Diels Alder Experiment

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EXPERIMENT
OBJECTIVE
The aim of this experiment is synthesize hexaphenylbenzene via an aldol condensation reaction, followed by a Diels-Alder [4+2] cycloaddtion. This is final step in the multistep synthesis pathway to form hexaphenylbenzene, and uses the products of the previous experiments: benzil and diphenylacetylene
REACTION DIAGRAM

TABLE OF REAGENTS

BENZIL
DIBENZYL KETONE
TRITON B
40wt% IN METHANOL (1.79 M)
TRIETHYLENE GLYCOL
TETRAPHENYL-CYCLOPENTA-DIENONE
DIPHENYL ACETYLENE
HEXAPHENYL-BENZENE
FORMULA

EQUIV

MW

DENSITY

VOLUME

MASS

Mmol

MELTING POINT

BOILING POINT
-
-
210 °C
-

PROCEDURE
1 A hot plate with an aluminum block was preheated to 150°C.
2 100mg of benzil and 100mg of dibenzylketone were added to a conical vial with a spin vane and an air condenser.
3 0.5mL of triethylene glycol was added to the vial, and the mixture was stirred on the hot plate until a homogenous mixture was obtained.
4 The heat was turned off and 0.1mL of Triton B was added through the condenser.
5 The vial and its contents were allowed to cool to room temperature, and purple crystals were observed.
6 1.3mL of methanol was added to the vial as it was stirred at room temperature.
7 The vial was then placed in an ice bath for further cooling.
8 The purple crystals were collected and were dried using vacuum filtration with a Buchner funnel.
9 The crystals were washed with ice-cold methanol until the filtrate was a purple-pink color, and were then left under vacuum.
10 The dried crystals were placed in a test tube, and 178 mg of diphenylacetylene and 2mL of silicon oil were added.
11 A clamp was attached to the tube and the contents were heated to a boil over a Bunsen Burner until the solution was a pale pink color.
12 The test tube was allowed to cool to room temperature.
13 6.0mL of hexanes was added to the tube and the mixture was stirred with a spatula.
14 The crystals were



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