1. Organic Chemistry Chapter 19
Introduction to
Organic Chemistry Chapter 19
This power point is from the old text. The Prentice Hall text is chapter The content you are expected to know for ch is the Organic Molecules Lab and the worksheet that follows this power point (ch. 22 worksheet)
Eugene Passer Chemistry Department Bronx Community College
© John Wiley and Sons, Inc.
Hein and Arena (modified 5-06 with a couple of corrections 08)
Version 1.0

2. Chapter Outline 19.2 The Carbon Atom 19.12 Hydrocarbon Derivatives
Hydrocarbons
Alkyl Halides
Alkanes
Alcohols
Structural Formulas and Isomerism
Naming Alcohols
Ethers
Naming Alkanes
Aldehydes and Ketones
Alkenes and Alkynes
Naming Aldehydes and Ketones
Naming Alkenes and Alkynes
Carboxylic Acids
Reactions of Alkenes
Aromatic Hydrocarbons
Esters
Naming Aromatic Compounds
Polymers–Macromolecules

3. Organic Chemistry
The branch of chemistry that deals with carbon compounds.
fats, proteins, carbohydrates
fabrics
wood and paper products
plastics
medicinals

4. Sources of Organic Compounds
Carbon-containing raw materials
petroleum and natural gas
coal
carbohydrates
fats and oils

5. The Carbon Atom

6. The carbon atom is central to all organic compounds.

7. Carbon has four valence electrons
1s2, 2s2, 2p2

8. Carbon forms four single covalent bonds by sharing electrons with other atoms.

9. Carbon forms four single covalent bonds by sharing electrons with other atoms.

10. The bonds between carbon and other atoms are often drawn at right angles.

11. Actually the angle between the bonds is 109.5o

12. The bonds point to the corners of a tetrahedron.

13. Regular Tetrahedron
A geometric figure with four equal sides.
19.1 a

14. The bonds point to the corners of a tetrahedron.

15. Space filling models.
19.2

16. A dash represents a covalent bond.
One covalent bond can be formed between two carbon atoms. C
single bond

17. C One covalent bond can be formed between two carbon atoms.
single bond

18. C C Two covalent bonds can be formed between two carbon atoms.
double bond

19. C C Two covalent bonds can be formed between two carbon atoms.
double bond

20. C C Three covalent bonds can be formed between two carbon atoms.
triple bond

21. C C Three covalent bonds can be formed between two carbon atoms.
triple bond

22. Long chains of carbon atoms form by linking one carbon atom to another through covalent bonds.
seven carbon chain

23. Long chains of carbon atoms form by linking one carbon atom to another through covalent bonds.
nine carbon chain C C

24. Long chains of carbon atoms form by linking one carbon atom to another through covalent bonds.
nine carbon branched chain

25. Hydrocarbons

26. Hydrocarbons are compounds composed entirely of carbon and hydrogen atoms bonded to each other by covalent bonds.

27. Saturated hydrocarbons have only single bonds between carbon atoms.
Unsaturated hydrocarbons contain a double or triple bond between two carbon atoms.
Aromatic hydrocarbons include benzene and all compounds resembling benzene.

28. carbon to carbon triple bonds carbon to carbon double bonds
This is not the chart to copy for ch. 22 worksheet
carbon to carbon triple bonds
carbon to carbon double bonds
carbon to carbon single bonds
19.3

29. Alkanes

30. Alkanes are also known as paraffins or saturated hydrocarbons.
They are straight- or branched-chain hydrocarbons.
There are only single covalent bonds between the carbon atoms of alkanes.

31. Successive members in the alkane series differ from each other by one carbon and two hydrogen atoms. They form a homologous series.
Each member of a homologous series differs from the next member by a CH2 group.
The members of a homologous series are similar in structure but differ in formula.

32. The general formula of alkanes is CnH2n+2
2 x = 16
C7H16
This is the chart you copy for the ch. 22 ws

33. Structural Formulas and Isomerism

34. The properties of an organic substance are dependent on its molecular structure.
Structure means the way in which the atoms bond within the molecule.

35. Alkane molecules contain only carbon-carbon and carbon-hydrogen bonds.
Each carbon atom is joined to four other atoms by covalent bonds.
These bonds are separated by angles of 109.5o.
Alkane molecules are essentially nonpolar.

