#15 Synthesis of Ethyl Salicylate from Salicylic Acid

#15 Synthesis of Ethyl Salicylate from Salicylic Acid ____________________________________________________________ _______________ Purpose: Salicylic acid is converted to the liquid ethyl salicylate by addition of ethanol. Yields of salicylic acid (week 1) and ethyl salicylate will be found, as well as the overall yield of the 2-step conversion of acetyl salicylic acid to ethyl salicylate. Introduction: Esters are formed from the reaction of acids and alcohols: O O || || R-C-OH + HO-R’ → R-C-OR’ + H2O acid alcohol ester water The pleasant smelling oil of ethyl salicylate is made by reacting salicylic acid (week 1) with excess†¦show more content†¦Overall Yield for 2 steps (product of 2 yields above) : Questions: 1. Recalculate the overall yield for a three-step process including the 75% extraction. 2. The synthesis of a new drug may require as many as 30 steps, some of which produce much less than 90% yields. Comment on this (without doing any calculations). ____________________________________________________________ _______________5 Instructor’s Guide Ethyl Salicylate Part B: Melting Points Compound Measured Melting Point (ËšC) Literature Value (ËšC) Acetyl Salicylic Acid 134 134 - 135 Salicylic Acid 159 158 - 160 Yields: Assuming ASA (from extraction of 50 aspirin tablets) = 12 g SA (from hydrolysis of ASA) 7.3 g Reactant SA esterified: 7.0 g (usually most of the amount above) Approximate volume of ethyl salicylate: 3.0 mL (density ES = 1.1 g/mL) Mass ethyl salicylate 3.3 g Maximum g SA: 10 g ASA x 1 mol ASA x 1 mol SA x 138 g SA = 9.2 g SA 180 g ASA 1 mol ASA 1 mol SA Maximum g ES: 7.0 g SA x 1 mol SA x 1 mol ES x 166 g ES = 8.4 g ES 138 g SA 1 mol SA 1 mol ES Enter amounts where indicated in the table below and find the yields. Reaction Reactant → Product Mass Reactant (g) Mass Product (g) Maximum MassShow MoreRelatedSynthesis of Salicylic Acid and Potentiometric Determination of Its Purity and Dissociation Constant4209 Words   |  17 PagesSynthesis of Salicylic Acid and Potentiometric Determination of its Purity and Dissociation Constant ------------------------------------------------- Abstract The purpose of the study is to synthesize salicylic acid from the ester, methyl salicylate, and determine the acid’s dissociation constant and purity. The ester was converted to salicylic acid by base hydrolysis. The products were refluxed and recrystallized, to ensure maximum purity, and filtered, dried, and weighed. The melting point