Chapter 20 Organic Chemistry 2008, Prentice Hall Chemistry: A Molecular Approach, 1 st Ed. Nivaldo Tro Roy Kennedy Massachusetts Bay Community College.

Chapter 20Organic

Chemistry

2008, Prentice Hall

Chemistry: A Molecular Approach, 1st Ed.Nivaldo Tro

Roy KennedyMassachusetts Bay Community College

Wellesley Hills, MA

Tro, Chemistry: A Molecular Approach 2

Structure Determines Properties• Organic compounds all contain carbon

CO, CO2 , carbonates and carbides are inorganic

other common elements are H, O, N, (P, S)

• Carbon has versatile bonding patterns chains, rings, multiple bondschain length nearly limitless

• Carbon compounds generally covalent molecular; gases, liquids, or low melting solids; varying

solubilities; nonconductive in liquid

• C - C bonds unreactive (very stable)


Bond Energies and Reactivities

C-C 347 kJ H3C-CH3NONREACTIVEIN AIR

S-S 214 kJ HS-SH EXTREMELYREACTIVE

Si-Si 213 kJ H3Si-SiH3SPONTANEOUSBURNS IN AIR

N-N 159 kJ H2N-NH2EXTREMELYREACTIVE

O-O 138 kJ HO-OH REACTIVE


Allotropes of Carbon - Diamond


Allotropes of Carbon - Graphite


Carbon Bonding• mainly forms covalent bonds• C is most stable when it has 4 single covalent bonds,

but does form double and triple bondsC=C and C≡C are more reactive than C−CC with 4 single bonds is tetrahedral, 2 singles and 1 double is trigonal planar2 doubles or 1 triple and 1 single is linear


Hydrocarbons• hydrocarbons contain only C and H

aliphatic or aromatic

• insoluble in waterno polar bonds to attract water molecules

• aliphatic hydrocarbons saturated or unsaturated aliphatics

saturated = alkanes, unsaturated = alkenes or alkynes

may be chains or ringschains may be straight or branched

• aromatic hydrocarbons

8

Uses of HydrocarbonsNumber of

C atomsState Major Uses

1-4 gasheating and cooking fuel

5-7liquids,

(low boiling)solvents, gasoline

6-18 liquids gasoline

12-24 liquidsjet fuel; camp stove fuel

18-50liquids,

(high boiling)

diesel fuel, lubricants, heating oil

50+ solidspetroleum jelly, paraffin wax

1-4 gasheating and cooking fuel

5-7liquids,

(low boiling)solvents, gasoline

6-18 liquids gasoline

12-24 liquidsjet fuel; camp stove fuel

18-50liquids,

(high boiling)

diesel fuel, lubricants, heating oil

50+ solidspetroleum jelly, paraffin wax


Saturated Hydrocarbons

• a saturated hydrocarbon has all C-C single bondsit is saturated with hydrogens

• saturated aliphatic hydrocarbons are called alkanes

• chain alkanes have the general formula CnH2n+2


Unsaturated Hydrocarbons• unsaturated hydrocarbons have one of more C=C double

bonds or CC triple bonds• unsaturated aliphatic hydrocarbons that contain C=C are

called alkenes the general formula of a monounsaturated chain alkene is

CnH2n

remove 2 more H for each additional unsaturation

• unsaturated aliphatic hydrocarbons that contain CC are called alkynes the general formula of a monounsaturated chain alkyne is

CnH2n-2

remove 4 more H for each additional unsaturation

http://wps.prenhall.com/wps/media/objects/477/489271/st1802.html


Unsaturated Hydrocarbons

CH3

CH

CH

CH3

CH3 C C CH3

CH3

CC

CH3

CH3

CH3

CH

CH2 CH2

CH2

CH2

CH

CH2

CH2 CH2

CH2

CH2

CH2CH2

C C CH2

CH2

CH2

CH2

CH2

CH2

CH2


Aromatic Hydrocarbons

• contain benzene ring structure

• even though they are often drawn with C=C, they do not behave like alkenes


alkanes

CH3

CH

CH

CH3CH3

CC

CH3

CH3

CH3

CH

CH2 CH2

CH2

CH2

CH

alkenes

CH3 C C CH3

CH2

CH2 CH2

CH2

CH2

CH2CH2

C C CH2

CH2

CH2

CH2

CH2

CH2

CH2

alkynes


15

Formulas• molecular formulas just tell you what

kinds of atoms are in the molecule, but they don’t tell you how they are attached

• structural formulas show you the attachment pattern in the molecule

• models not only show you the attachment pattern, but give you an idea about the shape of the molecule


Condensed Structural Formulas• attached atoms listed in order

central atom with attached atoms

• follow normal bonding patterns use to determine position of multiple bonds

• () used to indicate more than 1 identical group attached to same previous central atom unless () group listed first in which case

attached to next central atom


Line-Angle Formulas

• each angle, and beginning and end represent a C atom

• H omitted on Cincluded on functional groups

• multiple bonds indicateddouble line is double bond, triple line is triple bond


Formulas


FormulasCH4

C

H

H

H

H

C2H6 CH3CH3 C

H

C

H

H

H

H

H

C3H8 CH3CH2CH3 C

H

C

H

H

H

C

H

H

H

H

C4H10 CH3CH2CH2CH3 C

H

C

H

H

H

C

H

H

C

H

H

H

H

C4H10 C(CH3)2 C

H

C

H

H

H

C

C

H

H

H

H

H

H


Isomerism• Isomers = different molecules with the same molecular

formula• Structural Isomers = different pattern of atom attachment

Constitutional Isomers

• Stereoisomers = same atom attachments, different spatial orientation


Structural Isomers of C4H10

Butane, BP = 0°C Isobutane, BP = -12°C

C C C C

H

H

H H

H H

H H

H

HC

H

H

H

H H

H

C HC

CH H

H


Rotation about a bond is not isomerism


Possible Structural IsomersCarbonContent

MolecularFormula

PossibleIsomers

4 C4H10 25 C5H12 36 C6H14 57 C7H16 98 C8H18 189 C9H20 35

10 C10H22 75


Ex 20.1 – Write the structural formula and carbon skeleton formula for C6H14

start by connecting the carbons in a line

determine the C skeleton of the other isomers

C C C C C CC C C C C

C

C C C C C

CC C C C

C

CC C C C

C C

fill in the H to give each C 4 bonds

C C C C

C

CH

H

H

H H H

H

H

H

HHHH

H

C C C C

C

C

H

H

H H H

HHHH

H

H

H

H

H

C C C C C CH

H

H

H

H

H

H

H

H

H H

H

HH


C C C C

C

H

H

H H

HH

HH

H

HH

C H

H

H

C C C C C C

C C C C C

C

C C C C C

C

C C C C

C

CC C C C

C C

C C C C

C

H

H

H H

H

CHHH

HH

H

HH

H

convert each to a carbon skeleton formula – each bend and the ends represent C atoms

C C C C

C

CH

H

H

H H H

H

H

H

HHHH

H

C C C C

C

C

H

H

H H H

HHHH

H

H

H

H

H

C C C C C CH

H

H

H

H

H

H

H

H

H H

H

HH


C C C C

C

H

H

H H

HH

HH

H

HH

C H

H

H

C C C C

C

H

H

H H

H

CHHH

HH

H

HH

H


Stereoisomers

• stereoisomers are different molecules whose atoms are connected in the same order, but have a different spatial direction

• optical isomers are molecules that are nonsuperimposable mirror images of each other

• geometric isomers are stereoisomers that are not optical isomers


Nonsuperimposable Mirror Images

mirror image cannot be rotated so all its atoms align with the same atoms of the original molecule


Chirality• any molecule with a nonsuperimposable mirror

image is said to be chiral• any carbon with 4 different substituents will be

a chiral center• a pair of nonsuperimposable mirror images are

called a pair of enantiomers


Optical Isomers of 3-methylhexane


Plane Polarized Light

• light that has been filtered so that only those waves traveling in a single plane are allowed through


Optical Activity• a pair of enantiomers have all the same physical

properties except one – the direction they rotate the plane of plane polarized lighteach will rotate the plane the same amount, but in opposite

directionsdextrorotatory = rotate to the right levorotatory = rotate to the left

• an equimolar mixture of the pair is called a racemic mixture rotations cancel, so no net rotation


Chemical Behavior of Enantiomers• a pair of enantiomers will have the same

chemical reactivity in a non-chiral environment

• but in a chiral environment they may exhibit different behaviorsenzyme selection of one enantiomer of a pair


