Organic ChemistryOrganic ChemistryChapters 22-23Chapters 22-23

Straight Chain AlkanesStraight Chain Alkanes An alkane is a saturated hydrocarbondAn alkane is a saturated hydrocarbond

– i.e. it has no double bonds, and every carbon i.e. it has no double bonds, and every carbon has the maximum possible number of hydrogenshas the maximum possible number of hydrogens

CHCH44 = methane = methane CHCH33CHCH44 = ethane = ethane CHCH4 4 CHCH33CHCH44 = propane = propane CHCH44CHCH33CHCH33CHCH44 = butane = butane Beyond 4 carbons, standard Greek prefixes Beyond 4 carbons, standard Greek prefixes

are usedare used– E.g. 5C = pentane, 6C = hexane E.g. 5C = pentane, 6C = hexane

Branched Chain AlkanesBranched Chain Alkanes1.1. Identify the main chain.Identify the main chain.

– It will have the highest number of carbon atoms in itIt will have the highest number of carbon atoms in it2.2. Name the main chain using standard conventionsName the main chain using standard conventions3.3. Number the carbons in the main chain from left to rightNumber the carbons in the main chain from left to right4.4. Identify which carbon the secondary chain branches fromIdentify which carbon the secondary chain branches from5.5. Identify the number of carbons in the secondary chainIdentify the number of carbons in the secondary chain6.6. Name the secondary chainName the secondary chain7.7. The final name is the number you identified in step 4, The final name is the number you identified in step 4,

followed by the name of the secondary chain with the followed by the name of the secondary chain with the ending –yl, followed by the name of the main chain.ending –yl, followed by the name of the main chain.

E.g. 2-methylpropane indicates is the name for the E.g. 2-methylpropane indicates is the name for the moleculemolecule

CycloalkanesCycloalkanes1.1. Identify the number of carbons in backbone of the ring.Identify the number of carbons in backbone of the ring.

– Use the carbon number to name the ring, adding the prefix Use the carbon number to name the ring, adding the prefix “cyclo” to indicate that it is a ring“cyclo” to indicate that it is a ring

– E.g. the smallest ring possible is cyclopropane, which has 3 E.g. the smallest ring possible is cyclopropane, which has 3 carbons in the main ringcarbons in the main ring

2.2. Number the carbons in the main ring, starting at the top Number the carbons in the main ring, starting at the top and working clockwise.and working clockwise.

3.3. If any substituent groups branch off the main ring, identify If any substituent groups branch off the main ring, identify which number carbon the branch fromwhich number carbon the branch from

4.4. Name the substituent group, remembering to add the Name the substituent group, remembering to add the suffix –yl to the stemsuffix –yl to the stem

5.5. The final name is the number you identified in step 3, The final name is the number you identified in step 3, followed by the name of the secondary chain with the followed by the name of the secondary chain with the ending –yl, followed by the name of the main ring.ending –yl, followed by the name of the main ring.

E.g. 2-methylcyclopropane indicates is the name for the E.g. 2-methylcyclopropane indicates is the name for the moleculemolecule

AlkenesAlkenes An alkene is unsaturated because it contains at An alkene is unsaturated because it contains at

least C-C double bondleast C-C double bond..– i.e. it does not contain the maximum number of i.e. it does not contain the maximum number of

hydrogen atoms around every carbon atomhydrogen atoms around every carbon atom Use the same naming convention as alkanes, but Use the same naming convention as alkanes, but

use the ending –ene instead of –ane.use the ending –ene instead of –ane. Also, by numbering the carbons, indicate the Also, by numbering the carbons, indicate the

number of the first C in the C-C double bond.number of the first C in the C-C double bond. So, 2-butene is the name of the molecule below.So, 2-butene is the name of the molecule below. N.B. Because there must be a C-C double bond, N.B. Because there must be a C-C double bond,

the smallest possible alkene is ethene.the smallest possible alkene is ethene.

Branched-Chain AlkenesBranched-Chain Alkenes

Number the carbons in order to give Number the carbons in order to give the lowest number possible to the the lowest number possible to the carbon containing the double bond.carbon containing the double bond.

