Alkenes, alcohols, carboxylic acids

Alkenes are a homologous series of unsaturated hydrocarbons – this means that their C atoms contain double bonds.

No. of
Carbons

Root Name

Formula
CnH2n

Structure

2

ethene

C2H4

CH2=CH2

3

propene

C3H6

CH2=CHCH3

4

1-butene

C4H8

CH2=CHCH2CH3

5

1-pentene

C5H10

CH2=CHCH2CH2CH3

Alkenes are also called OLEFINS because they form oily liquids on reaction with chlorine gas.

Ethene is the number one organic chemical synthesized in the US and the world. The small quantities of ethane, propane, and butane found in natural gas are converted into ethene.

It can be produced by thermal cracking  (heating at high pressure -7 atmospheres and high temperatures  – 800 degrees C- of ethane to produce ethene and a hydrogen molecule.

Alkenes are the raw materials for a number of plastics such as polyethylene, PVC, polypropylene, and polystyrene. See later.

Alcohols are compounds where a H atom is replaced by an OH group. They boil in general at higher temperatures to their corresponding alkane

Draw these out and name them.

CH3OH           CH3CH2OH           CH3CH2CH2OH

Carboxylic Acids, finally..

The parent chain must include the carboxyl carbon, (COOH) which, incidentally, is given position number 1. The name of the alkane attached is changed by replacing the -e with -oic acid.  They have  higher boiling points than the corresponding alkane.

You should be able to draw this one out CH3COOH – ethanoic acid (aka acetic acid, a weak acid and constituent of vinegar)

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s