Title: Organic Chemistry I: Compounds
1Chapter 25
- Organic Chemistry I Compounds
2Chapter Goals
- Saturated Hydrocarbons
- Alkanes and Cycloalkanes
- Naming Saturated Hydrocarbons
- Unsaturated Hydrocarbons
- Alkenes
- Alkynes
- Aromatic Hydrocarbons
- Benzene
- Other Aromatic Hydrocarbons
- Hydrocarbons A Summary
3Chapter Goals
- Functional Groups
- Organic Halides
- Alcohols and Phenols
- Ethers
- Aldehydes and Ketones
- Amines
- Carboxylic Acids
- Some Derivatives of Carboxylic Acids
- Summary of Functional Groups
4Chapter Goals
- Fundamental Classes of
- Organic Reactions
- Substitution Reactions
- Addition Reactions
- Elimination Reactions
- Polymerization Reactions
5Saturated Hydrocarbons
- Hydrocarbons are chemical compounds that contain
only C and H atoms. - Saturated hydrocarbons contain only single or
sigma (?) bonds. - There are no double or triple bonds in these
compounds. - The primary source of hydrocarbons is petroleum
and natural gas.
6Alkanes and Cycloalkanes
- The simplest saturated hydrocarbons are called
alkanes. - Methane, CH4, is the simplest alkane.
- The alkanes form a homologous series.
- Each member of the series differs by a specific
number and kind of atoms.
7Alkanes and Cycloalkanes
- The alkanes differ from each other by a CH2 or
methylene group. - All alkanes have this general formula.
- CnH2n2
- For example ethane, C2H6 , and propane, C3H8 ,
are the next two family members.
8Alkanes and Cycloalkanes
- Isomers are chemical compounds that have the same
molecular formulas but different structures. - Two alkanes have the molecular formula C4H10.
- They are a specific type of isomer called
structural isomers.
9Alkanes and Cycloalkanes
- Three alkanes have the formula C5H12.
- There are three structural isomers of pentane.
10Alkanes and Cycloalkanes
- Three alkanes have the formula C5H12.
- There are three structural isomers of pentane.
11Alkanes and Cycloalkanes
- Three alkanes have the formula C5H12.
- There are three structural isomers of pentane.
12Alkanes and Cycloalkanes
- There are five isomeric hexanes, C6H14.
- You draw them!
13Alkanes and Cycloalkanes
- There are five isomeric hexanes, C6H14.
14Alkanes and Cycloalkanes
- There are five isomeric hexanes, C6H14.
15Alkanes and Cycloalkanes
- There are five isomeric hexanes, C6H14.
16Alkanes and Cycloalkanes
- There are five isomeric hexanes, C6H14.
17Alkanes and Cycloalkanes
- The number of structural isomers increases
rapidly with increasing numbers of carbon atoms. - The boiling points of the alkanes increase with
molecular weight.
18Alkanes and Cycloalkanes
- Cyclic saturated hydrocarbons are called
cycloalkanes. - They have the general formula CnH2n.
- Some examples are
19Alkanes and Cycloalkanes
- Cyclic saturated hydrocarbons are called
cycloalkanes. - They have the general formula CnH2n.
- Some examples are
20Alkanes and Cycloalkanes
- Cyclic saturated hydrocarbons are called
cycloalkanes. - They have the general formula CnH2n.
- Some examples are
21Naming Saturated Hydrocarbons
- The International Union of Pure and Applied
Chemistry (IUPAC) names for the first 12
"straight-chain" or "normal" alkanes are given in
this table.
Number of carbon atoms in chain Name
1 Methane
2 Ethane
3 Propane
4 Butane
5 Pentane
6 Hexane
22Naming Saturated Hydrocarbons
Number of carbon atoms in chain Name
7 Heptane
8 Octane
9 Nonane
10 Decane
11 Unidecane
12 Dodecane
23Naming Saturated Hydrocarbons
- Other organic compounds are named as derivatives
of the alkanes. - Branched-chain alkanes are named by the following
rules. - Choose the longest continuous chain of carbon
atoms which gives the basic name or stem.
24Naming Saturated Hydrocarbons
- Number each carbon atom in the basic chain,
starting at the end that gives the lowest number
to the first group attached to the main chain
(substituent). - For each substituent on the chain, we indicate
the position in the chain (by an Arabic numeric
prefix) and the kind of substituent (by its
name). - The position of a substituent on the chain is
indicated by the lowest number possible. - The number precedes the name of the substituent.
