Question

Assume your starting with 10.324 grams of benzil for 1

IÓ _NH2 Ñ c HC CH "CH acid + 2 H2O HC ZCZ CH HC CH 2C 'N NH2 UI N quinoxaline 1,2-phenylenediamine glyoxal

1. Calculate the theoretical yield of your predicted product (2,3-diphenylquinoxaline)

2. Write the balanced overall equation of benzaldehyde to 2,3-diphenylquinoxaline. Combine the three equations of Benzaldehyde --> Benzoin, Benzoin --> Benzil, and Benzil --> 2,3-diphenylquinoxaline using structural representations

Answer 1

1)

Mass of Benzil = 10.324 g

Molar Mass of Benzil = 210.23 g/mol

Moles of Benzil = Mass/Molar Mass = (10.324 g) / (210.23 g/mol) = 0.049108 mol

Moles of 2,3-diphenylquinoxaline = Moles of Benzil = 0.049108 mol

Molar Mass of 2,3-diphenylquinoxaline = 282.3 g/mol

Mass of 2,3-diphenylquinoxaline = Moles * Molar Mass = (0.049108 mol) * (282.3 g/mol) = 13.863 g

2)

Balanced Reactions are given in the adjoining figure

a) Benzaldehyde to Benzoin

b) Benzoin to Benzil

c) Benzil with 1,2,phenylenediamine to 2,3-diphenylquinoxaline

d) Overall reaction

CN а) 2 Н20/EtOH Benzoin Benzaldehyde HNO3 +2H20 NO2 b) Benzil Benzoin с) +2H20 acid Benzil 1.2-phenylenediamine 2,3-diphenylquinoxaline : +3H20+NO2 CN H20/EtOH 2 d) ii) HNO3 iii) 1.2-phenylenediamine acid Benzaldehyde 2,3-diphenylquinoxaline