DFliyerz
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DIY/Cheap Tube Reactor
Does anyone have a design or a source for a relatively inexpensive tube reactor? I may not be using the right term, but I'm thinking of a tubular
reactor that can be heated and used for reactions such as reductions of metals with hydrogen and ambient pressure catalytic reactions of gases. It
could even be makeshift, as long as it's suitable for the described reactions.
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WGTR
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Tube Furnace
My own meager attempt:
https://www.sciencemadness.org/whisper/viewthread.php?tid=55...
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MrHomeScientist
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Another very good example is Garage Chemist's: http://www.sciencemadness.org/talk/viewthread.php?tid=9705
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JJay
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After my last tube furnace crumbled, I ordered some more nichrome and will be attempting this again soon. Magpie also has a nice tube furnace.
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DFliyerz
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Can any of these designs be used for reduction of oxides? How would the powders be loaded?
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WGTR
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Sure, but it depends on what you're trying to reduce. That determines how much heat you need, and whether the particular metal can be reduced with
hydrogen at all.
If you have a particular reaction in mind, then maybe we can offer some suggestions on how to adapt the various designs to do what you want.
My particular design was intended to produce acetaldehyde from alcohol, and in the process, the copper catalyst was reduced from oxide to the metal.
It was, however, highly porous copper, dark purple in color. You don't necessarily have to use hydrogen. Alcohol vapors may work. Even ammonia
might do the trick. In any case, you'll need to have a tube long enough for the gas to preheat before it interacts with your sample.
Catalysis is fun, and there are a number of different things you can try. The equilibrium for ammonia goes more towards hydrogen and nitrogen at high
temperatures and low pressures. You can react ammonia gas over a finely divided iron catalyst, wash the unconverted ammonia by bubbling through
water, and collect the exit gasses (they should be mostly hydrogen).
Isopropanol can be dehydrogenated over copper to acetone + hydrogen gas. The reverse reaction can occur if excess hydrogen is fed into the reactor
with acetone.
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DFliyerz
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Hmm, interesting! One of the reactions that I was considering looking into was a low-pressure conversion of CO2 and H2 to methanol over a
nickel-gallium catalyst, which would additionally have to be reduced with hydrogen. Attached is the paper on this catalyst.
Attachment: studt2014.pdf (1023kB)
This file has been downloaded 621 times
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WGTR
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Neat project idea!
This was one topic that got me initially interested in chemistry, several years ago. I have a binder full of different journal articles on the
catalytic conversion to methanol. The idea would probably work on a "just to say you did it" scale. There is a certain audience that the journal
authors are catering to, and that's most likely big industry. As such, there are certain assumptions made about the reader's prior knowledge, and
some things may be left unsaid.
One thing to look out for is the distinction between product selectivity and overall percentage conversion. I've seen several articles talk about
high selectivity, but with only maybe 5-10% conversion rate per pass. If you have very high selectivity, then it's possible to condense out your
methanol, and feed the exit gasses into a second (and third, etc) similar reactor to affect further conversion. If there is poor selectivity, and
there is a lot of CO produced, it may be necessary to run some of the exit gasses through a water gas shaft reaction to restore the correct
CO2 and H2 balance for the next conversion stage.
If you're not looking to run your car with it, or go into business selling methanol, then whatever conversion % you get would probably be enough.
I'd make sure that the feed gasses are dry. One way might be to make a condenser by coiling up some copper tubing in a large glass of ice water.
Whatever gasses that go through there will be pretty dry when they come out, as the moisture will condense inside the tubing. That should work until
water starts bubbling out the other end.
Second, when preparing the catalyst, run dry air through the heated catalyst tube to make sure that any moisture in the tube is completely swept away.
Then, switch to dry H2 to reduce the catalyst. When reduction commences, you should see water condensing on the output side of the tube.
Some Q-tips should be sufficient to swab away water from the end of the reaction tube, and hydrogen can be run through until the tube is dry again.
With the catalyst reduced, when CO2 is added to the reaction, anything condensing on the output should contain your alcohol.
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DFliyerz
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Another reaction that would be a primary use for a tube furnace for me would probably be making aluminum chloride. However, I have a bit of trouble
understanding how the aluminum chloride is condensed.
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chemrox
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I have a tube furnace and 1 inch od X 12" tube. I don't use these. They could be had for a price. I also have a tube furnace that got damaged in
shipping. I repaired the ceramic insert with high temp, ceramic glue. I haven't tested it. You could have it for $60 + shipping. Or trade if you have
something I want like ergotamine or thebaine..;^)
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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yobbo II
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'Phenylacetone via the tube furnace' is a chapter in a book (AFAICR) by Uncle Fester.
It give some details for making same (the tube reactor that is).
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