25Naming Saturated Hydrocarbons
- When there are two or more substituents of a
given kind, use prefixes to indicate the number
of substituents. - di 2, tri 3, tetra 4, penta 5, hexa 6,
hepta 7, octa 8, and so on. - The combined substituent numbers and names serve
as a prefix for the basic hydrocarbon name. - Separate numbers from numbers by commas and
numbers from words by hyphens. - Words are "run together".
26Naming Saturated Hydrocarbons
- Alkyl groups (represented by the symbol R) are
common substituents. - Alkyl groups are fragments of alkanes in which
one H atom has been removed for the connection to
the main chain. - Alkyl groups have the general formula CnH2n1.
- In alkyl groups the -ane suffix in the name of
the parent alkane is replaced by -yl. - A one carbon group is named methyl.
- A two carbon group is named ethyl.
- A three carbon group is named propyl.
27Unsaturated Hydrocarbons
- The three classes of unsaturated hydrocarbons
are - alkenes and cycloalkenes, CnH2n
- alkynes and cycloalkynes, CnH2n-2
- aromatic hydrocarbons
28Alkenes
- The simplest alkenes contain one CC bond per
molecule. - The general formula for simple alkenes is CnH2n.
- The first two alkenes are
- ethene, C2H4
29Alkenes
- The simplest alkenes contain one CC bond per
molecule. - The general formula for simple alkenes is CnH2n.
- The first two alkenes are
- and propene, C3H6
30Alkenes
- Each doubly bonded C atom is sp2 hybridized.
- The sp2 hybrid consists of
- two s bonds (single bonds) and
- one s and one p bond (double bond)
31Alkenes
- The systematic naming system for alkenes uses the
same stems as alkanes. - In the IUPAC system, the -ane suffix for alkanes
is changed to -ene. - Common names for the alkenes have the same stem
but use the suffix -ylene is used. - In chains of four or more C atoms, a numerical
prefix shows the position of the lowest-numbered
doubly bonded C atom. - Always choose the longest chain that contains the
CC bond.
32Alkenes
- Polyenes contain two or more double bonds per
molecule. - Indicate the number of double bonds with
suffixes - -adiene for two double bonds.
- -atriene for three double bonds, etc.
- The positions of the substituents are indicated
as for alkanes. - The position of the CC bond(s) is/are given the
lowest number(s) possible.
33Alkenes
34Alkenes
35Alkenes
36Cycloalkenes
- Cycloalkenes have the general formula CnH2n-2.
- Examples are
- cyclopentene
37Cycloalkenes
38Cycloalkenes
39Alkynes
- Alkynes contain C?C bonds.
- The simplest alkyne is C2H2, ethyne, or
acetylene. - Alkynes with only one C ? C bond have the formula
CnH2n-2. - Each carbon atom in a C ? C bond is sp
hybridized. - Each sp hybrid contains two ? bonds and two ?
bonds. - The carbon atom will have one single bond and one
triple bond.
40Alkynes
- Alkynes are named like the alkenes except that
the suffix -yne is used with the characteristic
stem - The alkyne stem is derived from the name of the
alkane with the same number of carbon atoms.
41Alkynes
- Acetylene is an important industrial chemical.
- It is prepared by the reaction of calcium carbide
with water.
42Alkynes
- Acetylene burns in a highly exothermic reaction
- The combustion produces temperatures of about
3000C. - Acetylene is used in cutting torches for welding.
- Alkynes are very reactive
- The two p bonds are sights of special reactivity.
- Addition reactions, such as hydrogenation, are
common.
43Hydrocarbons A Summary
Carbon Atom Hybridization C uses C forms Example
sp3 tetrahedral 4 sp3 hybrids 4 ? bonds CH4
sp2 trigonal planar 3 sp2 hybrids 1p orbital 3 ? bonds 1 ? bond C2H4
sp linear 2 sp hybrids 2 p orbitals 2 ? bonds 2 ? bonds C2H2
44Aromatic Hydrocarbons
- Historically, aromatic was used to describe
pleasant smelling substances. - Now it refers to benzene, C6H6, and derivatives
of benzene. - Other compounds that have similar chemical
properties to benzene are also called aromatic.
