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Author: Subject: Collecting fumes with glassware?
dennisfrancisblewettiii
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[*] posted on 14-8-2012 at 01:59
Collecting fumes with glassware?


A long time ago, and it's passed me now, I read something in a lab manual about collecting fumes from chemistry experiments. I think it had to do with a balloon and a funnel and somehow the fumes were eventually collected in the funnel.

Besides this, however, I'm more interested in how to collect fumes with glassware. And I understand that I'm generating this discussion too broad to be of too much use, but experiences with collecting fumes with glassware would be a much appreciated read by those participating. Yes, I used the search engine.

So, what I'm interested in is why does a person often have to bother with a fume hood in chemistry experiments?

Having worked with cell culturing, I find the fume hood to be extremely valuable to ward off invading pathogens and bacterial cells. So, I know of how valuable it is.

In relation to chemical synthesis, I see it as a fast and easy method if you have the money and ability to vent out the stuff, say in an industrial or academic lab. Thus, there isn't that desire to collect fumes and decompose them by another chemical synthesis.

However, in a home setting, I don't think having a fume hood is easy to buy nor use when dealing with very toxic chemicals (leading to some specificity of what fumes I would be dealing with).

As such, isn't it practical to find a way to collect the fumes in a flask, beaker, large glass jar, compress them (if necessary), and find a way to export them to a different area for destruction, break-down, decomposition, etc?

I'm sure this method would take much more time than for having a fume hood, but I think it would also give a further level of security if the fumes are adequately contained. Then again, as there would be glassware leading to the container, problems would obviously arise if attempting to disconnect things. So, there would need to be a way to seal the fume container before disconnecting the glassware.

I keep thinking that maybe having a tank of liquid nitrogen would be necessary in this situation. Then again, I have a feeling that immediately taking a gas/vapor out of such a situation may lead to immediate combustion or breaking of the glassware, thus more hell to deal with.

[Edited on 14-8-2012 by Genecks]
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Dr.Bob
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[*] posted on 14-8-2012 at 05:13


In some cases it is possible to keep "fumes" out, but most reactions require weighing and dispensing of chemicals, solvents, reagents into and out of a flask, during which time it cannot be sealed. Also, many reactions produce pressure, which cannot be allowed to build up in glass flasks (for obvious safety reasons). Lastly, many of the vapors, fumes, etc might not be compatible if compressed or stored together, and might be flammable, which makes compressing them bad (See Diesel engine concept for examples why compressing flammable gases might be bad idea.)

There are fume hoods that filter and trap fumes and vapors, but most are meant for very small amounts of solvent and fumes, and not particularly harmful ones (in general). But they are only useful for work within those very tight limits, and still require the filter material (particulate filters, carbon filters, etc) to be changed often, which is quite expensive. This is a case, where it might be doable for certain cases, but that limits the design a lot, and the logistics are much more complex that they might appear.
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SM2
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[*] posted on 14-8-2012 at 06:42


There's a very nice ghetto set-up right here in SM which consists of drilling a hole in one of your sinks pipes, post loop. Your unwanted effluent is led through this, and eventually finds it's way to the sanitary sewer.
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dennisfrancisblewettiii
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[*] posted on 15-8-2012 at 00:15


Hello, Dr. Bob.

So, from what I gather from what you have discussed, it would be wise to find a way to regulate the amount of pressure in the glassware system, thus preventing combustion, cracking, and destruction of the glassware from kinetic energy released from a reaction. I suspect this would be possible with the right gears and reading technology.

Do you think this would be a reasonable way to route pressure that becomes generated in the system?

To have a pressure regulator that limits the amount of undesired gas/fumes/vapors exporting the glassware into the collecting container?

With diesel engine fuel, I believe it becomes gelatinous when it becomes cold. However, I understand the complexities that may occur when some organic chemicals are released from cold storage, thus leading to possible explosion.

