Stir the mixture until the solid dissolves. Calculation Here limiting reagent is p-nitrobenzoic acid; hence yield should be calculated from its amount taken. The decreasing concentration of starting material paminobenzoic acid and increasing concentration of product benzocaine impedes the reaction from moving to the forward direction. Pour the reaction mixture along with the stir bar into a mL beaker containing 30 mL of ice water. Different from the technique of distillation, the fractions of mixture are not removed in the refluxing process. Attach a reflux condenser to the flask, secure the apparatus with clamps, and heat the mixture at a gentle reflux for minutes using a heating mantle and Variac power controller.
All of the significant peaks are present at Its impossible to run this reaction completely Although the refluxing process lasted about an hour, the refluxing process only extends the reaction time without proceeding the reaction. Mixture is cooled in ice and sulfuric acid 0. Allow to cool somewhat and decant the liquid into a 1-litre beaker; wash the residual tin by decantation with 15 ml of water, and add the washings to the contents of the beaker. The mechanism of this reaction is involved in several steps.
The use of traditional acidic catalyst such as sulfuric acid will cause side reactions and corrosion of equipment and require removal large amount of salt waste during neutralization of acid.
Its impossible to run this reaction completely Although the refluxing process lasted about an hour, the refluxing process only extends the reaction time without proceeding the reaction. The Fischer esterification is normally catalytic in acid, since the acid is regenerated in the mechanism. This can be accomplished by physical e. The two doublets, 7. The IR data is a good reference however for the presence of the product, benzocaine. The methyl protons appear as triplet at 1.
Rummel, A. But it does not show up in the IR spectrum.
Mixture is then refluxed for 70 minutes. Introduce 35 g 0. Gas evolution will be observed as the acid is neutralized; the final pH should be approximately 8.
Percutaneous Local Anesthesia. Final purified product was vacuum filtered and dried as a white crystalline solid mg; Copy the reaction and the reaction table below in your own writing into your notebook and complete all empty cells in the table. Pass dry hydrogen chloride through the alcohol until saturated; the increase in weight is about 20 g; remove the gas inlet tube, introduce 12 g 0. Edited by Ellis Horwood Limited in On the other hand, the benzocaine lacks the acidic protons and cannot be deprotonated by the base.
Add concentrated ammonia solution d 0. Figure 2: The mechanism walkthrough of the esterification of benzocaine. Volume 53 Issue2 Philip A.
If any acid gets onto your skin, wash with excessive water. IR spectra of Fluorescein on sigmaaldrich.
The - protons next to the ester group appear from4. Such applications are administered with the leprosy drug, chaulmoogra oil and even reducing the pain from needle injections 4 7. Related Interests.
Acidify the liquid to litmus with glacial acetic acid and evaporate on a water bath until crystals commence to separate; cool in ice, filter the crystals at the pump and dry in the steam oven.