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Unformatted text preview: Notes: Alcohols, Ethers, Phenols and Thiols This set of notes discusses another set of related organic functional groups. The groups can be found attached to normal straight chain alkanes as well as unsaturated organics: alkenes, alkynes and aromatics. The alcohols, ethers and phenols, deal with oxygen groups and the thiol deals with a sulfur group. Here are the general formula and examples of each. alcohol phenol thiol ether general structure OH R OH SH R R O R example structure C C H H H OH H H OH Br C C H H H SH H H C C H H H O H H C H H H example name ethanol or ethyl alcohol o-bromo phenol or 2-bromo phenol ethanethiol ethylmethyl ether or methoxy ethane Nomenclature of Alcohols: 1. Select the longest chain containing the alcohol, -OH. 2. Number the chain with the –OH group getting the lowest possible number. 3. Replace the –e at the end of the suffix with –ol. 4. If there are more than one –OH group do not remove the –e from the suffix, but add a di- or tri- prefix to the –ol suffix. 5. Add a prefix number to indicate which carbon the –OH group is bonded to. This is not always necessary. Examples: ethanol 2-propanol or isopropyl alcohol (rubbing alcohol) 2,4-pentanediol cyclopentanol C C H H H OH H H C C H H H C H OH H H H OH OH OH • For the first example there is no prefix number to indicate the location of the –OH group. The reason is that no matter which carbon the –OH group is attached to that carbon is carbon number one. The name 1-ethanol would be redundant. • For the last example there is no prefix number to indicate the location of the –OH group. The reason is that no matter which carbon the –OH group is attached to that carbon is carbon number one. The name 1-cyclopentanol would be redundant. 1 Alcohols are often classified based on the classification of the carbon they are attached to. Remember the following diagrams. • primary carbon is bonded to one other carbon: o both of these carbons C C H H H H H H • secondary carbon is bonded to two other carbons: o the center red carbon only C C H H H C H H H H H • tertiary carbon is bonded to three other carbons: o the center red carbon only C C H H H C H H H H C H H H Following the format of the above diagrams, if we replace one hydrogen with a –OH group we get the following classifications of alcohols: • 1 ° , primary alcohol has –OH group bonded to a carbon which is bonded to one other carbon: C C H H H H H OH • 2 ° , secondary alcohol has –OH group bonded to a carbon which is bonded to two other carbon: C C H H H C H OH H H H • 3 ° , tertiary alcohol has –OH group bonded to a carbon which is bonded to three other carbon: C C H H H C OH H H H C H H H The classification dictates what types of reactions the alcohol will undergo. A simple test can be performed to determine which classification of alcohol is present....
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- Spring '10
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