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ORGANIC CHEMISTRY
1.1 Functional Groups
 are used to identify compounds but also to explain properties like
solubility, melting & boiling points, etc.
 there are many different functional groups but they contain one of
3 main components
i.e.
Carbon-Carbon Bonds
 C-C single bonds are strong covalent bonds and are not very
reactive
 C=C and CΞC are more reactive and their 2nd and 3rd bonds are
more easily broken
 this allows these parts of a compound to be the sites where
reactions occur
Single Bonds Between C & more Electronegative Bonds
 where there is an unequal attraction of the electrons the bond is
polar e.g. between C and a more electronegative atom
 the C atom becomes more +ve and the O,N or halogen atom is
more –ve
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 an increase in polarity increases intermolecular forces which in
turn increases the melting & boiling points
 O-H and N-H bonds form bonds with special properties and they
can form H-bonds with other OH groups, they increase
intermolecular attractions but also enables these molecules to
dissolve in polar solutes & solvents
 “like dissolves like”
Double Bonded Carbon & Oxygen
 this double covalent bond has 4 electrons being shared with ALL 4
electrons being more strongly attracted to the O atom
 this bond is very polar with an accompanying increase in melting
& boiling points and increased solubility in polar solvents
1.2 Hydrocarbons
 alkanes- single C-C bonds, if all C’s have H’s attached, molecules
are called saturated hydrocarbons
 alkenes- have one or more C=C double bonds
 alkynes- have one or more CΞC triple bonds
 alkenes & alkynes are called unsaturated hydrocarbons because
they have fewer than the maximum possible number of H atoms
 can form either a straight chain or a cyclic (ring) structure
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 hydrocarbons which are attached to the main structure are called
alkyl groups and are named according to the number of carbons
 a 4th group are the aromatic hydrocarbons which have a unique
ring structure
 simplest is benzene and all others are derivatives of benzene
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Note: When naming propyl & butyl groups we have to consider how
these groups attach onto the parent chain
i.e. when an alkyl group has 3 or more C atoms the group can attach
either at an end C atom or at a middle C atom (see Fig.4 & 5)
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Aromatic Hydrocarbons
 benzene ring usually considered to be the parent chain and
attached alkyl groups are the branches
 if a methyl group is attached, the molecule is called
methylbenzene and we don’t need to assign a number
 when we have 2 or more alkyl groups attached we need to use
numbers (again numbering so that we have the lowest numbers)
Note: a) also known as ortho- or o-diethylbenzene
b) also known as meta- or m-diethylenebenzene
c) also known as para- or p-diethylenebenzene
 when an aromatic molecule is too difficult to name sometimes we
would consider the benzene ring as the attached branch and not
the parent molecule
 when the benzene ring is the attached branch it is called a phenyl
group
(see Fig. 9 on page 20)
2-phenylbutane or s-butylbenzene
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Physical Properties of Hydrocarbons
 essentially nonpolar because they are made of C & H, atoms with
similar electronegativities
 main intermolecular forces are Van der Waals forces (electrons of
one molecule with the nucleus of another)
 because these forces are weak, molecules are easily separable
from one another
 small molecules have fewer electrons and weaker Van der Waal
forces and therefore have lower boiling & melting points when
compared to larger molecules
 due to low polarity hydrocarbons generally have low solubility in
polar solvents, like water
 however, they will be good solvents for other nonpolar molecules
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1.3 Reactions of Hydrocarbons
 alkanes because of their C-C bonds are relatively unreactive due to
their being difficult to break
 they do participate in combustion reactions, making them useful
as fuels
 although C-C bonds are difficult to break, the hydrogen atoms can
be substituted by halogens in substitution reactions i.e. with F2,
Br2, or Cl2
 the product is referred to as a halogenated alkane, which are
referred to as an organic family called alkyl halides
 as the reaction above proceeds the concentration of bromoethane
increases and bromine will react again to form 1,2-dibromoethane
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Reactions of Alkenes & Alkynes
 both exhibit greater reactivity than alkanes i.e. if reacted with Br2
the reaction will be fast and will occur at room temperature
 both undergo a characteristic reaction called an addition reaction,
where atoms are added to the molecule with no loss of H atoms
 addition reactions can involve halogens, H, hydrogen halides,and
water, given the right conditions
Examples:
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 common prefixes for functional groups include;
 when molecules consisting of 2 identical atoms (H2) are added to
a double bond only 1 possible product is formed, i.e a H atom gets
added to each side of the double bond
 but when molecules of a non-identical atom is added, 2 different
products may form e.g.
