"the scientific article seems to heat the mixture to 100°C for 6 hours, although Dreamer claims to have heated the mixture using a water bath, and
that can't be used very functional above 70°C (else it would just be slowly vaporized). These two descriptions seem contradicting. "
The first article is not as well written as the second. The first say "All was refluxed for 6h on a water bath", when reflux means to boil with a
condenser attached so that the reaction stays at the BP of the lowest BP component of the mixture. None of the reactants there boil below 100C, I
believe, so they were really held at some temp at or below 100C, which is what the second prep says more clearly. But it is quite possible to keep
water at near 100C for a while, I do it often in water baths, you just have to refill them often.
"Also, the scientific article describes adding glacial acetic acid. I was not able to find a reason for this in my literature."
Often changing the polarity of the solvent will change the reaction rate, as well as change the pH of the reaction. Acetic acid is used for both
reasons in many other reactions, as well as it might help to dehydrate intermediate to the product. But often papers don't say why an additive was
used, the key is that they give the specific amounts and procedure, as often it is not exactly clear why an additive is used. There are still people
fighting over the exact mechanism of many reactions by giving opposite reasons why a certain chemical changes the reaction outcomes. The key to good
science is stating what you did clearly; the reproducibility does not depend on a valid mechanism, only a good experimental writeup.
"At last I wonder if heating nitroalkyl compounds, such as nitroethane, to 100°C is very safe when working with somewhat larger quantities."
While nitroethane is stable, any fumes will be highly flammable, so this work should be done in a safe hood that has a non-sparking blower. The
larger any experiment is scaled to, the more dangerous. Look at the number of refinery explosions which have occurred despite being run by teams of
skilled chemical engineers. Having seen at least one nitromethane reaction explode in the hands of a very experienced chemist, I can safely say that
no reaction with nitro compounds is without some danger and a strong need for caution. |
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The end results
from the effort applied