Synthesis of Methyl Salicylate Fuentes, C.K.A ,Gales, B.T.B , Gepulango, E.P.A. ,Hernandez, M.R., Lantion, E.A.S. University of Santo Tomas: Faculty of Pharmacy Group 4 3F Pharmacy Pharmaceutical Pharmaceutical Chemistry 2 Laboratory
ABSTRACT Methyl Salicylate was synthesized through esterification of salicylic acid with methanol in the presence of sulfuric acid, H2SO4, which serves as dehydrating agent. Heat was involved in the esterification process until a mint odor was obtained. The purpose of this experiment was to synthesize methyl salicylate from salicylic acid and to illustrates the properties of organic synthesis
INTRODUCTION Salicylic acid is a phenolic acid, indicating it has two functional groups on the benzene ring, an -OH group and a -COOH group whil e Carboxylic acids react with alcohols in the presence of an acid catalyst to produce esters. Esters are classes of organic compounds with strong, pleasant smell and taste. They compromise an acid, in which hydroxyl groups are replaced by an alkoxy group. They are usually produced through a condensation reaction of an alcohol and a carboxylic acid, in a presence of a strong acid catalyst.
Figure 1 Figure 1. This reaction shows esterification, since the product of the reaction is an ester, a compound containing the CO2R group Fischer esterification is when a carboxylic acid reacts with excess alcohol and a strong acid to produce an ester. The reaction is reversible, but the production of ester is favored with a l arge presence of alcohol. This mechanism is a common method used to produce esters and is essential in processes such as wine agi ng. During wine aging, the organic acids and ethanol in wine undergo Fischer Esterification to create esters that contribute to the final aroma and taste of t he wine.
In this reaction, the reactants undergo a transesterification which is when an ester reacts with an alcohol to form a new ester. Transesterification Transesterification is a crucial mechanism in the formation of various products such as biodiesel fuels which is an alternative alternative fuel source. source. Animal fat or vegetable oil contains triglyceride, an ester, which undergo transesterification to form glycerol, the by-product, and methyl ester. Methyl salicylate is an organic ester easily recognized by its odor and is known as oil of wintergreen and involves a reaction of the -COOH group of salicylic acid. It can be used commercially as an antipyretic, an analgesic, or as a non-steroidal anti-inflammatory anti-inflammatory drug (NSAID). Methyl salicylate has a pale yellow color and produces a mint odor ; thus, it can also be used as a fragrance for liniments, as well as a flavouring agent for chewing gums and mints. Methyl salicylate can be produced through esterification of salicylic acid with methanol in the presence of an acid catalyst, particularly sulfuric acid, providing a large amount of Hydrogen ions and speeding up the rate of reaction.
EXPERIMENTAL A. Materials Hard glass test tubes, 10-mL graduated cylinder, dropping pipette, stirring rod, thermometer Compounds tested(or samples used) Salicylic acid, Methyl alcohol, Sulphuric acid B. Procedure In a hard glass test tube, 5ml of methyl alcohol was added to a 1 gram of salicylic acid. 3 drops of concentrated sulphuric acid was added and then it was stirred until salicylic dissolved. The hard glass test tube was placed on a water bath
that was maintained at 70˚C for 15 minutes until a mint odor was observed.
http://www.roanoke.edu/Chemistry/CSteechler/c hem_112/aspirin_experiment.PDF http://safegardmedical.ca/Methyl%20Salicylate.p hp
RESULTS AND DISCUSSION When salicylic acid reacts with methanol in the presence of an acid catalyst, methyl salicylate, or oil of wintergreen, is produced according to the following equation:
Figure 2 Figure 2. Illustrates the formation of methyl salicylate by the acid catalysed reaction of salicylic acid with methanol. Methyl salicylate produces a minty odor after it was placed in a water bath for 15 mi nutes. It is a liquid at room temperature (mp = -9°C) and i s relatively insoluble in water. It is al so quite toxic (average lethal dose for adults is 30 mL). Ester chemistry is of great importance in the organic chemistry field. Methyl salicylate or evergreen oil is a component in many products because of its pleasant fragrances. Moreover, Transesterification and Fischer Esterification are crucial in the synthesis of some vital chemicals.
REFERENCE http://www.biologie.uni-hamburg.de/bonline/library/newton/Chy251_253/Lectures/Acyl Substitution/AcylSubstitution.html http://myweb.brooklyn.liu.edu/lawrence/che4x/e 6aspirin.pdf htpp://www.nhs.uk/medicineguides/pages/MedicineOverview.aspx?medicine= Methyl%20salicylate/Menthol/Camphor http://otcsafety.org/en/ingredients/methylsalicylate/