45Benzene
- The structure of benzene, C6H6, is
46Other Aromatic Hydrocarbons
- Coal tar is the common source of benzene and many
other aromatic compounds. - Some aromatic hydrocarbons that contain fused
rings are - napthalene
47Other Aromatic Hydrocarbons
48Other Aromatic Hydrocarbons
- Many aromatic hydrocarbons contain alkyl groups
attached to benzene rings (as well as to other
aromatic rings). - The positions of the substituents on benzene
rings are indicated by the prefixes - ortho- (o-) for substituents on adjacent C atoms
- meta- (m-) for substituents on C atoms 1 and 3
- para- (p-) for substituents on C atoms 1 and 4
49Other Aromatic Hydrocarbons
50Functional Groups
- Functional groups are groups of atoms that
represent potential reaction sites. - Compounds that contain a given functional group
usually undergo similar reactions. - Functional groups influence physical properties
as well.
51Organic Halides
- A halogen atom may replace almost any hydrogen
atom in a hydrocarbon. - The functional group is the halide (-X) group.
- Examples include
- chloroform, CHCl3
52Organic Halides
- 1,2-dichloroethane, ClCH2CH2Cl
53Organic Halides
54Alcohols and Phenols
- The functional group in alcohols and phenols is
the hydroxyl (-OH) group. - Alcohols and phenols can be considered
derivatives of hydrocarbons in which one or more
H atoms have been replaced by -OH groups. - Phenols are derivatives of benzene in which one H
has been replaced by replaced by -OH group.
55Alcohols and Phenols
- Ethyl alcohol (ethanol), C2H5OH, is the most
familiar alcohol.
56Alcohols and Phenols
- Phenol, C6H5OH, is the most familiar phenol.
57Alcohols and Phenols
- Alcohols are considered neutral compounds because
they are only very slightly acidic. - Alcohols can behave as acids but only in the
presence of very strong bases. - Phenols are weakly acidic.
- Ka ? 1.0 x 10-10 for phenol
- Although phenols are very weakly acidic, they are
also very corrosive.
58Alcohols and Phenols
- Alcohols can be classified into three classes
- Primary (1) alcohols like ethanol have the -OH
group attached to a C atom that has one bond to
another C atom.
59Alcohols and Phenols
- Secondary(2) alcohols have the OH group
attached to a C atom that has bonds to 2 other C
atoms. - For example,2-propanol
60Alcohols and Phenols
- Tertiary (3) alcohols have the OH group
attached to a C atom that is bonded to 3 other C
atoms. - For example, 2-methyl-2-propanol
61Alcohols and Phenols
- The stem for the parent hydrocarbon plus an -ol
suffix is the systematic name for an alcohol. - A numeric prefix indicates the position of the
-OH group in alcohols with three or more C atoms.
- Common names are the name of the appropriate
alkyl group plus alcohol.
62Alcohols and Phenols
- Alcohols are named using the stem for the parent
hydrocarbon plus an -ol suffix in the systematic
nomenclature. - A numeric prefix indicates the position of the
-OH group in alcohols with three or more C atoms.
- Common alcohol names are the name of the
appropriate alkyl group plus the word alcohol.
63Alcohols and Phenols
- There are several isomeric monohydric acyclic
(contains no rings) alcohols that contain more
than three C atoms. - There are four isomeric four-carbon alcohols.
64Alcohols and Phenols
65Alcohols and Phenols
- There are eight isomeric five-carbon alcohols.
- You do it!
66Alcohols and Phenols
- Polyhydric alcohols contain more than one -OH
group per molecule.
67Alcohols and Phenols
- Phenols are usually called by their common
(trivial) names.
68Alcohols and Phenols
- Phenols are usually called by their common
(trivial) names.
69Alcohols and Phenols
- Phenols are usually called by their common
(trivial) names.
70Alcohols and Phenols
- Phenols are usually called by their common
(trivial) names.
71Alcohols and Phenols
- Because the -OH group is quite polar, the
properties of alcohols depend upon the number of
-OH groups per molecule and the size of the
organic group. - The boiling points of monohydric alcohols
increase with increasing molecular weight. - The solubility of monohydric alcohols in water
decrease with increasing molecular weight. - Polyhydric alcohols are more soluble in water
because of the two or more polar groups (-OH).
