![]() ![]() ![]() Test a small amount of the product for the presence of unreacted salicylic acid using the ferric chloride solution. Air dry the crystals and transfer them to a watch glass to dry. Remove all the liquid from the crystals by pressing with a clean stopper or cork. Filter the solid by suction and wash the crystals 3X with 5 mL of cold water each.Make sure that the resulting solution is acidic (blue litmus paper) and that the aspirin has completely precipitated out. HCl in 10 mL of water) in a 150-mL beaker and cool the mixture in an ice bath. Carefully pour the filtrate with stirring, a small amount at a time, into an ice cold HCl solution ( ca 3.5 mL of conc.Wash the beaker and the funnel with 5 to 10 mL of water. Filter the solution through a Buchner funnel to remove any insoluble impurities or polymers that may have been formed.Stir the crude solid with 25 mL of a saturated aqueous sodium bicarbonate solution in a 150 mL beaker until all signs of reaction have ceased (evolution of \(CO_2\) ceases).Record the weight of the crude solid which probably contains water. Test this crude product for the presence of unreacted salicylic acid using the ferric chloride test. Rinse the crystals several times with small portions (5 mL) of cold water and air dry the crystals on a Buchner funnel by suction until the crystals appear to be free of solvent.You can use some of the filtrate to rinse the Erlenmeyer flask if necessary. Vacuum filter the product using a Buchner funnel.Do not add the water until crystal formation is complete. Add 50 mL of water and cool the mixture in an ice bath.The product will appear as a solid mass when crystallization is completed. Cool the mixture slightly in an ice bath until crystallization is completed. If acetylsalicylic acid does not begin to crystallize out, scratch the walls of the flask with a glass rod. Allow the flask to cool to room temperature.Heat the flask gently on the steam bath for at least 10 minutes.H 2SO 4 ( use a dropper, H 2SO 4 is highly corrosive) and swirl the flask gently until the salicylic acid dissolves. Add 5 mL (0.05 mole) of acetic anhydride, followed by 5 drops of conc.Place 2.0 g (0.015 mole) of salicylic acid in a 125-mL Erlenmeyer flask.SYNTHESIS OF ASPIRIN (acetylsalicylic acid) ![]() The Merck Index, which is an encyclopedia of chemicals, drugs and biologicals, lists the following information under aspirin: acetylsalicylic acid monoclinic tablets or needle-like crystals mp 135 ☌ (rapid heating) is odorless, but in moist air it is gradually hydrolyzed into salicylic and acetic acids one gram dissolves in 300 mL of water at 25 ☌, in 100 mL of water at 37 ☌, in 5 mL alcohol, in 17 mL chloroform. One popular drug that does both is aspirin. During this semester, you will have an opportunity to isolate some pharmacologically active natural products and to synthesize other active compounds from suitable starting materials.Īnalgesics are compounds used to reduce pain, antipyretics are compounds used to reduce fever. In addition, various transformations of these and other compounds have led to even more medically useful compounds. These natural products have been obtained from plants, minerals, and animals. Over history, many compounds obtained from nature have been used to cure ills or to produce an effect in humans. ![]()
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