Download Chemical Bingo: Naming Review

Chemical Bingo: Naming
Review
• There are 27 structures or names drawn on the next slide.
Select 24 of them to be placed on your bingo card.
• Because of space issues, I would number each bingo square
and then list the names or structures on a separate sheet of
paper
• If I give you a name, you must match it to a structure. If I give
you a structure, you must match it to a name
• Any bingo winner will be awarded 20 Beaker Bank points
Chemical Bingo: Alkanes
R
isopropyl
sec-butyl
tert-butyl
isobutyl
decane
nonane
2,3,4,5-tetramethylhexane
3,4-diethylhexane
3,5-diethyl-4-isopropylheptane
R
R
4-tert-butyl-3,5-dimethylheptane
4-ethyl-2,2,3,5,6,6-hexamethylheptane
Any isomer of C5H12
Any isomer of C6H14
R
Any isomer of C7H16
Alkyl Halides
• The halogen is treated as a substituent on an alkane chain
• The halo-substituent is considered of equal rank with an alkyl
substituent in the numbering of the parent chain
• In the case where each would have the same position number,
the substituent that comes first in the alphabet takes the lower
number!
3
Naming Alkyl Halides
• Follow the same system as with alkanes
• Give the name and carbon number for the halide just like a
side branch!
C-C-F
C-C-C
1-fluoroethane
Cl
C-C-C-C-C
C-Br
2-chloropropane
1-bromo-2-ethylbutane
Naming Practice: Haloalkanes
Two equal numbering options?
Number based on alpha order
Cl
6
1
2
5
3
4
4F
2
5
3
Cl
1
6
F
5-chloro-2-fluorohexane
2-chloro-5-fluorohexane
Br
2-chloro-4-fluoro-2,3-dimethylpentane
I
Br
Cl
2-bromo-3-ethyl-4-iodopentane
2-bromo-4-chloro-3-isopropylpentane
ALKENES AND ALKYNES
Alkenes and Alkynes
• Alkanes are saturated hydrocarbons
• Simply put, a saturated hydrocarbon has no double bonds between the
carbon atoms
• Therefore, there is a maximum number of hydrogens present
• Like the alkanes, the alkenes and alkynes form another
homologous hydrocarbon series
• Alkenes form one double covalent bond between two C
atoms
• Alkynes form one triple covalent bond between two C atoms
• Alkenes and alkynes are unsaturated hydrocarbons
• This means more hydrogen atoms can be added
• General formula for alkenes:
• General formula for alkynes:
CnH2n
CnH2n-2
Saturated vs Unsaturated
Naming Alkenes and Alkynes
• IUPAC nomenclature rules for alkenes and alkynes
are similar to alkanes
• Name the parent compound
• Find the longest chain containing the double or triple
bond and name the parent compound by adding the
suffix –ene or –yne to the name of the main chain
• Number the carbon atoms in the parent chain,
beginning at the end nearest the double or triple bond
• If the multiple bond is an equal distance from both ends,
begin numbering at the end nearer the first branch point
9
Naming Alkenes and Alkynes
•Assign numbers and names to the branching
substituents, and list the substituents alphabetically
•Use commas to separate numbers, and hyphens to
separate words from numbers
•Indicate the position of the multiple-bond carbon
•The number indicates which carbon the multiple bond is
AFTER
•Do not use a # if there is only one possible location
•If more than one multiple bond is present, identify the
position of each multiple bond and use the appropriate
ending diene, triene, tetraene, and so forth
•Assemble the name as previously discussed
10
Example
1-butene (not 3)
H
HH
C=C–C–C–H
H H H H
C4H8
CH2CHCH2CH3
2-butene
H H HH
H–C–C=C–C–H
H
H
Structural Formula
C4H8
Chemical formula
CH3CHCHCH3
Condensed
Structural formula
11
Another Example
2,3-dimethyl-1-butene
C=C–C–C
C C
Structural Formula
(w/o the H)
C6H12
Chemical formula
CH2C(CH3)CH(CH3)CH3
Condensed
Structural formula
Assigning Priority
• Alkenes and alkynes are considered to have equal
priority
• In a molecule with BOTH a double and a triple bond,
whichever is closer to the end of the chain
determines the direction of the numbering
• In the case where each would have the same position
number, the double bond takes the lower number
• In the name, “-ene” comes before “-yne” because of
alphabetization
13
Multiple Double/Triple Bonds
Learning Check
Write the IUPAC name for each of the following
unsaturated compounds:
A.
CH3CH2CCCH3
CH3
CH3
B.
CH3C=CHCH3
C.
