Methyl Vinyl Ether

 Methyl Vinyl Ether

The simplest unsaturated ether is methyl vinyl ether, which is prepared industrially by passing acetylene into methanol at 160-200^oC 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. 5-6^oC. 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    (0^oC) ⟶    CH₃CHClーOーCH₃

CH₂=CHOCH₃   +   CH₃OH    (2.5^oc + trace of HCl) ⟶    CH₃CH(OCH₃)₂

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