36. nitrogen has 3 bonds carbon has 4 bonds hydrogen has 1 bond
The majority of organic compounds are made from relatively few molecules: carbon, hydrogen, oxygen, nitrogen and the halogens.
nitrogen has 3 bonds
carbon has 4 bonds
hydrogen has 1 bond
fluorine has 1 bond
bromine has 1 bond
iodine has 1 bond
oxygen has 2 bonds
chlorine has 1 bond

37. Structures of Common Alkanes

38. CH4 line structure form of methane space filling form of methane
There is 1 possible structure for CH4.
19.4
19.4

39. CH3CH3 line structure form of ethane space filling form of ethane
There is 1 possible structure for C2H6.
19.4

40. CH3CH2CH3 line structure form of propane space filling form of propane
There is 1 possible structure for C3H8.
19.4

41. CH3CH2CH2CH3 line structure form of butane
space filling form of butane
CH3CH2CH2CH3
line structure form of butane
There are 2 possible structures for C4H10
unbranched chain
19.4

42. CH3 CH2CHCH3 space filling form of 2-methyl propane
line structure form of 2-methyl propane
branched chain
branched chain
There are 2 possible structures for C4H10.
19.4

43. normal butane (n-butane) C4H10
m.p oC
b.p. –138.3oC
m.p. –159.5oC
b.p. – oC
Isomers are compounds with the same molecular formula but different structural formulas.
Normal butane and 2-methyl propane are isomers.
2 –methyl propane
C4H10

44. Pentane (C5H12) has 3 isomers.
Hydrogen is added to each carbon to form four bonds.
This is the carbon skeleton with the longest continuous carbon chain. It is the first isomer of pentane.
n-pentane

45. Pentane (C5H12) has 3 isomers.
Hydrogen is added to each carbon to form four bonds.
Add the fifth carbon atom to either of the middle carbon atoms.
To form the next isomer write a four carbon chain.
2-methylbutane

46. Pentane (C5H12) has 3 isomers.
Hydrogen is added to each carbon to form four bonds.
Add the remaining two carbon atoms to the central carbon atom.
To form the third isomer write a 3 carbon chain.
2,2-dimethylpropane

47. structural formula CH3 condensed CH3CH2CH2CH3 structural formula
Condensed structural formulas are often used to save time and space.
CH2CHCH3
CH3
structural
formula
CH3CH2CH2CH3
condensed
structural formula
In a condensed structural formula the atoms and groups attached to a carbon atom are written to the right of that carbon atom.

48. Naming Alkanes

49. The corresponding alkane has the formula CnH2n+2
Alkyl groups are used to name organic compounds.
The general formula of an alkyl group is CnH2n+1.
The corresponding alkane has the formula CnH2n+2

50. The letter “R” is often used in formulas to represent any of the possible alkyl groups.
R= CnH2n+1 (any alkyl group)
R = CH3 — methyl group
R = CH3CH2 — ethyl group

52. The naming of organic compounds is now done in accordance with the IUPAC system.

53. Alkenes and Alkynes

54. Alkenes and alkynes are unsaturated.
They contain fewer than the maximum number of hydrogens.
Alkenes have two fewer hydrogen atoms than an alkane.
Alkynes have four fewer hydrogen atoms than an alkane.

55. Alkenes contain a carbon-carbon double bond.
General formula for alkenes: CnH2n
Alkynes contain a carbon-carbon triple bond.
General formula for alkynes: CnH2n-2

57. Alkene
Alkyne
double bond
19.5

58. Alkene
Alkyne
triple bond
19.5

59. Naming Alkenes and Alkynes

60. Reactions of Alkenes

61. Alkenes are more reactive than their corresponding alkanes.
This greater reactivity is due to the carbon-carbon double bonds.
Addition at the carbon-carbon double bond is the most common alkene reaction.

62. Addition Reactions Bromine adds across the double bond.
Addition of bromine to 2-pentene
double bond breaks
saturated
2,3-dibromopentane

63. Addition Reactions Hydrogen chloride adds across the double bond.
Addition of hydrogen chloride to 1-butene
double bond breaks
saturated
2-chlorobutane

64. Aromatic Hydrocarbons

65. Benzene and all substances with structures resembling benzene are classified as aromatic compounds.
Aromatic originally referred to the pleasant odor of these molecules, but this meaning has been dropped.

