Grignard Lab Statement

Grignard Reaction: Activity of Triphenylmethanol

Hai Liu

TA: Ara Austin

Monday: 11: 30-2: 20

Abstract:

In this test, phenylmagnesium bromide, a Grignard reagent was synthesized from bromobenzene and magnesium pieces in a diethyl ether solvent. The Grignard reagent was then converted to triphenylmethanol, a tertiary alcoholic beverages with HCl. The reaction intended for phenylmagnesium bromide was:

The response for Grignard to triphenylmethanol was:

Inside the formation from the Grignard reagent, the limited reagent, magnesium was identified and 0. 00617mol was calculated. In the second area of the experiment, a yield of 99. 85% was acquired for triphenylmethanol. A melting point of 160-162В°C was also determined. Additionally a great IR pertaining to triphenylmethanol was taken, and the major peaks were present. A broad top at ~3400 cm- suggested an alcohol group present. A optimum at ~3100 cm- suggesting a C-H bonds inside the benzene diamond ring. A top at ~1400-1500 cm- indicating a C=C bonds inside the ring. Intro:

In the initial part of the try things out, phenylmagnesium bromide (a Grignard reagent) was prepared via reacting magnesium (mg) strips with aqueous bromobenzene in diethyl ether. The response is illustrated below:

The Grignard reagent formed may then behave as basics or a nucleophile due to the partial charge involving the carbanion plus the alkyl group. The carbanion from the phenylmagnesium bromide work as a nucleophile and under go nucleophillic addition reaction with the carbonyl selection of the benzophenone forming an adduct. The adduct act as a strong base and protonate the wasserstoffion (positiv) (fachsprachlich) from HCl with present of ether forming triphenylmethanol (a tertiary alcohol) The reaction is illustrated below:

In the presence of warmth during refluxing the Grignard reagent, biphenyl impurity is created and can be isolated with petroleum ether simply by extraction. The merchandise can then be further more purified through recrystallization method using popular isopropyl alcoholic beverages. This is then cooled to room...