Sciencemadness Discussion Board

Rotary Evaporator

Ozonelabs - 9-4-2008 at 01:47

Hello everyone,

We hope the following few words do not defy any forum rules.

We are very much in need of a Rotary Evaporator, however there is a deficiancy in our funds.
If anyone has an old Buchi RE111 or simiar with glassware that could be shipped to the U.K. for a decent price, please do get in touch with us, either via the U2U here or via our website/gmail.

We thank you all in advance.

Ozonelabs

Sauron - 9-4-2008 at 02:22

The RE-111 is not my favorite model of Buchi because I do not much like its jackstand (same criticism applies to all that generation of Buchi. The original jackstand was OK, the jackstand for R-110 was fine, but the stand for the -111 etc sucks. To prove my point, I have a RE-111 jackstand sitting around here. If you want to pay for the shipping from Bangkok, Thailand to the UK you can have it for free. Saves me the trouble of throwing it away.

The ratchet to hold the head in lower position needs repair.

I do not have a motor head or a water bath for this model. The faceplate of the motor head for this model is rather fragile and often cracks in shipment if not packed carefully.

chemrox - 9-4-2008 at 19:38

Similarly I have some motors that will fit on the jackstand. You wopuld then need both the glassware and the gaskets that hold the inner adapter in place (in the drive). Piece by piece you will get there. I ws in a similar situation and it took a couple of years. I bought a "Buchi Rotary Evaporator" on LabX that turned out to be a stand. I paid too much for it but a lot less than the $1400-2200 I was seeing everywhere I looked. Be advised, there are two basic setups: an older one (that I have) where the condenser attaches to the rotar and sticks up at an angle. The other type has a little manifold that attaches to the rotar and the rest of the glass hooks onto this piece. On these, newer types, the condenser is vertical. A nice feature is the condensers can be swapped so that you could use a Dewar type of condenser and avoid running water. Anyway, you can have a rotar if you get Sauron's stand from him. You pay shipping from west coast US. Good luck!

Sauron - 9-4-2008 at 20:04

The glass tube that goes through the motor head is called a vapor duct and is locked in (sort of) by a ground glass taper joint and a small metal spring clip. The flexible seal is not what holds it in place but is there to help ensure a decent vacuum (when new) and protect the metal parts from corrosive vapor. This seal needs periodic replacement.

The basic condenser is the diagonal type. The setup that chemrox is talking about is via a distributor head, and allows you to swap between a vertical condenser and a dewar type condenser. The dewar condenser requires no cooling water plumbing but is charged typically with dry ice-acetone and is used when rotavaping low boiling solvents like Et2O.

Chemrox, the plan is now for me to donate a Model R V-stand and an older motor head to match. He will then need only glassware, and he can improvise a bath easily enough (hotplate and pan). If you really have a head to fit a RE-111 jackstand let me know. Either you take the stand from me or I'll take the motor head from you, but honestly, I already have a R-110 complete so I do not need another Buchi (I also have a R-152 20 liter job, you see.) At one time I had about 15-16 of the smaller Buchis. Madness!

panziandi - 10-4-2008 at 10:01

you can order from Buchi UK ltd with no hassel. Buchi glassware is hideously expensive but they will sell you the required gaskets seals etc which will be required. I could possibly get hold of the glassware you require at cost U2U me if that is required.

Sauron - 10-4-2008 at 13:01

Buchi glassware

Evaporator flasks. In USA these are mostly 24/40 but elsewhere 29/42. The choice is yours if you don't have a vapor duct yet. Or get two vapor ducts.

Vapor ducts with the combo-clip are better, as are Buchi flasks with the 90-degree shoulder for the clip.

Remember to never overfill the flasks, 1/3 to max 1/2 of nominal capacity is better.

Receiver flasks

35/20 socket joint and retained by a steel spring clip.

Distributor head

This you really need to get from Buchi.

Condensers

The vertical double coil condenser is hard to beat. For the dewar condenser I just put in a reducing adapter (45/50 to 29/42) and use a non-Buchi dewar fitted with vacuum takeoff. The female Buchi joint is 45/40 but no worries.

Except for the vapor duct and distributor head all the rest of the glassware can be gotten from sellers other than Buchi, who are vastly overpriced. Even the replacement double coil condenser (diagonal) with plastic screw cap and spring retainer are now made by aftermarket vensors.