Question

Preparation of Aspirin, Methyl Salicylate and Nylon Experiment #9 Pre-Lab Exercise Briefly describe the difference between an acid and an ester. Give an example of each. 2. Show the chemical reaction for the hydrolysis of the ester, ethyl acetate, indicating the two products of this reaction. 3. Describe what is meant by an amide, showing the structure of at least one example of a compound that is an amide. Be sure to give the correct name of the compound you have drawn. (Check your text book in chapter 18 on Amines and Amides).

Answer 1

Both carboxylic acids and esters contain a carbonyl group with a second oxygen atom bonded to the carbon atom in the carbonyl group by a single bond. In a carboxylic acid, the second oxygen atom also bonds to a hydrogen atom. In an ester, the second oxygen atom bonds to another carbon atom. The names for carboxylic acids and esters include prefixes that denote the lengths of the carbon chains in the molecules and are derived following nomenclature rules similar to those for inorganic acids and salts (see these examples):

H :0: H:0: н H-C-0-0-0-H H-C-0-0-H I-U-I H ethanoic acid (acetic acid) methyl ethanoate (methyl acetate)

We prepare carboxylic acids by the oxidation of aldehydes or alcohols whose –OH functional group is located on the carbon atom at the end of the chain of carbon atoms in the alcohol:

H I-0 R-C-0-H - > > R-C - :0: :ö-H R-C ::: carboxylic acid alcohol aldehyde

Esters are produced by the reaction of acids with alcohols. For example, the ester ethyl acetate, CH₃CO₂CH₂CH₃, is formed when acetic acid reacts with ethanol:

2)

Esters are neutral compounds, unlike the acids from which they are formed. In typical reactions, the alkoxy (OR′) group of an ester is replaced by another group. One such reaction is hydrolysis, literally “splitting with water.” The hydrolysis of esters is catalyzed by either an acid or a base.

Acidic hydrolysis is simply the reverse of esterification. The ester is heated with a large excess of water containing a strong-acid catalyst. Like esterification, the reaction is reversible and does not go to completion.

H+ R—C— OR + H20 - R—C—OH + ROH A carboxylic acid An alcohol An ester Water

As a specific example, butyl acetate and water react to form acetic acid and 1-butanol. The reaction is reversible and does not go to completion.

H + CH,COCH CHỊCH, + H2O = CHỮc–OH + CHỊCH,CH, CH OH Butyl acetate Water Acetic acid 1-Butanol (butyl alcohol)

3)

Amides are functional groups in which a carbonyl carbon atom is linked by a single bond to a nitrogen atom and either a hydrogen or a carbon atom.

Acetamide is an organic compound with the formula CH₃CONH₂. It is the simplest amide derived from acetic acid. It finds some use as a plasticizer and as an industrial solvent. The related compound N, N-dimethylacetamide is more widely used, but it is not prepared from acetamide.

Formula: C₂H₅NO

H3C^NH2

4)ASPIRIN

Aspirin is used to reduce fever and relieve mild to moderate pain from conditions such as muscle aches, toothaches, common cold, and headaches. ... Doing so can release all of the drug at once, increasing the risk of side effects

5)METHYLSALICYLATE

Methyl salicylate is a benzoate ester that is the methylester of salicylic acid. It has a role as a flavouring agent, a metabolite and an insect attractant. It is a benzoate ester and a member of salicylates. It derives from a salicylic acid.