Benzyl Phenyl Ether from Benzyl Chloride and a Dilute Solution
This is a procedure to make benzyl phenyl ether on the lab bench scale from
phenol and benzyl chloride. It is meant to show the ease with which one can
learn the basic PTC process and generate kinetic data. The reaction takes slightly
more than one hour. This would make a great undergraduate physical or organic
chemistry experiment since it uses standard laboratory glassware and chemicals
and analytical results are obtained from a GC that takes less than 15 minutes
Please follow all proper lab safety precautions and make sure that all of the
MSDS (material safety data sheets) are available and have been read and understood.
Follow standard laboratory protocols for dealing with these raw materials and
wastes, including the use of a well ventilated fume hood.
B. Major Equipment:*
500 ml Three Neck Round Bottom Flask
Heating Mantle or Water Bath
* excludes clamps, weighing scales, support stands etc.
of 50 wt% in water
Phase Transfer Catalyst
or Aliquat 336
All were purchased from Aldrich (usually the lowest grade) and used as purchased
without any additional purification. Tap water was used to prepare the aqueous
phase. This approach was chosen to show the robustness of the process.
1. Prepare the aqueous phase by adding 1.88 g of phenol (20 mmoles), 1.80 g
of 50 wt% sodium hydroxide (22.5 mmoles), sodium iodide (0.075 g), and 196.0
g of water to a 3- neck 500 mL reaction flask. After a brief stirring there
will be about 200 g of a solution containing little less than 1.0 w/w % of phenol
(in the form of phenolate). pH should be above 11.
2. Introduce a mechanical stirrer into the reactor and immerse the reactor
into a temperature controlled water bath kept at 40oC (or use a heating mantle
with temperature control). Keep the reactor content stirred mechanically at
600 rpm minimum.
3. Prepare the organic phase by mixing 7.59 g of benzyl chloride (60 mmols),
0.82 g of Adogen 464 or Aliquat 336 (both products consist mostly of methyltrioctylammonium
chloride), and 0.45 g of 3-methylanisole. Other internal standards may work
fine or one may choose an external standard. It is wise to analyze a sample
of the organic phase before the reaction to confirm the GC profile in the resulting
4. Once the temperature of the reaction mixture reached the temperature of
the bath (use a thermometer to confirm), transfer quickly the organic phase
into the stirred aqueous phase. This is time zero of the reaction. The average
temperature will be slightly below 40oC but the mixture will equilibrate within
three minutes due to the capacitance effect of the water bath.
5. Every 10 minutes stop the stirrer and allow 1 minute for the phases to separate.
Virtually no reaction will occur when the stirrer is stopped. Take aliquots
of the lower organic phase and briefly centrifuge the sample before injecting
the organic pahse into the GC (the density of benzyl chloride is 1.10 g/cc,
the organic phase is the lower phase, even after the formation of significant
quantities of the product).
6. The reaction will be complete after 70 minutes. The yield of benzyl phenyl
ether based on the limiting reactant (phenol) after 30 minutes of reaction was
70 %. For all of the samples the chromatogram contained the product, the unreacted
benzyl chloride (used in excess), the internal standard and minute quantities
of benzyl alcohol and benzyl iodide.
Gas Chromatograph: Hewlett-Packard/Agilent 6890 Gas Chromatograph
Integrator HP/Agilent 6890 Series Integrator
Column J&W Scientific DB-Wax column
Detector TCD detector with EPC
Initial Time 1 minute
Initial Temp 95 oC
Rate 15 oC/min,
Final Temp 225 oC
Final Time 3 minutes (total run time 12.66 minutes)
Carrier Gas Ultra pure helium from AirGas.
To determine the GC response factors against the internal standard, solutions
containing four different concentrations of reactants and the standard were
prepared and injected into the GC. Since no solvent was added to the reaction
mixture, benzyl chloride served a dual purpose and was also the solvent. The
run was not optimized. The reaction was stopped when it was considered to have
produced sufficient data to determine the second order rate constant (0.12 lit/min-gmol).
Please contact us if you would like help working up the data or creating the
plot to determine the reaction rate constant.
Disclaimer: Value Recovery, Inc. accepts no liability for
experiments done within the guidelines of this recipe. Therefore, the user explicitly
accepts all the responsibility to operate the equipment is a safe and environmentally