Something of interest to me is the ability to route the fumes to another container and then have them undergo a decomposition reaction with other chemicals to decrease their volatility and toxicity. I imagine a system where the volatile chemical is moved over a bath of other chemical that when the gas comes into contact with the reacting powder or liquid, the volatile compound decomposes and has decreased volatility (at best undergoing a formation reaction into a solid and/or liquid with a higher melting point and boiling point than previously occurring).

As another note, I have found that ace glass supplies a powder addition funnel, which may or may not generate a closed system with the glassware. This would enable the addition of powder. If the piece were glued into place and sealed, it would be a viable addition to generating a closed system.

Fennel Ass lh Tone,

This would not be a viable option for some toxic chemicals, as they may not be so easily broken down through the sewer system. Furthermore, releasing some chemicals into the environment would be illegal and environmentally unfriendly. As such, it is not of interest to me.


[Edited on 15-8-2012 by Genecks]
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RonPaul2012
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[*] posted on 16-8-2012 at 18:53


I just thought I would throw in my 2 cents.

I have done a few experiments that generate toxic fumes in a semi closed system e.g Chlorine.

The generated gas/vapor was led into a gas scrubbing bottle and neutralized.

I can't say how well this works but it might help if you had several gas washing bottle lined up in sequence.

This has the potential to be extremely dangerous.

For example , if you need to break the seal on your apparatus you run the risk of being exposed to whatever toxic byproducts you are working with :(

Please be safe and invest in a fumehood if you plan on doing experiments inside , otherwise do them outside with a respirator and a fan.

BTW, I use this http://i.ebayimg.com/t/NAPA-Grease-Dielectric-Silicone-1-oz-/00/$(KGrHqR,!hwE4p4P+uVRBOQeo5kpS!~~0_3.JPG to seal my glass joints and maybe a metal/plastic joint clip.
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dennisfrancisblewettiii
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[*] posted on 16-8-2012 at 23:42


Hello, RonPaul2012

Yes, I've continued to read about various scrubbing systems used in removing a particular chemical from the workbench environment. This can have the effect of collecting the chemical, yet making it somewhat impractical to re-obtain: Doesn't really decompose it but does "contain" it.

I've also come to understand that, although a fumehood or glovebox is very useful, it's also practical to use a big, plastic bag to work with chemicals. However, I've considered that if a chemical reaction is exothermic, it would need pressure release. I've recently come to learn about a hack-a-day nitrogen generator, which could provide useful in such an environment to prevent combustion of chemicals and reduce their kinetic nature by cooling the working environment for which the chemical of interest would be synthesized. Helium would also be a great and affordable alternative.

Nonetheless, that potential for gas release would increase the internal bag volume with due time, thus making it a somewhat unreasonable alternative for particular parts of the reaction.. Unless I had a really, really big plastic bag. I came about this knowledge from SFN and reading a graduate student's blog discussing the need to seal a chemical in a nitrogenous environment. It would easy to incinerate such a bag, considering I'm not making crazy BS like prions. But would be easier to dip it in some decomposing chemical for ease of toxin removal.

My apologies to all for having moved the discussion to a slight tangent of decomposition rather than collection. Considering that a chemical is toxic, it would be worthwhile to simply find a way to reduce it's environmentally toxicity from the workbench and worker.

As an interesting point, I've found that many people start discussing the use of scrubbers in chemistry much more in the 1970s, during an age which many potent and toxic chemicals came about. I assume the knowledge from that generation of chemists is useful, such as knowledge brought forth by chemist Charles R. Perry in the work of chemicals with amines and their gaseous collection.

A presentation by Charles R. Perry:
http://perrymanagement.com/news.php?extend.7


[Edited on 17-8-2012 by Genecks]
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RonPaul2012
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[*] posted on 17-8-2012 at 09:35


I would have to say that for lab work the simpler the better.

A stainless steel fumehood and a fire extinguisher would eliminate the danger of a fire breaking out.

Here is an example of what I am talking about http://www.sciencemadness.org/talk/files.php?pid=54302&a...

This was built by one of the forum members named Magpie.

Coming in contact with even small amounts of toxins is not worth it .

You have two choices say "Yes" to safety or say "No" to Chemistry :)

[Edited on 17-8-2012 by RonPaul2012]
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