Chapter 16 Alkanes and Aromatic Hydrocarbons
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Transcript of Chapter 16 Alkanes and Aromatic Hydrocarbons
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Chapter 16Chapter 16Alkanes and Aromatic Alkanes and Aromatic
HydrocarbonsHydrocarbonsOrganic CompoundsOrganic Compounds
Bonding in HydrocarbonsBonding in Hydrocarbons
Naming AlkanesNaming Alkanes
Properties of AlkanesProperties of Alkanes
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““The most important hypothesis in all ofThe most important hypothesis in all of
biology…is that everything that animals biology…is that everything that animals do,do,
atoms do. In other words, there is nothingatoms do. In other words, there is nothing
that living things do that cannot be that living things do that cannot be
understood from the point of view that understood from the point of view that
they are made of atoms acting according they are made of atoms acting according
to the laws of physics.” to the laws of physics.”
Richard Feynman (1918-1988)Richard Feynman (1918-1988)
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Organic CompoundsOrganic Compounds
Contain carbonContain carbon
Have covalent bondsHave covalent bonds
Have low melting pointsHave low melting points
Have low boiling pointsHave low boiling points
Burn in air (oxygen) Burn in air (oxygen)
Are soluble in nonpolar solventsAre soluble in nonpolar solvents
Form large moleculesForm large molecules
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AlkanesAlkanes
Contain C and H onlyContain C and H only
Contain single bonds C-CContain single bonds C-C
Have 4 bonds to every carbon (C) atomHave 4 bonds to every carbon (C) atom
Are nonpolarAre nonpolar
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Complete Structural FormulasComplete Structural Formulas
Show the bonds between each of the Show the bonds between each of the atoms atoms
HH H H
H H C C H H H C HH C H HH H H
CHCH4 4 , methane, methane
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More AlkanesMore Alkanes
H HH H Condensed Structural FormulasCondensed Structural Formulas
H C C HH C C H CHCH33 CH CH33
H HH H EthaneEthane
H H H H H H
H C C C HH C C C H CHCH33 CH CH22 CH CH33
H H H H H H PropanePropane
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IUPAC NamesIUPAC Names
NameName # carbons Structural Formula# carbons Structural Formula
MethMethaneane 11 CHCH44
EthEthaneane 22 CHCH33CHCH33
PropPropaneane 33 CHCH33CHCH22CHCH33
ButButaneane 44 CHCH33CHCH22CHCH22CHCH33
PentPentaneane 55 CHCH33CHCH22CHCH22CHCH22CHCH33
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IUPAC NAMESIUPAC NAMES
NameName # carbons # carbons Structural FormulaStructural Formula
HexHexane 6 CHane 6 CH33CHCH22CHCH22CHCH22CHCH22CHCH33
HeptHeptane 7 CHane 7 CH33CHCH22CHCH22CHCH22CHCH22CHCH22CHCH33
OctOctane 8 CHane 8 CH33CHCH22CHCH22CHCH22CHCH22CHCH22CHCH22CHCH33
NonNonane 9 CHane 9 CH3 3 CHCH2 2 CHCH22CHCH22CHCH22CHCH22CHCH22CHCH22CHCH33
DecDecane 10 CHane 10 CH33CHCH22CHCH22CHCH22CHCH22CHCH22CHCH22CHCH22CHCH22CHCH33
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Learning Check Alk1Learning Check Alk1
