1. Families of Organic Compounds
Chapter 22
Families of Organic Compounds

2. Tetrahedral Carbon Compounds.
In tetrahedral compounds the atom or group of atoms responsible for the characteristic properties of the compound is attached to a tetrahedral carbon atom.
Chloroalkanes
Alkanes
Alcohols

3. Chloroalkanes
Chloroalkanes-One or more of the H atoms in the alkane replaced by a Cl atom.
-Synthesised in the Lab
-Used as solvents
-Not soluble in water(no polarity).
-Dissolve in non-polar solvents like cyclohexane.

4. STRUCTURAL ISOMERISM IN HALOGENOALKANES
Different structures are possible due to...
Different positions for the halogen and branching of the carbon chain
1-chlorobutane
2-chlorobutane
2-chloro-2-methylpropane
1-chloro-2-methylpropane

5. Chloroalkanes

6. Chloroalkanes
One or more of the hydrogen atoms in an alkane molecule has been replaced by a chlorine atom, e.g.
Chloromethane - CH3Cl
Dichloromethane - CH2Cl2
Trichloromethane - CHCl3
Tetrachloromethane - CCl4

7. Chloromethane

8. Dichloromethane

9. Trichloromethane

10. Tetrachloromethane

11. Chloroethane

12. 1,1-dichloroethane

13. 1,2-dichloroethane

14. Naming chloroalkanes
Last part of name comes from base alkane on which the molecule is built, e.g. chloroethane [2 carbons]
Number of chlorine atoms indicated by prefix mono, di, tri, tetra etc. in front of chloromethane, e.g. trichloromethane
Position of each chlorine atom given by a number before the name, e.g.
1,2,2-trichloropropane

15. 1,2,2-trichloropropane

16. Physical properties
Physical state: Liquid, except for chloromethane and chloroethane, which are gases at room temperature
Boiling points higher than the corresponding alkanes, due to polar C-Cl bond(s)

17. Physical properties Not soluble in water
Soluble in non-polar solvents such as cyclohexane

18. Uses of chloroalkanes
Because of their lack of polarity, they are useful solvents, e.g. for
removing grease and oil from machinery
removing oil etc. from clothes - dry cleaning

19. Alcohols Alcohol’s form a homologous series of compounds.
The -OH group called the hydroxyl group is the functional group of the alcohols.

20. Alcohols

21. Alcohols Methanol CH3OH Ethanol C2H5OH Propan-1-ol C3H7OH
Butan-1-ol C4H9OH
Butan-2-ol C4H9OH

22. Methanol CH3OH

23. Ethanol C2H5OH

24. Propan-1-ol C3H7OH

25. Butan-1-ol C4H9OH

26. Propan-2-ol CH3CH(OH)CH3

27. Butan-2-ol CH3CH(OH)C3H7

28. Classification of alcohols
Primary alcohol: contains one carbon atom directly attached to the carbon that contains the hydroxyl group, e.g propan-1-ol

29. 2. Secondary alcohol: contains two carbon atoms directly attached to the carbon that contains the hydroxyl group, e.g. propan-2-ol

30. Physical properties Physical state: Liquid
Boiling points much higher than the corresponding alkanes, due to polar OH group

31. Physical properties Solubility of methanol in
(i) cyclohexane – not very soluble methanol is polar cyclohexane is not
(ii) water - completely soluble because it is polar.
As alcohol molecule gets bigger the polar part becomes less significant so the alcohol becomes less soluble in water and more soluble in cyclohexane

32. Butan-1-ol is
(i) soluble in cyclohexane
(ii) not very soluble in water
The polar OH group is becoming less significant as the molecule gets bigger

33. Comparison with water Both have polar OH groups
Alcohols have a non-polar part
Both form hydrogen bonds between their molecules
Water is more polar and has a greater capacity to form hydrogen bonds and so has a higher boiling point than methanol or ethanol

34. Methanol Methanol: is toxic (can cause blindness, insanity and death)
It is added to industrial alcohol to prevent people drinking it. This mixture is called methylated spirits.
The methanol acts as a denaturing agent – it renders a substance unfit for purpose without destroying the usefulness or applications of the substance. A purple dye is often added as a warning.

35. Ethanol
Ethanol: is produced by fermentation. Fruits provide the sugar and yeast may need to be added.
The enzyme zymase in yeast catalyses the reaction.
C6H12O C2H5OH CO2

36. Alcoholic Drinks Ingredient Drink % (v/v) alcohol Grapes Wine 12
Apples
Cider
4.5
Malted grain
Beer 5

37. Ethanol
To produce drinks of higher alcohol concentration the fermented liquids must be distilled.
Spirits (whiskey, brandy, gin, vodka) contain 40% alcohol.

38. Gasohol
Ethanol obtained from sugar cane is used for making gasohol in Brazil. This is then used as a fuel.

39. Uses of ethanol Alcoholic drinks Fuel
Solvent (can dissolve both polar and non-polar solutes)

40. Primary Secondary and Tertiary
Primary Alcohol -one C attached to the C which has the –OH group.
Secondary Alcohol -Two C attached to the C which has the –OH group.
Tertiary Alcohol -Three C attached to the C which has the –OH group.

42. C6H12O6 --------> 2C2H5OH + 2CO2
Examples of Alcohol’s
Methanol-added to industrial alcohol to prevent consumption.
Ethanol-Used in alcoholic drinks, as a fuel and as a solvent.
Ethanol is produced by fermentation.
Yeast
C6H12O > 2C2H5OH CO2
Zymase

43. Physical Properties of Alcohol’s
Boiling points
Alcohol’s have a higher boiling point than corresponding alkanes. This is due to Hydrogen bonding between the Alcohol molecules.

44. Hydrogen bonding between alcohol molecules

45. Solubility of Alcohols
Hydrogen bonding also results in Alcohol’s been soluble in water.(C1-C3)
This solubility decreases as the length of the Carbon chain increases. This is due to the polar -OH group(which is responsible for solubility) been counteracted by the larger insoluble alkyl group

46. Planar Carbon Compounds.
Alkenes Alkynes
Aldehydes Ketones
Carboxylic Acids Esters
Aromatic Compounds
Note.
These compounds have double bonds

47. Aldehydes
An aldehyde is a compound containing a carbonyl group with at least one hydrogen attached to it.
Functional Group –CHO (Carbonyl group)
Strongly Polar

48. Formal names for aldehydes include the prefix from the alkyl group and the suffix -al.
Two of the simplest aldehydes are
Aromatic aldehydes include oil of almonds, vanillin, and oil of cinnamon.

49. Aldehydes

50. Aldehydes Methanal HCHO Ethanal CH3CHO Propanal C2H5CHO
Butanal C3H7CHO

51. Methanal

52. Ethanal

53. Propanal

54. Butanal

55. Physical properties
Physical state: Liquid, except methanal, which is a gas at room temperature
Boiling points higher than the corresponding alkanes, due to polar +C = O- group, but lower than the corresponding alcohols

56. Physical properties
Short chain aldehydes are soluble in water due to the polar carbonyl group
As the number of carbon atoms in a molecule of the ester increases, solubility in water decreases, while solubility in cyclohexane increases

57. Benzaldehyde
Aromatic aldehyde
Found in almond kernels

58. Boiling points and solubility of the aldehydes
Not possible to form Hydrogen Bonds between the aldehyde molecules. There is however Dipole-Dipole bonds between the aldehyde molecules.
This results in the aldehydes having boiling point higher than corresponding alkanes but lower than corresponding alcohol.
Eg Ethanal Bp = 21C Ethanol Bp = 78C

59. Compare Boiling Points
Molecule
Type
Boiling point (°C)
CH3CH2CH3
alkane
-42
CH3CHO
aldehyde
+21
CH3CH2OH
alcohol
+78
Notice that the aldehyde (with dipole-dipole attractions as well as dispersion forces) has a boiling point higher than the similarly sized alkane which only has dispersion forces.
However, the aldehyde's boiling point isn't as high as the alcohol's.
In the alcohol, there is hydrogen bonding as well as the other two kinds of intermolecular attraction.
Although the aldehydes and ketones are highly polar molecules, they don't have any hydrogen atoms attached directly to the oxygen, and so they can't hydrogen bond with each other.

