Organic Chemistry

WHAT IS ORGANIC CHEMISTRY

The scientific study of carbon based compounds, hydrocarbons, and their

derivatives.

ORGANIC CHEMISTRY CON’T

Including the study of structure, properties, composition, reactions and preparation of these carbon based compounds

these carbon based compounds can include other elements such as: Hydrogen, Nitrogen, oxygen

COMPOUNDS ARE? The chemical union of two or more

elements

GENERAL THEMES IN ORGANIC CHEMISTRY

Organic chemistry=Ochem “ R”groups represent attached groups of

atoms, such as Hydrocarbon side chains.

Hydrocarbon: compounds containing only Carbon and Hydrogen.

Remember Carbon always have “4 bonding e-”

HOMOLOGOUS SERIES Organic compounds

are members of homologous series similar to a family

To be part of a homologous series the members differ by a –CH2 group

For example Alkanes:

HOMOLOGOUS SERIES CON’T Homologous series:

Show similar chemical reactivity.

Can be represented by same general formula

Show similar chemical properties

Show gradual changes in physical properties.

TYPES OF HYDROCARBONS Hydrocarbons are classified into

two main groups Aliphatics (alkanes, alkenes,

alkynes) which contain branches but do not contain a benzene ring.

Aromatic hydrocarbons are a unique type of cyclic hydrocarbon that is derived from a benzene ring

Hydrocarbons have two types of carbon-carbon (C-C) bonding

Single bonds only=Saturated Hydrocarbons contain only C-C single bonds throughout. Every available electron sharing site is

occupied (saturated) by hydrogen atoms

Double/triple bonds= Unsaturated hydrocarbons

contain at least one C-C double bond or triple bond.

This means that some electron sharing sites on the carbon atoms are occupied by other carbon atoms (not saturated with hydrogen atoms).

Formulas for organic compounds

There are 3 types: 1. Empirical- simplest whole number ratio

of the atoms it contains ethane: C2H6CH3 Ethanoic AcidCH3COOHC2H4O2CH2O Glucose C6H12O6CH2O doesn’t give a whole lot of detail so it is not

often used.

Formulas for organic compounds

2. Molecular Formulas The actual number of atoms of each element

present. Ethane C2H6

Ethanoic AcidC2H4O2

GlucoseC6H12O6

Molecular Formula It is a multiple of the empirical formula (empirical formula)*n=molecular formula Mr= relative molecular mass Mr= (molecular mass of empirical formula )

For ethane: Empirical formula is CH3 and Mr=30 Mr=(molecular mass )n

30=(12+(3*1.01))n

30=(15.03)n

n=2 Therefore the molecular formula is (CH3)2 or

C2H6

Structural formula

Structural Formula There are three types of structural:

Full structural Shows the bonds of every atom As well as the angle A 2D image

Condensed structural formula Does not show bonds, but groups atoms together The minimum amount of information CH3CH3

Structural formula con’t

Structural Formula Stereochemical

Attempts to show 3D image By convention: a solid enlarging wedge the bond

is coming out of the page A dotted line is going into the page

Which type am i?Full structural

Full structural

Stereochemical

Stereochemical

Condensed

A compound that contains only C and H◦ When naming it is important to find the longest

unbranched carbon chain First understand what the picture means

What is a hydrocarbon

1

2

3

4

5

6

Carbons?

3

2

2

2

2

3

1 2

3

4

5

6

1 2

3

4

5

6

Hydrogen?

HH

H

HH

HH

H

HH

HH

HH

Find the longest UNBRANCHED Hydrocarbon chain

PRACTICE

IUPAC=International union of Pure and Applied Chemistry

# of Carbon IUPAC Name Example

1 Meth- CH4-methane

2 Eth- C2H6-ethane

3 Prop- C3H8-propane

4 But- C4H10-Butane

5 Pent- C5H12-pentane

6 Hex- C6H14-hexane

ButaneHexane

ethane

propane

Side chains are elements or groups of elements attached to the hydrocarbon chain

Also called substituent groups. Important when it comes to naming.

