Organic Chemistry (Naming & Drawing)

Chemistry 30

Organic Chemistry ? UNIT NOTES

Organic Chemistry (Naming & Drawing)

A. Introduction

Organic Chemistry: the chemistry of CARBON compounds except Oxides & ionic compounds.

carbon compound = organic compound(O.C.)

Why OCs are so important in chemistry:

we are made of

there are so

them

many

they are very useful to us

Common OCs: glucose(C6H12O6), nicotine (C10H14N2), Teflon ([C2F4]x) ,

Carbon is called the "backbone" of organic chem.

The Abundance of OCs

Compounds containing: only C and H (called hydrocarbons) C, H, and other atoms (i.e. O, N, Cl, etc.)

Abundance: hundreds of thousands

over 8 million

Why so many types of hydrocarbons.....2 reasons: 1. Carbon compounds are chains of carbon linked in: straight lines(linear):

circular pattern(cyclic):

substituted (branched):

H2 C H2C

H2 C

CH2

H2C H2C

CH2 CH2

cyclooctane

2. Carbon atoms may form single, double, or triple bonds, each having different properties. eg) this molecule has single and double C-C bonds:

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Chemistry 30

Organic Chemistry ? UNIT NOTES

The Uses of OCs

Petroleum: "a fossil fuel" plant and animal remains trapped underground for hundreds of millions of years.

Using organic chemistry, many useful substances are derived from petroleum.

PETROLEUM

fuel

solvent

plastic

pharmaceutical

s

s

Personal care

5 Ways to represent butane

H

H

H

H

H

H

H

H

H

C

C

C

C

H

H

H

H

H

H

H

H

H

H

H

Full structure

Half skeleton structure

Skeleton structure

CH3-CH2-CH2-CH3 or CH3CH2CH2CH3 Condensed structure

C4H10 Molecular formula

B. Hydrocarbons ( only C and H )

3 main groups of hydrocarbons: alkanes, alkenes, alkynes.

Type 1. ALKANES

contain only single C-C bonds (also called saturated hydrocarbons) are divided into: linear, substituted, and cyclic alkanes types.

Definition: If an atom is saturated, it is bonded to the maximum number of other atoms (for C this is 4 other atoms, since the valence of C = 4)

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Chemistry 30

Organic Chemistry ? UNIT NOTES

a) NAMING LINEAR ALKANES

# of C

Prefix

Suffix

in chain

1

meth-

ane

2

eth-

ane

3

prop-

ane

4

but-

ane

5

pent-

ane

6

hex-

ane

7

hept-

ane

8

oct-

ane

9

non-

ane

10

dec-

ane

etc...

(notice; General formula = CnH2n+2)

ii) GEOMTERY:

Name

methane ethane propane butane pentane hexane heptane octane nonane decane

Molecular formula

CH4 C2H6 C3H8 C4H12 C5H12 C6H14 C7H16 C8H18 C9H20 C10H22

Mnemonic

Mark Eats Pizza But Penny Hates His Onion-breath Next day

On paper, bonds on carbon atoms are all at right angles BUT bond angles are actually = 109.5 ?.

The bonds are actually arranged in the shape of a 4 cornered pyramid. (tetra hedron) (4 sides)

eg) CH4

H

C H

H H

methane

= back arrow = forward arrow

b) SUBSTITUTED ALKANES These are alkanes with branches, and the branches are hydrocarbons themselves. To make a branch (alkyl group):

Alkane C2H6 ethane

Remove a Hydrogen

Branch form - C2H5 ethyl

alkyl group

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Chemistry 30 i) NAMING AND DRAWING:

Organic Chemistry ? UNIT NOTES

original alkane CH4 CH3CH3 CH3CH2CH3 CH3CH2CH2CH3

alkane name methane ethane propane butane

branch form ?CH3 ?CH2CH3 ?CH2CH2CH3 ?CH2CH2CH2CH3

branch name methyl ethyl propyl butyl

Molecule name:

1. Find the longest continuous carbon chain.

Steps

2. number the carbons in the chain, starting at end nearest to the branch/substitution and find the number where substitution is.

3. name the branch

4. put together the name as follows: (# of the substituted C) ? (branch name) (name

of longest chain)

always dashes between #'s and words

1. longest chain has __(9) carbons chain

name = (nonane)

eg) CH3?CH?CH2?CH2?CH2?CH2?CH3 CH2 CH2 CH3

Practice

2. substitution is at Carbon # (4)

3. Branch name = (methyl)

4. Name = (# of the substituted C) ? (branch name) ? (name of longest chain)

4-methylnonane

H31C H31C

H2 2C

3CH2

H

H2 H2

4C C

C

CH3

H25C

H2 6C

H2 7C

H2 8C

9CH3

H 2C

3CH2

H2 4C

H2 5C

H2 6C

7CH3

4-propylnonane 2-ethylheptane

H2C CH3

H31C

H2 2C

3CH2 4CH

CH3

4-methyloctane

5CH2

6CH2

H2 7C

8CH3

numbered and named. It should be numbered from the bottom.

Ex.2 is incorrectly ****3-Methyloctane

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Chemistry 30

Organic Chemistry ? UNIT NOTES

Notes:

If a molecule has multiple branches, list them in alphabetical order If an alkyl group is repeated:

- list each carbon number where the repeated group is attached separated by commas and... - prefix the repeated group name with di, tri, tetra, etc.. to show how many are attached.

Carbon can have only four bonds. Therefore this hydrogen cannot be part of this structure.

CH3

4-ethyl-2,2-dimethylheptane

CH3?CH?CH2?CH?CH2?CH2?CH3

CH3

CH2 CH3

Unit 5: Assignment 1 o P.361 #1, 4

o P.370 #7(a,b,f,g,h), 8, 9, 10(c,d), 11

ii) STUCTURAL ISOMERS:

- ALWAYS include both name & drawing

Compounds which have the same molecular formula but a different arrangement of atoms.

eg1) linear & branched C5H12

c) Type 2 . CYCLOALKANES These are hydrocarbon chains which connect "head-to-tail" (in a circle)

eg)

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