 experiments have shown that only one main product is formed
which leads us to Markovnikov’s Rule….”the rich get richer”
(see sample problem on page 26)
Reactions of Aromatic Hydrocarbons
 although aromatic hydrocarbons are unsaturated, they do not
undergo addition reactions except under extreme conditions
 they do undergo substitution reactions and in fact the H atoms are
more easily replaced than in alkanes
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 the reactivity of aromatic hydrocarbons are in between the alkanes
& alkenes
Examples:
 in reaction (b) further reaction of bromobenzene with Br2 results
in substitution of another Br, resulting in 3 possible isomers of
dibromobenzene
i.e.
 relatively low reactivity of benzene indicates that benzene is fairly
stable and that the bonds in benzene are different than in the
double & triple bonds in alkenes & alkynes
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 in another substitution reaction, benzene reacts with nitric acid in
the presence of sulphuric acid to form nitrobenzene
 benzene can also react with alkyl halides (R-X) in the presence of
an aluminum halide catalyst (AlX3) ; alkyl group attaches to the
benzene displacing an H atom on the ring
 these products can undergo further reactions where one can
design and synthesize compounds where the desired groups are
attached in specific positions on the ring
(see sample problem on page 29)
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1.4 Organic Halides
 organic halides are hydrocarbons with attached halogen atoms
e.g. Freon (chlorofluorocarbons),
Teflon (polytetrafluoroethene), etc.
Naming Organic Halides
 consider the halogen atom as an attachment on the parent
chain
 halogen name is shortened to its root name
i.e. Fl=fluoro-, Cl=chloro-, etc.
Properties of Organic Halides
 halogens are more electronegative so the organic halide molecules
are more polar i.e. C-halogen bonds polarity > C-H bonds
 therefore the intermolecular forces are stronger with halide
containing molecules and they have higher boiling points and
being more polar can dissolve in polar solvents
 compounds may contain 1,2, or 3 halogens per molecule
 the more halogen atoms per molecule, the more polar the
molecule, the higher the boiling point etc.
Read the Cost of Air Conditioning on page 34.
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Preparing Organic Halides
 can be produced by halogenation reactions
 similarly, if we wanted to produce a halide of a benzene ring, we
would arrange a substitution reaction with a halogen
Preparing Alkenes from Alkyl Halides: Elimination Reactions
 alkyl halides can eliminate a H atom and a halogen atom from
adjacent C atoms resulting in the formation of a double bond and
therefore an alkane in an elimination reaction
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1.5 Alcohols and Ethers
 structurally similar except that alcohols have the general form
R-O-H and ethers have the general form R-O-R, where R
represents alkyl groups
 properties are generally due to the polar OH groups and other
non-polar groups
Alcohols
Naming Alcohols
 IUPAC rules say that any R-OH should end with the suffix “–ol”
which is added to the parent chain i.e. methane with an OH is
called methanol
 an alcohol with 2 carbons is called ethanol and so on…..
