1. THE HISTORY AND CHEMISTRY BEHIND ASPIRIN By Angela Pacheco

2. PROPERTIES OF ASPIRIN Antipyretic: reduces fever Analgesic: reduces pain Anti-inflammatory: reduces swelling

3. HISTORICAL PAIN RELIEF Some of the earliest pain relievers were parts of plants. For example: The ancient Greeks used bark from willow and poplar trees. Records show Hippocrates prescribing it around 400 BC. Native Americans made teas from the bark of the willow. In the mid-1700s, these teas were introduced to Europe by Reverend Edward Stone, who dried willow bark and ground it into a powder. In the 1800s, the active ingredient, salicylic acid, was identified. It began to be produced in large quantities and not just for pain relief. It was also used as a food preservative.

4. PROBLEMS WITH SALICYLIC ACID However, salicylic acid was hard on the body. Being highly acidic, it caused irritation to the mouth and digestive system. Various scientists began to experiment, trying to come up with a suitable alternative.

5. FELIX HOFFMAN, JR. A 25 year old chemist working in Bayer Laboratories in Germany in 1893, Felix Hoffman Jr had a personal interest in finding a replacement for salicylic acid. His father relied on the medicine to treat his arthritis, but suffered from the stomach discomfort it caused. Working after hours, Hoffman Jr synthesized acetylsalicylic acid. The Bayer company would patent the drug and call it Aspirin (a- for the acetyl group and the “sprin” for the group of plants that produce salicylic acid. In some countries, such as Canada, the name “aspirin” can only be used for the product sold by Bayer.

6. ASPIRIN = ACETYLSALICYLIC ACID Aspirin is formed by reacting salicylic acid with acetic anhydride. C 7 H 6 O 3 + C 4 H 6 O 3  C 9 H 8 O 4 + HC 2 H 3 O 2 Salicylic acid and acetic anhydride react to form acetylsalicylic acid and acetic acid.

7. PROBLEMS WITH ASPIRIN Though not as badly as its salicylic acid predecessor, aspiring still causes blood loss from the stomach. It interferes with the clotting of blood, which can be a good thing for some heart problems. This is one of the reasons why heart patients may take a “baby” aspirin every day. Because of the clotting problem, aspirin should not be taken prior to or immediately after surgery. Aspirin has been linked to “Reyes Syndrome” in children and young teens suffering from viral infections. Aspirin is toxic in large doses.

8. OUR ASPIRIN SYNTHESIS The reaction doesn’t occur quickly, so we will use sulfuric acid as a catalyst. This is the same reaction that aspirin companies use to make aspirin! Once we have created our aspirin, we will purify it with ice cold water. Aspirin is not soluble in cold water, but the impurities are. We will test our product with iron (III) chloride. Iron (III) chloride reacts with a phenol group (found in salicylic acid, but not in aspirin) to produce a colorful result. If your aspirin results look like that of the salicylic acid, then your aspirin is impure. We will also test for starch. Starch is added to aspirin power to help it form a tablet. In this way, aspirin serves as a “binder.” Iodine reacts with starch to form a blue or black color.