Properties of Alkenes and
Alkynes
• Like the alkanes, alkenes and alkynes are:
•
•
•
•
•
•
Non-polar
Insoluble in water
Soluble in non-polar organic solvents
Less dense in water
Flammable
Non-toxic
• Unlike the alkanes:
• Alkenes and alkynes are chemically reactive at the multiple bond
• Alkenes display cis-trans isomerism when each double-bond
carbon atom has different substituents
WAIT…WHAT IS CIS-TRANS
ISOMERISM?
Recall Way Back When…
• Draw the Lewis Dot structures and predict
the shapes of the following molecules:
•Methane
•Ethylene (C2H4)
•Acetylene (C2H2)
•What carbon families are these molecules a
apart of?
Answers
• As predicted by the VSEPR theory discussed
earlier:
• Methane (an alkane) is tetrahedral (sp3 hybridization)
• Ethylene (an alkene) is planar (sp2 hybridization)
Acetylene (an alkyne) is linear (sp hybridization)
Molecule Rotation
• In alkanes, there is free rotation around the single bond
• In alkenes, there is NO rotation around the double bond
• The double bond is “fixed”
• As a consequence, a new kind of structural isomerism is
possible
• Called stereoisomerism
• More specifically, this type of stereoisomerism is called cis-trans
isomerism
Stereoisomerism
• To see this new kind of isomerism, look at the following butene
compounds:
• The two 2-butenes are called cis-trans isomers
• They have the same formula and connections between atoms, but
different structures
Cis- and Trans- Isomerism
•
•
•
•
A cis-isomer contains substituents on the same side of the
double bond
A trans-isomer contains substituents on opposite side of the
double bond
Cis-trans isomerism occurs in an alkene whenever each
double-bond carbon is bonded to two different substituent
groups
If one of the double-bond carbons is attached to two identical
groups, cis-trans isomerism is not possible as shown below
TIME FOR PRACTICE!
AROMATIC COMPOUNDS
Benzene Structure
• Benzene as 6 electrons shared equally among the 6 C atoms
• Resonant bonding
 It is also represented as a hexagon with a circle drawn inside
 Benzene, C6H6, is one of the most important industrial chemicals
 Benzene is regarded as a highly carcinogenic substance
• Use and disposal of benzene are regulated
• Compounds containing benzene rings are not necessarily toxic
Aromatic Compounds
• At the time of its discovery, many compounds containing
benzene had fragrant odors
• So, the family of benzene compounds became known as
aromatic compounds
Common Aromatic Compounds
Naming Aromatic Compounds
• Aromatic compounds are named
• with benzene as the parent chain
• with one side group named in front of benzene
CH3
Methylbenzene
Cl
Chlorobenzene
Naming Aromatic Compounds
Several base names…
benzene
aniline
toluene
benzaldehyde
phenol
benzoic acid
Abbreviations Used with Di-Substitution
1,2 difluoro benzene
Ortho difluoro benzene
o – difluoro benzene
1,3 dichloro benzene
Meta dichloro benzene
m – dichloro benzene
1,4 dibromo benzene
Para dichloro benzene
p – dichloro benzene
Toluene
• For methylbenzene, the common name, toluene, may be used
Xylene
• For isomers of dimethylbenzene, the common name, xylene
may be used
Naming Aromatic Compounds with Three Substituents
• Use numbers for giving the positions:
Cl
CH3
Cl
Cl
1
CH3
Br
1
Br
Cl
Br
Cl
1,3,5-Trichlorobenzene
2,6-Dibromo-4-chlorotoluene
4-Bromo-2-chlorotoluene
Learning Check
Select the correct name(s) for each of the following compounds.
A. chlorocyclohexane
B. chlorobenzene
Cl
C. 1-chlorobenzene
A. 1,2-dimethylbenzene
B. 1,3-dimethylbenzene
C. m-xylene
CH 3
CH 3
Solution
Cl
B. chlorobenzene
CH 3
B. 1,3-dimethylbenzene or
C. m-xylene
CH 3
Learning Check
Draw the condensed structural formulas for each of the
following.
1. 1,3-dichlorobenzene
2. o-chlorotoluene
Solution
One possible way to draw each…
Cl
1. 1,3-dichlorobenzene
Cl
CH 3
2. o-chlorotoluene
Cl
Benzene as a Substituent…
• If you have the aromatic ring as an attachment, it is named phenyl
Try one…
• What would this name be?
Answer…
• 4-phenyl octane
Learning Check
Draw and identify the organic family (functional group) for each
of the following.
A.
B.
C.
D.
