Question: why bimolecular dehydration not appropriate?
Answer: "Bimolecular dehydration" is a way of preparing diethyl ether from the dehydrating action of concentrated sulfuric acid on ethanol. So this method works only with symmetrical ethers: di[alkyl] ethers. Methyl Ethyl ether is better prepared from Sodium ethoxide and methanol or Sodium methoxide and ethanol.