2

It readily polymerises, and is used for making polyvinyl ether plastics.