Side chains

Side chain/Substituent

group

IUPAC prefix name

example

-CH3 Methyl CH3CH(CH3)CH3- 2-Methylpropane

-C2H5 Ethyl CH(C2H5)3 3-Ethylpentane

Side chain/Substituent group

IUPAC prefix name

example

-C3H7 Propyl CH(C3H7)3 4-propylheptane

-F,-Cl,-Br,-I Fluoro, chloro, bromo,iodo

CCl4 tetrachloromethane

FUNCTIONAL GROUPS Are specific groups of

atoms within molecules that are responsible for characteristic chemical reactions.

For example: Alcohols are

characterized by their functional group—OH

FUNCTIONAL GROUP 1- ALKANES

ALKANES (CnH2n+2) Alkanes are aliphatic hydrocarbons

They have only carbon-carbon single bonds this means they are saturated hydrocarbons)

Carbon

Hydrogen

ALKANES

Properties of Alkanes: Boiling point are dependent on:

intermolecular forces primarily, like London dispersion forces.

molecular size and surface area of the structure

They do not conduct electricity [because they are molecular compounds]

Are nonpolar so they are not miscible in water

React with oxygen in combustion reactions

1. Find longest unbranched chain of Carbons and number the carbon atoms this is the “root”

2. Based of the number of carbons find the IUPAC name=the suffix

3. Located and identify any sidechains= the prefix

4. Use the attached Carbon To identity where the side group is located.

NAMING (NOMENCLATURE) FOR SIDECHAINS

5. If there is more than 1 of the same kind of branch, use prefixes di, tri, tetra etc. to indicate this.

Place branches in (alphabetical order) in the name

Use commas to separate #s, and "–" to separate letters from #s.

written as:

C# sidechain attached too-sidechainprefixrootofcarbonchain

EXAMPLE

2,5-dimethylhexane

# to identify position of branches

Alkyl prefix

Suffix

Root

# of the alkyl group

Comma to separate the #s

WHAT DOES 5-DIMETHYLHEXANE LOOK LIKE?

FOR EXAMPLE

C 3

Ethyl

octane

3-ethyloctane

ALKENES- CNH2N

Are unsaturated hydrocarbons [i.e. Have at least one double bond]

– end with suffix “ene” A # must be used to indicate the position of

the double bond. Such as but-2-ene The longest chain must contain the double

bond Physical properties very similar to the alkane

ALKENES- CNH2N- CON’T

tend to have fewer dispersion forces than alkanes, which allows them to be liquids at room temp, rather than solids

If there are two double bonds, then use the prefix “di” before the “ene”and indicate the placement of the double bonds with #’s, Three double bonds requires the prefix “tri” before the “ene”

ALKENES- CNH2N- CON’T

Chemical properties of Alkenes Because of the strain at the location of the

double bond, it is the reactive site of the molecule.

Undergo addition reactions to produce alkanes

H atoms tend to add on to the C atoms involved in the C-C double bond

ALKYNES( CNH2N-2)

Alkynes are also examples of unsaturated hydrocarbons.

They have at least one triple bond Triple bonds are more reactive than double

bonds Alkyne names end with “yne”. Use a number

to indicate the position of the triple bond. Ethyne is the most common alkyne (also

called acetylene)

NAMING AND DRAWING ALKENES AND ALKYNES

Identify the longest continuous chain which includes the double or triple bonds.

Identify the suffix which for alkenes is ``ene`` and for alkynes is ``yne.``

The suffix must also include the location of the double or triple bonds. -2-yne

Number from the end that will give the location of the double or triple bond the lowest value.

NAMING AND DRAWING ALKENES AND ALKYNES

The location of the double or triple bond is indicated by the number of the carbon atom that precedes the bond.

Use a hyphen, a number, a hyphen and then the suffix “ene” or “yne”

Name the side or substituent groups same as done with alkanes.