72Ethers
- Ethers may be thought of as derivatives of water
in which both H atoms have been replaced by alkyl
or aryl groups.
73Ethers
- Ethers may be thought of as derivatives of water
in which both H atoms have been replaced by alkyl
or aryl groups.
74Ethers
- Ethers may be thought of as derivatives of water
in which both H atoms have been replaced by alkyl
or aryl groups.
75Ethers
- Ethers are not very polar and not very reactive.
- They are excellent solvents.
- Common names are used for most ethers.
76Aldehydes and Ketones
- The functional group in aldehydes and ketones is
the carbonyl group.
77Aldehydes and Ketones
- Except for formaldehyde, aldehydes have one H
atom and one organic group bonded to a carbonyl
group.
78Aldehydes and Ketones
- Ketones have two organic groups bonded to a
carbonyl group.
79Aldehydes and Ketones
- Common names for aldehydes are derived from the
name of the acid with the same number of C atoms.
- IUPAC names are derived from the parent
hydrocarbon name by replacing -e with -al.
80Aldehydes and Ketones
- Common names for aldehydes are derived from the
name of the acid with the same number of C atoms.
- IUPAC names are derived from the parent
hydrocarbon name by replacing -e with -al.
81Aldehydes and Ketones
- Common names for aldehydes are derived from the
name of the acid with the same number of C atoms.
- IUPAC names are derived from the parent
hydrocarbon name by replacing -e with -al.
82Aldehydes and Ketones
- The IUPAC name for a ketone is the characteristic
stem for the parent hydrocarbon plus the suffix
-one. - A numeric prefix indicates the position of the
carbonyl group in a chain or on a ring.
83Aldehydes and Ketones
- The IUPAC name for a ketone is the characteristic
stem for the parent hydrocarbon plus the suffix
-one. - A numeric prefix indicates the position of the
carbonyl group in a chain or on a ring.
84Aldehydes and Ketones
- The IUPAC name for a ketone is the characteristic
stem for the parent hydrocarbon plus the suffix
-one. - A numeric prefix indicates the position of the
carbonyl group in a chain or on a ring.
85Aldehydes and Ketones
- Many aldehydes and ketones occur in nature.
86Amines
- Amines are derivatives of ammonia in which one or
more H atoms have been replaced by organic groups
(aliphatic or aromatic or a mixture of both). - There are three classes of amines.
87Amines
- Amines are derivatives of ammonia in which one or
more H atoms have been replaced by organic groups
(aliphatic or aromatic or a mixture of both). - There are three classes of amines.
88Amines
- Amines are derivatives of ammonia in which one or
more H atoms have been replaced by organic groups
(aliphatic or aromatic or a mixture of both). - There are three classes of amines.
89Amines
- Amines are derivatives of ammonia in which one or
more H atoms have been replaced by organic groups
(aliphatic or aromatic or a mixture of both). - There are three classes of amines.
90Amines
- Aniline is the simplest aromatic amine. It is
much less basic than NH3. - Aniline is a very important industrial chemical.
91Amines
- Heterocylic amines have one or more N atoms in a
ring structure. - Many are important in living systems.
92Amines
- Heterocylic amines have one or more N atoms in a
ring structure. - Many are important in living systems.
93Amines
- Heterocylic amines have one or more N atoms in a
ring structure. - Many are important in living systems.
94Carboxylic Acids
- Carboxylic acids contain the carboxyl functional
group.
- The general formula for carboxylic acids is
- R represents an alkyl or an aryl group
95Carboxylic Acids
- IUPAC names for a carboxylic acid are derived
from the name of the parent hydrocarbon. - The final -e is dropped from the name of the
parent hydrocarbon - The suffix -oic is added followed by the word
acid. - Many organic acids are called by their common
(trivial) names which are derived from Greek or
Latin.
96Carboxylic Acids
97Carboxylic Acids
- Positions of substituents on carboxylic acid
chains are indicated by numeric prefixes as in
other compounds - Begin the counting scheme from the carboxyl group
carbon atom. - They are also often indicated by lower case Greek
letters. - ? 1st C atom
- ? 2nd C atom
- ? 3rd C atom, etc.
98Carboxylic Acids
99Carboxylic Acids
100Carboxylic Acids
101Carboxylic Acids
- Dicarboxylic acids contain two carboxyl groups
per molecule.
