Sciencemadness Discussion Board

3 way Claisen Adapters?

smaerd - 21-7-2010 at 21:17

Is a 3 way Claisen adapter a better investment than a 2 way? I was thinking about getting a 2 way just for a pressure equalized addition funnel, temp readings, etc. Mainly being able to save out on buying a 2 armed flask.

I mean I'm not doing micro-scale or anything but my biggest boiling flask is 250mL. So I do keep things little(I'm just trying to learn no need to do anything big). I doubt that it would really interfere with any operation I'd be needing it for by any means even if stoppered.

I know this is probably a pretty dull basic question, but learning the equipment is kind of a big thing for me, and I am mortified by the thoughts of spending money(student) on something that won't be adequate for my needs. Thanks for any advice!

DJF90 - 22-7-2010 at 04:27

Get a three neck flask. You won't regret it. Its common in research as you can attach, for example, a funnel, thermometer and column/stillhead/reflux condenser all at the same time.

Panache - 23-7-2010 at 17:41

My serious advice is not to sweat the decision, go with what you want as your needs will likely change quickly anyway, or if you are at all like me you will break the thing within weeks regardless. If you are not doing anything super elaborate i would advise using dual drilled silicon corks for adding necks anyway for starters, they are more forgiving and only in rare circumstances do they actually play a role in the reaction. Multinecks are super great but costly(i think you can et like 3 rb's for the price of one three neck), shit to clean, and often make your practical problem solving brain very lazy!

Temperature can always be taken by feeding your thermocouple down through the condenser into your flask, likewise for addition.

[Edited on 24-7-2010 by Panache]

entropy51 - 23-7-2010 at 18:14

Quote: Originally posted by DJF90  
Get a three neck flask. You won't regret it. Its common in research as you can attach, for example, a funnel, thermometer and column/stillhead/reflux condenser all at the same time.
Three necks are handy, but in some of the hinterlands possession of a three neck is considered prima facie evidence of illegal drug synthesis. If you live elsewhere, DJF90 has a point.

peach - 24-7-2010 at 11:02

I'd get the three way if you can afford it. It's always handy to have another hole you can stick things in.

Provided you grease the tapers, leakage isn't an issue. It's not nuclear physics and we don't need a billionth of a torr for a distillation.

Claisens are nice because they have two ports facing upwards. I don't like having funnels and things sticking out at angles. Particularly if they weigh a lot and will snap without considerable support. And then you have the issue of getting the clamp to actually clamp it safely, as they tend to shift around a ton as the three screws are done up, putting strain on the glass.

BromicAcid - 24-7-2010 at 16:21

Three-way Claisen adapters can be annoying because you usually have the odd-ball neck sticking out at some angle. An added bonus of Claisen adapters over a 3-neck flask (although I would have at least a 2-neck because they do best in a side neck) is the extra degree of movement. A column in a Claisen gives a side to side motion to work with if you're clamping your setup in place and also gives you a decent amount of bump protection. I put them in my setup just for those reasons.

smaerd - 24-7-2010 at 21:45

I have been doing research on glassware since I wrote this post, which thankfully there is a lot of useful to the point information about this easily available on google(if any passer-bys were curious).

It seems like a claisen adapter has a really helpful bonus to it as mentioned above by a few people :). It helps to prevent/control bumping for vacuum distillation which is what my next goal for my set up was. That and I needed a spare port for an addition funnel(imaginary now but hopefully I'll have one soon enough).

I realized that the 3 ways I was referring to is actually considered a 4 way, and the 2 way I was referring to is actually a 3 way(these names make perfect logical sense to me I am just a bit dense I won't deny that).

So taking Panache's advice and a combination of everyone elses I've come to this conclusion:
- First I'm going to get a 2 necked flask and a 3 way claisen adapter(not a 4 way). This is also a good idea because if something should happen to my beloved 2 neck flask then I can still have my single neck with a claisen.
- Eventually I may invest in a three necked flask but for now it's not a necessity nor is a 4 way claisen on a single neck flask.

I really appreciate all of your input, it really helps me out to talk with people and make sure I'm doing the right thing or at least headed in the right direction.



[Edited on 25-7-2010 by smaerd]

chemrox - 24-7-2010 at 23:57

I'd like to see what a 4=neck Calisen adapter looks like....I saw one with a female neck at 60 deg up from the down male end (take-off). I couldn't think of a use for it. It's nice to have a claisen the right length for a cold finger to put atop a frax column. Cold finger-thermometer-take-off

peach - 25-7-2010 at 16:31

Quote: Originally posted by smaerd  
I needed a spare port for an addition funnel(imaginary now but hopefully I'll have one soon enough).


Not if I keep buying them all you won't... :P

Claisens do help with bumping, but an even better solution is, a bump flask;



Or, a fritted splash gaurd;



Images from United Glass Technologies

Once something really starts bumping, it can rocket through 600mm vigreux columns instantly. If it's bumping, it's often a sign that you're doing something wrong.

Wrong flask, no stir bar, no boiling chips (only works at atm pressure), too hard a vacuum, heating too rapidly etc... in general, too much aggression.

A ball and socket at the base of the column or the start of the condenser is extremely handy as well, as it allows the glass to rest at angles that'd usually strain it;


That's from BAFFCAT on eGimp. I've probably bought about $1k's worth of gear from him, nice guy.
Quote: Originally posted by chemrox  
I'd like to see what a 4=neck Calisen adapter looks like....


A mess :P

How about a four way... on a three neck flask... upside down. :D

It may have been something to do with collecting a fraction of the reflux, or maybe it could be used to capture a bump. Not sure myself.

I also don't fully understand your cold finger setup. Have you got a photo of that, or could you use it in a sentence? ;)

I'll take a vowel please.