maxpayne
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Diazotization safety
When an amine reacts with nitrous acid and HX in aq. solution, diazonium compound is formed. If temperature is higher than 5°C, this compund is
unstable and N2 gas is formed, and halogen replaces the amine group.
Why this process do not cause dramatic energy release as is when diazonium compound is isolated as crystals and detonated?
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Nicodem
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Quote: Originally posted by maxpayne  | | If temperature is higher than 5°C, this compund is unstable and N2 gas is formed, and halogen replaces the amine group.
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Where did you get that from? There is no such rule of the 5 °C. Diazonium compounds can either decompose immediately upon formation, deprotonate to
diazo compounds, or form isolable and stable salts at room temperature or higher. It all depends on their structure.
| Quote: | | Why this process do not cause dramatic energy release as is when diazonium compound is isolated as crystals and detonated? |
Obviously a reaction, even if highly exothermic, can never be as dramatic as a detonation. Reaction kinetics and shock waves make a world of a
difference.
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DraconicAcid
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| Quote: | | Quote: Originally posted by Nicodem | | Quote: Originally posted by maxpayne | | Why this process do not cause dramatic energy release as is when diazonium compound is isolated as crystals and detonated? |
Obviously a reaction, even if highly exothermic, can never be as dramatic as a detonation. Reaction kinetics and shock waves make a world of a
difference. |
An exothermic reaction in solution has the solvent to absorb most of the heat generated. The heat given off by the decomposition of a substance in a
crystal is transferred only to the parts of the crystal surrounding the bit that gave it off, which heats those parts up dramatically and causing them
to decompose as well. Then they give off heat, destroying their neighbors, and so on, and so on. |
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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maxpayne
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| Quote: Originally posted by Nicodem | | Quote: Originally posted by maxpayne | | If temperature is higher than 5°C, this compund is unstable and N2 gas is formed, and halogen replaces the amine group.
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Where did you get that from? There is no such rule of the 5 °C. Diazonium compounds can either decompose immediately upon formation, deprotonate to
diazo compounds, or form isolable and stable salts at room temperature or higher. It all depends on their structure.
| Quote: | | Why this process do not cause dramatic energy release as is when diazonium compound is isolated as crystals and detonated? |
Obviously a reaction, even if highly exothermic, can never be as dramatic as a detonation. Reaction kinetics and shock waves make a world of a
difference. |
I get it from Wikipedia : Diazonium_compound
"In aqueous solution diazonium salts are unstable at temperatures above +5 °C; the -N+≡N group tends to be lost as N2 (nitrogen
gas)."
So, this is not a general rule?
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maxpayne
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| Quote: | | Quote: Originally posted by DraconicAcid | | Quote: Originally posted by Nicodem | | Quote: Originally posted by maxpayne | | Why this process do not cause dramatic energy release as is when diazonium compound is isolated as crystals and detonated? |
Obviously a reaction, even if highly exothermic, can never be as dramatic as a detonation. Reaction kinetics and shock waves make a world of a
difference. |
An exothermic reaction in solution has the solvent to absorb most of the heat generated. The heat given off by the decomposition of a substance in a
crystal is transferred only to the parts of the crystal surrounding the bit that gave it off, which heats those parts up dramatically and causing them
to decompose as well. Then they give off heat, destroying their neighbors, and so on, and so on. |
I did not expect such beautiful explanation! Thanks!! |
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DraconicAcid
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| Quote: Originally posted by maxpayne |
I get it from Wikipedia : Diazonium_compound
"In aqueous solution diazonium salts are unstable at temperatures above +5 °C; the -N+≡N group tends to be lost as N2 (nitrogen
gas)."
So, this is not a general rule? |
*Very* general. Some are more stable than others, and they can decompose by different pathways.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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