Carbene Addition Lab

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Synthesis of 7, 7- dichloronorcarane in Carbon Addition Reaction CHM 337 | Dr. Pettit

Abstract:
A solution of cyclohexene, aqueous sodium hydroxide, and benzyltriethylammonium was used to synthesize 7,7 – dichloronorcarane by the following reaction:
+ CHCl3 + OH - H2O + + Cl -
After completion of the experiment, the percent recovery was calculated to be 46.21%

Introduction
The purpose of this experiment was to form 7,7-dichloronorcarane by means of carbene trapping. Cyclohexene, aqueous sodium hydroxide, and benzyltriethylammonium chloride were used to synthesize 7,7 – dichloronorcarane by the following reaction:

+ CHCl3 + OH- H2O + + Cl-
In order to carry out this reaction in reasonable time, a two phase reaction was used, avoiding the lengthy requirements to carry out the experiment as a single phase reaction, as well as the risk of undesirable products due to the presence of water. The components of the two stage reaction were as follows: An organic phase containing the alkene and CHCl2; and an aqueous phase containing the base OH –. Since the reactants, CHCl2 and OH – would separate into different phases, benzyltriethylammonium chloride was added as a phase-transfer catalyst. Because the benzyltriethylammonium chloride has both hydrophilic and hydrophobic properties, it could cross the phase boundary and facilitated the transport of the hydroxide ion from the aqueous phase to the organic phase.

Expected spectral changes in IR and 13C-NMR
Procedure
To begin, 0.324g of cyclohexene was mixed with 1 ml of 50% aqueous sodium hydroxide, 1ml of chloroform and 0.040g of the phase transfer catalyst benzyltriethylammonium chloride. The reaction was stirred and heated at 40 degrees Celsius for an hour before extracting the 7,7 dichloronorcarane through 2 methyl chloride extraction processes (1ml methylene chloride). The product was then air dried until no more liquid would evaporate, and weighed giving a...
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