Alkanes• aka paraffins

• aliphatic

• general formula CnH2n+2 for chains

• very unreactive

• come in chains or/and ringsCH3 groups at ends of chains, CH2 groups in the middle

chains may be straight or branched

• saturated

• branched or unbranched


N a m e L e w i sS t r u c t u r e

F o r m u l a B o i l i n gP o i n t

M e t h a n eC H

H

H

HC H 4 - 1 6 2 ° C

E t h a n eC

H

H

H C H

H

H

C H 3 C H 3 - 8 9 ° C

P r o p a n eCH

H

H

C

H

H

C

H

H

HC H 3 C H 2 C H 3 - 4 2 ° C

B u t a n eCH

H

H

C

H

H

C

H

H

C

H

H

HC H 3 C H 2 C H 2 C H 3 0 ° C

P e n t a n eCH

H

H

C

H

H

C

H

H

C

H

H

C

H

H

HC H 3 C H 2 C H 2 C H 2 C H 3 3 6 ° C

H e x a n eCH

H

H

C

H

H

C

H

H

C

H

H

C

H

H

C

H

H

HC H 3 C H 2 C H 2 C H 2 C H 2 C H 3 6 9 ° C


Naming• each name consists of 3 parts

prefix indicates position, number, and type of branches indicates position, number, and type of each functional group

parentindicates the length of the longest carbon chain or ring

suffixindicates the type of hydrocarbon

– ane, ene, yne

certain functional groups

37

Naming Alkanes1) Find the longest continuous carbon chain2) Number the chain from end closest to a branch

if first branches equal distance use next in3) Name branches as alkyl groups

locate each branch by preceding its name with the carbon number on the chain

4) List branches alphabetically do not count n-, sec-, t-, count iso

5) Use prefix if more than one of same group present di, tri, tetra, penta, hexa do not count in alphabetizing


Alkyl GroupsC

C C

C C C

C C

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

CH3

CH3-, METHYL

CH3CH2-, ETHYL

CH3CH2CH2-, PROPYL

(CH3)2CH-, ISOPROPYL


More Alkyl Groups

C C C C

C C C

C

H

H

H

H

H

H

H

H

H

H

H

H

H

H H

CH3

CH3

CH3

H3C

C C C

CH3H

H

H H

H

H

(CH3)2CHCH2-, ISOBUTYL

CH3CH2(CH3)CH-, sec-BUTYL

CH3CH2CH2CH2-, n-BUTYL

(CH3)3C-, tert-- BUTYL


Examples of Naming Alkanes

2-methylpentane

H H H H H

H C C C C C H

H CH3 H H H

3-isopropyl-2,2-dimethylhexane

H CH3 H H H H

H C C C C C C H

H CH3 CH H H H

CH3 CH3


Example – Name the alkane

1) find the longest continuous C chain and use it to determine the base name

CH3CHCH2CHCH3

CH3 CH3

CH3CHCH2CHCH3

CH3 CH3

since the longest chain has 5 Cthe base name is pentane



2) identify the substituent branches

CH3CHCH2CHCH3

CH3 CH3

there are 2 substituentsboth are 1 C chains, called methyl

CH3CHCH2CHCH3

CH3 CH3


CH3CHCH2CHCH3

CH3 CH3


3) number the chain from the end closest to a substituent branch

if first substituents equidistant from end, go to next substituent in

both substituents are equidistant from the end

1 2 3 4 5

2 4

then assign numbers to each substituent based on the number of the main chain C it’s attached to


CH3CHCH2CHCH3

CH3 CH3

Example – Name the alkane4) write the name in the following order

1) substituent number of first alphabetical substituent followed by dash2) substituent name of first alphabetical substituent followed by dash

if it’s the last substituent listed, no dash use prefixes to indicate multiple identical substituents

