Sciencemadness Discussion Board

The meaning of an old German term

Boffis - 15-11-2020 at 08:53

I am reading some old German papers about the chemistry of imidazole and 2,2'-bis-imidazole from the 1920s and 30s and I have come across a term that has left me mystified:

Does anyone know what "Zehnkugelrohrs" means? Depending on how you read "kugel" it can mean sphere, shot, ball, pellet etc. However, the usage suggests something like an absorption tube or bubbler, for example in:

Nach dieser Zeit war die Abspaltung basischer Dämpfe beendet; auf der Lauge schwamm eine bräunliche Ölschicht. Das Zehnkugelrohr enthielt Wasser mit 7.294g Salzsäure (200 Millimole).

Can anyone help please

Antigua - 15-11-2020 at 09:12

I'm not a German at all, but isn't kugelrohr like a Rotovap apparatus? And zehn is 10, so something like that? Carl, come here :D!

edit: or not exactly a rotovap, more like a short-path distillation apparatus meant for products and not solvents?

[Edited on 15-11-2020 by Antigua]

RedDwarf - 15-11-2020 at 09:31

There is a shortpath distillation apparatus kugelrohrs that consists of a glass pipe linking a number of glass bulbs. The idea is that you place the first glass bulb in some sort of tube heater, the second bulb is outside the heater, so you get short path distillation from bulb 1 to bulb 2. If you want greater purity then you push bulb 2 into the heater as well so you get a secondary distillation into bulb 3. Guessing, I'd assume a zehnkugelrohrs would be a ten stage kugelrohrs with ten bulbs?

Edit: Just in case you were wondering the tube is kept horizontal, so only the lower third of the bulb is of use.

[Edited on 15-11-2020 by RedDwarf]

Zehnkugelrohrs

MadHatter - 15-11-2020 at 14:20

Ten-ball tube from Google translate.

karlos³ - 15-11-2020 at 18:19

Have a look at this here: https://books.google.de/books?id=cSl9BwAAQBAJ&pg=PA57&am...
Its the thing right on the bottom near the apparatus.
In that specific example it contains a NaOH solution and is used for the absorption of CO2 for later titration.

Boffis - 17-11-2020 at 09:22

Hi guys, many thanks for your responses, yes some kind of absorption equipment is certainty what is implied from the text. In this case the tube contains hydrochloric acid to capture "basic vapours".