66. Benzene was discovered in 1825 by Michael Faraday.
Its molecular formula is C6H6
The determination of a structural formula for benzene was difficult.

67. In 1865 August Kekulé proposed that the carbon atoms in a benzene molecule are arranged in a six-membered ring with one hydrogen atom bonded to each carbon atom and with three carbon-carbon double bonds.

68. benzene Kekulé structure
6 carbons in a ring
3 double bonds
benzene space filling model

69. C6H6 + Cl2 → C6H5Cl + HCl Benzene does not react like an alkene.
Instead of addition reactions it undergoes substitution reactions.
C6H6 + Cl2 → C6H5Cl + HCl Fe
Chlorine substituted for a hydrogen.

70. Benzene is a hybrid of these two Kekulé structures.

71. The structure of benzene can be represented in two abbreviated ways.CH
The corner of each hexagon represents a carbon and a hydrogen atom.

72. Naming Aromatic Compounds

73. A substituted benzene is derived by replacing one or more of benzene’s hydrogen atoms with an atom or group of atoms.
A monosubstituted benzene has the formula C6H5G where G is the group that replaces a hydrogen atom.
All hydrogens in benzene are equivalent.
It does not matter which hydrogen is replaced by G.

74. Monosubstituted Benzenes

75. Some monosubstituted benzenes are named by adding the name of the substituent group as a prefix to the word benzene.
The name is written as one word.

76. nitro group
nitrobenzene

77. ethyl group
ethylbenzene

78. Certain monosubstituted benzenes have special names.
These are parent names for further substituted compounds.

79. methyl group
toluene

80. hydroxy group
phenol

81. carboxyl group
benzoic acid

82. amino group
aniline

83. C6H5— is the phenyl group.
It is used to name compounds that cannot be easily named as benzene derivatives.

84. diphenylmethane
4-phenyl-2-pentene

85. Disubstituted Benzenes

86. Three isomers are possible when two substituents replace hydrogen in a benzene molecule.
The prefixes ortho-, meta- and para- (o-, m- and p-) are used to name these disubstituted benzenes.

87. ortho disubstituted benzene
substituents on adjacent carbons
ortho-dichlorobenzene (1,2-dichlorobenzene) mp –17.2oC, bp 180.4oC

88. meta disubstituted benzene
substituents on adjacent carbons
meta-dichlorobenzene (1,3-dichlorobenzene) mp –24.82oC, bp 172oC

89. para disubstituted benzene
substituents are on opposite sides of the benzene ring
para-dichlorobenzene (1,4-dichlorobenzene) mp 53.1, bp 174.4oC

90. When one substituent corresponds to a monosubstituted benzene with a special name, the monosubstituted compound becomes the parent name for the disubstituted compound.
nitrophenol
phenol

91. When one substituent corresponds to a monosubstituted benzene with a special name, the monosubstituted compound becomes the parent name for the disubstituted compound.
m-nitrotoluene
toluene

92. Hydrocarbon Derivatives

93. Hydrocarbon derivatives are compounds that can be synthesized from a hydrocarbon.
In addition to carbon, they contain such additional elements as oxygen, nitrogen, or a halogen.
The compounds can be grouped into several classes. The compounds in each class have similar properties.

95. Alkyl Halides

96. An alkyl halide has the formula RX where X = Cl or Br.
They are formed in a substitution reaction in which a halogen replaces hydrogen.

97. When a specific halogen is used the name reflects this: chlorination
RH + X2 → RX + HX uv
light
When a specific halogen is used the name reflects this:
chlorination
CH3CH3 + Cl2 → CH3CH2Cl + HCl uv
light

98. Alcohols

99. Alcohols are organic molecules whose molecules contain the –OH functional group.
The general formula for alcohols is ROH.

100. Alcohols do not dissociate in water yielding OH- as do metallic hydroxides.
The –OH group is attached to the carbon by a covalent bond and not an ionic bond as in metallic hydroxides.
Alcohols form a homologous series.
Alcohols are classified as primary (1o), secondary (2o) or tertiary (3o).

