octave - 24-1-2008 at 14:34
Hello everyone! I have recently purchased a reflux double jacket condenser and am very pleased with it, except that it has to be vertical for
distillations(lovely for refluxing though 
). Now I've been looking for a
condenser for distillation and narrowed it down to a liebig or a west. The problem is I have yet to figure out the differences between them.So which
one should I get? and what are the differences between them? thanks for the help guys 
bio2 - 24-1-2008 at 15:57
The West has a more narrow water annular space which increases the velocity
and hence the cooling to some extent given the same flow rate.
In practice it doesn't matter which one is used only the West is more compact.
The most important thing in a diagonal condensor is the amount of hold up which
becomes important when cutting fractions.
Examine the entrance design of the condensor to determine the hold up.
Corning makes a special low hold-up Liebig. At least they used to.
chemrox - 24-1-2008 at 19:19
Holdup happens at the top and bottom where the joints are attached. If the condenser is designed so that the inner tube is straight from the top
joint through the end joint with a drip end there should be minimal holdup. I have two Liebegs that have holdup at the tops. It's a matter of a few
drops so I don't worry. One design feature to consider, and this would affect holdup, is having the condenser double as a column. Some chem-kits are
like this. Years ago I got a Sigma chem-kit because I had no equipment and a project I wanted to get started. I still have the box and all the
pieces. The angled vacuum adapter didn't match the angle of the distillation head and the only condenser was designed as a column. The addition
funnel is small and cylindrical. Having listed some of the shortcomings I will say that I would have paid big money to have had this stuff when I was
a mere ug at Berkeley. Corks, tubing, oil baths, burners, like Lavoisier's lab.
octave - 27-1-2008 at 18:13
What exactly does holdup mean?
MagicJigPipe - 27-1-2008 at 18:24
Holdup is when a portion of the distillate gets "held up" in the condenser and because of this the fractions you are trying to seperate get mixed
together. I suppose you could think of it as a "stepped" waterfall as opposed to one that goes straight down (yeah, I know, but I tried).
So, the flow rate of the condenser is important when hold up is an issue.
octave - 29-1-2008 at 04:09
Oh I think I'm grasping the picture now. This would be another reason to discard the first few ml of every fraction especially the desired one.