Identify the carbons with Identify the carbons with substituents attached.substituents attached.

Identify the substituents.Identify the substituents. See page 713, problem 22-3 for an See page 713, problem 22-3 for an

exampleexample

AlkynesAlkynes

Alkynes have at least one C-C triple Alkynes have at least one C-C triple bond, and are therefore also bond, and are therefore also unsaturated.unsaturated.

Alkynes use the same naming Alkynes use the same naming conventions as alkenes, but use the –conventions as alkenes, but use the –yne ending instead of –ene.yne ending instead of –ene.

IsomersIsomers Isomers have the same molecular formula, but Isomers have the same molecular formula, but

look different. look different. Structural isomers are bonded in different orders.Structural isomers are bonded in different orders.

– E.g. pentane, 2-methylbutane, and 2,2-dimethylpropane E.g. pentane, 2-methylbutane, and 2,2-dimethylpropane are all Care all C55HH1212 molecules, but they have 5, 4, or 3 carbons molecules, but they have 5, 4, or 3 carbons in their main chains, respectively, and 0, 1, or 2 methyl in their main chains, respectively, and 0, 1, or 2 methyl substituent groups, respectively.substituent groups, respectively.

Stereoisomers have the same bonding order, but Stereoisomers have the same bonding order, but are arranged differently in space. Stereoisomers are arranged differently in space. Stereoisomers are designated cis- or trans-.are designated cis- or trans-.

Optical isomers have the same bonding order, but Optical isomers have the same bonding order, but exhibit chirality. This means that they are mirror exhibit chirality. This means that they are mirror images of each other and bend light clockwise (D-images of each other and bend light clockwise (D-isomers) or counterclockwise (L-isomers)isomers) or counterclockwise (L-isomers)

Aromatic & Aliphatic Aromatic & Aliphatic HydrocarbonsHydrocarbons

Aromatic ringAromatic ring– An exceptionally stable planar ring of atoms with An exceptionally stable planar ring of atoms with

resonance structures that consist of alternating resonance structures that consist of alternating double and single bonds, e. g. benzene:double and single bonds, e. g. benzene:

Aromatic compound Aromatic compound – A hydrocarbon compound containing an aromatic A hydrocarbon compound containing an aromatic

ring.ring.– Aromatic compounds have strong, characteristic Aromatic compounds have strong, characteristic

odors.odors. Aliphatic Hydrocarbons Aliphatic Hydrocarbons

– A hydrocarbon compound lacking a ring structureA hydrocarbon compound lacking a ring structure

CarcinogensCarcinogens

Carcin= cancerCarcin= cancer Gen= createGen= create A carcinogen, therefore, causes A carcinogen, therefore, causes

cancercancer Many of the aromatic compounds are Many of the aromatic compounds are

known carcinogens, others are known carcinogens, others are suspected.suspected.

Fractionating PetroleumFractionating Petroleum All aromatic and aliphatic compounds are All aromatic and aliphatic compounds are

currently obtained from fossil fuelscurrently obtained from fossil fuels The most common source of hydrocarbons is The most common source of hydrocarbons is

petroleumpetroleum Raw petroleum has > 1000 different compounds Raw petroleum has > 1000 different compounds

in it and is called crude oilin it and is called crude oil It is therefore separated via fractional distillation It is therefore separated via fractional distillation

into its simpler components.into its simpler components. Industry can then take the simpler components to Industry can then take the simpler components to

create gasoline, plastics, shampoos, contact create gasoline, plastics, shampoos, contact lenses, and the wide variety of other lenses, and the wide variety of other hydrocarbon-based consumer products that all hydrocarbon-based consumer products that all originate from petroleum. originate from petroleum.

