Cracking of dicyclopentadiene - was my simple Liebig condenser distillation setup adequate? I recently did a distillation of dicyclopentadiene (bp 166 °C) to get cyclopentadiene (bp 40 °C). The setup as instructed by my supervisor consisted of a simple water-cooled Liebig condenser. Oil bath temp. at 180 °C, receiving flask held at -78 °C by a dry ice-acetone bath:



Everything seemed to work fine, and I got plenty of cyclopentadiene after distilling for about 4 hours.

Now (writing the report) I went hunting for some procedure references, and the first hit was this one (http://www.orgsyn.org/demo.aspx?prep=CV4P0238):



My interpretation of these instructions look like this:



My questions (too many I know, sorry):


Is my interpretation of that setup correct?
What is the Friedrichs condenser for?
Why should the water temp. be 50 °C? (and how important is it to get this temp. correct?)
Where would I attach the "calcium chloride drying tube" and what is it anyway, what's it for and how important is it to have one?
Other procedures I found attached Nitrogen to the setup. Why would I do that and how important is it?
How would you interpret "efficient water-cooled condenser"?
Finally, can you put me at ease and tell me that my simple distillation setup was just fine?
The Friedrichs condenser is for refluxing dicyclopentadiene (bp ~170 C). It's kept at 50 C to let the cyclopentadiene (bp ~40 C) pass without condensing.