 when an alcohol has more than 2 C’s or OH groups we number
the C atoms to locate the OH groups
 the 2 isotopes of C3H7OH are;
 2-propanol is also known as isopropanol, i-propanol or isopropyl
alcohol
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1°, 2° and 3° Alcohols
 can also be classified by the type of C where the –OH is attached
 since C can form 4 bonds, the C atom can be attached to 1, 2 or 3
alkyl groups resulting in 1°, 2° and 3° alcohols
example 1-propanol is a primary alcohol, 2-propanol is a
secondary alcohol, while 2-methyl-2-propanol is a tertiary alcohol
 important for predicting reactions because the reactions are
determined by the availability of H atoms or alkyl groups in key
positions
Polyalcohols
 alcohols containing more than 1 OH group are called
polyalcohols
 the suffixes –diol and –triol are added to the entire alkane
name to indicate the number of OH groups
e.g. 1,2-ethanediol (ethylene glycol) found in antifreeze
 the OH groups can also be considered as an added group to a
parent chain and has the prefix –hydroxy
i.e. 1,2,3-propanetriol is also called 1,2,3-trihydroxypropane
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Cyclic Alcohols
 cyclic compounds with OH groups attached are called cyclic
alcohols
 many compounds are known by their common names which
end in –ol i.e. menthol, cholesterol
 aromatic compounds with attached OH groups compose the
aromatic alcohol group
 simplest in this group is hydroxybenzene or phenol
 phenol is a colourless solid, slightly soluble in water (due to OH
group), used in industrial preparation of plastics, drugs, dyes &
weedkillers
 when naming cyclic or aromatic alcohols the OH group may be
considered as a group attached to the parent ring
i.e. phenol is also named hydroxybenzene
 a benzene ring with 2 adjacent OH groups would be named
1,2-dihydroxybenzene
(see sample problems and examples on pages 40 & 41)
Properties of Alcohols
 boiling points of alcohols are higher than those of their parent
alkanes due to their OH groups which make them more polar
and gives them the capability of forming H bonds
 simple alcohols are also more soluble in water for the same
reason
 in longer alcohols the hydrocarbon portion is nonpolar making
them good solvents for nonpolar molecular compounds, as well
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Reactions Involving Alcohols
a) Hydration Reactions
 many alcohols are prepared by addition reactions of water to
unsaturated hydrocarbons
 this type of addition reaction is called a hydration reaction (using
Markovnikov’s rule)
b) Combustion of Alcohols
c) Elimination Reactions
 reverse of a hydration reaction
 under certain conditions alcohols decompose to produce alkenes
and water
 this reaction is catalyzed by concentrated sulphuric acid
 called a dehydration reaction
(see sample problems on pages 43 & 44)
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Ethers
Properties of Ethers
 structure similar to water H-O-H and alcohols R-O-H only in
ethers, structure is R-O-R (where R=alkyl groups)
 alkyl groups may be identical or different
 there are no OH bonds in ethers so they do not form hydrogen
bonds
 C-O bonds are polar and the v-shape of the C-O-C group make
ether molecules more polar than hydrocarbons
 intermolecular attractions between ether molecules are stronger
than hydrocarbons but weaker than those in alcohols, which is
seen in Table 2 by looking at the boiling points
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 ethers are good solvents for organic reactions because they mix
readily with both polar and non-polar substances
 C-O bonds are polar so ethers can dissolve polar substances while
their alkyl groups allow them to dissolve non-polar substances
 C-O bonds are hard to break, making ethers unreactive another
property of a good solvent
Naming Ethers
 named by adding –oxy to the prefix of the smaller hydrocarbon
group and joining it to the alkane name of the larger hydrocarbon
group
example:
CH3-O-C2H5 is methoxyethane NOT ethoxymethane
 names are sometimes derived from the 2 alkyl groups followed be
the word ether
example: methoxyethane would be methyl ethyl ether
 when the 2 alkyl groups are the same di- is used i.e. ethoxyethane
is diethyl ether
Preparing Ethers from Alcohols: Condensation Reactions
 ethers are formed when 2 alcohols react eliminating a molecule of
water
 this type of reaction where water is released is called a
condensation reaction
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(see sample problem on page 47)
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Aldehydes & Ketones
 aldehydes and ketones are closely related in that they both
contain a carbonyl group (C=O)
 in ketones, the carbonyl group is attached to 2 alkyl groups and
no H groups
 in aldehydes, the carbonyl group is attached to at least 1 H atom
and is also attached to either another H atom or an alkyl group
i.e. in ketones the C=O is in the middle and in aldehydes the C=O is
at the end of the carbon chain
Naming Aldehydes & Ketones
 aldehydes are named by taking the parent alkane name, dropping
the e and adding the suffix -al
 the simplest aldehydes is HCHO, has only 1 C and therefore the
parent chain name is methane and as an aldehyde the name
becomes methanal (formaldehyde)
 2 carbon aldehyde would be named ethanal (acetaldehyde),etc.