3) repeat for other substituents alphabetically4) name of main chain

2 4

2,4 – dimethylpentane


Practice – Name the Following

CH3CHCHCH2CH3

CH3

CH2CH3



CH3CHCHCH2CH3

CH3

CH2CH3

3-ethyl-2-methylpentane


Drawing Structural Formulas

• draw and number the base chain carbon skeleton

• add the carbon skeletons of each substituent on the appropriate main chain C

• add in required H’s

4-ethyl-2-methylhexane

C C C CC C

C C C

CH3 CH2 CH2 CH3CH CH

CH3 H2C CH3

C C C C C C1 2 3 4 5 6


Practice – Draw the structural formula of 4-isopropyl-2-methylheptane


Practice – Draw the structural formula of 4-isopropyl-2-methylheptane

CH3 CH2 CH2CH CH

CH3 CH3HC

CH3

CH2 CH3


Alkenes• also known as olefins• aliphatic, unsaturated

C=C double bonds

• formula for one double bond = CnH2n

subtract 2 H from alkane for each double bond

• trigonal shape around Cflat

• much more reactive than alkanes• polyunsaturated = many double bonds



Alkenes

C CH H

HH

ethene = ethylene

C CH H

CH3H

propene


Name Formula Molar Mass BP, °C Density, g/cm3

ethene CH2=CH2 28 -104 0.52

propene CH2=CHCH3 42 -47 0.59

1-butene CH2=CHCH2CH3 56 -6 0.59

1-pentene CH2=CH(CH2)2CH3 70 30 0.64

1-hexene CH2=CH(CH2)3CH3 84 64 0.68

1-heptene CH2=CH(CH2)4CH3 98 93 0.70

1-octene CH2=CH(CH2)5CH3 112 122 0.72

1-nonene CH2=CH(CH2)6CH3 126 146 0.73

1-decene CH2=CH(CH2)7CH3 140 171 0.74

Physical Properties of Alkenes


Alkynes

• also known as acetylenes

• aliphatic, unsaturated

• CC triple bond

• formula for one triple bond = CnH2n-2

subtract 4 H from alkane for each triple bond

• linear shape

• more reactive than alkenes



Alkynesethyne = acetylene propyne

C C HH C C CH3H


Physical Properties of AlkynesName Formula Molar Mass BP, °C Density, g/cm3

ethyne CHCH 28 -104 0.52

propyne CHCCH3 42 -47 0.59

1-butyne CHCCH2CH3 56 -6 0.59

1-pentyne CHC(CH2)2CH3 70 30 0.64

1-hexyne CHC(CH2)3CH3 84 64 0.68

1-heptyne CHC(CH2)4CH3 98 93 0.70

1-octyne CHC(CH2)5CH3 112 122 0.72

1-nonyne CHC(CH2)6CH3 126 146 0.73

1-decyne CHC(CH2)7CH3 140 171 0.74


Naming Alkenes and Alkynes

• change suffix on main name from -ane to -ene for base name of alkene, or to -yne for the base name of the alkyne

• number chain from end closest to multiple bond

• number in front of main name indicates first carbon of multiple bond


Examples of Naming Alkenes

2-methyl-1-pentene

3-isopropyl-2,2-dimethyl-3-hexene

H H H

H C C C C C H

H CH3 H H H

H CH3 H H

H C C C C C C H

H CH3 CH H H H

CH3 CH3


Examples of Naming Alkynes

3-methyl-1-pentyne

4-isopropyl-5,5-dimethyl-2-hexyne

H H H

H C C C C C H

CH3 H H

H CH3 H H

H C C C C C C H

H CH3 CH H

CH3 CH3


Name the Alkene1) find the longest, continuous C chain that

contains the double bond and use it to determine the base name

since the longest chain with the double bond has 6 Cthe base name is hexene

H3C CH C

H2C CH3

CH CH3

H2C CH3


Name the Alkene


there are 2 substituentsone is a 1 C chain, called methyl

the other one is a 2 C chain, called ethyl

H3C CH C

H2C CH3

CH CH3

H2C CH3


H3C CH C

H2C CH3

CH CH3

H2C CH3

Name the Alkene

3) number the chain from the end closest to the double bond


1234

5 6

4

3


Name the Alkene4) write the name in the following order

1) substituent number of first alphabetical substituent – substituent name of first alphabetical substituent – use prefixes to indicate multiple identical substituents

2) repeat for other substituents3) number of first C in double bond – name of main chain

3–ethyl– 4–methyl–2–hexene

H3C CH C

H2C CH3

CH CH3

H2C CH3

1234

5 6

4

3



H3C C C

CH3

CH2 CH3

H2C CH3



H3C C C

CH3

CH2 CH3

H2C CH3

3,4-dimethyl-3-hexene

12

3 4 5 6


Name the Alkyne1) find the longest, continuous C chain that

contains the triple bond and use it to determine the base name

since the longest chain with the triple bond has 7 Cthe base name is heptyne

CH3 CH2 CCH CH

CH3 CH3HC

CH3

C CH3


Name the Alkyne


there are 2 substituentsone is a 1 C chain, called methylthe other one is called isopropyl

