A simple reflux
apparatus is shown in Figure
1 on the right. To set up the reflux apparatus, set a stirrer/hot
plate and ring
stand in
the hood. Place a heating mantle on the stirrer. Insert a round
bottom flask (distilling flask) into the heating mantle and clamp the
neck
of the flask to the ring stand. Be sure to position the flask over the
center of the stirrer plate. Measure out the reactants and
solvent that will be used in the reaction and add them to the reaction
flask, using a funnel. Add a magnetic
stir bar to the flask and continue to set up the reflux
apparatus
as shown in Figure 1. Insert a condenser tube into the flask and
clamp at the top joint of the condenser, if necessary, to stabilize the
apparatus. Connect the water hoses to the
condenser,
with water “in” at the bottom, and draining “out” to the sink at the
top
end of the condenser. Connect the heating mantle to the Variac,
and
set the Variac at approximately 50V. Check your apparatus against
the diagram in Figure 1. Carefully turn the water on, turn on the
magnetic stirrer and the
Variac
(heat). As the apparatus is heated, the liquid in the reaction
flask will begin to bubble. The actual refluxing will begin
when
the solvent volatilizes and moves up into the condenser tube where it
experiences a lower temperature. As
the
vapor rises through the condenser
(which
is cold from the water running through it) the solvent will condense
back to the liquid phase and drip into the reaction flask.
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