octave
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liebig or west?
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 
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bio2
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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.
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chemrox
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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.
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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octave
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What exactly does holdup mean?
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MagicJigPipe
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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.
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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octave
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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.
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