CHEM 2332H Chapter Notes - Chapter 14: Benzene, Crown Ether, Dimethyl Ether
Document Summary
14. 2b) boiling points of ethers; hydrogen bonding: ethers don"t do hydrogen bonding like alcohols b/c no oh groups lower boiling. H bonding needs h bond donor and h bond acceptor donor = molecule w/ oh or nh group acceptor = molecule whose lone electron pairs form weak partial bond to. H from donor; ether has lone pair on o ethers can"t h bond w/ other ether molecules = more volatile than similar-weighted alcohols. Can"t use alcohols as solvents for reagents more basic than alkoxide ion b/c oh group protonates base basic reagent destroyed. Boron trifluoride (bf3) used as lewis catalyst in variety of rxns: toxic like diborane forms stable complex w/ ethers convenient storing/measuring complex w/ diethyl ether called boron trifluoride etherate, crown ether complexes. Crown ethers: large cyclic polyethers that specifically solvate metal cations by complexing metal in center of ring different crown ethers solvate different cations depending on relative size of ether and # binding sites around cation.