 ketones are named by replacing the e ending of the alkane with
-one
 the simplest ketone is propanone, CH3COCH3 (acetone)
 if a ketone has 5 or more carbons in the carbon chain containing
the carbonyl group than we need to specify the location of the
carbonyl group
Example: in 2-pentanone the carbonyl group is the second carbon in
the chain
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(see the sample problem on pages 50 & 51)
Properties of Aldehydes & Ketones
 aldehydes & ketones have lower boiling point’s than analogous
alcohols and are less soluble in water as they don’t have OH
groups and don’t participate in H bonding
 C=O is a strongly polar group so that they are both more soluble
in water than are hydrocarbons
 Are good solvents because they will mix with both polar and nonpolar substances
Preparing Aldehydes and Ketones from Alcohols: Oxidation Reactions
 oxidation reaction in organic chemistry implies a gain of oxygen or
a loss of hydrogen
 in the following reactions oxygen is supplied by compounds called
oxidizing agents like H2O2 (hydrogen peroxide), K2Cr2O7
(potassium dichromate) and KMnO4 (potassium permanganate)
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 the (O) removes 2 H atoms, one from the OH and the other from
the “R” group resulting in the formation of a C=O group + an H2O
From Aldehydes & Ketones to Alcohols: Hydrogenation Reactions
 the carbonyl group can undergo an addition reaction with H but
not other reactants
 high heat, pressure and a catalyst are needed for this
hydrogenation reaction
 the reaction adds H to the C=O which results in an OH group
which produces an alcohol
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 Note: due to the type of groups attached to the carbonyl C atom,
aldehydes always produce primary alcohols while ketones always
produce secondary alcohols
(see sample problems on pages 55 & 56)
Carboxylic Acids & Esters
 organic acids have a carboxyl functional group –COOH and are
called carboxylic acids
 like inorganic acids, carboxylic acids can react with OH containing
compounds to form an organic “salt” called an ester
Carboxylic Acids
 are generally weak acids, are found in citrus fruits, crab apples,
rhubarb, and other foods known by their sour tangy taste
 carboxylic acids also have distinct odours that can be used in law
enforcement
Naming Carboxylic Acids
 the carboxyl group -COOH combines the C=O and OH groups that
we are familiar with already
 IUPAC name is formed by taking the name of the alkane or alkene
with the same number of C atoms as the longest chain in the acid
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 (don’t forget to include the C in the –COOH group)
 the ending –e in alkane or alkene is changed to –oic and adding
the word acid
Examples:
methane….methanoic acid (HCOOH)
methanoic acid is commonly called formic acid
ethane…ethanoic acid (CH3COOH) commonly called acetic acid
(makes vinegar taste sour)
 simplest aromatic acid is phenylmethanoic acid (benzoic acid)
 some acids contain multiple COOH groups i.e. oxalic acid
(2 COOH groups bonded to each other)
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 when naming acids with multiple COOH groups, use –dioic acid
when COOH’s are at each end of the parent chain
e.g HOOC-CH2-COOH is propanedioic acid
 when more COOH groups are present the COOH groups can be
named as groups on the parent chain and are not counted as part
of the parent chain
(see sample problem on page 60)
Properties of Carboxylic Acids
 due to C=O and OH groups in carboxyl groups these molecules
are polar and can form hydrogen bonds with each other and water
molecules
 smaller acids have similar solubility to alcohols but larger ones are
relatively insoluble
 carboxylic acids have the properties of acids and can react organic
“bases” to form “salts”
 due to intermolecular attractions between the carboxyl functional
groups the melting points are higher than their corresponding
hydrocarbons
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Preparing Carboxylic Acids
 when an alcohol is mildly oxidized an aldehyde is produced and
further oxidation results in the formation of a carboxylic acid
i.e.
 (O) in these reactions is supplied by an oxidizing agent
 using an oxidizing agent that changes colour is that basis of the
breathalyser test
(see sample problems on pages 62-63)
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From Carboxylic Acids to Organic “Salts”: Esterification
 carboxylic acids can react in neutralization reactions
 in reactions with alcohols (where the alcohol acts as an organic
base)
 this reaction forms an ester and water
Esters
 responsible for the colours and odours of plants (table 2 p. 64&65)
 generally have the structure of
Naming and Preparing Esters
 name has 2 parts
 first part from the alkyl group from the alcohol used and the
second part is from the acid
 the second part also changes its suffix from –oic to –oate
e.g.
 the general formula can be written as RCOOR1
 RCO from the carboxylic acid while the OR1 comes from the
alcohol
 i.e.
