Sciencemadness Discussion Board

Reaction Vessel Lining Materials

4-Stroke - 8-11-2024 at 10:01

Borosilicate glass is the material most laboratory equipment is made of, and industrial reactors are also glass-lined (when required), but glass lining reaction vessels is very hard for the amateur. Here are some ideas I came up with:

Lead
Lead lined reaction vessels have been used for over a century. Lead is fairly inert and temperature resistant. It is also soft which makes working with it easier. Considering that only a thin sheet is needed, lead is also pretty cheap.

Pros:
-Inert
-Temperature resistant
-Relatively cheap
-Malleable (easier to work with)

Cons:
-Hard to connect joints (blowtorch?)


Teflon (PTFE) Film
Used industrially in autoclave systems. PTFE is usually very expensive, but a very thin (0.1mm) film is relatively cheap. It is extremely chemically resistant (arguably even more so than glass) and fairly temperature resistant (>250°C). A 0.1mm film might be hard to work with, however. It is also very "slippery" and I don't know of any adhesives that could permanently attach it to the inside of a container (while also being temperature resistant).

Pros:
-Extremely inert
-Fairly temperature resistant
-Relatively cheap

Cons:
-Very fragile (a 0.1mm film)
-Very hard to permanently attach to the container


Water Glass (Sodium Silicate)?
If a steel container was "painted" with concentrated water glass, allowed to dry, and then heated with a blowtorch, the sodium silicate would decompose into silica gel (SiO2) forming a protective coating. I do foresee some problems with this (such as applying and keeping the water glass evenly distributed thought the entire container until it dries, making sure it doesn't crack during the decomposition, etc.), and while it is probably a crackpot idea, it is something nonetheless so I'll leave it here.

Pros:
-Extremely inert
-Very temperature resistant (it's essentially glass)
-Very cheap

Cons:
-Very hard to actually make
-Silica gel is very porous, so it (might?) let corrosive liquids pass through it


Sodium Silicate Bonded Glass Wool?
Similar to the previous idea, but different. This could be made by taking two identical containers (that can fit into each other), putting enough (to make a ~5-10mm layer when compressed) glass wool (or fiberglass insulation, it should be pure enough) in between them, soaking it with sodium silicate, keeping it all compressed in between the two containers until it dries, and then blasting it with a blowtorch to decompose the sodium silicate to silica gel as before. I suspect cracking will be less of a problem because of the glass wool.

Pros:
-Extremely inert
-Very temperature resistant (it's essentially glass fibers bonded with glass)
-Very cheap

Cons:
-Might be hard to actually make
-Will likely have poor heat transfer (it is made out of insulation after all), so will have to be heated internally as a flame/oil bath won't pass enough heat through this


Polycarbonate
Polycarbonate (PC) is like most plastics fairly inert while being significantly more heat resistant. PC has a working temperature of about ~130°C, which is enough for many reactions. PC sheets are also not very expensive. A PC sheet can be thermoformed to perfectly fit the inside of a container. If it is thick enough, it might even be possible to use it as a standalone reaction vessel (without any steel outer shell). It will, however, also have poor heat transfer and thus will have to be heated internally.

Pros:
-Fairly inert
-Fairly temperature resistant
-relatively cheap
-Easy to make and use

Cons:
-Poor heat transfer
-Not very heat resistant


What do you think?

Sir_Gawain - 8-11-2024 at 11:12

You can buy PTFE-coated frying pans, so there is a way to attach it to metal that can handle high temperatures.

Pumukli - 8-11-2024 at 11:19

Sorry, I can't really see the purpose of this "lining".

I'd rather chose an appropriate vessel (glass, steel (paint can), sometimes plastic (PP food grade things up to say 100 C) than trying to line something with either lead or glasswool soaked in Na-silicate.

Do you have something specific reaction in mind or just thinking about something that (for me) seems to be overcomplicating things?

I have the feeling that if a vessel with an amateur lining fails it would be very unhealthy for everyone nearby... And have the feeling that the proposed linings are harder to do properly than acquiring a proper vessel to start with.

4-Stroke - 8-11-2024 at 13:14

Quote: Originally posted by Sir_Gawain  
You can buy PTFE-coated frying pans, so there is a way to attach it to metal that can handle high temperatures.


Yes, that's what I thought about before too. I'm afraid that it might require high temperatures or expensive specialized equipment. But something that I think could be possible is buying ~1 micron PTFE dust, mixing it with some acetone, painting on the container, and when the acetone dries off, it should hopefully create a film. Premade PTFE emulsions are also sold quite cheaply. Do you think it will work?
Quote: Originally posted by Pumukli  
Sorry, I can't really see the purpose of this "lining".


Steel (even stainless) is easily corroded by chlorides, acids, some alkalis, and many other things, but with a lining, the steel provides the structural support while the lining provides chemical resistance. Apart from the significantly reduced price compared to an all-glass setup, this also has the advantages of higher thermal shock resistance, not cracking, easily scalable volume (up to a 55 gallon drum) and other things.
Quote: Originally posted by Pumukli  
I'd rather chose an appropriate vessel (glass, steel (paint can), sometimes plastic (PP food grade things up to say 100 C) than trying to line something with either lead or glasswool soaked in Na-silicate.


Me too! But I unfortunately don't have [tens of] thousands of dollars for a glass reactor. :( If someone gave me one, I sure wouldn't be doing all this.
Quote: Originally posted by Pumukli  
Do you have something specific reaction in mind or just thinking about something that (for me) seems to be overcomplicating things?


Both. I do have some specific reactions I would like to try, but also it is just nice to have a larger, cheaper, more-or-less-expendable container that is also easier to clean than real glassware!
Quote: Originally posted by Pumukli  
I have the feeling that if a vessel with an amateur lining fails it would be very unhealthy for everyone nearby...


Unless the vessel is pressurized (which it shouldn't be) I don't see how it would be any more "dangerous" than a normal flask imploding/breaking/cracking. The outer steel shell would also provide some amount of time (depending on the reactants) until it fails too.

Quote: Originally posted by Pumukli  
And have the feeling that the proposed linings are harder to do properly than acquiring a proper vessel to start with.


You're right! To get a proper vessel, you just pay a few thousand dollars and the vessel shows up at your door (or the DEA does)! But I unfortunately don't have that kind of money. Even second hand vessels are prohibitively expensive (for me). It's all just a balance of the amount of time or money you are willing to spend. For now, I've got more time then money. Plus, this vessel could be used as something expendable unlike a "real" one.

To be honest, I don't know if all the things I proposed are even feasible, but because I don't know, I'm asking for the opinion of people more knowledgeable and experienced than I am.