I'm having challenges with a simple starter task of boiling water.
I tried to record the details of my experience in order to help answer potential questions, as a good record of experiments is essential. This was a ‘dry-run’ of future lab experiments, so my measurements are approximate. A real experiment I would have recorded more information and significant figures. Safety goggles are worn by myself and my wife when doing an experiment.
My motivation is that while I'm an engineer in a very separate technology, my wife is majoring in chemistry, and I'd like to gain some information / skills in chemistry. You know, I feel the need to be helpful.
I tend to over think things, but find that in technology design, this is not always a flaw.
I am starting to work my way through:
Illustrated Guide to Home Chemistry Experiments
https://www.amazon.com/Illustrated-Guide-Home-Chemistry-Experiments/dp/0596514921Lab: 6.2 - Distillation: Purify ethanol.
The distillation apparatus is an overly simple pair of Erlenmeyer flasks 2 stoppers a little glass tubing and some rubber hoses. (similar to this setup:
http://www.scienceforums.net/topic/33873-homemade-distilation-apparatus/).
Foolishly, I changed the main chemical from drugstore ethanol to hardware store metal can “Denatured alcohol.” When I get back to this experiment, I’ll switch to the Walgreen’s rubbing ethanol alcohol.
I did not see any bubbles until 70 C. This may have been from an allotrope of Acetone of Methanol in the solution. When I boiled the alcohol, the experiment produced a lot of vapor which caused me to cancel the experiment and took some time to clear. This may have been the acetone (bp 57 C) added to as part of the alcohol.
I discovered an error. The apparatus really has to have a condenser (though the experiments book does not mention one in the book, and I am seriously disappointed in the author over the potential safety problem this exposes the reader to). The Periodic Table of Videos has a very clear warning for those attempting distillation (
https://youtu.be/iX5ZTieAUXI) You need a condenser to reduce fumes or you might get an explosion! In the case of the book, adding a coil of tubing between the distillation flask and the receiving flask with that coil submerged in a little cool water might seem to be enough.
After an appropriate dressing down from my wife, I ordered a proper 24/40 distillation rig (
https://www.southernlabware.com/laboratory-glassware/distillation/liebig-condenser-distillation-kit-complete-500ml.html), tubing, an aquarium pump, …
This is all being heated by a hotplate stirrer (
https://www.amazon.com/gp/product/B0147TTNJS/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1). I have a little fuel driven camping stove heater for bending glass, or flame tests. I think for distillation, avoiding flame is a good idea.
New temporary goal: Distill ordinary water
The previous vapor problem motivated me to read more about distillation problems and accidents. Apparently, even borosilicate glass can break given enough thermal shock, so I wanted to heat the 500 mL flask slowly and evenly.
I was reading about different ways of heating the Distillation Flask, and decided that a water bath would not work. I got a 2.5 qt. stainless steel pan. I read an article from someone using baby oil. I setup the new rig and put 300 mL tap water into the first flask + 2 drops green food coloring.
I poured about 600mL baby oil into the pan around the round flask (to the side of the round flask), until about 2 cm of the flask was submerged into the oil. Added a stirring rod to the flask. With help of a 3-fingered clamp, dipped a thermometer into the oil and turned on the meter.
Applied heat. (long story short). After about 60 C the baby oil smell is increasing. At 80 C, the smell warranted opening more windows, adding more fans. The water is starting to create vapors as well (little droplets on the top of the distillation flask all the way to the bottom of the 24 / 40 joint. At 90 C, my wife is concerned about the vapors and so watches the setup as I reread the MSDS on baby oil (white mineral oil) to double check the BP of the oil).
There are too many inconsistencies in the SDS of white mineral oil. Frequently boiling point is simply listed as N/A. And the flash point is between 25 C and 230 C.
We decide the fumes are getting dangerous. I turn off the hotplate, and also unplug it.
When the oil reaches below 40 C again, I recover it back into the bottles, disassemble the gear and clean all the glass and tubing in Alconox. I like this soap, when used separately, it takes tea stains off tea and coffee cups easily!
Fumes again! I need to get help.
I eventually found this article on baths by U Iowa:
https://ehs.research.uiowa.edu/print/1365But, it still does not answer all my questions.
Questions:
How do you recommend heating flasks for distillation (< 150 C) without fumes from the setup?
Should I place a Flat-bottomed beaker (Round or Erlenmeyer) straight on the hotplate?
Or, should I place a wire gauze square with a clay center between the heating surface and flask?
Would you recommend using a sand bath (pure SiO2 in a stainless-steel pan)?
Other arrangement?
Are there any key questions I am missing and should know about?
Should I run the output from the vacuum adapter out a window when working with volatiles like ethanol?
Thanks!