Cou
National Hazard
Posts: 958
Registered: 16-5-2013
Member Is Offline
Mood: Mad Scientist
|
|
Is it possible to do free radical halogenation with normal lab supplies?
It's the first reaction we learn in organic I, but I've never seen any examples of real world applications.
could you just mix chlorine gas and butane gas in a flask, and shine a UV light on it, then various chlorobutanes would condense? then you could use
fractional distillation to separate the difference chlorobutanes
|
|
|
fusso
International Hazard
Posts: 1922
Registered: 23-6-2017
Location: 4 ∥ universes ahead of you
Member Is Offline
|
|
Quite long time ago I tried condensing butane into liquid in a test tube with dry ice, and bubble Cl2 made in situ into the liquid butane to see what
would happen. In the middle of the experiment a small fire suddenly sparked and made some weird smell and forming some grey liquid from where the
mixture burnt, ruining the mixture.
|
|
|
WGTR
National Hazard
Posts: 971
Registered: 29-9-2013
Location: Online
Member Is Offline
Mood: Outline
|
|
https://www.sciencemadness.org/talk/viewthread.php?tid=70963
|
|
|
SWIM
National Hazard
Posts: 970
Registered: 3-9-2017
Member Is Offline
|
|
If you decide to try this, have a look at the transmission percentages for various wavelengths through different materials.
UVA can make it through borosilicate much better than UVB or UVC.
Get down to 254 NM and transmission through boro is terrible, but it will go through quartz or Vycor just fine.
Get down to under 200 NM, and even quartz stops quite a bit unless it's fairly thin, like a few mm.
I didn't find this out until I bought a 250 mm by 12 mm quartz disc which it turns out is kinda thick for the short wavelengths I wanted to push
through it. (anybody need a big friggin' piece of quartz?)
UVC bulbs with a few watts of power are cheap, and require no ballast in many cases, but the ballasted UVC bulbs in water and air duct sterilizers can
have much higher wattage and aren't too bad price-wise.
There are 110 volt, and 220 volt UVC bulbs that look like CFLs are available for sterilizing your home (Yikes!) which would be simple to use. The
ballast is built right into the bulb base and they go in regular threaded lightbulb sockets.
Getting as much of the radiation into the reaction vessel as possible would be important with these sort of bulbs.
Magpie used a lot more wattage( 80?) when he made carbon tet, but he was using a big borosilicate flask with the bulb outside, so was probably losing
a lot of that energy. However there are commercial photochemical reactors that work just that way; and he did get good results.
A quartz flask, or Vycor, is an obvious choice if you've got one, but clamping a quartz disc as a window onto the top of a reaction vessel that has a
jacket and a bottom drain could work too.
Vapor rises from a boiler below into the vessel through the bottom drain and hopefully gets condensed on the cooled surface and runs back down to the
boiler.
Stick a fractionating column between them and perhaps the halogenated material would tend to stay in the boiler so you might be able to get partially
halogenated products in better yield.
This sort of thing might require a baffle in the upper chamber. Something like a beaker with a short tube projecting from the bottom and through the
bottom drain of the reaction vessel.
Yungkang quartz makes a quartz dewar condenser like item that should do the trick with one of those UVC bulbs they use to sterilize houses. Just put
the bulb in where the coolant would normally go and wrap the outside in something reflective. the geometry of the situation would make for very
efficient use of the radiation emitted.
If you're into do-it-yourself equipment, an old lava lamp rewired for a 3 to 6 watt uvc bulb like those ones in toothbrush sterilizers (they take
something like 2 VDC) would be a decent holder and reflector for a quartz RBF.
Using a reaction kettle with the regular lid may be a good possibility too if you get one of those quartz jacketed UVC lights for sterilizing water
and find a way to jam it in one of the top joints without leakage.
I expect the seals in actual water sterilizer units wouldn't hold up to the hydrocarbons and chlorine radicals it would be subjected to if you just
tried to use the unit as a reaction chamber.
Ace photochemical reactors in various sizes show up on Ebay all the time, but seldom have the bulb and ballast.
The big ones are easy to find, but the little ones are less common.
Those reactors use LOTS of wattage, but I suspect they're supposed to work with a single pass through the reactor instead of refluxing stuff around in
there for a while.
They are pretty damn expensive with bulb and ballast though. Like a grand or two maybe for a decent looking used one of 1000 ml.
|
|
|
S.C. Wack
bibliomaster
Posts: 2419
Registered: 7-5-2004
Location: Cornworld, Central USA
Member Is Offline
Mood: Enhanced
|
|
Quartz tubes (e.g. technicalglass.com) would be a rather cheaper ebay item of interest. Get more than one if you do, because they're probably more
fragile than you think they are. The tube (or several connected sections of tubes arranged to suit) can be as long as it has to be with as many lights
along it as necessary. A quartz tube from a toaster oven or other heater could be repurposed.
[Edited on 6-4-2019 by S.C. Wack]
|
|
|
Rhodanide
Hazard to Others
Posts: 348
Registered: 23-7-2015
Location: Ｔｈｅ ８０ｓ
Member Is Offline
Mood: That retro aesthetic
|
|
You don't even need a UV lamp, actually...
Trichloroisocyanuric acid chlorinates Toluene to form Benzyl Chloride. If you mix them in a flask and leave it outside on a sunny day, it's supposed
to proceed by a free-radical chlorination route, or so I've heard.
|
|
|
DavidJR
National Hazard
Posts: 908
Registered: 1-1-2018
Location: Scotland
Member Is Offline
Mood: Tired
|
|
I made a small amount of carbon tetrachloride by bubbling chlorine gas into chloroform while under a UVC germicidal lamp
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
