chapter 19: organic compounds

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley

Chapter 19: ORGANIC COMPOUNDS


This lecture will help you understand:

• Hydrocarbons• Unsaturated Hydrocarbons• Functional Groups• Alcohols, Phenols, and Ethers• Amines and Alkaloids• Carbonyl Compounds• Polymers


Organic Chemistry

A branch of chemistry involving the study of carbon-containing chemical

compounds.


100,000 new ones each year

Organic Chemistry

Organic Compound:

A carbon containing chemical compound

naturalnatural syntheticsynthetic Over 13 m

illion known!

Over 13 m

illion known!


Organic Chemistry

Why is carbon so special?


Organic Chemistry


• Carbon atoms connect with one another through strong and stable covalent bonds.


Organic Chemistry

C C C

C

C

C

N N NN

N

N

O O OO

O

O

S SS

S S


Organic Chemistry

C C C

C

C

C

N N NN

N

N

O O OO

O

O

S SS

S S

347 kJ/mol


Organic Chemistry

C C C

C

C

C

N N NN

N

N

O O OO

O

O

S SS

S S

347 kJ/mol 159 kJ/mol


Organic Chemistry

C C C

C

C

C

N N NN

N

N

O O OO

O

O

S SS

S S


138 kJ/mol


Organic Chemistry

C C C

C

C

C

N N NN

N

N

O O OO

O

O

S SS

S S


138 kJ/mol

226kJ/mol


Organic Chemistry

S SS

S S

S

SS

Sulfur, S8


Organic Chemistry

S SS

S S

S

SS

Sulfur, S8More atoms of the same element bound together like this is rare…


Organic Chemistry

S SS

S S

S

SS

Sulfur, S8More atoms of the same element bound together like this is rare…

…for every element except carbon….


C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

Diamond


Organic Chemistry


• Carbon atoms connect with one another through strong and stable covalent bonds.

• Carbon atoms also readily form bonds with many other types of atoms. This provides for a near infinite number of different kinds of organic compounds.


Organic Chemistry

To appreciate organic chemistry, please minimize memorization…


Hydrocarbons

Hydrocarbon: A chemical compound containing only hydrogen and carbon.


Hydrocarbons


Hydrocarbons

Structural isomer: Molecules having the same molecular formula but different structures.


Hydrocarbons

Structural isomer: Molecules having the same molecular formula but different structures.

“configurations”


Hydrocarbons

Structural isomer: Molecules having the same molecular formula but different configurations.

Configuration: The specific way in which the atoms of a molecule are connected to one another.


Hydrocarbons

Structural isomer: Molecules having the same molecular formula but different configurations.

Configuration: The specific way in which the atoms of a molecule are connected to one another.

“Configuration” = “Connectivity”


C7H16

C8H18

C10H22

C20H42

C6H14

C5H12

9

18

75

366,319

5

3

Formula

Number of possible isomers


Hydrocarbons

Conformation: The spatial orientation of a single configuration.


Hydrocarbons


Rotate this bond


Hydrocarbons



Hydrocarbons


Like pivoting your arm at the elbow


Hydrocarbons


These are two “conformations” of the same configuration.


What is the chemical formula for the following structure?

A. C3H8

B. C4H10

C. C5H12

D. C6H14

HydrocarbonsCHECK YOUR NEIGHBOR



A. C3H8

B. C4H10

C. C5H12

D. C6H14

HydrocarbonsCHECK YOUR ANSWER



A. C3H8

B. C4H10

C. C5H12

D. C6H14

cc

cc

c




A. C3H8

B. C4H10

C. C5H12

D. C6H14

cc

cc

c

H

HH

HH

HH

H

H

HH

H



Hydrocarbons


Unsaturated Hydrocarbons

Carbon always forms four bonds.



Carbon always forms four bonds.

Some of these bonds, however, may be within multiple bonds.



Unsaturated Hydrocarbon: A hydrocarbon containing one or more multiple bonds.



Unsaturated Hydrocarbon: A hydrocarbon containing one or more multiple bonds.

A special case of an unsaturated hydrocarbon is the benzene ring.



A. C5H10

B. C5H12

C. C6H12

D. C6H14

Unsaturated HydrocarbonsCHECK YOUR NEIGHBOR



A. C5H10

B. C5H12

C. C6H12

D. C6H14

Unsaturated HydrocarbonsCHECK YOUR ANSWER



A. C5H10

B. C5H12

C. C6H12

D. C6H14

cc

cc

c




A. C5H10

B. C5H12

C. C6H12

D. C6H14

cc

cc

c

H

HH

HH

H

H

HH

H



Functional Groups

Heteroatom: Any atom other than hydrogen or carbon in an organic molecule.


Functional Groups


Functional Group: A combination of carbon, hydrogen, and heteroatoms that behave as a single unit.


Functional Groups



Organic molecules are classified by the functional groups they contain.


Functional Groups



Organic molecules are classified by the functional groups they contain.

For example…


Functional Groups


In which of the following structures is carbon bonded five times?

A. B. C. D.

Functional GroupsCHECK YOUR NEIGHBOR


A. B. C. D.

Explanation:

Carbon can never be bonded five times! In none of the above structures is carbon indicated to be bonded five times. Sorry for the trick question…


Functional GroupsCHECK YOUR ANSWER


A. B. C. D.


Functional GroupsCHECK YOUR NEIGHBOR


A. B. C. D.

Explanation:

Carbon can never be bonded five times! Structure C, therefore, is NOT a plausible structure for any existing organic compound.