Functional GroupsFunctional Groups

A functional group in an organic A functional group in an organic molecule is an atom or molecule that molecule is an atom or molecule that always reacts in a predictable always reacts in a predictable mannermanner

The addition of functional groups to a The addition of functional groups to a basic hydrocarbon always produces a basic hydrocarbon always produces a substance with distinct properties substance with distinct properties from the basic hydrocarbonfrom the basic hydrocarbon

HalidesHalides HalidesHalides

– Any of the Group 7A elements that are attached to a hydrocarbonAny of the Group 7A elements that are attached to a hydrocarbon– Alkyl halides are organic compounds containing a halogen covalently bonded to Alkyl halides are organic compounds containing a halogen covalently bonded to

an aliphatic carbon atoman aliphatic carbon atom– Aryl halides are organic compounds containing a halogen covalently bonded to Aryl halides are organic compounds containing a halogen covalently bonded to

an aromatic carbon atoman aromatic carbon atom 1. The simplest halogenoalkane is exemplified by chloromethane (methyl 1. The simplest halogenoalkane is exemplified by chloromethane (methyl

chloride)chloride)

2. to 7. Are examples of multi-substituted halogenoalkanes based on 2. to 7. Are examples of multi-substituted halogenoalkanes based on methane … methane …

2. trichlorofluoromethane, (CFC-11, a chlorofluorocarbon or CFC)2. trichlorofluoromethane, (CFC-11, a chlorofluorocarbon or CFC) 3. dichlorodifluoromethane, (CFC-12)3. dichlorodifluoromethane, (CFC-12) 4. difluoromethane (a hydrofluorocarbon or HFC, methylene difluoride) 4. difluoromethane (a hydrofluorocarbon or HFC, methylene difluoride) 5. tribromomethane 5. tribromomethane 6. tetrachloromethane, (carbon tetrachloride) 6. tetrachloromethane, (carbon tetrachloride) 7. chlorodifluoromethane, (HCFC-22 a hydrochlorofluorocarbon or HCFC) 7. chlorodifluoromethane, (HCFC-22 a hydrochlorofluorocarbon or HCFC)

Carboxylic AcidsCarboxylic Acids

The primary suffix name for a carboxylic The primary suffix name for a carboxylic acid is based on the "longest carbon chain acid is based on the "longest carbon chain name *" + "oic acid" for the COOH acidic name *" + "oic acid" for the COOH acidic bond system bond system

methanoic acid (formic acid): methanoic acid (formic acid): – HCOOHHCOOH

ethanoic acid (acetic acid): ethanoic acid (acetic acid): – CHCH33COOHCOOH

Propanoic acid (propionic acid): Propanoic acid (propionic acid): – CHCH33CHCH22COOHCOOH

AlcoholsAlcohols AlcoholsAlcohols have the hydroxy group have the hydroxy group OHOH attached to at least attached to at least

one of the carbon atoms in the chain. one of the carbon atoms in the chain. – If the If the OH group is directly attached to a benzene ringOH group is directly attached to a benzene ring , ,

it is classified as a it is classified as a phenolphenol. . The primary suffix name is ..The primary suffix name is ..olol for alcohol and so for the for alcohol and so for the

longest carbon chain (longest carbon chain (alkanolalkanol) the names are based on: ) the names are based on: – 1 carbon, methanol; 1 carbon, methanol; – 2 carbons, ethanol; 2 carbons, ethanol; – 3 carbons, propanol; 3 carbons, propanol; – 4 carbons, butanol, etc.4 carbons, butanol, etc.

The positions of the substituent alkyl (or other) groups The positions of the substituent alkyl (or other) groups are denoted by using the lowest possible numbers for the are denoted by using the lowest possible numbers for the associated carbon atoms in the main chain. associated carbon atoms in the main chain.

If there is more than one 'type' of substituent eg using If there is more than one 'type' of substituent eg using the prefixes: methyl… and ethyl.. etc., they are written the prefixes: methyl… and ethyl.. etc., they are written out in alphabetical order (di, tri are ignored in using this out in alphabetical order (di, tri are ignored in using this rule). rule).

