Organic peroxides (two)

3.

Organic peroxides are extremely sensitive to heat, vibration and friction, are easily decomposed, and are flammable and explosive

(1) Decomposition explosive and flammable

From the analysis of bond length and bond energy, H ₂ O ₂ molecule has an asymmetric chain structure, the -O-O- bond length is 0.

From the bond level analysis, the O ₂ ^2- in the H ₂ O ₂ molecule is diamagnetic, and has an isoelectronic structure with F2.

The decomposition of organic peroxides is an exothermic reaction.

(2) Explosion hazard of post-reaction processing

In the application practice of organic peroxides in organic synthesis, explosion accidents often occur due to ignorance of the dangerous properties of organic peroxides and violation of operating regulations

In order to improve the yield of oxidation and other reactions, organic peroxyacids are generally used in excess, and the molar ratio is usually 1.

(3) Organic peroxides with negative effects

Some organic compounds are not peroxides originally, but after exposure to air, peroxides are generated through free radical mechanism after exposure to light, which is dangerous, which is very troublesome

Case 1

When a doctoral student in a school was preparing to take the unused and dried THF in a single-necked flask, the hollow plug exploded as soon as he pulled out the ground hollow plug, resulting in a bloody face

Case 2

A doctoral supervisor in a school exploded violently while concentrating the ether extract, and the glass of the locker on the console was blown to pieces by splashed glass.

Case 3

A researcher used ether that had been stored for a long time for extraction, and then concentrated and evaporated the ether at low temperature under reduced pressure.

1.

In addition to ether compounds, some compounds composed of weak C—H bonds and double bonds that are easy to cause polymerization will also undergo oxidation reactions at room temperature in contact with air, forming unstable and explosive organic peroxides, see table 16-2

Table 16-2 The structure of groups that easily form organic peroxides in the air

The items listed in Table 16-2 will generate organic peroxides after long-term contact with air.

The formation and rate of peroxide formation are directly related to factors such as exposure to air, light, heat, humidity, and metal pollution

The peroxide is most likely to be formed at the contact point between the inner and outer threads of the container and the lid, because the organic vapor is blocked here, and it is oxidized into a higher boiling point organic peroxide in long-term contact with air
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If there is already obvious peroxide formation in the liquid, as well as the presence of crystals or precipitates, it will explode due to friction when the cap is unscrewed or tightened
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Related links: Organic peroxides (1)