Solution
The functional groups are as follows…
A.
alkene
B.
cycloalkane (alkane)
C.
alkyne
D.
aromatic
FUNCTIONAL GROUPS
Classified
according Compounds
to functional group
Types of
Organic
Alkane
Alcohol
Carboxylic acid
O
OH
OH
Alkene
Ether
Amine
NH2
O
Alkyne
C
Ketone
Amide
O
O
C
NH2
Haloalkane
Aldehyde
Amino acid
O
O
Cl
Br
H2N
H
OH
Problems:
• Draw the following alkenes:
•
•
•
•
2-Butene
methylpropene
4–Methyl–2-pentene
3,3-Dimethyl-1-butene
45
Can you name this compound?
46
3-ethyl-1-pentyne
Problems
Name this alkyne:
C
C-C-C=C-C-C-C-C
C
C
C
C
C
C
5,7-diethyl-3-methyl-4-decyne
47
Isomers
The fat dog shook himself, and then rolled over on the
wet rug.
OR
The dog shook the fat rug, then rolled over and wet on
himself.
These two statements use the same words...
but have very different meanings!
Likewise, isomers may have the same formula, but
have very different structures…
Structural Isomers of C4H10
2-methylpropane
or
• On piece of your
own paper,
draw AND name ALL
Structural
Isomer
Practice
of the isomers for the following alkanes:
# isomers
Formulas
Pentane C5H12
3
Hexane C6H14
5
Heptane C7H16
9
Some of your drawings may look different, but they are
only different structures (isomers) if they also have
different names
If you complete that, try to draw and name all of the
isomers for octane (C8H18). There are 18 of them!
On piece of your
own paper,
draw AND name ALL
Structural
Isomer
Practice
of the isomers with the following formulas:
Formulas
C 4H 9I
C3H6Cl2
C5H11Br
C4H8Cl2
# isomers
4
4
8
9
To be honest, there may be more…this is what I
found, so try and prove me wrong! Extra Credit to
anyone who can find more structures…
Some of your drawings may look different, but they are
only different structures (isomers) if they also have
different names
Structural Isomers: C4H9I
I
1-iodobutane
I
2-iodobutane
I
I
2-iodo-2-methylbutane
I
1-iodo-2-methylbutane
Structural Isomers: C3H6Cl2
Cl
Cl
Cl
Cl
1,1-dichloropropane
Cl
Cl
1,3-dichloropropane
1,2-dichloropropane
Cl
Cl
2,2-dichloropropane
Structural Isomers: C5H11Br
Br
Br
1-bromopentane
Br
3-bromopentane
2-bromopentane
Br
1-bromo-3-methylpentane
Structural Isomers: C5H11Br
Br
Br
1-bromo-2-methylbutane
Br
1-bromo-2,2-dimethylbutane
2-bromo-3-methylbutane
Br
2-bromo-2-methylbutane
Structural Isomers: C4H8Cl2
Cl
Cl
Cl
1,1-dichlorobutane
Cl
1,2-dichlorobutane
Cl
Cl
Cl
Cl
1,3-dichlorobutane
1,4-dichlorobutane
Structural Isomers: C4H8Cl2
Cl
Cl
Cl
Cl
1,1-dichlorobutane
1,2-dichloro-2-methylpropane
Cl
Cl
2,2-dichlorobutane
Cl
Cl
Cl
1,3-dichloro-2-methylpropane
Cl
2,3-dichlorobutane
Structural Isomers: Pentane
(C5H12)
pentane
2-methylbutane
2,2-dimethylpropane
Structural Isomers: Hexane (C6H14)
hexane
2,3-dimethylbutane
2-methylpentane
2,2-dimethylbutane
3-methylpentane
Structural Isomers: Heptane (C7H16)
heptane
2,2-dimethylpentane
2-methylhexane
2,3-dimethylpentane
3-methylhexane
Structural Isomers: Heptane
(C7H16)
2,4-dimethylpentane
3-ethylpentane
3,3-dimethylpentane
2,2,3-trimethylbutane
Comparing Structural Isomers
C5H12
Structure
(Same formula, different structure)
Name
Boiling point (°C)
pentane
36.0
2-methylbutane
27.9
2,2-dimethylpropane
9.5
More branching → weaker London dispersion forces
BP/MP of Linear alkanes > BP/MP of branched alkanes
Structural Isomers
What are the possible structural isomers of C3H7Br?
Br
Br
1-bromopropane
2-bromopropane
What are the possible structural isomers of C4H9Cl?
Cl
Cl
1-chlorobutane
2-chloro-2-methylpropane
Cl
2-chlorobutane
Cl
1-chloro-2-methylpropane