Alcohols and phenols may be viewed as organic derivatives of
water. Alcohols and phenols have a common functional group, the
hydroxyl group, OH. Alcohols, and Phenols In alcohols the hydroxyl
group is attached to an alkyl group, R. In phenols the hydroxyl
function is attached to an aromatic ring, Ar. Alcohols are
classified into: Classification and Nomenclature of Alcohols
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1. Select the longest continuous carbon chain that contains OH
group. Replace the ending the suffix -ol. IUPAC Name 2. If a
molecule contains both an -OH group and a C=C or CC triple bond. -
The name should include both the hydroxyl and the unsaturated
groups. - If a compound contains both OH and a double or triple
bond, choose the chain that include them both even if this is not
the longest chain. - The -OH group takes preference before the
double or triple bonds in getting the lower number. -
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3. In the IUPAC system. The suffix diol is added to the name of
the parent hydrocarbon when there are two OH groups. triol is added
when there are three OH group 4- Cyclic alcohol, no. starts from C
near to OH Two OH groups on adjacent carbons are known as
1,2-glycols.
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Primary alcohol CH 3 OH CH 3 CH 2 OH CH 2 =CHCH 2 OH Common
Methyl alcohol Ethyl alcohol Allyl alcohol IUPAC Methanol Ethanol
2-Propen-1-ol Secondary and tertiary alcohol Common name listing
the alkyl substitutents attached to the hydroxyl group, followed by
the word alcohol.
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Physical Properties of Alcohols As the number of carbons in the
alcohol increases, the solubility in water decreases. when No. of
OH Soluble. in H 2 O inc. The Increase of alcohol BP. is due to the
presence of hydrogen bonding The boiling points increase with
increase in molecular weights. Triols Diols and are more soluble in
water than monohydroxy alcohols. Solubility Boiling points BP. In
straight chains is higher than branched
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Alcohols are week acids. In isomer BP. Dec. with in alkyl gp. 3
< 2