EstersOne of many organic families

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What are Esters?

They are the product of the dehydration of an alcohol and a carboxylic acid. This process is called esterification. Water is also formed during these reactions

Alcohol + Carboxylic Acid = Ester + Water

What are Esters Cont ..

Esters are formed from carboxylic acids . Carboxylic acids contain -COOH groups, and in esters, the hydrogen in this groups are replaced by a hydrocarbon group, such as a methyl or an ethyl. They could also contain a benzene ring, such as phenyl.

http://www.hcc.mnscu.edu/chem/V.22/page_id_59629.html

What are Esters Cont ..

In the formation of esters, there must be an acid catalyst present. The catalyst is most often concentrated sulphuric acid but can also be dry hydrogen chloride gas.

Dry hydrogen chloride gas is not used as often as it tends to cause aromatic esters.

Naming EstersNaming esters is nearly the same as naming carboxylic acids.

In order to name the acid, you begin by counting up the total number of carbon atoms in the parent acid. You then change the suffix from -oic to -oate

Ex. CH3CH2COOH is propanoic acid

Therefore CH3CH2COO is the propanoate group

Ex CH3CH2COO is the propanoate group of the ester.

Naming Esters

Change the name of the alcohol to a suffix of -yl.

Ex. methyl, ethyl

The name of the alcohol precedes the name of the acid.

Ethyl EthanoateThe H in the -COOH group has been replaced by an ethyl group.

O CH3 - C Ethyl Ethanoate O C2H5

Examples

CH3COOC6H11

Hexane; hexylTwo carbons; ethanoate

hexyl ethanoate

C2H5COOCH3

Methane; MethylThree carbons;

propanoate

Methyl Propanoate

** Typically, when propanoate is used,

its given name is propionate.

Where are Esters found?

Esters often contribute to flavours of fruit and many of them have fragrant odours.

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Where are Esters found cont ...

Esters are also found in fats and oils.

These esters are quite complex.

The difference between fats and oils are that they have different mixtures of esters

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Where are Esters found?

Many Esters are produced naturally and can be derived from a variety of plants.

They can be used to enhance the flavour of food, and are also used in synthetic fragrances. http://survivalofthesickestthebook.com/blog/?p=39

http://boomeria.org/chemlectures/organic/organic2.html

Name that Ester!

For this game we will need to divide the class into two teams.

The way the game will work is that one at a time, the groups will get a chance to answer a skill testing question. Should they get it wrong, the other group will get the chance to steal.

Rules of the Game

Once the question is read, anyone in that group can have a chance to answer the question by standing up. If they do have the correct answer, their group will receive one point for everyone standing up. If they get it wrong, they will lose a point for everyone standing up. Also, the opposing team will have a chance to answer, with the same rules applying.

Rules of the game

Once someone has been chosen to answer, said individual must do so without aid from team-members and within a reasonable amount of time, or else they will lose the points for their team.