Assignment:
Q1. Show the product of the reaction of the Grignard you prepared with oxygen. This is a by-product of the preparation of a Grignard under normal atmosphere.
anhydrous
Bromobenzene + Mg ------------> phenylmagnesium bromide
Ether
H3O+
Q2) Phenylmagnesium bromide + methyl benzoate → triphenyl-C-O-MgBr ====→ Triphenylmethanol
“Mix 5g (.037mol) of methyl benzoate and 15 mL of absolute ether in a separatory funnel, cool the flask containing the phenylmagnesium bromide solution briefly in an ice bath, remove the drying tube, and insert the stem of a separatory funnel into the top of the condenser. Run in the methyl benzoate solution slowly with only such cooling as is required to control the midly exothermic reaction, which affords as intermediate salt that separates as a white solid. Replace the calcium chloride tube; swirl the flask until it is at room temperature and the reaction has subsided. The reaction is then completed by either refluxing the mixture for 30 min or stoppering the flask
with the calcium chloride tube and letting the mixture stand overnight.”
Draw the structure of the product that will form after about a day and remain in the reaction flask until the work-up procedure the following lab period.
Q3) Identify the product using IR and NMR spectra given.
Q4) Why in this work-up procedure is ordinary not anhydrous ether used for rinsing the reaction flask and to provide a satisfactory volume for extraction? (Using question 1 and 2 if necessary)
Q5) Sometimes iodine is necessary to initiate the Grignard reaction. What chemical is used to remove excess iodine. Write an equation for how it works. (Using equations for question 1 and 2)
Q6) What is the purpose of adding 10% H2SO4 to begin the work-up and recovery of triphenylmethanol? Illustrate your answer with an equation. (Use equations in question 1 and 2)
Q7) Show the product of the reaction of the Grignard reagent (in question 1) you prepared with formaldehyde, ethanal, cyclohexanone, and 2,3-dimethyloxirane.
Q8) Write a step-wise mechanism for the preparation of triphenylmethanol from diethylcarbonate (don’t do ethylbenzoate).
Q9) Show a mechanism to explain why your triphenylmethanol product turns red in sulfuric acid.
Provide complete and step by step solution for the question and show calculations and use formulas.