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Chapter 22

Organic Chemistry!!!!!

Chapter 6 in rxn workbook

Chapter 16 in PR

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Organic Chemistry Is…..

The study of carbon containing compounds and their properties

Organic compounds are typically in chains or rings

All organic molecules are produced by living things/systems

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Vocabulary

Chain

Parent chain and substituent

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The Name Game …again

Alkanes = hydrocarbons (chains of C and H)

All bonds are single i.e “Saturated”

An alkane is a hydrocarbon in which each carbon atom is bonded to four other carbon or hydrogen atoms.

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10 “normal” alkanes

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The Rest

Pentane C5H12 

Hexane C6H14          

Heptane C7H16          

Octane C8H18          

Nonane C9H20      

Decane C10H22

A note on Boiling Point:

BP Octane C8H18      <    Nonane C9H20 

More C = more bonds to break and more energy required.

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Isomers

Same number and type of molecules but bonded in a different location

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Draw all isomers Pentane

1 2 3

4 5

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IUPAC

International Union of Pure and Applied Chemistry

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Rules for Naming Alkanes

Read Page 1061 For chain alkanes beyond butane add the

suffix –ane to the Greek root for the number of carbons

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For Branched alkanes find the longest continuous carbon chain and use this name as the base

(a). If two chains of equal length are present, choose the one with the more branch points as the parent.

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When alkane groups appear as substituent groups they are named by dropping the -ane and adding –yl.

For example CH3 (methane) = methyl . C3H7 is called propyl

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The position of substituent groups are specified by numbering the longest chain of carbon atoms sequentially starting at the end with the closest branching.

C

C-C-C-C-C-C

1 2 3 4 5 6 correct numbering

6 5 4 3 2 1 incorrect numbering

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Last rule!

The location and name of each substituent is followed by the root alkane name.

Substituents are listed in alphabetical order and the prefixes (di, tri,) are used to indicate multiple identical substituents.

A number denotes which carbon that substituent is boned to.

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Example

CH3

CH3 – CH2 - CH – CH2 – CH2 - CH3 1 2 3 4 5 6

3 - methylhexane

Smallest number for substituent Substituent name Parent chain root name Hyphen between number and substituent name

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Try some

Draw all structural isomers or C6H14

1. Start with the longest chain and then rearrange the carbons to form the shorter

CH3-CH2 -CH2 -CH2 –CH2-CH3 1 2 3 4 5 6

Hexane

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Take one carbon out of the chain and make it a methyl substituent

CH3

CH3-CH2 -CH -CH2 –CH3 2 - methylpetane

1 2 3 4 5

CH3

CH3-CH –CH2 -CH2 –CH3 3 - methylpetane

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Next take two carbons out of the chain

CH3

CH3-C –CH -CH3 2,2-dimethylbutane CH3

1 2 3 4

CH3 CH3

CH3-CH –CH -CH3 2,3-dimethylbutane1 2 3 4

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Write the structure for each of the following compounds 4-ethyl-3,5-dimethylnonane

(note the substituents are in alphabetical order separated by a dashed line)

4-tert-butylheptane

(see your cheat sheet for tert structure)

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4-ethyl-3,5-dimethylnonane

1 94

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4-tert-butylheptane

1 2 3 4 5 6 7

CH3-CH2-CH2-CH-CH2-CH2- CH3

H3C-C-CH3

CH3

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Reactions of Alkanes

Combustion reaction Substitution reactions Dehydration reactions

page1065

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Cyclic Alkanes

Add Cyclo to the number of carbons present

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Naming cyclic structures with substituent Give substituent the lowest number possible

(can start with one this time)

If more than one substituent is present number in alphabetical order insuring that all substituents have the lowest possible number

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Homework

Read Page 1066 sample exercise 22.4 naming cyclic alkanes

Do page 1100 #’s: 15, 17, 19, 20,

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22.2 Alkenes and alkynes

Hydrocarbons that contain carbon carbon double bonds.

C2H4

C2H2

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Rules for naming Alkenes

Root hydrocarbon chain ends in –ene

methene

Ethene

Propene

butene

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In alkenes with more than three carbons, the location of the double bond is indicated by the lowest numbered carbon atom INVOLVED in the double bond.

CH2= CHCH2CH3 1-butene

CH3CH=CHCH3 2-butene

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Double Bonding

σ sigma bond

π Pi bond

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Isomers of Alkenes

Cis:

H on

The same side of

The molecule

Trans:

H on

opposite sides of

the molecule

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Practice naming

Find the longest chain

and number it in the direction that gives the double bond the lowest number.