Alcohol ClassificationAlcohol Classification Alcohols are classified according to the atoms/groups attached to Alcohols are classified according to the atoms/groups attached to

the carbon of the hydroxy group the carbon of the hydroxy group – Primary alcoholsPrimary alcohols have the structure R-CH have the structure R-CH22-OH, R = H, alkyl, aryl etc. -OH, R = H, alkyl, aryl etc.

ie apart from methanol they have one alkyl/aryl group attached to the ie apart from methanol they have one alkyl/aryl group attached to the C of the C-OH group. C of the C-OH group.

– Secondary alcoholsSecondary alcohols have the structure R2CH-OH, R = alkyl or aryl have the structure R2CH-OH, R = alkyl or aryl etc. ie they have two alkyl/aryl groups attached to the C of the C-OH etc. ie they have two alkyl/aryl groups attached to the C of the C-OH group. group.

– Tertiary alcoholsTertiary alcohols have the structure R3C-OH, R = alkyl or aryl etc. ie have the structure R3C-OH, R = alkyl or aryl etc. ie they have three alkyl/aryl groups attached to the C of the C-OH group. they have three alkyl/aryl groups attached to the C of the C-OH group.

Ethers Ethers are named on the basis of the longest carbon chain with are named on the basis of the longest carbon chain with the O-R or alkoxy group, eg methoxy CH3O- or ethoxy CH3CH2O- the O-R or alkoxy group, eg methoxy CH3O- or ethoxy CH3CH2O- etc. treated as a substituent group. etc. treated as a substituent group.

DiolDiol, , trioltriol and and CycloalcoholCycloalcohol ( (cycloalkanolscycloalkanols) structures and names are on a separate web page) structures and names are on a separate web page

Some 'old' names are quoted in () though their use should be Some 'old' names are quoted in () though their use should be avoided if possible [but many still used - just put one into avoided if possible [but many still used - just put one into GOGGLE!]. GOGGLE!].

Alcohol ExamplesAlcohol Examples

MethanolMethanol– CHCH33OH OH

EthanolEthanol– CHCH33CHCH22OHOH

Propan-1-olPropan-1-ol– CHCH33CHCH22CHCH22OHOH

Propan-2-olPropan-2-ol– CHCH33CH(OH)CHCH(OH)CH33

EthersEthers Ethers are formed from the condensation of 2 Ethers are formed from the condensation of 2

alcoholsalcohols R-OH + R'-OH = R-O-R' + HR-OH + R'-OH = R-O-R' + H22OO This is called a dehydration synthesis reaction This is called a dehydration synthesis reaction N.B. R and R' represent organic groups. N.B. R and R' represent organic groups.

Methoxymethane (methyl ether)Methoxymethane (methyl ether)– CHCH33OCHOCH33

Ethoxyethane (ethyl ether)Ethoxyethane (ethyl ether)– CHCH33CHCH22OCHOCH22CHCH33

EstersEsters

An ester is a compound formed from An ester is a compound formed from an acid and an alcohol . an acid and an alcohol .

In esters of carboxylic acids , the -In esters of carboxylic acids , the -COOH group of one hydrocarbon and COOH group of one hydrocarbon and the -OH group from another the -OH group from another hydrocarbon lose a water and hydrocarbon lose a water and become a -COO- linkage: become a -COO- linkage:

R-COOH + R'-OH = R-COO-R' + HR-COOH + R'-OH = R-COO-R' + H22OO

Primary and Secondary Primary and Secondary AminesAmines

An amine is an organic compound that contains a nitrogen An amine is an organic compound that contains a nitrogen atom bound only to carbon and possibly hydrogen atoms. atom bound only to carbon and possibly hydrogen atoms.

Primary Amines:  these have two hydrogen atoms and one Primary Amines:  these have two hydrogen atoms and one alkyl or aryl group attached to the nitrogen to form the alkyl or aryl group attached to the nitrogen to form the amine or amino group -NHamine or amino group -NH22..– MethylamineMethylamine

CHCH33NHNH22

– 2-aminopropane2-aminopropane CHCH33CH(NHCH(NH22)CH)CH33

Secondary Amines: these have one hydrogen atom and two Secondary Amines: these have one hydrogen atom and two alkyl or aryl groups attached to the nitrogen alkyl or aryl groups attached to the nitrogen – DimethylamineDimethylamine