102Nomenclature of Carboxylic Acids
- Dicarboxylic acids contain two carboxyl groups
per molecule.
103Nomenclature of Carboxylic Acids
- Dicarboxylic acids contain two carboxyl groups
per molecule.
104Carboxylic Acids
- Aromatic acids are usually called by their common
names. - Sometimes, they are named as derivatives of
benzoic acid which is considered to be the
"parent" aromatic acid.
105Carboxylic Acids
106Carboxylic Acids
107Carboxylic Acids
- Acid strengths of simple carboxylic acids vary
little with chain length. - However, substituents on a carbon atom in the
chain can cause large variations in acid
strengths .
108Carboxylic Acids
109Carboxylic Acids
110Carboxylic Acids
- The -OH group in the carboxyl group of carboxylic
acids, is displaced in many of their reactions.
- The non -OH portion of a carboxylic acid is
called an acyl group.
111Some Derivatives of Carboxylic Acids
- Four important classes of compounds contain acyl
groups - They are all considered to be derivatives of
carboxylic acids. - In these structures R's may represent either
alkyl or aryl groups.
112Some Derivatives of Carboxylic Acids
113Some Derivatives of Carboxylic Acids
114Some Derivatives of Carboxylic Acids
- Acid anhydrides are related to their parent acids
as follows - The word anhydride means without water.
115Some Derivatives of Carboxylic Acids
- Acyl halides are much more reactive, and more
volatile, than their parent acids. - They react with water to form their parent acids
and a hydrohalic acid.
116Some Derivatives of Carboxylic Acids
- Acyl halides are prepared by reacting their
parent acids with PCl3, PCl5, or SOCl2. - The more volatile acid halide is then distilled
out of the reaction mixture.
117Some Derivatives of Carboxylic Acids
- Esters are prepared by heating a carboxylic acid
with an alcohol in the presence of a small amount
of an inorganic acid. - The reaction mixture will contain some ester and
water, as well as unreacted acid and alcohol.
118Some Derivatives of Carboxylic Acids
- Esters are usually called by their common names.
- Many simple esters occur naturally and have
pleasant odors. - Esters are frequently used in fragrances and as
artificial flavors.
119Some Derivatives of Carboxylic Acids
- Fats are solid esters of glycerol and (mostly)
saturated acids at room temperature. - Oils are liquid esters of glycerol and primarily
unsaturated acids at room temperature. - The "acid" parts of fats and oils usually contain
even numbers of C atoms in naturally occurring
fats and oils. - 16 and 18 carbon chains are the most commonly
found chain sizes in nature.
120Some Derivatives of Carboxylic Acids
- Some acids that are found (as their esters) in
fats and oils include
121Some Derivatives of Carboxylic Acids
- Stearic acid is often found in beef fat.
122Some Derivatives of Carboxylic Acids
- Triglycerides are the triesters of glycerol.
- The common name for triglycerides is tri (acid
stem) plus an -in suffix. - For example, tripalmitin.
123Some Derivatives of Carboxylic Acids
- Waxes are esters of long chain fatty acids and
alcohols other than glycerol. - Commonly, waxes are derived from monohydric
alcohols. - Beeswax and carnauba wax are esters of myricyl
alcohol, C30H61OH.
124Some Derivatives of Carboxylic Acids
- Carnauba wax is often used in car waxes.
125Some Derivatives of Carboxylic Acids
- Dihydric alcohols (2 OHs per molecule) can
react with dicarboxylic acids (2 COOHs per
molecule) to form polyesters. - Ester linkages are formed at both ends of both
molecules to give polymeric esters with very high
molecular weights.
126Some Derivatives of Carboxylic Acids
127Some Derivatives of Carboxylic Acids
- Amides are derivatives of organic acids and
primary or secondary amines. - The functional groups of amides are
128Some Derivatives of Carboxylic Acids
- Amides are also named as derivatives of
carboxylic acids. - The suffix -amide is substituted for -ic acid or
-oic acid.
129Some Derivatives of Carboxylic Acids
- When an aryl or alkyl substituent is present on
the N atom, the letter N and the name of the
substituent are prefixed to the name of the
unsubstituted amide.
130Some Derivatives of Carboxylic Acids
- Acetaminophen Tylenol - is an amide.