A. What is the condensed formula forA. What is the condensed formula for H H H H H H H H
H C C C C HH C C C C H
H H H H H H H H
B. What is its molecular formula?B. What is its molecular formula?C. What is its name?C. What is its name?
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Solution Alk1Solution Alk1
A.A. CHCH33CHCH22CHCH22CHCH33
B. B. CC44HH1010
C.C. butanebutane
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Reactions of AlkanesReactions of Alkanes
Combustion Combustion
alkane + Oalkane + O22 CO CO22 + H + H22O + O + heatheat
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Combustion In the CellCombustion In the Cell
Metabolic oxidation is combustionMetabolic oxidation is combustion
CC66HH12 12 OO66 + 6O + 6O22 6CO 6CO22 + 6H + 6H22O + O + heatheat
glucoseglucose
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Learning Check Alk2Learning Check Alk2
Complete the combustion reaction forComplete the combustion reaction for
CC33HH88 + O + O22 + +
Balance your equationBalance your equation
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Solution Alk2Solution Alk2
Step 1Step 1
CC33HH88 + O + O22 CO CO22 + H + H22OO
Step 2Step 2
CC33HH88 + O + O22 3 CO 3 CO22 + 4 H + 4 H22OO
Step 3Step 3
CC33HH88 + 5 O + 5 O22 3 CO 3 CO22 + 4 H + 4 H22OO
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Learning Check Alk3Learning Check Alk3
Complete and balance the reaction for Complete and balance the reaction for the complete combustion of Cthe complete combustion of C77HH1616
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Solution Alk3Solution Alk3
Step 1Step 1
CC77HH1616 + O + O22 CO CO22 + H + H22OO
Step 2Step 2
CC77HH1616 + O + O22 7 CO 7 CO22 + 8 H + 8 H22OO
Step 3Step 3
CC77HH1616 + 11 O + 11 O22 7 CO 7 CO22 + 8 H + 8 H22OO
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HaloalkanesHaloalkanes
An alkane in which one or more H atoms An alkane in which one or more H atoms is replaced with a halogen (F, Cl, Br, or I)is replaced with a halogen (F, Cl, Br, or I)
CHCH33BrBr 1-bromomethane1-bromomethane
BrBr (methyl bromide)(methyl bromide)
CHCH33CHCH22CHCHCHCH33 2-bromobutane2-bromobutane
ClCl
chlorocyclobutanechlorocyclobutane
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Learning Check HA1Learning Check HA1
Name the following:Name the following:
Br
Cl
Cl
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Solution HA1Solution HA1
Name the following:Name the following:
bromocyclopentanebromocyclopentane
1,3-1,3-dichlorocyclohexanedichlorocyclohexane
Br
Cl
Cl
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SubstituentsSubstituents
List other attached atoms or group List other attached atoms or group in alphabetical orderin alphabetical order
Br = bromo, Cl = chloroBr = bromo, Cl = chloro
Cl BrCl Br
CHCH33CHCHCHCH22CHCHCHCH22CHCH22CHCH33
4-bromo-2-chloroheptane4-bromo-2-chloroheptane
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Learning Check HA2Learning Check HA2
The name of this compound is:The name of this compound is:
ClCl CH CH33
CHCH33CHCH22CHCHCHCH22CHCHCHCH33
1)1) 2,4-dimethylhexane2,4-dimethylhexane
2)2) 3-chloro-5-methylhexane3-chloro-5-methylhexane
3)3) 4-chloro-2-methylhexane4-chloro-2-methylhexane
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Solution HA2Solution HA2
The name of this compound is:The name of this compound is:
ClCl CH CH33
CHCH33CHCH22CHCHCHCH22CHCHCHCH33
3) 4-chloro-2-methylhexane3) 4-chloro-2-methylhexane
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Haloalkanes as AnestheticsHaloalkanes as Anesthetics
Halothane (Fluothane) Halothane (Fluothane)
F ClF Cl
FF C C Br C C Br
F HF HFluothane is a haloalkane that is widely Fluothane is a haloalkane that is widely used as an anesthetic, which is a used as an anesthetic, which is a compound that decreases the ability of the compound that decreases the ability of the nerve cells to conduct pain.nerve cells to conduct pain.
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Chapter 16Chapter 16Haloalkanes, Alkenes, and AlkynesHaloalkanes, Alkenes, and Alkynes
Alkenes and AlkynesAlkenes and Alkynes
Geometric Isomers of AlkenesGeometric Isomers of Alkenes
Addition ReactionsAddition Reactions
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Saturated and Unsaturated Saturated and Unsaturated CompoundsCompounds
Saturated compounds (alkanes) have Saturated compounds (alkanes) have the maximum number of hydrogen the maximum number of hydrogen atoms attached to each carbon atomatoms attached to each carbon atom
Unsaturated compounds have fewer Unsaturated compounds have fewer hydrogen atoms attached to the carbon hydrogen atoms attached to the carbon chain than alkaneschain than alkanes
Unsaturated compounds contain double Unsaturated compounds contain double or triple bondsor triple bonds
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AlkenesAlkenes
Carbon-carbon double bondsCarbon-carbon double bonds Names end in -Names end in -eneene
HH22C=CHC=CH22 ethetheneene (ethyl (ethyleneene))
HH22C=CH-CHC=CH-CH33 proppropeneene (propyl (propyleneene))
cyclohexcyclohexeneene
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AlkynesAlkynes
Carbon-carbon triple bondsCarbon-carbon triple bonds Names end in -Names end in -yneyne
HCHCCHCH ethethyneyne(acet(acetyleneylene))
HCHCC-CHC-CH33 proppropyneyne
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Naming Alkenes and AlkynesNaming Alkenes and Alkynes
When the carbon chain has 4 or more C atoms, When the carbon chain has 4 or more C atoms, number the chain to give the lowest number to number the chain to give the lowest number to the double or triple bond.the double or triple bond.