60. Methanal- only aldehyde that is a gas at room Temperature
Methanal- only aldehyde that is a gas at room Temperature.(also called Formaldehyde)
Lower members of the aldehyde’s are soluble in H20 and like the alcohol’s will dissolve in both polar and non-polar substances. This is due to H bonding between the O atom in the carbonyl and the H atom of the water molecule.
Like the alcohol’s, the solubility in water decreases with the length of the carbon chain.

61. Ketones Functional group R-CO –R
Physical properties similar to the Aldehydes due to the Dipole-Dipole forces between the Ketone molecules.
Solubility similar to the Aldehydes.
Since Propanone(acetone) and Butanone can act as solvents in both polar and non polar solvents they are widely used in industry

62. In ketones, the carbonyl group has two hydrocarbon groups attached.
Notice that ketones never have a hydrogen atom attached to the carbonyl group.
Propanone is normally written CH3COCH3. Notice the need for numbering in the longer ketones. In pentanone, the carbonyl group could be in the middle of the chain or next to the end - giving either pentan-3-one or pentan-2-one.

63. Ketones

64. Ketones
Propanone CH3COCH3
Butanone C2H5COCH3

65. Propanone

66. Butanone

67. Physical properties
Physical state: Butanone and propanone are liquids at room temperature
Boiling points higher than the corresponding alkanes, due to polar +C = O- group, but lower than the corresponding alcohols
Short chain ketones such as propanone are soluble in water due to the polar carbonyl group
Ketones are soluble in non-polar solvents such as cyclohexane

68. Uses of propanone
Propanone is used as a solvent (e.g. In nail varnish remover)

69. Carboxylic acids

70. Carboxylic Acids. Functional Group R- COOH
Examples of Carboxylic Acids
Methanoic Acid HCOOH
Ethanoic Acid CH3COOH
Propanoic Acid C2H5COOH

71. Carboxylic acids Methanoic acid HCOOH Ethanoic acid CH3COOH
Propanoic acid C2H5COOH
Butanoic acid C3H7COOH

72. Methanoic acid HCOOH

73. Ethanoic acid CH3COOH

74. Propanoic acid C2H5COOH

75. Butanoic acid C3H7COOH

76. Physical properties
Physical state: Methanoic acid and ethanoic acid are liquids, while propanoic acid and butanoic acid are solids
Short chain carboxylic acids are soluble in water due to the polar COOH group
Carboxylic acids are soluble in non-polar solvents such as cyclohexane

77. Boiling points of carboxylic acids
Boiling points higher than the corresponding alcohols
This is because carboxylic acids form dimers, where two carboxylic acid molecules are held together by two hydrogen bonds
This is possible due to polarity in both the C=O and O-H bonds in each carboxylic acid molecule

78. Ethanoic acid dimer δ- δ+ δ- δ+ δ+ δ- δ+ δ-

79. Occurrence and uses
Methanoic acid is found in the sting of ants and nettles
Ethanoic acid is the principal acid in vinegar
Ethanoic acid is used in the manufacture of cellulose acetate
Propanoic acid, benzoic acid and their salts (e.g. sodium benzoate) are used as food preservatives

80. Examples of Carboxylic acid and uses
Methanoic acid(formic acid) sting of nettles and ants
Ethanoic acid(acetic acid)-vinegar,Cellulose acetate used in varnishes,laquers, photographic film, rayon
Propanoic acid, Benzoic acid-Preservatives
Butanoic acid- smell of rancid butter,smelly socks

81. Examples of carboxylic acids
The name counts the total number of carbon atoms in the longest chain - including the one in the -COOH group. If you have side groups attached to the chain, notice that you always count from the carbon atom in the -COOH group as being number 1

82. Solubility and Boiling Points
Ethanoic Acid Higher Bp/Mp than corrisponding Alcohol.Why?
This is due to the effects of Hydrogen
Bonding.
In pure acid the molecules
group together to form clusters of
dimers(two molecules) held together by
2 Hydrogen Bonds.