EXAMPLE

1. find the root- the longest chain of unbranched carbons that contains the double bond 6 Carbon long

2. identify the suffix- remember if it has a double bond the suffix ends with–ene Hexene

3. Number the carbons, so the double bond has the lowest number possible Hex-1-ene

4. identify the prefix- One methyl on C-4, One ethyl on C-4 One methyl on C-5

4,ethyl-4,5-dimethyl

4-ETHYL-4,5-DIMETHYLHEX-1-ENE

The C# that the ethyl is attached too

In alphabetical order the type of side chain or substituent groups attached

The C#s that the methyl is attached too

Indicates the number of the particular side chain

#C in the longest chain on Cs

C# that the double bond is attached too

Indicates double bond

Think about a review game for the stuff we have gone overhave a few practice questions for the board ready as well

Cyclic Hydrocarbons

Alkanes, Alkenes and alkynes that are in rings They have no beginning and no end

Naming and Drawing Hydrocarbons

Root: determine the number of carbon atoms in the ring (do not count those carbons that are part of a side group).

The root name would coincide with this number, preceded by “cyclo”

Suffix: determine if the compound contains all single bonds, at least one double bond, or at least one triple bond.

The suffix will be“ane” “ene” or “yne” respectively.

There are no numbers used to indicate the location of the double or triple bond because it is assumed to be between carbons 1 and 2.

Prefix: Similar to naming the aliphatic hydrocarbons with a few extra things to consider: atoms are not numbered:

if there are no side groups or only one side group

If more than one side group, number the C atoms to give you the lowest number in the name.

If double or triple bonds present in cyclic structure, ALWAYS number so C closest to these bonds is number one.

1.Identify the root: 6 carbons=cyclohex

2.Idenitfy the suffix: double bond present

=ene

3. Assign position numbers of C, so they go in the direction of the side group

4. Name the side group based off of the number of C atoms present

2=ethyl

Name

4-ethylcyclohexene

1

24

3

5

6

1.Identify the root: 6 carbons=cyclohex

2.Idenitfy the suffix: double bond present

=ene

3.Assign position numbers

4. Name side groups

one carbon=methyl

3 methyl sidegroups=trimethyl

5. Locations of side groups: 1,2,4

Name:

1,2,4-trimethylcyclohexene

6 1 5

2 4 3

More practice

1.Identify the root: 4 carbons=cyclobut

2.Idenitfy the suffix: triple bond present

=yne

3.Assign position numbers

4. Name side groups

one florine=floro

5. Locations of side groups: 1

Name:

1-florocyclobutyne

F

3 2

4 1

Organic Chemistry in Oil Sands

http://www.oilsands.alberta.ca/

Oil Sands fun!

In general to remember, Oil sands are transported in hydrotransport

pipelines to prevent sands from dryingBitumen is separated out based on density, then

is skimmed out Bitumen is composed of 20% alkanes and 80%

aromatic=OCHEMBitumen is separated into petroleum and other

useful products Through coking(removing C) and hydrocraking (adding H)

petroleum is produced

Refining petroleum

The process of fractional distillation 1. heat the petroleum 2. the vapor rises up the fractional distillation tower

and then gradually cools 3. each Hydrocarbon component has a unique boiling

point, so it condenses at different times So different components can be removed at different

times

Structural Isomers

Structural isomers: have the same molecular formula but different structures. Because of different structures, different physical

properties exist as well

As the number of carbon atoms increase the number of possible isomers also increases Pentane (C5H10)= 3 Isomers Hexanes (C6H14)= 5 Isomers Heptane (C7H16)= 9 Isomers Nonane (C9H20)=35 Isomers

FOR example

C5H12CH3

CH2CH2

CH2CH3

CH CH2

CH3

CH3

CH3

CH3 C CH3

CH3

CH3

Homologous Series

REMEMBER** Members in a Homologous series differ by a mthylene

group (CH2) Homologous series can be thought of as families

The mp. and bp. increase as the number of C atoms increase because there is an difference in strength of the LD forces (or van der Waal’s forces)

The mp. and bp. also differ in some cases depending on polarity or hydrogen bonding.

Organics in General

Most organic compounds are non-polar and therefore insoluable in water(polar)

** Like dissolves like**Solubility decreases as chain length increasesIf an organic compound contains a functional

group, it may allow it to hydrogen bond with water, and relatively water soluble

Aromatic Hydrocarbons