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Organic Chemistry Text Book (CHEM 3401 and 3402)

2.2 Functional Groups

Functional Groups

 

Functional groups are atoms or small groups of atoms (two to four) that exhibit a characteristic reactivity when treated with certain reagents. A particular functional group will almost always display its characteristic chemical behavior when it is present in a compound. Because of their importance in understanding organic chemistry, functional groups have characteristic names that often carry over in the naming of individual compounds incorporating specific groups. In the following table the atoms of each functional group are colored red and the characteristic IUPAC nomenclature suffix that denotes some (but not all) functional groups is also colored.

 

Functional Group Tables

 

Exclusively Carbon Functional Groups 

Group Formula

Class Name Specific Example IUPAC Name Common Name
Alkene H2C=CH2 Ethene Ethylene
Alkyne HC≡CH Ethyne Acetylene
Arene C6H6 Benzene Benzene

Functional Groups with Single Bonds to Heteroatoms 

Group Formula
 
Class Name
 
Specific Example
 
IUPAC Name
 
Common Name
 
Halide H3C-I Iodomethane Methyl iodide
Alcohol CH3CH2OH Ethanol Ethyl alcohol
Ether CH3CH2OCH2CH3 Diethyl ether Ether
Amine H3C-NH2 Aminomethane Methylamine
Nitro Compound H3C-NO2 Nitromethane  
Thiol H3C-SH Methanethiol Methyl mercaptan
Sulfide H3C-S-CH3 Dimethyl sulfide  

Functional Groups with Multiple Bonds to Heteroatoms 

Group Formula
 
Class Name
 
Specific Example
 
IUPAC Name
 
Common Name
 
Nitrile H3C-CN Ethanenitrile Acetonitrile
Aldehyde H3CCHO Ethanal Acetaldehyde
Ketone H3CCOCH3 Propanone Acetone
Carboxylic Acid H3CCO2H Ethanoic Acid Acetic acid
Ester H3CCO2CH2CH3 Ethyl ethanoate Ethyl acetate
Acid Halide H3CCOCl Ethanoyl chloride Acetyl chloride
Amide H3CCON(CH3)2 N,N-Dimethylethanamide N,N-Dimethylacetamide
Acid Anhydride (H3CCO)2O Ethanoic anhydride Acetic anhydride