Safety Precautions for Synthesis of Acetic Anhydride
Acetic anhydride is an irritant and also flammable, therefore gloves and goggles should be worn at all times during the experiment. It is reactive to water, so in the case of fire, alcohol foam or carbon dioxide is preferred to use as an extinguisher. This chemical has harmful fumes and use of a fume hood is strongly recommended.
Sulphuric and Salicylic Acid
These acids may irritate the skin in high concentrations. Take appropriate care to avoid contact.
Handle all hot equipments with caution and never leave the Bunsen burner flame unattended. The hot beakers and test tubes must be handled with care and should only be moved using tongs. Also, tie back long hair to prevent any accidental fire, and be familiar with the location of the fire extinguisher.
The synthesis of aspirin demonstrated here demonstrates several relevant suggestions that should be considered in the synthesis of a substance.
Firstly, the recrystallization of a product should be performed if possible and relevant. In most reactions, the amount of product exceeds the impurities. As a result, the crystals of the product should form first by virtue of greater volume. The remaining solution will be left with a greater concentration of impurities.
Secondly, melting point is a useful method of determining the purity of a product. When the theoretical melting range of a product is known, the melting range of a final product is usually narrower and closer to the theoretical melting range than the melting range of the crude product.
Finally for practical purposes, it is suggested that a beaker rather than a test tube be used in the synthesis of aspirin. Although a slanted test tube reduced the evaporation of reactants during the synthesis of aspirin, it was later found that the thin shape of the test tube made it difficult to seperate the product from the sides of the container using a...
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