Copyright 2002 by Amelia Potter Naming of Hydrocarbons SCH4U

copyright 2002 by Amelia Potter

Naming of Hydrocarbons

SCH4U


Hydrocarbons

Alkanes Alkenes Alkynes

CnH2n+2 CnH2n CnH2n-2

All C bonds are single (fully saturated)

C=C (double bond)

unsaturated

Triple C bond

unsaturated

CH3CH3

ethane

CH2CH2

ethene

CHCH

ethyne


How can we represent Alkanes?C – C – C – C – C Demonstration (No H)

H H H H H

| | | | |

H - C – C - C – C - C – H Fully Expanded

| | | | |

H H H H H

CH3 – CH2 – CH2 – CH2 – CH3 Condensed

CH3 CH2CH2CH2CH3 Fully Condensed

C5H12 Molecular Formula


Naming Alkanes (all single bonds)Chain Length

In Carbons

Name Alkane name

Alkane Formula CnH(2n+2)

1 meth methane CH4

2 eth ethane C2H6

3 prop propane C3H8

4 but butane C4H10

5 pent pentane C5H12

6 hex hexane C6H14


Rules for Naming of Alkanes

Determine the longest continuous carbon chain: also known as the PARENT CHAIN!!!!


Example

Count from one end to another, and determine the longest carbon chain (parent chain)

C –C-C-C– C | hexane C – C Use longest chain in any direction


Chain Length

C –C-C-C-C-C-C

| nonane

C-C-C-C-C-C


Naming the Chain

C –C –C -C –C –C -C – C

| decane

C – C – C – C – C –C -C – C


Naming Alkanes

Determine Chain LengthUse longest Chain (parent chain)

Name the longest chainUse ending for alkane (“ane”)


Naming Branches (Side Chains)

After naming the longest chain, draw a line through all the carbons you use.

Everything that is left are the side chains. Name the side chain (branch) using the

“yl” ending (methyl, ethyl, propyl, etc)


Naming Side Chains

* isopropyl, n-butyl, s-butyl,t-butyl

Side Chain Length

In Carbons

Name Side chain name

Alkyl Formula

1 meth methyl - CH3

2 eth ethyl - C2H5

3 prop Propyl* - C3H7

4 but Butyl* - C4H9

5 pent pentyl - C5H11

6 hex hexyl - C6H13


Naming the Side Chain

Determine the longest chain (parent chain) – name it! Number the carbon atoms in the parent chain starting from the end

that is CLOSEST to a branch/side chain Name the side chain and indicate on which carbon it’s located

C –C-C-C– C | C – C

Parent Chain: hexane


Numbering right to left : 6 5 4 3 ←

C –C-C-C- C

|

C – C

2 1 ←

the side chain is on the #3 carbon of hexane

Naming - Side Chain Locator Number

C –C-C-C- C

|

C – C


Numbering left to right: → 1 2 3 4

C –C-C-C- C

|

C – C

→ 5 6 the side chain is on the #4 carbon of hexane

C – C-C-C- C

|

C – C


3 is lower than 4, so use 3

3 C –C-C-C- C

|

C – C

3 – methylhexane

Naming – Side Chain Locator Number


Naming the Side Chain

C –C-C-C – C -C-C | C –C-C-C-C -C-C

5- ethyl-6- ethyl decaneOR: 5,6-diethyl decane


Multiple Side Chains

C –C –C -C –C -C-C-C

|

C – C – C – C – C-C-C

Parent: decane

6-ethyl-5- propyldecane

ALWAYSALWAYS list side chains alphabetically – E for Ethyl before P for Propyl


C – C – C

|

C – C – C – C – C - C – C – C

Parent Chain: octane

Side Chain: isopropyl (not just propyl)

Name: 4-isopropyloctane


Halogen Substituted Carbon Hydrogen(one hydrogen substituted by a halogen (X))

Name by the Halogen used in the compound

Chloroalkanes (C-C-Cl)

Bromoalkanes (C-C-Br)

Flouroalkanes (C-C-F)

Halogen Substituted Carbon Hydrogen


Naming the Chain

C –C-C-C– Cl | C – C

Parent Chain: hexane Side chain: 3-chloro

Name: 3 - chlorohexane


C –C -C –C -Cl | C – C – C – C – C –C-C-C – C

Naming the Chain

C –C -C –C -Cl | C – C – C – C – C –C-C-C – C

decane chloro propyl decane

4 - chloro 5-propyl decane


C –C -C - Cl | C – C – C – C – C – C - C –C -C – C

Naming the Chain

Let’s name this:


Naming the Chain

C –C –C -C - Br | C – C – C – C – C - C –C -C – C

Example 13

C –C –C -C - Br | C – C – C – C – C - C –C -C – C

nonane bromo butyl nonane

4 - bromo 5 - butyl nonane


DONE with Alkanes!

Your turn to practice!


Naming Alkenes

Determine the longest continuous chain of carbons that have the double bond between two of its carbons. The parent chain must contain the double bond.

C – C – C = C – C – C –C


Naming Alkenes

Number the carbons in the chain so that the double bond would be between the carbons with the lowest designated number.

C1 – C2 – C3 = C4 – C5 – C6 –C7

3-heptene


Naming Alkenes

The location of the double bond, not the location of the branches are used for numbering the alkene.

NOTE THE –ENE ending as well!


Naming Alkenes

Identify the side chains/branch and the position of the branch.

The format is as follows:

(location of branch)-(branch name)(parent chain)


Cis and Trans Isomers


Example


Example:


Naming of Alkynes

Indentify the parent chain with the TRIPPLE bond!

Number from the end closest to the TRIPPLE bond!

Ending is –YNE Ethyne, propyne, 1-butyne, etc… All other rules of naming are the same as for the

other hydrocarbons

Documents

Copyright 2002 by Amelia Potter Naming of Hydrocarbons SCH4U