Question

1. What is the theoretical yield + limiting/excess reagents for experiment? [Please show working so I can understand, thankyou!]


Reaction C Ullmann reaction Copper mediated C-N bond formation он 0.2 mmol Cu(OAc)2 0.4 mmol Ligand B 21 mmol 2,6-lutidine NH2 1.5 mmol 1 mmolair, rigorous stirring 2 mL Tol, room temp, 24 h Phenylboronic acid Benzyl amine N-Phenylbenzylamine or N-Benzylaniline

Phenylboronic acid; 183mg (1.5mmol)
Toulene; 2mls (0.5M of benzyl amine dissolved in toulene solution)
Cu(OAc)2; 0.2mmol
2,6-lutidine; 1mmol
Myristic acid (ligand B); 91mg (0.4mmol)

I really need to know how to go about the two questions, please show detail in your working out. Thankyou so much in advance.

Answer 1

0.2 mmol Cu(OAc)₂ is the catalyst. It is regenerated thus it can't be a limiting reagent. Myristic acid (ligand B); 91mg (0.4mmol) is the ligand which work in tandem with the metal catalyst. Therefore it is also not a limiting reagent.

Benzyl amine is the limiting reagent as it has the lowest number of moles = 1 mmol. 2,6-lutidine is also used at 1 mmol scale. It can also act as a limiting reagent.

Excess reagent : Phenylboronic acid; 183mg (1.5mmol)

Now from the equation in the question,

theoretically, 1 mmol benzyl amine would produce 1 mmol N-benzylaniline

Molar mass of N-benzylaniline = 183 g/mol

Therefore, 1 mmol or 10^-3 mol of N-benzylaniline = 183 x 10^-3 g = 0.183 g

Thus, the theoretical yield of N-benzylaniline = 0.183 g