CH3 CH2 CCH CH

CH3 CH3HC

CH3

C CH3


CH2 CCH CH

CH3 CH3HC

CH3

C CH3CH3

Name the Alkyne

3) number the chain from the end closest to the triple bond


46

1234567


Name the Alkyne4) write the name in the following order

1) substituent number of first alphabetical substituent – substituent name of first alphabetical substituent – use prefixes to indicate multiple identical substituents

2) repeat for other substituents3) number of first C in double bond – name of main chain

4–isopropyl–6–methyl–2–heptyne

CH2 CCH CH

CH3 CH3HC

CH3

C CH3CH3

46

1234567



H3C C

CH3

CH2CH3

C CH



H3C C

CH3

CH2CH3

C CH

3,3-dimethyl-1-pentyne

123

4 5


Geometric Isomerism

• because the rotation around a double bond is highly restricted, you will have different molecules if groups have different spatial orientation about the double bond

• this is often called cis-trans isomerism

• when groups on the doubly bonded carbons are cis, they are on the same side

• when groups on the doubly bonded carbons are trans, they are on opposite sides


Free Rotation AroundC─C


Cis-Trans Isomerism


Reactions of Hydrocarbons

• all hydrocarbons undergo combustion

• combustion is always exothermicabout 90% of U.S. energy generated by combustion

2 CH3CH2CH2CH3(g) + 13 O2(g) → 8 CO2(g) + 10 H2O(g)

CH3CH=CHCH3(g) + 6 O2(g) → 4 CO2(g) + 4 H2O(g)

2 CH3CCCH3(g) + 11 O2(g) → 8 CO2(g) + 6 H2O(g)


Other Alkane Reactions• Substitution

replace H with a halogen atominitiated by addition of energy in the form of

heat or ultraviolet light to start breaking bonds

generally get multiple products with multiple substitutions

C C

H H

H

HH

H

heat or UV light

H ClC C

H Cl

H

HH

HCl Cl + H Cl+

78

Other Alkene and Alkyne Reactions• Addition reactions

adding a molecule across the multiple bond

• Hydrogenation = adding H2

converts unsaturated molecule to saturatedalkene or alkyne + H2 → alkane

• Halogenation = adding X2

• Hydrohalogenation = adding HXHX is polarwhen adding a polar reagent to a double or triple

bond, the positive part attaches to the carbon with the most H’s


Addition Reactions

H

C C

H H

CH3

Cl2 C C

Cl

Cl

CH3

HH

H

+H

C C

H H

CH3

C C

H

H

CH3

HH

H

+ H2

H

C C

H H

CH3

C C

H

Cl

CH3

HH

H

+ + H-Cl -


Aromatic Hydrocarbons • contain benzene ring structure

• even though they are often drawn with C=C, they do not behave like alkenes


Resonance Hybrid

• the true structure of benzene is a resonance hybrid of two structures


Naming Monosubstituted Benzene Derivatives

• (name of substituent)benzenehalogen substituent = change ending to “o”

• or name of a common derivative

F

fluorobenzene

CH2CH2CH3

propylbenzene

CH3 NH2 OH HC CH2

toluene aniline phenol styrene


Naming Benzene as a Substituent

• when the benzene ring is not the base name, it is called a phenyl group

H2C CH CH2 CH2 CH3CH

4-phenyl-1-hexene


Naming Disubstituted Benzene Derivatives

• number the ring starting at attachment for first substituent, then move toward secondorder substituents alphabeticallyuse “di” if both substituents the same

F

Br1

23

1-bromo-3-fluorobenzene

CH3

CH31

2

1,2-dimethylbenzene


Naming Disubstituted Benzene Derivatives

• alternatively, use relative position prefixortho- = 1,2; meta- = 1,3; para- = 1,4

