Ethers Unit 7

Ethers!  Ether – organic compounds where two alkyl or aryl groups joined singly with an oxygen atom  R-O-R’ R-O-Ar Ar-O-Ar

Ethers  Symmetrical ethers – 2 identical groups bonded to the oxygen  Unsymmetrical ethers – two different groups bonded to the oxygen

Nomenclature  Name the attached groups followed by ether  C-O-C-C Methyl ethyl ether ( unsymm )  C-C-O-C-CDiethyl ether ( symm )  C-C-O-  C-C-C-C-O-

Preparation of Ethers 1. Symmetrical ethers = dehydrate alcohols 2R-OH H2SO4 R-O-R + H 2 O Form dipropyl ether 2 C-C-C-OH H2SO4 C-C-C-O-C-C-C + H 2 O 2CH 3 CH 2 CH 2 OH H2SO4 CH 3 (CH 2 ) 2 O(CH 2 ) 2 CH 3 + H 2 O

Preparation of Ethers 2. Unsymmetrical ethers = Williamson Synthesis Alkyl halide + alcohol salt  ether + metal halide RX + RO - M +  ROR’ + MX

Preparation of Ethers - Williamson  If there are 2 alkyl groups, the smaller alkyl group is the halide and the larger is the metal salt  If there is an alkyl group and a phenyl, the phenyl is ALWAYS the salt

Preparation of Ethers - Williamson  Form methyl ethyl ether (name reactants) CH 3 Cl + (C-C-O - )Na +  C-O-C-C + NaCl CH 3 Cl+(CH 3 CH 2 O - )Na +  CH 3 OCH 2 CH 3 +NaCl Methyl chloride + sodium ethoxide (chlormethane)

Preparation of Ethers - Williamson  Form propyl phenyl ether

Reactions of Ethers  Ether + hydrogen halide  alcohol + alkyl halide  ROR + HX  ROH + RX  If either had two alkyl groups, the smaller one forms the alcohol. If it is a phenyl and an alcohol, the phenyl forms phenol

Reactions of Ethers  React ethyl phenyl ether w/HBr  C-C-O- + HBr  C-C-Br + -OH  React methy phenyl ether w/HF