The chemical name for the compound he discovered was called as acetylsalicylic acid, an ester of salicylic acid. It was patented by Bayer in 1899 and was for sale in the name of Aspirin. By federal law, each 5-grain aspirin tablet must contain 324mg of acetylsalicylic acid. Firm tablets are made by combining aspirin with binders like starch. .
2. Effects of Aspirin.
Aspirin has its own shortcomings though it has been used widely as an analgesic and antipyretic. Aspirin can cause serious stomach irritation in some people. This is the reason why aspirin should be taken with food. Aspirin tablets are also now coated with a substance known as icterus coating that is not affected by the acids in the stomach therefore making the tablet intact till it reaches the small intestine. Another way is to use buffering agents such as magnesium carbonate, to neutralize the acidic nature of the aspirin partially, thus lessening the stomach irritation. Recrystallisation is a procedure used to purify solids by removing impurities. It consists of dissolving the solid in a hot solvent, filtering the solution to remove impurities that are insoluble if there were to be, cooling the filtrate till the process is over, separating the crystals from its solution and drying of the crystals. Esterification is the process of combining an organic acid (RCOOH) with an alcohol (ROH) to form an ester (RCOOR) and water.
3. Theory.
Aspirin is a derivative of salicylic acid. The structural formula of salicylic acid is:.
Salicylic acid contains both a carboxylic group and a hydroxyl group bonded to the benzene ring. When a carboxylic acid such as salicylic acid reacts with an alcohol (or a phenol) in the presence of a strong acid, an ester is formed. The catalyst is usually concentrated sulfuric acid. Dry hydrogen chloride gas is used in some cases, but these tend to involve aromatic esters (ones containing a benzene ring). This process is known as esterification.