Functional GroupsCHECK YOUR ANSWER


Alcohols, Phenols, and Ethers


Alcohols Contain the Hydroxyl Group

Hydroxyl Group


Methanol

(bp 65°C)


Ethanol

(bp 78°C)


2-Propanol

(bp 97°C)


Phenols Contain the Phenol Group

Phenol


Phenols are acidic


Phenols are acidic

H+


Phenols are acidic


4-n-Hexylresorcinol


Thymol


Ethers contain an oxygen bonded to two carbons

Ether Group


Dimethyl ether (bp −25°C)


Dimethyl ether (bp −25°C)

Ethanol

bp 78°C


Diethyl ether


Amines and Alkaloids


Amines form alkaline solutions

Amine Group


Ethyl amine


Hydroxide ion


Caffeine

Phosphoric acid


Phosphoric acid

Caffeinesalt


Phosphoric acid

Caffeinesalt

Water soluble


Which of the following compounds should have a higher boiling point?

A. Structure A.

B. Structure B.

C. Both the same.

D. No way to tell.

N

H

O

Structure A Structure B

Amines and AlkaloidsCHECK YOUR NEIGHBOR


Which of the following compounds should have a higher boiling point?

A. Structure A

B. Structure B

C. Both the same

D. No way to tell

Explanation:

Structure B has a hydrogen attached to a strongly electronegative atom, nitrogen. This makes for a polar N—H bond that participates in hydrogen bonding.

N

H

O

Structure A Structure B

Amines and AlkaloidsCHECK YOUR ANSWER


Carbonyl Compounds


Carbonyl

A carbon atom double bonded to an oxygen

atom

Carbonyl


Ketone Group


Ketone Group

Aldehyde Group


Acetone


Acetone Acetaldehyde


FormaldehydeAcetone


Citral


Cinnamonaldehyde


Benzaldehyde


Vanillin


Amide Group


N,N-Diethyl-m-toluamide

DEET


Carboxyl group


Salicylic acid


Acetylsalicylic acid

Aspirin


Ester group


Salicylic acid


Salicylic acid

H2SO4

CH3OH


Methyl salicylate

(Wintergreen)


Penicillin


The amino acid lysine is shown below. What functional group must be removed in order to produce the very smelly amine cadaverine, which is 1,5-pentanediamine?

A. The hydrogen (shown) must be

removed and replaced with an amino

(NH2) group.

B. Lysine is 1,5-pentanediamine. Nothing

has to be removed.

C. The carboxyl group must be removed

and replaced with a hydrogen.

D. One amino group must be removed and

replaced with a hydrogen.

Lysine

Carbonyl CompoundsCHECK YOUR NEIGHBOR


The amino acid lysine is shown below. What functional group must be removed in order to produce the very smelly amine cadaverine, which is 1,5-pentanediamine?

A. The hydrogen (shown) must be

removed and replaced with an amino

(NH2) group.

B. Lysine is 1,5-pentanediamine. Nothing

has to be removed.

C. The carboxyl group must be removed

and replaced with a hydrogen.

D. One amino group must be removed and

replaced with a hydrogen.

Lysine

Carbonyl CompoundsCHECK YOUR ANSWER


Polymers

Polymer: A very long organic molecule made by the joining together of smaller organic molecule units known as monomers.


Polymers

Polymer: A very long organic molecule made by the joining together of smaller organic molecule units known as monomers.

MonomerMonomer MonomerMonomer MonomerMonomer MonomerMonomer


Polymers

Addition Polymer:

A polymer whose mass is equal to the sum of the masses of the monomer units.


Polymers

Ethylene

C CH

HH

HC C

H

HH

H

Ethylene

Addition Polymer:



Polymers

Ethylene Ethylene

H

C C

H

H

H

C C

H

HH

H

Addition Polymer:



Polymers

H

C C

H

H

C C

H

H H

H H

Addition Polymer:



Polymers

H

C C

H

H

C CH

H H

H H

H

C C

H

H H

H

C C

H

H H

C

H

H

H

CH

Addition Polymer:



Polymers

H

C C

H

H

C C

H

H H

H H

H

C C

H

H H

H

C C

H

H H

C

H

H

H

C

H

Ethylene Ethylene Ethylene Ethylene EthyleneEthylene

Polyethylene

C

H

H

C

H

H


Polymers

Propylene

C CCH3

HH

HC C

CH3

HH

H

Propylene


Polymers

Polypropylene

C

H

C C

H

H

C C

H H

H

H

C C

H

H CH3

C C

H H

H

C

H H

HCH3 CH3 CH3 CH3

Propylene Propylene Propylene Propylene Propylene Propylene

H

C

H

C

H

CH3


Polymers


Polymers

Condensation Polymer:

A polymer formed when the joining of monomer units is accompanied by the loss

of a small molecule, such as water.


Polymers


PolymersCONSIDER THIS…

Many of the natural product molecules synthesized by plants are formed by the joining together of isoprene monomers via an addition polymerization. A good example is the flavoring molecule citral, which is made of two isoprene units. Find and circle these units within the structure shown to the right.

Isoprene

(2-methyl-1,3-butadiene)Citral

Polymers


Many of the natural product molecules synthesized by plants are formed by the joining together of isoprene monomers via an addition polymerization. A good example is the flavoring molecule citral, which is made of two isoprene units. Find and circle these units within the structure shown to the right.

Isoprene

(2-methyl-1,3-butadiene)Citral

Polymers


Beta-carotene is a natural addition polymer made of eight isoprene units. Find and circle these units within the structure shown below.

Isoprene

(2-methyl-1,3-butadiene)

Beta-carotene

Polymers

chapter 19: organic compounds

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