Expt. 7

• Ethers

  • class of organic compounds that contain an oxygen between two alkyl groups.
• Ethers

  • have the formula R-O-R, with R’s being the alkyl groups
• Ethers

  • these compounds are used in dye, perfumes, oils, waxes and industrial use
• Ethers

  • used as solvent in Soxhlet apparatus
• Ethers

  • smells like plastic balloon
• Ethers

  • compounds having two alkyl or aryl groups bonded to an oxygen atom (R-O-R)
• Ether functional group does not have a characteristic IUPAC nomenclature suffix, so it is necessary to designate it as a substituent
• Alkyl group - carbon

  Alkoxy group - oxygen
• 2-methoxy-2-methylpropane or tert-butyl methyl ether

  
• example of ether: 4-ethoxy-2-methyl-1-hexene

  
• example of ether: 3-isopropoxy-1-butanol

  
• example of ether: cis-1-ethyl-3-phenoxycyclohexane

  
• In cyclic ethers (heterocycles), one or more carbons are replaced with oxygen or any atom other than carbon or hydrogen and it is often called heteroatoms.
• In this case, the stem is called the oxacycloalkane, where the prefix ”oxa-“ is an indicator of the replacement of the carbon by an oxygen in the ring.

  These compounds are numbered starting at the oxygen and continues around the ring.
• Example of heterocycles or cyclic ether: 1,4-dioxacyclohexane

  
• Example of heterocycles or cyclic ether: 1-oxacyclopentane

  
• Ethers have weak polarity, so its boiling point are not affected.
• Ethers have BP comparable to alkenes but have lower boiling points compared to isomeric alcohols.
• Ether molecules have no hydrogen atom on the oxygen atom. Therefore, there is no intermolecular hydrogen bonding between ether molecules, and ethers therefore have quite low boiling points for a given molar mass.
• Indeed, ethers have boiling points about the same as those of alkanes of comparable molar mass and much lower than those of the corresponding alcohols.
• Ethers with up to 3 carbon atoms are soluble in water.
• The higher the number of carbon atoms, the lower its solubility.
• Ethers are appreciably soluble in organic solvents.
• Ether molecules do have an oxygen atom, however, and engage in hydrogen bonding with water molecules.
• Due to hydrogen bonding, an ether has about the same solubility in water as the alcohol that is isomeric with it.