Org. Synth. 1943, 23, 98
Submitted by W. E. Bachmann and H. P. Hetzner.
Checked by R. L. Shriner and P. L. Southwick.
In a 2-l. three-necked flask
, fitted with a separatory funnel
, a reflux condenser
, and a mercury-sealed stirrer
, 27 g. (1.1 gram atoms) of magnesium
, 181 g. (122 ml., 1.15 moles) of bromobenzene
, and a total of 450 ml. of anhydrous ether (Note 1)
are converted into phenylmagnesium bromide
by the procedure described in Org. Syntheses Coll. Vol. 1, 226 (1941)
. Calcium chloride tubes
are used to prevent the entrance of moisture through the condenser and the separatory funnel
during the addition. In order to dissolve all the magnesium
it may be necessary, in some instances, to continue stirring for longer than the prescribed 10 minutes after addition is complete.
To the Grignard solution, 75 g. (71.5 ml., 0.5 mole) of ethyl benzoate in 200 ml. of dry benzene (Note 2) is added at such a rate that the mixture refluxes gently. The flask is cooled in a pan of cold water during the addition, which requires about an hour. After the addition is complete, the mixture is refluxed for an hour on a steam bath. The reaction mixture is cooled in cooled an ice-salt bath and then poured slowly, with constant stirring, into a mixture of 1.5 kg. of cracked ice and 50 ml. of concentrated sulfuric acid. The mixture is stirred at intervals until all the solid that separates at the benzene-water interface has dissolved. If necessary, 50 g. of ammonium chloride is added to facilitate the decomposition of the magnesium salt, and additional benzene may be added if the amount present is insufficient to dissolve all the product. When the solids have disappeared, the benzene layer is separated and washed, successively, with 200 ml. of water, 200 ml. of a 5% solution of sodium bicarbonate, and finally with 200 ml. of water. The solvents are removed as completely as possible by distillation on a steam bath, and the remaining solution or solid mass is steam-distilled to remove biphenyl and unchanged bromobenzene. The product is filtered, washed with water, and dried. The crude triphenylcarbinol, which weighs 120–125 g., is recrystallized from carbon tetrachloride (4 ml. of solvent per gram of solid). The weight of the first crop of colorless triphenylcarbinol is 110–115 g. (Note 3). A second crop may be obtained by heating the filtrate with a gram of Norit, then concentrating to about 125 ml. and cooling the solution. The total yield of triphenylcarbinol melting at 161–162° is 116–121 g. (89–93%) (Note 4).
Commercial anhydrous ether
, before it is used, should be dried over slices of sodium
, and the bromobenzene
should be dried by distillation.
may be dried over anhydrous magnesium sulfate
separates from carbon tetrachloride
with solvent of crystallization. The solvent is readily lost on exposure of the crystals to air. The weight mentioned is that of the solvent-free product.
Practically the same yield of triphenylcarbinol
was obtained from benzophenone
and phenylmagnesium bromide
; in this reaction only one-half as much Grignard reagent is required as that needed for the reaction with ethyl benzoate
. To the cooled Grignard reagent prepared from 13.5 g. (0.55 gram atom) of magnesium
, was added a solution of 91 g. (0.5 mole) of benzophenone
in 200 ml. of dry benzene
at such a rate that the mixture refluxes gently. After the mixture had been refluxed for 1 hour, the isolation of the triphenylcarbinol
was carried out in the manner described above.
has been obtained by the reaction between phenylmagnesium bromide
,1 methyl benzoate
or ethyl or butyl pyrocarbonate
by action of phenylsodium
, benzoyl chloride
, ethyl chlorocarbonate
, or ethyl benzoate
by hydrolysis of triphenylchloromethane
and by oxidation of triphenylmethane
This preparation is referenced from:
Chemical Abstracts Nomenclature (Collective Index Number);
ethyl or butyl pyrocarbonate
sulfuric acid (7664-93-9)
ammonium chloride (12125-02-9)
sodium bicarbonate (144-55-8)
carbon tetrachloride (56-23-5)
benzoyl chloride (98-88-4)
ethyl benzoate (93-89-0)
Phenylmagnesium bromide (100-58-3)
methyl benzoate (93-58-3)
ethyl chlorocarbonate (541-41-3)
Carbinol, triphenyl- (76-84-6)
magnesium sulfate (7487-88-9)
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