101. Each member of a homologous series differs from the next member by a CH2 group.

102. Primary Alcohol
The carbon to which the – OH group is attached is bonded to one carbon.

103. Secondary Alcohol
The carbon to which the –OH group is attached is bonded to two carbons.

104. Tertiary Alcohol
The carbon to which the –OH group is attached is bonded to three carbons.

105. 19.6

106. Polyhydroxy Alcohols
Alcohols that contain more than one OH group attached to different carbons are called polyhydroxy alcohols.
Monohydroxy: one OH group per molecule.
Dihydroxy: two OH groups per molecule.
Trihydroxy: three OH groups per molecule.

108. Naming Alcohols

109. Ethers

110. An ether has the formula ROR´.
R and R´ can be the same or different groups.
R and R´ can be saturated, unsaturated or aromatic.
Saturated ethers have little chemical reactivity but are often used as solvents.

111. Alcohols and ethers are isomeric.
They have the same molecular formula but different structural formulas.
An alcohol and its isomeric ether have different chemical and physical properties.

112. CH3CH2OH
ethanol B.P. 78.3oC hydrogen bonds soluble in water
C2H6O
CH3–O–CH3
dimethyl ether B.P. –27.3oC does not hydrogen bond insoluble in water
C2H6O

113. Naming Ethers

114. Common Names
Common names of ethers are formed from the names of the groups attached to the carbon atom in alphabetical order followed by the word ether.
CH3CH2CH2 — O — CH2CH3
propyl
ether
ethyl
ethyl propyl ether

115. Aldehydes and Ketones

116. carbon is double bonded to the oxygen
carbonyl group
carbon is double bonded to the oxygen
Aldehydes and ketones contain the carbonyl group.

117. Aldehydes have at least one hydrogen bonded to the carbonyl group
Aldehydes have at least one hydrogen bonded to the carbonyl group. The other group bonded to the carbonyl group is an alkyl (R) or aromatic (Ar) group.

118. Ketones have two alkyl (R) or aromatic (Ar) groups bonded to the carbonyl group.

119. Naming Aldehydes and Ketones

120. Naming Aldehydes

121. The IUPAC names of aldehydes are obtained by dropping the –e and adding -al to the name of the parent hydrocarbon.
butane al
butanal

122. Naming Ketones

123. The IUPAC name of a ketone is derived from the name of the alkane corresponding to the longest carbon chain that contains the ketone-carbonyl group.
The parent name is formed by changing the –e ending of the alkane to -one.
propane
one
propanone

124. Carboxylic Acids

125. OH bonded to a carbonyl carbon.
carbonyl group
OH bonded to a carbonyl carbon.
Carboxylic acids contain the carboxyl group.

126. The carboxyl group can also be written asor

127. Open-chain carboxylic acids form a homologous series.
The carbonyl group ( ) is always at the beginning of a carbon chain.
The carbonyl carbon atom is always designated as C-1. 3 2 1

128. The IUPAC name of a carboxylic acid is derived from the name of the alkane corresponding to the longest carbon chain that contains the carboxyl group.
The parent name is formed by changing the –e ending of the alkane to –oic acid.
methane
oic acid
methanone

129. The IUPAC name of a carboxylic acid is derived from the name of the alkane corresponding to the longest carbon chain that contains the caroxyl group.
The parent name is formed by changing the –e ending of the alkane to –oic acid.
propane
propanone
oic acid

130. Organic acids are usually known by common names.
These names usually refer to a natural source of the acid.
acetic acid
common name
ethanoic acid
IUPAC name

131. Organic acids are usually known by common names.
These names usually refer to a natural source of the acid.
formic acid
common name
methanoic acid
IUPAC name

132. This is the simplest aromatic acid.
benzoic acid

134. Esters

135. OR´ bonded to a carbonyl carbon.
An ester is an organic compound derived from a carboxylic acid and an alcohol.
carbonyl group
OR´ bonded to a carbonyl carbon.
The ester functional group is –
COOR.

137. Polymers-Macromolecules

138. A polymer (macromolecule) is a natural or synthetic giant molecule formed from smaller molecules (monomers).
Monomers are the small units that undergo polymerization to form a polymer.
Polymerization is the process of forming very large, high molar-mass molecules from monomers.

139. Formation of Polyethylene
ethylene monomer
nCH2=CH2 →
CH2 CH2[CH2 CH2]n CH2 CH2 CH2 CH3
n = the number of monomer units.
n ranges from 2,500 to 25,000

143. The End