Identify if the molecule is cis or trans

4-methyl-cis-2-hexene

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Alkynes

Unsaturated hydrocarbons containing a carbon-carbon triple bond.

The simplest alkyne is C2H2 called acetylyne

In a triple bond there is one sigma bond and two pi bonds.

Replace the –ane ending –yne Alkenes and alkynes can exist as ringed

structures as well.

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2-methyl-3-heptyne

Due to the triple bond there is no H to be cis or trans

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Homework

Pg 1101 #’s : 21, 22, 23,24

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Aromatic Hydrocarbons

A special class of cyclic unsaturated hydrocarbons.

The simplest is benzene C6H6

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Resonance of Benzene

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Nomenclature

If there is more than one substituent numbers are used to indicate position.

1,2,4-trichlorobenzene 2,4,6-trinitrotoluene (TNT)

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FYI

Toluene or Methylbenzene

Common name IUPAC name

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Some systems use prefixes for substituent position.

Ortho (o) for two adjacent substituent

meta (m) two substituent with 1 carbon between them.

para (p) two substituents opposite of each other

When benzene is used as a substituent it is called a phenyl group.

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0-dichlorobenzene m-dichlorobenzene p-dichlorobenzene

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Give substituents lowest number and place in alpha order.

o-bromochlorobenzene p-bromochlorobenzene

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Complex aromatics pg 1072 table22.3

Naphthalene 

 Anthracene 

Phenanthrene

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Homework

25, 27(skip d) ,28, 29, 37, 38

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22.5 hydrocarbon Derivatives

Molecules that are fundamentally hydrocarbons (C&H) but have additional atoms or groups of atoms called functional groups

Functional Group: functional groups are specific groups of atoms with in molecules, that are responsible for the characteristics of those molecules

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Common functional groups pg 1077 table 22.5Class General Formula Halohydrocarbons RX

(x = F, Cl, Br, I) Alcohols ROH

Ethers ROR

Aldehydes

R and R’ = hydrocarbon fragments CRO

H

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The Common Functional Groups

Class General Formula

Ketones

Carboxylic Acids

Esters

Amines RNH2

CRO

R'

CRO

OH

CRO

O R'

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Alcohols

Have a hydroxyl group

Replace final -e with –ol

Position of –OH group is specified with a number (smallest number goes to substituent)

Classified according to how many hydrocarbon fragments (R) they have

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See table 22.6 for common alcohols

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Example: Name and state 1º, 2º, 3º

Number the chain

Giving OH smallest number

Note carbon that –OH is attached to has –CH3 and a -CH2CH3 groups attached.

Thus it is a secondary alcohol.

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Name and state 1º, 2º, 3º

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3-chloro-1-propanol

Primary alcohol

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Phenol

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Aldehydes and Ketones

Aldehydes and ketones contain carbonyl groups.

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Ketones

Carbonyl group bonded two carbons atoms Ex: acetone

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Aldehydes

Carbonyl group is bonded to at least one hydrogen

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Naming Aldehydes and Ketones

Aldehydes: Named from parent alkane and removing the e and adding –al.

Ketones: The final e is replaced with –one.

In both cases a number indicates the position of the carbonyl group where necessary.

Note: since aldehyde functional group is always a the end of the carbon chain the aldehyde carbon is always assigned as number 1 for referencing the substituent position in the name.

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Naming Aldehydes and Ketones

The parent chain selected must contain the carbonyl group.

Number the carbon chain, beginning at the end nearest to the carbonyl group.

Number the substituents and write the name, listing substituents alphabetically.

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Carboxylic Acids

Carboxylic Acids have a carboxyl group.

RCOOH

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Naming carboxylic acids

Name from parent alkane by dropping e and adding -oic

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Esters

Carboxylic acid reacting with an alcohol to form an ester.

Sweet fruity smell (bananas, oranges)

Acetylsalicylic acid

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Amines

Have one carbon nitrogen bond. N-C

1° one N-C bond 2° two N-C bond 3° three N-C bond

Common names are often used rather than IUPAC names.

Fish like odor

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methyl amine                 

ethyl amine                      

propyl amine                             

cyclobutyl amine

                           

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Homework

Pg 1102-1103

#’s: 41, 47, 49, 50