Lab Report 7

Experiment #7 Chigoziri Konkwo

4/5/16 Katie Crocker

Grignard Synthesis

Synopsis of Notes on Experimental Procedure

Synthesis of Methyl Benzoate

* 12.5 mL of methanol, 1.48 mL of sulfuric acid, and 5.02 g of benzoic acid were added to a 50 mL round-bottomed flask

* A small amount of benzoic acid precipitated upon the addition of sulfuric acid, but a clear solution reappeared

* Refluxing solution turned yellowish-brown, could have been from the stir bar

* Residue from the stir bar was not collected with the dichloromethane layer to avoid contamination

* Dichloromethane began to distill at 54oC, and about 0.6 mL of dichloromethane distilled out

* Ester began to distill at 187oC

* 3.48 g of ester distillate was obtained

* 0.07 g of unreacted benzoic acid was obtained from the acidified and recrystallized bicarbonate layer

Synthesis of Triphenylmethanol

* 0.50 g of magnesium turnings, 2.00 mL of bromobenzene, and 5.05 mL of ether were added to a 50 mL round-bottomed flask

* Solution turned cloudy after heating, then yellow-brown, then brown while bubbling more vigorously

* Some magnesium was still left in the flask before the addition of the methyl benzoate solution; 1.25 mL of methyl benzoate and 5.00 mL of ether was added

* Solution turned reddish-brown after addition of methyl benzoate; refluxing solution then turned reddish-orange, and a solid formed in the flask

* White residue was on every piece of glassware used

* 1.42 g of crude triphenylmethanol was obtained, was a yellow powder

* 15 mL of cyclohexane was used to recrystallize; no product was obtained after a second recrystallization

* 1.38 g of pure triphenylmethanol was obtained, was a white powder

Method of Purification

Synthesis of Methyl Benzoate

* The methyl benzoate was extracted by the addition of dichloromethane to the aqueous solution in the separatory funnel

* The methyl benzoate was dried...