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Author: Subject: Hydrothermal/solvothermal chemistry
chironex
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[*] posted on 17-10-2016 at 19:40
Hydrothermal/solvothermal chemistry


So I was poking around and noticed the overwhelming lack of hydro thermal chemistry on the board. Frankly I think it's a shame since it's been some of the most interesting for me.

There are a few variations but I'll start with your most basic. While some hydrothermal reactions can happen at lowish temperatures and standard pressure, most are preformed in some sort of autoclave. The size and style of your autoclave will determine a lot about your reaction.

Your standard reactor is a shell of stainless steel with a removable Teflon capsule in the middle. Though you can also make one using simple plumbing parts from the hardware store with reasonable success. This type of reactor is a batch reactor and has no moving parts. The small ones have a 20ml capacity but can the big ones canget up to a litre easily if not more. Normally the whole thing is placed inside of an oven and the reactions take place between 100-230 C. The reactions take half an hour on the short end, to a month on the long end, with an average of 8-10 hours being the most common.

These reactor can be used for all sorts of things. I mostly use it for the preparation of nanostructures and inorganic materials, but it has loads of industry uses as well. A simple example is the carbonization of organic materials such sugar. Here's a video on the formation of carbon nanofoam from sugar link.
The reaction works by radical chemistry mostly, first hydrolyzing the sucrose to glucose and fructose, the glucose is then converted to fructose, then that is converted to hydroxymethyl furfuryl and so on, down to either amorphous or graphitic carbon. By messing with the addatives, the temperature, the pH and so on, you can. shape the material at a microscopic scale or add further functionality. By changing your carbon source in the above reaction, to something with more nitrogen content, you can dope the surface of the carbon with nitrogen and amine groups which can be used later.

Hydrothermal is also great for digesting organic material for this reason and can be used to convert things like cellulose to acetic acid and other smaller organic molecules very easily.

The technique is also incredible for producing inorganic materials. I've made a series of videos covering many different reactions and will be adding many more soon. Here's a small selection: carbon based quantum dots, copper crystal, copper sulfide wires

There are so many more reactions that are possible though. I've tested a lot and refined my reactions down and will be filming all of them in a couple months. Pretty much most metal oxides and sulfides are very feasible and you can sculpt them into way more shapes than you can normally. Hydrothermal is also a good intermediate step in other reactions.

I could go on but this post is getting long. I'll post more once I've got more videos to explain things better. There are so many possibilities with this chemistry and the reactors are easy to get online. I would highly suggest this be an addition to your chemistry tool set.
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j_sum1
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[*] posted on 17-10-2016 at 19:56


Is this your channel? It has been referenced before here. Nice work.

TBH, I don't know that it is an area that many here know much about. Amateurs tend to avoid high pressure high temperature stuff (for obvious reasons) and also nanoparticles do require analysis methods that many do not have access to. But this is definitely an open field. Why don't you stick around and start a thread that catalogues your experiments and progress. You will certainly get a following and quite possibly some who will duplicate your attempts. Maybe begin with the details of your apparatus -- I have not yet watched the video of your furnace construction.




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Metacelsus
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[*] posted on 17-10-2016 at 19:58


Safety would definitely be a concern for these kinds of things. The pressure involved will require careful design and planning.



As below, so above.
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chironex
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[*] posted on 17-10-2016 at 22:01


Ya it's my channel, though it's been cleaned up a lot since it was first mentioned. I just remembered this forum today and realized it was a great place to share my research.

As to heating the reactor and the reactors themselves, I bought mine on ebay for 40-100 bucks each. And a standard cooking oven works perfectly fine as a heat source.

http://www.ebay.ca/itm/Hydrothermal-Synthesis-vessel-kettle-...

That's the one I have, though there are tons of sellers (mostly from china, because a) china and b) nanotech research is massive there)
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j_sum1
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[*] posted on 17-10-2016 at 22:12


Well thanks for that. I will keep an eye on any postings you make here and also peruse your channel from time to time. I don't think it is something that I will get into any time soon but my students regularly express interest in nanoparticles (as does the textbook we use). If there is something that looks like it might be a suitable project we might have someone interested in having a go.

Good to know that suitable equipment is not too pricey.




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chironex
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[*] posted on 18-10-2016 at 09:06


If nanotech interested them then I've got lots they'll enjoy coming up. I'm actually gonna be teaching a course myself in january all about nanotech. Hence the new and improved videos. I'll be covering lots of different nano techniques. Planning on doing a lot with organic and inorganic cryogels, pyrolysis, graphene, nanotubes, hydrothermal and some STP chemical techniques as well as a bunch of biology and assorted other bits. So as I teach, we'll film it and make it into videos.

I find that with nano tech everyone thinks its complex and inaccesible but honestly it's pretty straight forward and easy.

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[*] posted on 18-10-2016 at 15:21


Sounds fantastic. Looks like I will be making some time to slowly work my way through your YT channel.
(As soon as I have finished rewatching chemplayer in order. It is rather fun.)




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chironex
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[*] posted on 18-10-2016 at 17:59


i'd start with the newest and work backwards. Other than the fusor stuff from back in the day, the new videos are where I started doing actual research and cleaned things up a bunch
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[*] posted on 22-10-2016 at 05:43


Glad you are still enjoying our channel! Looking back it was a crazy time and a lot of work, but lots of fun. Working on a wish-list for 'series 2' but no promises on when it will be though.



Watch some vintage ChemPlayer: https://www.bitchute.com/channel/chemplayer/
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[*] posted on 22-10-2016 at 15:47


@chemplayer
I watched nearly a dozen vids last night. That was enough work by itself - let alone producing them. It will be at least a year before I am in a position to make my own videos. In the meantime, ideas are brewing.

And lest I hijack this thread - does anyone else have any experience of hydrothermal chemistry? It sounds interesting.




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[*] posted on 22-10-2016 at 20:04


When he mentioned hydro-thermal chemistry, it got me thinking of hot springs as they age and go through different periods that deposit minerals of varying compositions.
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chironex
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[*] posted on 23-10-2016 at 06:55


I mean those reactions are what this technique basically replicates. One of the activities in that course I'll be running, after a week of learning about and experimenting with these reactions will be to "fossilize" a seashell. Basically growing crystals and such on the shell to mineralize it further and make it look cool. I'm really excited to see what people come up with. And since the crystals are all stable in water and air they should be much harder to damage, unlike the usual crystal growing kits that'll just dissolve away.
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[*] posted on 23-10-2016 at 07:05


When I was first messing around with this technique I would pick a random mineral and then see if I could grow it. Though, every now and again I'd make something, and have no idea what it is. These crystals for example, have been driving me crazy since I made them. I know they're some sort of copper/graphene compound, but I can't figure out what it is. Far as I can tell, it's not in any literature. LINK TO IMAGE
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[*] posted on 23-10-2016 at 10:50


Wooo ! In one of your videos you mention using molten KOH to 'activate' carbon !

Any references to that process please ?

P.S. well made and interesting videos BTW.




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chironex
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[*] posted on 16-11-2016 at 08:27


The most interesting use of molten hydroxide i've seen is this process for converting hemp to incredibly high energy density supercapacitor materials. If you can't get access I can dig up the paper and share it

https://ecs.confex.com/ecs/228/webprogram/Paper59165.html

And thanks! glad you like them :)
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