CH3Cl

2-chlorotolueneortho-chlorotoluene

o-chlorotoluene

CH3

Cl

CH3

Cl3-chlorotoluene

meta-chlorotoluenem-chlorotoluene

4-chlorotoluenepara-chlorotoluene

p-chlorotoluene



F

Cl

Br

Br



F

Cl

Br

Br

1-chloro-4-fluorobenzene 1,3-dibromobenzeneor meta-dibromobenzene

or m-dibromobenzene


Polycyclic Aromatic Hydrocarbons• contain multiple benzene rings fused together

fusing = sharing a common bond


Reactions of Aromatic Hydrocarbons• most commonly, aromatic hydrocarbons

undergo substitution reactions – replacing H with another atom or group


Functional Groups• other organic compounds are hydrocarbons in which

functional groups have been substituted for hydrogens• a functional group is a group of atoms that show a

characteristic influence on the properties of the moleculegenerally, the reactions that a compound will perform are

determined by what functional groups it hassince the kind of hydrocarbon chain is irrelevant to the

reactions, it may be indicated by the general symbol R

CH3—OHR group functional group

91


Alcohols• R-OH• ethanol = CH3CH2OH

grain alcohol = fermentation of sugarsalcoholic beverages

proof number = 2X percentage of alcoholgasohol

• isopropyl alcohol = (CH3)2CHOH2-propanol rubbing alcoholpoisonous

• methanol = CH3OHwood alcohol = thermolysis of woodpaint solventpoisonous


Naming Alcohols• main chain contain OH• number main chain from end closest to OH• give base name ol ending and place number of C on chain

where OH attached in front • name as hydroxy group if other higher precedence group

present

CH3 CH2 CH C

OH CH3

CH2CH3

CH CH21 2 3 4 5 6

4-ethyl-4-methyl-3-hex-5-enol


Reactions of AlcoholsNucleophilic Substitution

CH3 OH + HCl CH3Cl + H2O

Acid Catalyzed Elimination (Dehydration)

CH3 CH2OH CH2 CH2 + H2OH2SO4

Oxidation

CH3 CH2OH CH3 CHO CH3 COOH - 2 H - 2 H

with Reactive Metals

CH3 OH + Na CH3O−Na+ + ½ H2


Aldehydes and Ketones• contain the carbonyl group• aldehydes = at least 1 side H• ketones = both sides R groups• many aldehydes and ketones have

pleasant tastes and aromas• some are pheromones• formaldehyde = H2C=O

pungent gas formalin = a preservativewood smoke, carcinogenic

• acetone = CH3C(=O)CH3

nail-polish remover

O

C

formaldehyde

acetone

96

Aldehyde Odors and Flavors• butanal = butter

• vanillin = vanilla

• benzaldehyde = almonds

• cinnamaldehyde = cinnamon

O

H

C CH2CH2CH3

O

CH

HC

O

C C

H

H

H

OO

HO

HO

97

Ketone Odors and Flavors• acetophenone = pistachio

• carvone = spearmint

• ionone = raspberries

• muscone = musk

O

CH3C

O CH3

O

H3C

C

CH3

CH2

CH3

CH3H3C O

C CH3CCH

H


Reactions

• aldehydes and ketones are generally synthesized by the oxidation of alcohols

• therefore, reduction of an aldehyde or ketone results in an alcohol


Carbonyl Group

C=O group is highly polarmany reactions involve addition across C=O,

with positive part attached to O


Addition to C=O


Carboxylic Acids• RCOOH• sour tasting• weak acids• citric acid

found in citrus fruit

• ethanoic acid = acetic acidvinegar

• methanoic acid = formic acidinsect bites and stings

O

OHCH

O

OHCCH3

OH

O

HO C C

CH2 C

C

O

O

OH

OH

CH2


Carboxylic Acids• made by the oxidation of

aldehydes and alcoholsOH on the end of the chain

• always on main chainhas highest precedence

• C of group always C1position not indicated in name

• change ending to oic acid

H3C CH2

OH

H3C

O

C OHoxidation

ethanoic acidethanol

oxidation

O

CH

O

COH

benzaldehyde benzoic acid


Naming Carboxylic Acids


Esters• R–COO–R

• sweet odor

• made by reacting carboxylic acid with an alcohol

RaCOOH + RbOH RaCOORb + H2O

• name alkyl group from alcohol, then acid name with oate endingprecedence over carbonyls, but not

carboxylic acidnumber from end with ester group

O

COH

C CH3

O

O

aspirin

methyl butanoate


Naming Esters


Condensation Reactions• a condensation reaction is any organic reaction

driven by the removal of a small molecule, like water

• esters are made by the condensation reaction between a carboxylic acid and an alcohol

the reaction is acid catalyzed

• acid anhydrides are made by the condensation reaction between 2 carboxylic acid molecules

the reaction is driven by heat

R C

O

OH OH C

O

R' R C

O

O C

O

R'

