Donald Yeargin
CH 222, Section 24221
Department of Chemistry
Portland Community College
Portland, OR
Abstract The various methods available to synthesize aspirin lead to the need to examine and evaluate production efficiency and purity. The purpose of our experiment was to synthesize acetyl salicylic acid (aspirin) and then determine the relative purity of the synthesized sample by observing the melting point temperature range. The procedure performed in our experiment involved chemically reacting salicylic acid and acetic anhydride in order to form acetyl salicylic acid. The limiting reactant in this chemical reaction was salicylic acid, with acetic anhydride present in excess in order to react with any water produced during the reaction of the reactants, and thus improve the yield of aspirin. The addition of a catalyst, 85% phosphoric acid, facilitated an increase in the reaction rate during the initial synthesis process. Once synthesized, the crude aspirin was recrystallized in order to attain a sample with a higher level of purity. The percent yield of our crude and recrystallized aspirin samples was 77.81% and 53.81%, respectively. By obtaining the percent yield of our synthesis process we were able to infer some conclusions regarding the efficiency of the techniques performed. The melting point temperature ranges were 126oC-132oC and 129oC-134oC for the crude and recrystallized aspirin samples, respectively. Determining the relative percent yield and attained purities of different synthesis processes is vital to the viability of an affordable commercial product for the aspirin market.
Introduction The objective of this experiment was to synthesize acetyl salicylic acid (aspirin) from salicylic acid and acetic anhydride and then determine the purity of the samples from the observed melting point temperature ranges and the efficiency of the techniques performed from the
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