131Summary of the Functional Groups
- A summary of the functional groups is
132(No Transcript)
133Substitution Reactions
- In a substitution reaction an atom or group of
atoms attached to a carbon atom is replaced
(substituted for) by another atom or group of
atoms. - There is no change in the degree of saturation at
the reactive carbon atom. - Halogenation reactions are an important class of
substitution reactions. - Chlorine reacts with alkanes in free radical
chain reactions (also substitution reactions).
134Substitution Reactions
- Free radical chain reactions
- The halogenation of methane is one example.
135Substitution Reactions
136Substitution Reactions
137Substitution Reactions
- Free radical chain reactions
- Many substitution reactions of alkanes produce
more than one product.
138Substitution Reactions
139Substitution Reactions
140Substitution Reactions
- Nitration reaction of an aromatic hydrocarbon
replaces an H atom attached to an aromatic ring
with a nitro, -NO2, group.
141Addition Reactions
- An addition reaction involves an increase in the
number of groups attached to carbon. - The degree of saturation of the molecule is
increased.
142Addition Reactions
- Hydrogenation is a very important kind of
addition reaction. - Hydrogenation is used to convert unsaturated fats
and oils to saturated fats or oils.
143Elimination Reactions
- An elimination reaction involves the removal of
groups attached to carbon. - The degree of unsaturation increases.
144Elimination Reactions
- Dehydration is an important kind of elimination
reaction.
145Polymerization Reactions
- A polymer is a large molecule that consists of a
high-molecular weight chain of small molecules. - The small molecules that have been joined to form
the polymer are called monomers. - Synthetic polymers are a relatively new class of
molecules. - The first one, bakelite, was discovered in 1909.
- Nylon, which is still extensively used, was
discovered in 1930s.
146Polymerization Reactions
- Addition polymerization is a large commercial
process in the United States. - Polyethylene is the addition polymer made in the
largest quantities in the United States. - Polyethylene is used to make Coke bottles,
plastic bags, etc.
147Polymerization Reactions
- Addition polymerization
- Polyethylene formation
148Polymerization Reactions
- Addition polymerization
- Teflon is the material used in nonstick frying
pans and other kitchen utensils.
149Polymerization Reactions
- Formation of rubber
- Natural rubber is a polymer made of isoprene
(2-methyl-1,3-butadiene) units that form a unique
stereoisomeric structure.
150Polymerization Reactions
- Vulcanization of rubber
- Natural rubber is a sticky, soft compound when
heated which limited its commercial potential. - Charles Goodyear discovered in 1839 that heating
rubber with sulfur removed the stickiness and
made the substance elastic. - This is the basis of modern tire production.
- Vulcanization provides disulfide cross-linking
bonds between the isoprene units.
151Polymerization Reactions
- Copolymers
- If two different monomers are mixed and the
polymerized, copolymers are formed. - Styrene butadiene rubber - SBR - is an important
copolymer used in tire production.
152Polymerization Reactions
153Polymerization Reactions
154Polymerization Reactions
- Condensation Polymers
- Condensation polymers occur when two molecules
react and eliminate a small molecule. - Molecules eliminated commonly are water and HCl.
- Important condensation polymers include nylon,
dacron, and kevlar. - Dacron is used in clothing to make it wrinkle
free. - Blood does not clot in contact with dacron thus
it is used in artificial arteries.
155Polymerization Reactions
- Condensation Polymers
- Dacron formation
156Polymerization Reactions
157Polymerization Reactions
- Condensation Polymers
- Nylon was first made by Wallace Carothers in the
1930s. - Nylon is widely used in a variety of commercial
products including stockings, rope, guitar
strings, fire-proof clothing.
158Polymerization Reactions
- Condensation Polymers
- Nylon 66 formation
159Polymerization Reactions
160Synthesis Question
- TNT, the explosive ingredient in dynamite, has
the correct name of 2,4,6-trinitrotoluene. Draw
the structure of TNT.
161Synthesis Question
162Group Question
- Aerobic respiration produces carbon dioxide and
water as its end products. Anaerobic respiration
has different end products. What are the end
products of anaerobic respiration? How could you
easily detect that someone has switched from
aerobic to anaerobic respiration?
163End of Chapter 27
- There are more organic compounds than any other
type of chemical species.