+ + HOH


Synthesis of Aspirin(Acetylsalicylic Acid)


Ethers• R– O – R

• ether = diethyl ether = CH3CH2OCH2CH3

anesthetic

• to name ethers, name each alkyl group attached to the O, then add the word ether to the end

diethyl ether


Amines• N containing organic molecules• very bad smelling• form when proteins decompose• organic bases• name alkyl groups attached to the N, then add

the word amine to the end

H3C CH2

NH2

ethylamine

H3C CH2

NHH3C

ethylmethylamineH2NCH2CH2CH2CH2CH2NH2

cadaverine

putrescineH2NCH2CH2CH2CH2NH2


Amines• many amines are biologically active

dopamine – a neurotransmitterepinephrine – an adrenal hormonepyridoxine – vitamin B6

• alkaloids are plant products that are alkaline and biologically active toxicconiine from hemlockcocaine from coca leavesnicotine from tobacco leavesmescaline from peyote cactusmorphine from opium poppies

HO

HO

CH2CH2NH2

dopamine

N

N

CH3

nicotine


Amine Reactions

• weak basesreact with strong acids to form ammonium salts

RNH2 + HCl → RNH3+Cl−

• react with carboxylic acids in a condensation reaction to form amides

RCOOH + HNHR’ RCONHR’ + H2O


Macromolecules

• polymers are very large molecules made by repeated linking together of small molecules monomers

• natural• modified natural polymers• synthetic

plastics, elastomers (rubber), fabrics, adhesives• composites

additives such as graphite, glass, metallic flakes


Natural Polymers• polysaccharides

cellulose (cotton) starch

• proteins

• nucleic acids (DNA)

• natural latex rubber, etc.

• shellac

• amber, lignin, pine rosin

• asphalt, tar


Modified Natural Polymers

• Cellulose AcetateRayon film

• Vulcanized Rubber • Gun Cotton • Celluloid

ping-pong balls• Gutta Percha

fill space for root canal• Casein

buttons, mouldings, adhesives


Polymerization

• the process of linking the monomer units together

• two processes are addition polymerization and condensation polymerization

• monomers may link head-to-tail, or head-to-head, or tail-to-tailhead-to-tail most common regular pattern gives stronger attractions between chains than

random arrangements

116

Head-to-Tail

Head-to-Head, Tail-to-Tail

Cl

C CH

H H

H Cl

C C

H H

HHead Tail Head Tail

H

C CH

H H

Cl Cl

C C

H H

H

Tail TailHead Head


Addition Polymerization• monomers add to the growing chain in

such a manner that all the atoms in the original monomer wind up in the chainno other side products formed, no atoms

eliminated

• first monomer must “open” to start reactiondone with heat or addition of an initiator

• chain reactioneach added unit ready to add another

Addition Polymerization

initiatorC C

H

H

H

Cl Cl

C CH

H H

H

Cl

C CH

H H

H

+ C C

H

H

H

ClCl

C CH

H H

H Cl

C C

H H

H

•

•

Cl

C CH

H H

H Cl

C C

H H

H

+ C C

H

H

H

Cl Cl

C CH

H H

H Cl

C C

H H

H Cl

C C

H H

H

•

initiatoretc.


Condensation Polymerization

• monomer units are joined by removing small molecules from the combining unitspolyesters, polyamides lose water

• no initiator needed

• chain reaction

• each monomer has two reactive ends, so chain can grow in two directions


Condensation Polymerization

+ +

+C C

O O

HO OH HO CH2 CH2 OH

H C C

O O

O O CH2 CH2 OH + H2O


Nylon• polyamides• good physical properties

affected by moisture

• very good heat resistance• excellent chemical resistance• excellent wear resistance• nylon 6,6 made by condensing

1,6–hexandiamine, H2N–(CH2)6–NH2, with hexandioic acid, HOOC–(CH2)4–COOH

(CH2)6 NH C

O

(CH2)4 C

O

HN

http://wps.prenhall.com/wps/media/objects/167/171580/SynthesisofNylon610.html


Chapter 20 Organic Chemistry 2008, Prentice Hall Chemistry: A Molecular Approach, 1 st Ed. Nivaldo Tro Roy Kennedy Massachusetts Bay Community College.

Documents

c slide

cc single bonds

molecular approach14

c skeleton

triple bonds c

c double bonds

c atom h

covalent bonds c