(CH(CH33))22NHNH– EthylpropylamineEthylpropylamine

– DiphenylamineDiphenylamine

Tertiary AminesTertiary Amines

Tertiary amines have no hydrogen Tertiary amines have no hydrogen atom and three alkyl or aryl groups atom and three alkyl or aryl groups attached to the nitrogen attached to the nitrogen

TrimethylamineTrimethylamine EthyldimethylamineEthyldimethylamine N,N-dimethylphenylamineN,N-dimethylphenylamine

Carbonyl CompoundsCarbonyl Compounds

Aldehydes and ketonesAldehydes and ketones are a group of compounds containing the are a group of compounds containing the carbonyl groupcarbonyl group, , C=OC=O..

AldehydesAldehydes always have a hydrogen atom attached to the carbon of the always have a hydrogen atom attached to the carbon of the carbonyl group, so the functional group is carbonyl group, so the functional group is -CHO-CHO (see diagram above). (see diagram above). – The The functional groupfunctional group is shown by using ' is shown by using 'alal' in the suffix part of the name eg ' in the suffix part of the name eg

methanal, ethanal, propanal etc.methanal, ethanal, propanal etc. KetonesKetones always have two carbon atoms attached to the carbon atom of always have two carbon atoms attached to the carbon atom of

the carbonyl group, so the functional group is the carbonyl group, so the functional group is C-CO-CC-CO-C (see diagram (see diagram above). above). – The The functional groupfunctional group is shown by using ' is shown by using 'oneone' in the suffix part of the name ' in the suffix part of the name – eg propanone, butanone, hexan-3-one etc. eg propanone, butanone, hexan-3-one etc.

The The substituent numberssubstituent numbers are based on giving the C=O carbon the are based on giving the C=O carbon the lowest number lowest number – eg 2-methylbutanal ('al' position = 1). eg 2-methylbutanal ('al' position = 1). – The number position of the C=O group in ketones needs to be specified for The number position of the C=O group in ketones needs to be specified for

carbon chains of over 4, or less, if substituents are present carbon chains of over 4, or less, if substituents are present – eg 3-methylbutan-2-one, heptan-2-one, heptan-3-one and heptan-4-one (there is eg 3-methylbutan-2-one, heptan-2-one, heptan-3-one and heptan-4-one (there is

no heptan-1-one, this is heptanal!). no heptan-1-one, this is heptanal!). For the same 'carbon number', For the same 'carbon number', aldehydes and ketones are structural aldehydes and ketones are structural

and functional group isomersand functional group isomers : C : CnnHH2n2nO. O.

Aldehyde ExamplesAldehyde Examples

Methanal (formaldehyde)Methanal (formaldehyde)– HCHOHCHO

Ethanal (acetaldehyde)Ethanal (acetaldehyde)– CHCH33CHOCHO

2-methylpropanal2-methylpropanal– CHCH33CH(CHCH(CH33)CHO)CHO

Ketone ExamplesKetone Examples

Propanone (acetone)Propanone (acetone)– CHCH33COCHCOCH33

Butanone (methyl ethyl ketone)Butanone (methyl ethyl ketone)– CHCH33COCHCOCH22CHCH33

1-Phenylethanone1-Phenylethanone

AmidesAmides

An amide is an organic compound that contains a An amide is an organic compound that contains a carbonyl group bound to nitrogen, also known as carbonyl group bound to nitrogen, also known as an acid amide.an acid amide.

Naming: The primary suffix name for an amide is Naming: The primary suffix name for an amide is based on the "longest carbon chain name" + based on the "longest carbon chain name" + "amide" for the CONH"amide" for the CONH22 bond system eg bond system eg methanamide, ethanamide etc. methanamide, ethanamide etc.

Methanamide (formamide)Methanamide (formamide)– HCONHHCONH22

Ethanamide (acetamide)Ethanamide (acetamide)– CHCH33CONHCONH22

Benzenecarboxamide (benzamide)Benzenecarboxamide (benzamide)– CC66HH55CONHCONH22

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