Experiment III-DETERMINATION OF ACTIVATION ENERGY & A REACTION RATE CONSTANT

Experiment III-DETERMINATION OF ACTIVATION ENERGY & A REACTION RATE CONSTANT                                  see experiment report ......                                                                                                                                                                                                            Percobaan III-penentuan energi aktivasi dan tetepan laju reaksi                               laporan praktikum selengkapnya ......... 

ACETYLSALICYLIC ACID/ASPIRIN

Experiment VII

ACETYLSALICYLIC ACID (Aspirin)

This experiment illustrates a very useful method of acetylating phenols: the phenolic substance is suspended in acetic anhydride and a small quantity of concentrated sulfuric acid is added to serve as a catalyst. The strong mineral acid is very effective in accelerating the reaction and frequently no external heating is required. Certain basic substances may also be employed as catalysts, the commonest ones being fused sodium acetate and pyridine (a tertiary amine). It should be observed that phenols (unlike amines) cannot be acetylated satisfactorily in aqueous solution; the hydroxyl group of a phenol is not attacked much more rapidly by acetic anhydride than is the hydroxyl group of water, with which the phenol would be competing.

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