Question

3. Two students recrystallize crude methyl m-nitrobenzoate from ethanol instead of methanol. One has no problems and gets pure product mp 775-785°C. But for the other student, the product initially oils out instead of giving crystals. After a tremendous amount of work, she finally gets a low yield of crystals. However, the mp is 45-47 °C instead of 775-78. with ethanol and what product has the second student isolated? (Hint: see your lecture text book Chapter 21 section 6.) 5。c. what chemical reaction has taken place

Very stuck on this question so any help would be greatly appreciated! The chapter in the textbook discusses transesterification. Thank you!

Answer 1

For student 1 the compound recrystallized is methyl-m-nitrobenzoate m.p. 77.5-78.5 oC. However, for student 2, the compound recrystallized is an ethyl-m-nitrobenzoate, m.p. 45-47 oC ( for pure 41 oC). The methyl-m-nitrobenzoate has undergone a transesterification with ethanol to give an ethyl ester of m-nitrobenzoate under the recrystallization conditions.