Addition of distilled methyl benzoate (5 g) in anhydrous
diethyl ether (15 mL) to the Grignard reagent.
Figure 6.9
Cooling of the reaction mixture to control the exothermic
reaction.
Figure 6.10
Note the white solid of magnesium alkoxide intermediate
at the end of the reaction.
Figure 6.11
The reaction mixture is stored with a drying tube
containing calcium chloride until the next lab period.
Figure 6.12
Color of the reaction mixture after standing
overnight.
Figure 6.13
Reaction mixture work-up: acid hydrolysis of the
magnesium salt with 10% aqueous sulfuric acid (50 mL) and
ice (25 g). Additional diethyl ether (10 mL) is used to
rinse the round-bottom flask. Stir the reaction mixture
until bubbling stops.
Figure 6.14
Draining the aqueous lower layer from the ether layer.
The product is in the upper layer.
Figure 6.15
Why is the product in the upper layer?
The upper layer (ether) containing the product.
Figure 6.16
Addition of 10% aqueous sulfuruc acid (10 mL) to ensure
removal of magnesium salts by venting and shaking for about
a minute. Then the ether layer is washed with saturated
aqueous NaCl by shaking for another minute. Drain and
discard the lower layer
Figure 6.17
The ether layer is poured into an erlenmeyer flask
containing calcium chloride (5 g). Swirl the mixture;
calcium chloride absorbs the moisture in the ether layer as
observed by the clumping of the calcium chloride.
Figure 6.18
Removal of calcium chloride by gravity filtration using a
fluted filter paper.
Figure 6.19
To the yellow filtrate, add ligroin (25 mL) to
precipitate the product.
Figure 6.20
Use a boiling stick and concentrate the ether-ligroin
solution over the steam bath to accelerate
precipitation.
Figure 6.21
Cooling the mixture in an ice bath to complete
crystallization.
Figure 6.22
Vacuum filtration of the product. Use ligroin (50 mL) to
rinse the Erlenmeyer flask.
Figure 6.23
Collection of the triphenylmethanol product in the
Buchner funnel.
Figure 6.24
White crystalline product (triphenylmethanol).
Figure 6.25