75. Salicylic acid, HOC6H4CO2H, and its derivatives have been used as pain relievers for a long time. Salicylic acid occurs in small amounts in the leaves, bark, and roots of some vegetation (most notably historically in the bark of the willow tree). Extracts of these plants have been used as medications for centuries. The acid was first isolated in the laboratory in 1838.
(a) Both functional groups of salicylic acid ionize in water, with Ka = 1.0 × 10−3 for the—CO2H group and 4.2 × 10−13 for the −OH group. What is the pH of a saturated solution of the acid (solubility = 1.8 g/L).
(b) Aspirin was discovered as a result of efforts to produce a derivative of salicylic acid that would not be irritating to the stomach lining. Aspirin is acetylsalicylic acid, CH3CO2C6H4CO2H. The −CO2H functional group is still present, but its acidity is reduced, Ka = 3.0 × 10−4. What is the pH of a solution of aspirin with the same concentration as a saturated solution of salicylic acid (See Part a).
75. Salicylic acid, HOC6H4CO2H, and its derivatives have been used as pain relievers for a long...
19. Salicylic acid, CeH,OHCOOH, is used in the manufacture of acetylsalicylic acid (aspirin) and methyl salicylate (wintergreen flavor). A saturated solution of salicylic acid contains 2.2 g of the acid per liter of solution and has a pH of 2.43. What is the value of Ka for salicylic acid?
1) Which reactant, salicylic acid or acetic anhydride, is in excess? Show your work. 2) If you were to use 3.17 g of starting material, how much product would you expect? Again, show your work. 3) Why is phosphoric acid added to the reaction? 4) A small amount of water is added at the end of the reaction to react with the excess acetic anhydride. Show a balanced equation for that reaction. 5) Explain the purpose of the FeCl3 test...
Pre-lab Questions: Importance A one-step preparation of aspirin from its precursor, salicylic acid, via an ester formation illustrates one of synthetic organic chemistry's most important uses, making the drugs that treat all types of illnesses. OH HOOH Background Aspirin is a prodrug of salicylic acid, the actual active drug. A compound related to salicylic acid, salicin, was first isolated from willow bark in the mid 1700's, but willow-bark extract was used by the ancient Greeks as a treatment for pain...
PREPARATION OF PHARMACEUTICALS - Fischer Esterification Reactions Q: Calculate the expected mass of both methyl salicylate and aspirin assuming 100% yield. EXPERIMENT7 PREPARATION OF PHARMACEUTICALS Fischer Esterification Reactions Almost 2500 years ago, physicians such as Hippocrates recommended that patients chew on the bark of the willow to alleviate pain. The active ingredient in willow bark was found to be salicin, a compound made of a molecule of salicyl alcohol bonded to a p-D-glucose molecule. In the stomach, the bond between...