1 2 3 41 2 3 4
CHCH22=CHCH=CHCH22CHCH33 1-butene1-butene
CHCH33CH=CHCHCH=CHCH33 2-butene2-butene
CHCH33CHCHCHCHCHCH33 2-butyne2-butyne
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Learning Check HA3Learning Check HA3
Write the IUPAC name for each of the following Write the IUPAC name for each of the following unsaturated compounds:unsaturated compounds:
A.A. CHCH33CHCH22CCCCHCCH33
CHCH33
B. B. CHCH33C=CHCHC=CHCH33 C. C.
CH3
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Solutions HA3Solutions HA3
Write the IUPAC name for each of the following Write the IUPAC name for each of the following unsaturated compounds:unsaturated compounds:
A.A. CHCH33CHCH22CH=CHCHCH=CHCH33 2-pentyne2-pentyne
CHCH33
B. B. CHCH33C=CHCHC=CHCH33 C. C.
22-methyl-2-butene 3-methylcyclopentene-methyl-2-butene 3-methylcyclopentene
CH3
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Cis and Trans IsomersCis and Trans Isomers
Double bond is fixedDouble bond is fixed Cis/trans Isomers are possibleCis/trans Isomers are possible
CHCH33 CH CH33 CH CH33
CH = CHCH = CH CH = CH CH = CH
ciscis trans trans CH CH33
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HydrogenationHydrogenation
Adds a hydrogen atom to each carbon Adds a hydrogen atom to each carbon atom of a double bondatom of a double bond
H HH H H H H H
NiNi
H–C=C–H + H–C=C–H + HH2 2 HH––CC––CC––HH
H H H H
ethene ethaneethene ethane
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Products of HydrogenationProducts of Hydrogenation
Adding HAdding H2 2 to vegetable oils produces to vegetable oils produces
compounds with higher melting pointscompounds with higher melting points
MargarinesMargarines
Soft margarinesSoft margarines
Shortenings (solid)Shortenings (solid)
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Learning Check HA4Learning Check HA4
What is the product of adding HWhat is the product of adding H22 (Ni (Ni
catalyst) to 1-butene?catalyst) to 1-butene?
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Solution HA4Solution HA4
What is the product of adding HWhat is the product of adding H22 (Ni (Ni
catalyst) to 1-butene?catalyst) to 1-butene?
NiNi
CHCH22=CHCH=CHCH22CHCH33 + H + H22
CHCH33CHCH22CHCH22CHCH33
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Adding HalogensAdding Halogens
Halogens also add to the double bond of an Halogens also add to the double bond of an alkene.alkene.
HH22CCCHCH22 + + ClCl2 2
H2C CH2
Cl Cl
CH3C CCH2CH3 + Br2 CH3C CCH2CH3
Br Br
Br Br
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Learning Check HA5Learning Check HA5
Write the product of the following addition Write the product of the following addition reactions:reactions:
CHCH33CH=CHCHCH=CHCH33 + H + H22
+ Br2
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Solution HA5Solution HA5
Write the product of the following addition Write the product of the following addition reactions:reactions:
CHCH33CH=CHCHCH=CHCH33 + H + H22 CHCH33CHCH22CHCH22CHCH33
+ Br2Br
Br
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Unsaturated Fatty AcidsUnsaturated Fatty Acids
Fatty acids in vegetable oils are omega-6 acids Fatty acids in vegetable oils are omega-6 acids (the first double bond occurs at carbon 6 counting (the first double bond occurs at carbon 6 counting from the methyl group)from the methyl group)
A common omega-6 acid is linoleic acidA common omega-6 acid is linoleic acid
CHCH33CHCH22CHCH22CHCH22CHCH22CH=CHCHCH=CHCH22CH=CH(CHCH=CH(CH22))77COOHCOOH
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linoleic acid, a fatty acid linoleic acid, a fatty acid
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TransTrans Fats Fats
In vegetable oils, the unsaturated fats usually In vegetable oils, the unsaturated fats usually contain contain ciscis double bonds. double bonds.
