Zadanie 6b
Wzorowane na: Chemistry HL Paper 2, November 2023, TZ1, pytanie 6(b). Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Polecenie
Heating benzaldehyde with concentrated nitric and sulfuric acids nitrates the ring by the same type of reaction as in benzene. The acid mixture generates the electrophile NO2+, and the product is 3-nitrobenzaldehyde.
Explain the mechanism of this reaction of benzaldehyde with NO2+, using curly arrows to show the movement of electron pairs.
Sprawdź rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
curly arrow going from the delocalized electrons of the benzene ring to the nitrogen atom of NO2+ ✔
representation of the carbocation intermediate with the correct formula: the ring with H and NO2 on the same carbon atom, −CHO retained, and the positive charge delocalized over the ring ✔
curly arrow going from the C–H bond to the benzene ring «reforming the delocalized system» ✔
formation of 3-nitrobenzaldehyde AND H+ «accepted by HSO4−» ✔
Schemat punktowania
Maximum [3] if the nitro group is attached at any other ring position. Do not penalize if NO2+ is drawn as + NO2. Accept a curly arrow going to either the nitrogen atom or the positive charge on NO2+ in M1. In M2 accept different ways of showing the delocalized charge, and a mechanism with Kekulé structures.