Wednesday, August 13, 2008

Melting point then and now - Kofler Hotbench vs. OptiMelt

I think that most chemists will agree that doing melting point determinations sucks big time. Especially when you have been putting it off for 6 months and have to do 22 in one day (yes I learnt my lesson and it took two days). Until recently I only knew of a few ways to determine melting points. My preferred method was to get a rough melting point using a Kofler Hotbench followed by an accurate determination using a full-on old school Reichert melting point microscope. The microscope beats getting your compound into a melting point tube and watching it melt through a crappy magnifying glass. Firstly, you place your crystals between two wafer thin glass plates (very simple). Secondly, you get to see your beautiful crystals through the microscope. On one occasion I managed to have a small rainbow in my crystals which sure beats staring at a melting point tube. Nevertheless, melting point determinations suck so I have toyed with the idea of having a camera record the melting in my absence and then come back a couple of hours later and fast forwarding the movie to the melting point and recoding the numbers. Now that would be easy.
As always someone else got the idea first and where I work now melting point determinations are fully automated using an OptiMelt system. It records a little movie and prints out the numbers while you are at home watching Buffy. Amazing stuff!
So what happened to the redundant Kofler Hotbench? I found it on display in the Departments historical collection of hopelessly ancient relics. Strange to think that where I worked only two months ago this was state of the art equipment. D!


Bunsen Honeydew said...

It's great to have you back!

pmgb said...

Thanks for this useful info on a very important instrument used in the practice of organic chemistry. What is cost of this amazing instrument?

Daniel Sejer said...

Errrhhh I assume that the amazing instrument is the OptiMelt? I have no idea how much this piece will set you back. D

Kevin K said...

I have asked for a quote on OptiMelt. It costs roughly $1950 AUD plus postage and handling from the US to Australia. Available in the US for about $1675 AUD. Pls do not quote me on the price as it is subject to change from time to time.

Heavy Equipment Parts said...

What I dont understand is how can Optimelt REALLY be a solution to something I've been trying to figure out for months!!!

Anonymous said...


I'm trying to find a cheap second hand one, could anyone point me in an inexpensive direction?

Anonymous said...

Does anybody knows where I could buy a Kofler bench in North America?

Dave Sanders said...

I bought an old Kofler bench at an auction today in Cincinnati. The seller obviously didn't know what it was. The description in the catalog said
Model: R3838
Specifications: 110V/ 60HZ
Width: 14''
Depth: 6''
Here's a link to the auction photo: