Esters

1. Esters Formal Lab

2. Chemistry Joke Q: Why is uranium my favorite element? A: Because I love U!!

3. What are Esters? • Esters belong to a group of organic compounds called carbonyl compounds. • A carbonyl compound contains a C double-bonded to an O (C=O). • Esters have characteristic odors associated with flavoring and scents. • We will be synthesizing esters having the specific odors of banana, wintergreen, pineapple, apple, and orange.

4. Formula of an Ester • The general formula is • R and R’ are symbols used to designate alkyl groups. The methyl and ethyl groups are examples.

5. How are Esters Synthesized? • Esters are prepared from the condensation (removal of water) of a carboxylic acid and an alcohol. • A strong acid, such as sulfuric, is used as a catalyst.

6. Example • Notice that the acid is drawn with the OH on the left to show that it combines with the H of the alcohol to form water.

7. Naming an Ester Alkyl Designation • 1 C: meth- • 2 C: eth- • 3 C: prop- • 4 C: but- • 5 C: pent- • 6 C: hex- • 7 C: hept- • 8 C: oct- • 1. Remove the –anolsuffix from the name of the alcohol and change it to the corresponding alkyl designation. • Ethanol becomes ethyl • Propanol becomes propyl • 2. Remove the –ic acid suffix and replace it with –ate. • Ethanoic acid becomes ethanoate • Propanoic acid becomes propanoate

8. Naming an Ester • So, the ester formed from condensing methanol and propanoic acid would be called methyl propanoate. • Some organic compounds have common names that are used instead of their IUPAC system name in the same way that H2O is not dihydrogen monoxide, but water.

9. Chemistry Joke I asked my Spanish teacher if silicon had the same name in Spanish??? She said… “Si!”