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Preparation of aspirin. It is prepared by the esterfication of the phenolic hydroxyl group of salicylic acid.

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Introduction

Preparation Of Aspirin Introduction Aspirin (acetylsalicylic acid) is an anti-inflammatory painkiller, which is extensively used, worldwide, for pain relief, to reduce inflammation and temperatures, and to reduce the risk of heart attacks and strokes. Uses of aspirin * Pain relief, particularly where there is inflammation involved, including dental pain and period pain (menorrhagia). * Reducing temperature (as an antipyretic). *Making the blood flow better through narrowed blood vessels. It is prepared by the esterfication of the phenolic hydroxyl group of salicylic acid. The structural formula for aspirin is: Its empirical formula is C9H8O4 Equation The equation for aspirin is: C7H603 + (CH3CO)20 C9H804 Method What I am going to do is * Weigh out 2.0g of 2-hydroxybenzoic acid and place in a 50-cm3 pear shaped flask. * Add 4-cm3 ethanoic anhydride to this. * Add 5 drops of 85% phosphoric acid and swirl to mix. Do this in a fume cupboard. ...read more.

Middle

To overcome this check the temperature before if it is not quite high enough the leave the substance in for more than 5 minutes. * When weighing the product at the end make sure you do not lean on the table as this will change the weight and the percentage yield will not be as accurate. * Some of the substances we are using may be harmful so handle them with care. * Impurities to over come this make sure all the apparatus are washed with deionised water to make sure there are no contaminants. * Apparatus error. Make sure the balance is accurate before weighing out the substances. * When drying the crystals the weight of the product can be affected because if it is not dried properly then the yield will be higher and it will not be pure aspirin. Apparatus The apparatus, which I used, were: * Hydroxybenzoic acid * Pear shaped flask * Ethanoic anhydride * Phosphoric acid * Boiling water * Condenser * ...read more.

Conclusion

=78 % Expected Conclusion The percentage yield I got was lower than expected I think this was because we may have lost some when: * Filtering the substance as it may have been stuck to the filter paper. * When we used the funnel maybe not all of the substance went through * When drying the substance some of it may have been stuck to the paper towel. The melting point I got was the same as the expected melting point; this shows that the substance was pure. This document was downloaded from Coursework.Info - The UK's Coursework Database - http://www.coursework.info/ This document was downloaded from Coursework.Info - The UK's Coursework Database - http://www.coursework.info/ This document was downloaded from Coursework.Info - The UK's Coursework Database - http://www.coursework.info/ Samina Ghafoor This document was downloaded from Coursework.Info - The UK's Coursework Database - http://www.coursework.info/ This document was downloaded from Coursework.Info - The UK's Coursework Database - http://www.coursework.info/ This document was downloaded from Coursework.Info - The UK's Coursework Database - http://www.coursework.info/ ...read more.

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