83. Solubility Soluble in Water due to their ability to form Hydrogen bonds with water.This solubility decreases with increasing length of the carbon chain.

84. Esters

85. Esters
Esters are formed by the reaction of a carboxylic acid with an alcohol e.g.
CH3COOH CH3OH = CH3COOCH H2O
Ethanoic acid Methanol Methyl ethanoate

86. Naming esters: methyl ethanoate
The first part of the ester name comes from the parent alcohol with the - anol changed to – yl and the second part of the name comes from the parent acid with the - oic acid changed to – oate.

87. Methyl methanoate HCOOCH3

88. Ethyl methanoate HCOOC2H5

89. Methyl ethanoate CH3COOCH3

90. Ethyl ethanoate CH3COOC2H5

91. Physical properties Physical state: Liquid
Boiling points higher than the corresponding alkanes, but lower than the corresponding alcohols

92. Physical properties
Soluble in water and non-polar solvents such as cyclohexane
As the number of carbon atoms in a molecule of the ester increases, solubility in water decreases, while solubility in cyclohexane increases

93. Occurrence and uses of esters
Occur naturally in fruits – are responsible for their flavours -
and flowers – are responsible for their pleasant smells
Fats and oils are naturally occurring esters of long chain carboxylic acids
Ethyl ethanoate is used as a solvent for printing inks and paints

94. Alcohol + Carboxylic Acid  Ester + Water
Esters.
Functional Group R-COO-R
Alcohol + Carboxylic Acid  Ester Water
This reaction is called a condensation reaction since it results in the loss of a water molecule
Lower members of the Ester family are volatile liquids with Fruity smell.
-Low Bp because H bonds are not formed with each other.
-Polar molecules that can form H bonds with Water.
Lower members(up to C-5) are fairly soluble in water
Polyester-millions of ester molecules linked together
Solid ester = Fat
Liquid Ester = Oil

95. Aromatic compounds Aromatic compounds contain a Benzene ring.
Benzene itself is carcinogenic though many aromatic compounds are not dangerous.
Form basis of many pharmaceutical compounds, dyes detergents, herbicides, disinfectants e.t.c.

96. STRUCTURE OF BENZENE - DELOCALISATION
The theory suggested that instead of three localised (in one position) double bonds,
the six p (p) electrons making up those bonds were delocalised (not in any one
particular position) around the ring by overlapping the p orbitals. There would be no
double bonds and all bond lengths would be equal. It also gave a planar structure.
6 single bonds

97. STRUCTURE OF BENZENE - DELOCALISATION
The theory suggested that instead of three localised (in one position) double bonds,
the six p (p) electrons making up those bonds were delocalised (not in any one
particular position) around the ring by overlapping the p orbitals. There would be no
double bonds and all bond lengths would be equal. It also gave a planar structure.
6 single bonds
one way to overlap
adjacent p orbitals

98. STRUCTURE OF BENZENE - DELOCALISATION
The theory suggested that instead of three localised (in one position) double bonds,
the six p (p) electrons making up those bonds were delocalised (not in any one
particular position) around the ring by overlapping the p orbitals. There would be no
double bonds and all bond lengths would be equal. It also gave a planar structure.
6 single bonds
one way to overlap
adjacent p orbitals
another
possibility

99. STRUCTURE OF BENZENE - DELOCALISATION
The theory suggested that instead of three localised (in one position) double bonds,
the six p (p) electrons making up those bonds were delocalised (not in any one
particular position) around the ring by overlapping the p orbitals. There would be no
double bonds and all bond lengths would be equal. It also gave a planar structure.
6 single bonds
one way to overlap
adjacent p orbitals
another
possibility
delocalised pi
orbital system

100. STRUCTURE OF BENZENE - DELOCALISATION
The theory suggested that instead of three localised (in one position) double bonds,
the six p (p) electrons making up those bonds were delocalised (not in any one
particular position) around the ring by overlapping the p orbitals. There would be no
double bonds and all bond lengths would be equal. It also gave a planar structure.
6 single bonds
one way to overlap
adjacent p orbitals
another
possibility
delocalised pi
orbital system
This final structure was particularly stable and
resisted attempts to break it down through normal
electrophilic addition. However, substitution of any
hydrogen atoms would not affect the delocalisation.

