Question

Calculate the theoretical yield of this Williamson Ether Synthesis:

Materials:

25 mL Erlenmeyer flask with stir bar

0.8 mL (0.83g) p-cresol

0.7 mL 1-bromopropane

50 mg (0.05g) t-butyl ammonium bromide

-Add all reagents at room temperature, reflux ~1hr at a 3 setting on a hotplate, cool to room temperature

Workup:

- add 5 mL diethyl ether

-etc.

-etc.

-etc....

Answer 1

Mass of p-cresol = 0.83 g

Molar mass of p-cresol = 108.13 g/mol

Therefore moles of p-cresol = mass of p-cresol/molar mass of p-cresol = 0.83/108.13 = 0.0077 mol

Volume of 1-bromoprpane = 0.7 mL

Density of 1-bromopropane = 1.35 g/mL

Therefore mass of 1-bromopropane = volume of 1-bromopropane x density of 1-bromopropane

                                                          = 0.7 x 1.35

                                                          = 0.945 g

Molar mass of 1-bromopropane = 123 g/mol

Therefore moles of 1-bromopropane = 0.945/123 = 0.0077 mol

Moles of both of the reactants are same.

From the above equation, it is clear that theoretically 1 mol of each reactant will produce 1 mol of product.

Therefore, 0.0077 mol of each reactant will produce 0.0077 mol of product.

Molar mass of the product = 150.22 g/mol

Therefore, the theoretical yield of the product = 150.22 x 0.0077 = 1.16 g.