 for an ester the acid is the first part drawn but is the 2nd part of
the name
(see sample problem on p. 65&66)
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Properties of Esters
 compared to a carboxylic the functional group is similar but is
missing the OH group
 i.e. the –OH is replaced by an –OR group
 therefore esters are less polar, less soluble in water and have
lower melting and boiling points than their parent acids
 acidity of carboxylic acids is from the H on the OH group, esters
missing the OH group are not acidic
Reactions of Esters: Hydrolysis
 when an ester is treated with an acid or base, it will split into its
acid and alcohol components
 this type of reaction is called hydrolysis
 saponification is a reaction where an ester is hydrolyzed
 basis of soap making where fats and oils (esters of long chain
acids) are heated with a strong base which causes a hydrolysis
reaction and the sodium salts of the acids are “soap”
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Amines and Amides
 these are compounds that contain nitrogen, as well as, carbon,
hydrogen, oxygen, etc.
 amines are like NH3 with 1,2, or 3 of its H’s replaced with alkyl
groups and are classified as 1°, 2° or 3°
 amines are organic bases and can react with carboxylic acids to
form nitrogen-containing (nitrogenous) organic salts called
“amides”
 amides have the functional group –CON, which can be found in
proteins, etc.
Amines
 when once living things break down to form amines which have an
unpleasant odour e.g. smell of rotting fish due to a mixture of
amines
 decomposing animal tissue produce amines called putrescine and
cadaverine
Naming Amines
 can be named in 2 ways;
1. as a nitrogen derivative of an alkane (IUPAC way) e.g.
CH3NH2 would be aminomethane or
2. as an alkyl derivative of ammonia e.g. methylamine
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Examples:
 if there are 2 amino groups, they are called diamines so IUPAC
name for cadaverine is 1,5-diaminopentane
 a shortcut is to use N to show the substituted groups on the N
atom of the amino group i.e see last 2 molecules above
 an alternative naming system is where the name implies a
derivative of ammonia
 see 2° amine above, which has 2 alkyl groups on the N atom, a
methyl and a butyl which is given the name butylmethylamine
 see 3° amine above, which has 3 methyl groups around the
central N atom, which is given the name trimetylamine
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(see sample problems on page 71)
Properties of Amines
 amines have higher boiling points and melting points than
hydrocarbons of the same size and smaller amines are soluble in
water due to N-C and N-H both of which are polar
 when N-H bonds are present, hydrogen bonding can occur with
water which explains the high solubility of amines in water
 N-H bonds are less polar than O-H so amines will boil at lower
temperature
Preparing Amines
 can be prepared by reaction of ammonia (a weak base) with an
alkyl halide
 this reaction if left to continue can produce a mixture of 1°, 2°, 3°
amines i.e.
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 these 3 components can be separated by fractional distillation due
to their different boiling points
Amides
 similar to esters but here we have a N atom replacing the O atom
 the amide functional group consists of a carboxyl group attached
to an N atom
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Naming and Preparing Amides
 carboxylic acids react with ammonia or with 1° and 2° amines
(organic bases) to produce amides (organic salts)
 both of these reactions are condensation reactions and water is
formed
 again, the amide functional group is carbonyl group attached to a
N atom
 N makes 2 more bonds to either H atoms or alkyl groups
 tertiary amines will not undergo the above reaction which needs a
H atom on the amine
 note the similarity between the synthesis of an ester and the
synthesis of an amide from a primary amine below
 naming amides is similar to naming esters
 esters end in –oate while amides end in –amide
 name of an amide is made up of 2 parts:
1. first part from the amine
in the example above the amine is methylamine so name
begins with methyl
2. second part comes from the name of the acid
in the example above butanoic acid…oic is dropped and
amide is added…butanamide
 the name therefore is methyl butanamide, as with esters the name
is separated into 2 words
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 when there are 1 or more alkyl groups attached to the N atom in
the amide linkage we use the letter N to clarify the location of the
group i.e.
(see sample problem on page 75)
Properties of Amides
 amides are weak bases, insoluble in water
 low molecular weight amides are slightly soluble in water because
of the hydrogen bonding taking place between the amides` polar
N-H bonds and the water molecules
 amides whose N atoms are bonded to 2 H atoms have higher
melting and boiling points than amides that have more attached
alkyl groups
 explained by increased hydrogen bonding
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Reactions of Amides
 like esters, amides can be hydrolyzed in acidic or basic conditions
to produce a carboxylic acid and an amine
 reverse of formation reactions of amides
(See sample problem on page 77)
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