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Grignard Synthesis of Triphenylmethanol 1. Give two reasons why anhydrous condit

ID: 551761 • Letter: G

Question

Grignard Synthesis of Triphenylmethanol 1. Give two reasons why anhydrous conditions must be maintained during a Grignard 2. After the reaction mixture is transferred to a separatory funnel, d aonoa synthesis. Write chemical reactions to explain. a. What substances (including solvent) make up the lower layer? b. What substances (including solvent) make up the upper layer? 3. The procedure (paragraphs 2 and 3) states that the additions of bromobenzene, methyl benzoate and hydrochloric acid must be done slowly. What might happen if any of these were done too rapidly? 4. Give equations that show how each of the following can be prepared by a Grignard synthesis: a. 1-phenyl-1-octanol b. 3-phenyl-1-octanol

Explanation / Answer

Q1

- anhydrous implies --> no humidity

this is mainly because:

water deprotonates Grignard reagent

R-MgX + H2O = R-H + Mg(OH)X

- Note that Mg(OH)X is also very reactive

so we need to take care to avoid this from reacting

Q2.

lower layer --> organic layer, i.e. most dense --> triphenylmethanol will be the most dense

aqueous layer is the upper layer

Q3

if we add this rapidly --> protonation will occurs fast

there will be not enough time for reaction, elmination reaciton could occur as well

Addition of HCl will increase drastically the temperature changes