experiments. Expt.1. Acetylation of α-D-glucopyranose Add slowly 2.5 g (0.014 mol) of powdered D-glucose in small portions (roughly in 7-10 portions and 5 min for each addition) into a preheated solution of ZnCl2 (0.5 g anhydrous ZnCl2 in 12.5 ml acetic anhydride‚ this will be provided by lab. technician) in a 50 ml pear shape flask (heat in water bath for 10-15 min before addition start). The flask is attached with an air condenser. Swirl the mixture gently during the addition to control the vigorous
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Sypnopsis In this experiment‚ acetylsalicylic acid was synthesized from the acidification of salicylic acid and acetic anhydride. The objective was to convert a specific amount of salicylic acid into the same amount of aspirin that was high in purity. Furthermore‚ the other objectives were to enable students to conduct the synthesis of aspirin‚ reinforce skills or recrystallisation and the technique of melting point determination. The amount of each compound should be the same because there is
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Preparation and Recrystallisation of Aspirin Contents Page Synopsis iii 1 Introduction 1 1.1 Objective 1 1.2 Background 1 2 Theory 1 3 Procedure 2 3.1 Materials 2 3.2 Preparation 2 3.3 Recrystallisation 3 3.4 Determination of Melting Point 3 4 Results and Calculation 4 4.1 Mass 4 4.2 Percent yield 4 4.3 Melting Point 4 4.4 Appearance 4 5 Discussion 5
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filtering the chilled reaction solution. Purification is essential to remove any unreacted salicylic acid and acetic anhydride as well as the acetic acid product and phosphoric acid. Acetic anhydride is caused to decompose by the addition of water once the formation of aspirin is complete. C4H6O3 (Acetic anhydride) + H2O (Water) -------------------------> 2C2H4O2 (Acetic Acid) The acetic acid and phosphoric acid are water soluble and it is removed by washing the aspirin with chilled water
Free Solubility Chemical substance Oxygen
presence of acetic anhydride‚ acetylsalicylic acid (aspirin or ASA) is formed. Correspondingly‚ an excess of methanol will form methyl salicylate‚ which is also an analgesic. In this experiment‚ we shall use the former reaction to prepare aspirin. Salicylic acid will not react significantly with acetic acid to produce aspirin. Acetic acid anhydride‚ however‚ is more reactive than acetic acid because the acetoxy group (-O2CCH3) is a much better leaving group than the OH- of acetic acid.
Free Aspirin Acetic acid Carboxylic acid
Molar Mass: 138.12 g/mol Melting Point: 1590C Boiling Point: 2110C Density: 1.44 g/cm3 Mildly irritating (pulmonary irritants). Harmful by inhalation‚ ingestion and through skin absorption. Acetic Anhydride Starting‚ Material‚ serves also as the solvent colorless liquid with a smell of acetic acid Molar Mass: 102.09 g/mol Melting Point: -73.1 0C Boiling Point: 139.8 0C Density: 1.082g/cm3 Corrosive Flammable and Lachrymator which makes eyes teary. It is poisonous and will cause
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that on August 10‚ 1897 Felix Hoffmann‚ a German chemist who obtained his PhD with Adolf von Baeyer (see below) and working at "Farbenfabriken vorm. Friedr. Bayer & Co." made a discovery of historic significance. By acetylating salicylic acid with acetic acid‚ he succeeded in creating acetylsalicylic acid (ASA) in a chemically pure and stable form. Esterifying the salicylic acid to aspirin reduces the irritation of the stomach lining. The company developed a cost-effective production process that
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acid‚ was synthesized from salicylic acid and acetic anhydride. In the reaction the hydroxyl group on the benzene ring in salicylic acid reacted with acetic anhydride to form an ester functional group. This method of forming acetylsalicylic acid is an esterification reaction. Since this esterification reaction is not spontaneous‚ sulfuric acid was used as a catalyst to initiate the reaction. After the reaction was complete some unreacted acetic anhydride and salicylic acid was still be present in the
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Acetylsalicylic Acid Introduction: The purpose of this experiment is to create and isolate pure acetylsalicylic acid from the substances salicylic acid and acetic anhydride. Then one will find the melting point to determine purity. Procedure: Make a hot bath. Weigh some salicylic acid and place in conical vial. Add .480mL of acetic anhydride and a drop of concentrated phosphoric acid. Drop in a magnetic spin vane and attach air condenser to vial. Partially submerge it in hot water. Stir with
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6‚ 2014 Introduction Acetaminophen‚ also commonly known as Tylenol‚ is an over-the-counter medicine used to relieve pain and reduce fevers. Within this experiment‚ Acetaminophen will be formed through the reaction between p-aminophenol and acetic anhydride. This reaction will incur Acetaminophen as a crude solid being impure‚ which will be purified further through the use of a recrystallization technique. The purification process involves dissolving a solid and recrystallizing as a crystal solid
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