EES 4200 Nomenclature Worksheet for Alcohols, Alkyl Halides, Alkenes, and
Please also refer to your textbooks (Ouellette and Banks) for more detailed
explanations of IUPAC nomenclature of these compound classes.
Note: Start counting carbons from the end that results in the
lowest number for the carbon with the hydroxyl group. In this
case, this carbon is the 1-carbon! This is a terminal, or primary,
HO CH3 Note: Regardless of the direction of the counting, the third
carbon is the one bearing the hydroxyl group.
Note: The position of the hydroxyl group dictates the sequence of
counting carbons. Always strive for the lowest numbers; therefore, this
HO CH3 is NOT 4-methyl-2-pentanol. The –OH group takes precedence in
numbering and should always be the lowest possible number.
Note: The “1-“ is not required since the C with the
hydroxyl group is automatically assigned the “1” position.
Note: Again, since the C with the hydroxyl group is always the “1” carbon,
the “1-“ designation is not necessary in front of the “cyclohexanol.” Note that
the counting around the ring should proceed in a way that results in the lowest
number for the other substituents.
OH Name: 1-methyl-1,4-pentanediol
Note: This is a di-substituted alcohol. Note the “diol” on the
end, and the 2 numbers that signify positions of both hydroxyl
groups. Note that the numbers should be the lowest as
H3C Cl Note: Always strive to obtain the lowest number
Note: Present the substituents in alphabetical order.
H3C Cl Strive for the lowest numbers possible. Therefore,
this would NOT be 4-bromo-6-chlorohexane.
Note: Recall that the –OH group takes precedence for
OH alkyl groups and halogens.
Note: The first C of the C=C is used in the numbering
scheme. Always use the lowest number possible.
Note: The –ene group has precedence over the
alkyl group (and also over halogens). Thus, the first
C of the C=C should have the lowest possible
CH3 Name: 3-methyl-1,4-hexadiene
Note: Note the addition of the “diene” at the end of the
name to signify two double bonds. Examples of other
di-substituted alkenes include butadiene, pentadiene,
octadiene, dodecadiene, etc.
Some common names have been used to frequently that they have been
accepted as IUPAC names. Names of environmentally relevant compounds
include the following:
Benzene Toluene Phenol Styrene Benzoic Acid
You should know be able to recognize these compounds by structure and
Cl Name(s): 1,2-dichlorobenzene, or ortho-dichlorobenzene
Note: If the substituents are on neighboring carbons, they are
Cl designated as following ortho-substitution.
Name(s): 1,3-dichlorobenzene, or meta-dichlorobenzene
Note: If the substituents are on the 1 and 3 carbons, they are
designated as following meta-substitution.
Name(s): 1,4-dichlorobenzene, or para-dichlorobenzene
Note: If the substituents are on the opposite (1- and 4-)
carbons, they are designated as following para-substitution.
Cl Name: 1,3,5-trichlorobenzene
Cl Cl Note: The –OH group takes precedence. Since chlorines
substitute all remaining carbons on the ring, no numbers are
necessary! If one were to number this, however, the C with
HO Cl the –OH group is always the 1-C. (2,3,4,5,6-
More Examples: Please do not forget that Ouellette has examples of
nomenclature for each of the compound classes (just check the chapters for
these classes). Banks will provide examples to work as well!
Name: trichlorofluoromethane (also called CFC-11)
Note: What does this other nomenclature system mean?
Cl Cl For CFCs and HCFCs with one carbon, the right number denotes the number of
fluorines and the left number denotes one more than the number of hydrogens. For
CFCs and HCFCs (with hydrogens) with more than one carbon, the far right
Cl number is the number of fluorines, the middle number is one less than the number
of carbons, and the left number is one more than the number of hydrogens. Can
you draw one representation of CFC-12 and CFC-134 (a replacement of CFC-12)?
Note: The –OH rules over halogens and alkyl groups.
Thus, the C with the –OH must be lower in number.
Note the use of “en” and “ol” in the name.
OH Name: 2-bromo-6-methyl-6-hepten-3-ol
Note: This one is loaded! Recall that the –OH must always
have the lowest designation possible. The longest chain must
include the C=C! Recall also that the alkene has precedence
over the alkyl and halogen groups, which are then alphabetized
in front of the –en and –ol designations.