Question

Exercises 1. (a) Calculate the volume of 6 M NaOH required to react completely with the amount of methyl salicylate you used. How much of the 6 M NaOH that you used was in excess of the theoretical amount? (b) What volume of 3 M H SO is needed to neutralize all of the disodium salicylate and the excess NaOH present after the initial reaction? How much sulfuric acid was in excess? 2. Refer to the reaction equations in the "Reactions and Properties" seca tion as you answer the following questions. (a) Which two hydrogen atoms of salicylic acid are most likely to be acidic? Which hydrogen atom(s) of methyl salicylate would you expect to be acidic? (b) Based on your answer to (a), draw the structure of the white solid that forms immediately after NaOH and methyl salicylate are combined, and write an equation for its formation. (Hint: Acid-base reactions are much faster than most organic reactions.) 3. (a) Write an equation for the overall reaction in this experiment, and use it to calculate the atom economy of the synthesis and your reaction efficiency. (b) Describe some green features of your synthesis, and any that aren't so green. 4. Based on the amount of water you used during the recrystallization, estimate the amount of salicylic acid that was lost as a result of being dissolved in the filtrate. Assume that the recrystallization solution was cooled to 10°C; the solubility of salicylic acid at that temperature is 0.14 g per 100 mL of water. 5. Describe and explain the possible effect on your results of the followin experimental errors or variations. (a) You added only enough 3 H SO, to bring the pH down to 4.(b) Your reaction mixture had an only layer on top when you added the 3 M sulfuric acid. (c) Because of label-reading error by a lab assistant, the bottle labeled "salicylic aci from benzene" actually contained acetylsalicylic acid (aspirin). 6. From the equations in the "Reactions and Properties" section, you see that methanol and sodium sulfate are by-products of the synthe of salicylic acid. During which step of the synthesis would these co pounds have been separated from the final product? Explain yo answer, based on any relevant properties of salicylic acid and by-products. (If necessary, you can look up the properties in a referen book.) 3M acid and the

question 2 and 6 thabk you

Answer 1

Salicylic acid - Phis two hydrogen is most acidic, among this the ® hydrogen (pka =5) is more acidic than ) (PR=16). This hydrogen atoon in methyl Salicylate is acidio in nature. Naot Sodinn ( White salicylate Solid errystal) - ос) А4 () - OH o H800 Lthou 04 8 + MgO, Methyl Salicylic acid Salicylaté Mechanisms 10 do who 07 ILour I groot 2 NaoH tions 2n ESO Nao long 5 - 1 Doub) -cthoH of Nasoy This is the sleg where Cholt CS Scanned with migrate. This släp Nansoy migrate. CamScanner

Here the methyl salicylate is the limiting . reactant in this syothesis sodinn hjaroxide is used in excess to ensure a resonably fast, complete reaction. The experiment is relatively green because the reactant and products are not highly toxic. . This is a base catalyzed hydrolysis reaction. Methyl salicylle & relas weak phenol and carboxaglic functional group that are imporfant in this experiment it has a minst like snell and reacts rapidly with Naolt. the nucleophilic attack by the oth in on the corobosyl h carbon, the Meat has been migrate and finally, the Na atoon replaced by the HS04 as a Nasou Scanned with CamScanner