During hydrogenation, some During hydrogenation, some cis cis double bonds double bonds are converted to are converted to trans trans double bonds (more double bonds (more stable) causing a change in the fatty acid stable) causing a change in the fatty acid structure structure
If a label states “partially” or “fully If a label states “partially” or “fully hydrogenated”, the fats contain hydrogenated”, the fats contain transtrans fatty fatty acids. acids.
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TransTrans Fats Fats
In the US, it is estimated that 2-4% of our total In the US, it is estimated that 2-4% of our total Calories is in the form of Calories is in the form of transtrans fatty acid. fatty acid.
trans trans fatty acids behave like saturated fatty fatty acids behave like saturated fatty acids in the body. acids in the body.
Several studies reported that trans fatty acids Several studies reported that trans fatty acids raise LDL-cholesterol. Some studies also raise LDL-cholesterol. Some studies also report that trans fatty acid lower HDL-report that trans fatty acid lower HDL-cholesterolcholesterol
The trans fatty acids controversy will continue The trans fatty acids controversy will continue to be debated. to be debated.
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Fats and AtheroschlerosisFats and Atheroschlerosis Inuit people of Alaska have a high fat diet Inuit people of Alaska have a high fat diet
and high blood cholesterol levels, but a very and high blood cholesterol levels, but a very
low occurrence of atherosclerosis and heart low occurrence of atherosclerosis and heart
attacks. attacks.
Fat in the Intuit diet was primarily from fish Fat in the Intuit diet was primarily from fish
such as salmon, tuna and herring rather than such as salmon, tuna and herring rather than
from land animals (as in the American diet). from land animals (as in the American diet).
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Omega-3 Fatty AcidsOmega-3 Fatty Acids
Fatty acids in the fish oils are mostly the omega-3 type Fatty acids in the fish oils are mostly the omega-3 type (first double bond occurs at the third carbon counting (first double bond occurs at the third carbon counting from the methyl group). from the methyl group).
linolenic acid 18 carbon atoms linolenic acid 18 carbon atoms
CHCH33CHCH22CH=CHCHCH=CHCH22CH=CHCHCH=CHCH22CH=CH(CHCH=CH(CH22))77COOHCOOH
eicosapentaenoic acid (EPA)eicosapentaenoic acid (EPA) 20 carbon atoms 20 carbon atoms
CHCH33CHCH22(CH=CHCH(CH=CHCH22))55(CH(CH22))22COOH COOH
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AtherosclerosisAtherosclerosis
Plaques of cholesterol adhere to the walls of the Plaques of cholesterol adhere to the walls of the
blood vessels blood vessels
Blood pressure rises as blood squeezes through Blood pressure rises as blood squeezes through
smaller blood vessels smaller blood vessels
Blood clots may formBlood clots may form
Omega-3 fatty acids decrease the “sticking” of Omega-3 fatty acids decrease the “sticking” of
blood platelets (fewer blood clots) blood platelets (fewer blood clots)
Omega-3 fatty acids can increase bleeding timeOmega-3 fatty acids can increase bleeding time
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Learning Check HA6Learning Check HA6
(1) Ture or (2) False(1) Ture or (2) False
A. ____ There are more unsaturated fats in A. ____ There are more unsaturated fats in vegetable oils.vegetable oils.
B. ____ Vegetable oils have more omega-3 oils B. ____ Vegetable oils have more omega-3 oils than found in fish.than found in fish.
C. ____ Hydrogenation of oils converts some C. ____ Hydrogenation of oils converts some cis-cis-double bondsdouble bonds to trans- to trans- double bonds. double bonds.
D. ____ Animal fats have more saturated fats.D. ____ Animal fats have more saturated fats.
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Solution HA6Solution HA6
(1) True or (2) False(1) True or (2) False
A. A. _T___T__ There are more unsaturated fats in There are more unsaturated fats in vegetable oils.vegetable oils.
B. B. _F___F__ Vegetable oils have more omega-3 oils Vegetable oils have more omega-3 oils than found in fish.than found in fish.
C. C. _T___T__ Hydrogenation of oils converts some Hydrogenation of oils converts some cis-cis-double bondsdouble bonds to trans- to trans- double bonds. double bonds.
D. D. _T___T__ Animal fats have more saturated fats. Animal fats have more saturated fats.