Is there anyone who has used Swagelok reactor (basically a small stainless steel autoclave without Teflon lining to be kept inside tube furnace, images attached) for magnesiothermic reduction of silica? I was wondering what precautions must one take while conducting this reaction? Here are the brief concerns that I have; minor doubts. If someone could answer any of them, it would be highly appreciated. I have a 7 ml vessel.
1. The reaction sample will be less than 1 g including Mg powder (1:0.5) and temperature absorber. The pressure limit that vendor told us is 30-50 mPa. Can the pressure rise above this pressure after reaction takes place ? I guess it should be okay because there is no liquid and the Mg powder vapours can't raise pressure above that.
2. Although, I plan to use NaCl, I am not sure if the temperature of the vessel might rise above 1100 degrees. What happens to the glass tube where it touches the reactor? Can it damage the glass?
3. Is it better to mix the reagents or should they be placed in layers?
4. Can Mg vapors penetrate and react inside mesopores?
5. Will the reaction damage the steel surface inside the reactor? Could the reactor be used again?
Many thanks to respondents in advance!
You can mix with NaCl as heat release agent.
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Adding NaCl limits the reaction temperature to 850-1100 degrees Celsius, even at a ratio of 10:1 of NaCl to sample. I am not sure if glass tube in the furnace can sustain that temperature, especially at the portion of reactor which touches the tube as I explained in point 2. Thanks for the article.
Just read the paper. Their reaction conditions are different. They did not carry out the reaction in furnace. I need to preserve the carbon nanostructure around the silica nanoparticles, so I cannot risk that by using similar conditions in addition to the fact that I am carrying out the reaction (MRR) in tube furnace.
If you are trying to carry out magnesiothermic reduction, I would suggest doing that in lower quantities. One, because even if you find a Swagelok reactor this big, you won't be able to fit it in the furnace. Secondly, if the reactor is not properly sealed (I seal it under Ar atmosphere in a glove box,) the produced hydrogen can cause explosion. An accident happened here in China few years ago where they tried such reaction in bulk (it was a very big centrifuge with more than 20 kgs sample.) I did not face any problem with the reactor that I use. I keep temperature at 750 and add NaCl (1:4) to compensate heat transfer and my sample size is 1-2 g. Here is a very good review if you want more information.
Review: 10.1039/c6tc02055k
Another good paper: 10.1038/srep02222
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