101. STRUCTURE OF BENZENE

102. The animation doesn’t work on early versions of Powerpoint
STRUCTURE OF BENZENE
ANIMATION
The animation doesn’t work on early versions of Powerpoint

103. WHY ELECTROPHILIC ATTACK?
Theory The high electron density of the ring makes it open to attack by electrophiles
HOWEVER...
Because the mechanism involves an initial disruption to the ring
electrophiles will have to be more powerful than those which react
with alkenes.
A fully delocalised ring is stable so will resist attack.

104. Aromatic compounds

105. Aromatic compounds
Aromatic compounds are compounds which contain a benzene ring in their molecules

106. Aromatic hydrocarbons
Benzene C6H6
Methylbenzene C7H8
Ethylbenzene C8H10

107. Benzene

108. Benzene molecule
The six carbon-carbon bonds in benzene are identical, intermediate in length between double and single bonds

109. Sigma bonding in benzene
Six carbon atoms joined to form a hexagonal planar ring.
Each carbon has four valence electrons
One of these is used to form a bond with a hydrogen atom.
Two other electrons are used to form sigma bonds with the carbon atoms on either side.

110. What the circle means
The 6 valence electrons not involved in sigma bonding are shared between the six carbon atoms in the molecule
not localised into 3 double bonds
For convenience the C and H atoms are not shown
Ring in centre indicates a delocalised pi bond

111. Methylbenzene

112. Ethylbenzene

113. Physical properties
Physical state: Benzene. methylbenzene and ethylbenzene are liquids
Insoluble in water
Soluble in non-polar solvents such as cyclohexane

114. Uses
Methylbenzene is used as an industrial solvent

115. Range and scope of aromatic chemistry
Pharmaceutical compounds, e.g. Morphine
Herbicides, e.g. Diuron
Detergents, e.g. Sodium dodecylbenzenesulfonate
Dyes, e.g. Martius Yellow

116. Aromatic acid-base indicators
The acid-base indicators phenolphthalein and methyl orange are also aromatic compounds
Phenolphthalein Methyl orange

117. Aromatic compounds and cancer
Some aromatic compounds are carcinogenic, e.g. Benzene
However, not all aromatic compounds are carcinogenic; aspirin is an example

118. Organic Compounds Many organic compounds are found free in nature.
Examples
Benzaldehyde(Almonds)
Caffeine(coffee)
Nicotine(cigarettes)
Pharmaceutical compounds(Aspirin, Iboprofen, Morphine, Paracetamol, Penicillin)
Food Flavouring(Vanilla)
insecticides(DDT, Diuron, Naphthalene)

119. Steam Distillation
A technique called steam distillation is used to separate oils from plants.
It involves carrying out distillation in a current of steam . The main purpose is to avoid too high a temperature during distillation as a high temperature may destroy the plant material.
It is found that the mixture of steam and oil distils below the boiling point of water and well below the boiling point of the oil in the plant.
The mixture of oil and steam is then passed through a Liebeg condenser and allowed to stand. The oil floats to the top.

120. Apparatus for steam distillation

121. Field of Lavender

122. Emulsion
An emulsion is where the oil droplets are dispersed throughout the water.
An organic solvent must be added that dissolves the oil(e.g. cyclohexane) but does not mix with the water. This is then separated and the solvent allowed to evaporate. This process is called solvent extraction.
Experiment: To extract clove oil from cloves by steam distillation
See Page 357(book)