Esters

By Cori and Shania

What Are Esters?

Esters are derivatives of carboxylic acids where the –OH of the carboxyl group has been replaced by an –OR from an alcohol. Esters also contain a carbonyl group and an ether link to the carbonyl carbon. (Wilbraham, 742)

(We will futher explain this during esterification… don’t worry!!!)

But first of all… Where are they found?

Naturally occurring • In fruit

• Animal fats (2Clark, 2)

• Vegetable oils (2Clark, 2)

• Flowers (Wilbraham, 742)

Other common household products that contain esters are…• Cosmetic (Marked, 1)

• Drinks and food (Choppin, 625)

• Artificial smell and flavouring (choppin 625)

• Soaps and Shampoos (Marked,1)

• Perfumes (Wilbraham, 742)(Thorne, 1) (Detergents,1

)(Romero, 1)

General structure for esters

c

OR’

R

Alkyl group (Alcohol)

Carbonyl group (Acid part)

Double bond between carbon and oxygen o

(Education,1)

(BBC, 1)

FYI: The R groups can be short-chain or long-

chain aliphatic alkyl or aromatic (aryl) groups or

saturated or non saturated.

(Wilbraham, 742)

Naming esters 101

These are the rules…• Two worded names

• Alkyl group R’ (alcohol) is the first part of the name

• Second word is adding OATE to the stem of the acid name.

(Richard 1)

• To name esters properly, their structural formula must be read backwards.

(Choppin 625)

Examples of naming…

C

O

O CH₂-CH₃CH₃

Ethyl ethanoate

CCH₂- CH₂-CH₃H

Propyl methanoate

CH₃CH₃-CH₂-CH₂

Methyl butanoate

CH₂- CH₂-CH₃CH₃

Propyl ethanoate

(CLARK,1)(2Clark,4)

Furthering your ester naming knowledge!

Ethyl benzoate

O

C

O CH₂-CH₃

(2015, 3)

C

O

O CH₂-CH₂-CH₃

Propyl benzoate

(TCI, 1)

OC

O

CH₃-CH₂-CH₂-CH₂

Cyclohexyl hexanoate

Esterfication synthesis

• To synthesize an ester, heat a carboxylic acid along with an alcohol or a phenol; an acid catalyst must be added as well. The oxygen of the alcohol adds to the carboxyl group, splitting out a molecule of water in the process.

• The reaction is reversible, meaning it often reaches an homeostasis state with a large amount of unreacted starting material still present.

(Seager, 23)

Esterification example

CH₃ C

O

OH

CH₃CH₂O HH+ CH₃ C

O

OCH₂CH₃

H₂O

Ethanoic acid EthanolEthyl ethanoate

Water

(Wilbraham, 743)

Properties of esters

Some properties of esters include…

• A fruity fragrance (Choppin 625)

• A boiling point of 77.1◦C (2Clark, 4)

• Small chained esters are soluble in water (polar)(2clark, 4)

• Larger chained esters are soluble in alcohol and are limited in term of solubility(choppin, 625)(Wilbraham, 742)

• Clear, colourless liquid (choppin, 625)

So you think you know esters?

• Take one of the netbooks provided to your group

• Close your notes, no cheating ;)

• Use the link provided below:

http://www.quizyourfriends.com/take-quiz.php?id=1509291831254319&lnk&

Rules…

Answer ten questions on esters, through multiple choice and true or false questions. Please raise your hand when you have completed the quiz; we will then come around and write down your mark. For participating, you will win an “estery” treat. Good luck!!!

Picture References.

Thorne, Alyssa. Carly Alyssa Thorne. WhatTypeofdecisionmakerareyou. 2015. Google image search. Web. 27 September 2015.

Unknown author. Detergents and soaps. Soaps&detergents-Ingredients. 2013. Google image search. Web. 27 September 2015.

Romero, Vanessa. Healthy Living How To. ReaderQ&A-WhatCosmeticsDoYouUse. 2013. Google image search. Web. 27 September 2015.

Unknown author. Mcat-review. OxygenContainingCoupounds-Alcohols. 2008. Google image search. Web. 27 September 2015.

Unknown author. BBC. Namingorganiccompounds. 2014. Google Search. Web. September 28 2015.

Information References

Richard, James. 3rd1000. IntroductiontoEsters. Revised 1998. Google search. Web. 24 September 2015.

Choppin, Gregory, et Al. Chemistry: Science of Matter, Energy, And Change. Silver Burdett Company, 1965. Print.

Unknown author. Education Scotland. Makingesters. Google search. Web. 24 September 2015.

Clark, Jim. Chem guide. IntroducingEsters. Google search. Web. 26 Sepember 2015.

Seager, Spencer. Chtf.Stuba.sk. CarboxylicAcidsandEsters. Google search. Web. 26 September 2015.

Unknown author. Marked by Teachers. WhatanEsteris,Howitismade,examplesofesters,animaltesingissues,andethics. 2013-2015. Google Search. Web. September 24 2015.

Clark, Jim. Chem Wiki. PropertiesofEsters. Google Search. Web. September 24 2015.

Wilbraham, Antony et Al. Prentice Hall Chemistry. Pearson Education Inc, 2008. Print.

Unknown author. 2012books.lardbucket. 15.6Esters:StructuresandNames. Google image search. Web. September 29 2015

Unknown author. TCI America. Propylbenzoate. Google image search. Web. September 29 2015.

Unknown author. Pubchem. Cyclohexylhexanoate. Google image search. Web. September 29 2015.