In the process of making controlled substances (such as explosive, highly toxic, easily toxic chemicals or highly active compounds), certain chemical reactions require special caution due to their dangerous nature. The following are the key reaction types and safety precautions： --- ### **1. Nitrification reaction (nitration)** -**Risk**: Nitrification reactions (such as the preparation of nitro compounds, TNT, etc.) are violently exothermic, which may cause explosions. Strong acids such as nitric acid and sulfuric acid can easily get out of control when mixed with organic matter. -**Precautions**： -Strictly control the temperature (ice bath or gradually add reagent drop by drop). - Avoid local overheating or excessive concentration. -Use explosion-proof equipment (such as pressure-resistant reactors, safety shields). --- ### **2. Oxidation reaction (Oxidation)** -**Risk**: The reaction of strong oxidizing agents (such as potassium permanganate, hydrogen peroxide, ozone) with organic matter may cause combustion or explosion (such as the accumulation of peroxide). -**Precautions**： - Avoid contact with reducing substances. - Monitor the reaction rate to prevent the generation of peroxide by-products. -Use inert gas protection (such as nitrogen). --- ### **3. High pressure or high temperature reaction** -**Risk**: Reactions (such as hydrogenation and polymerization) in autoclaves or airtight containers may explode due to a sudden rise in pressure. -**Precautions**： -Regularly check the pressure resistance of the container. -Install a pressure release valve and an automatic pressure relief device. - Avoid over-temperature and over-pressure operation. --- ### **4. Halogenation reaction (Halogenation)** -**Risk**: Halogen gases such as fluorine and chlorine or halogenated reagents (such as PCL₅ and SOCL₂) are highly corrosive and toxic, and may leak or cause severe reactions. -**Precautions**： - Operate in the fume hood to ensure that the gas absorption device is effective. - Wear chemical-proof gloves and masks to prevent contact with the skin or inhalation. --- ### **5. Reduction reaction (Reduction)** -**Risk**: Metal hydrides (such as LiAlH, NABH, etc.) react violently with water to release hydrogen gas and explode in case of fire. -**Precautions**： - Strictly operate without water and use dry solvents. -Slowly add the reagent drop by drop to avoid severe exothermia. --- ### **6. Diazotization reaction (Diazotization)** -**Risk**: Diazo salts (such as aromatic diazo compounds) are extremely unstable and may decompose and explode. -**Precautions**： -Operate at low temperature (0-5℃). - Avoid light, friction or long-term storage. --- ### **7. Reactions involving metal organic compounds** -**Risk**: Grignard reagent (Grignard reagent) or organolith reagent reacts violently with water and oxygen, and may spontaneously ignite. -**Precautions**： -Strictly isolate water and oxygen (inert gas protection). -Use dry glass instruments and solvents. --- ### **8. Distillation and purification steps** -**Risk**: When distilling high-boiling or heat-sensitive substances (such as ether peroxides), the residues may spontaneously ignite or explode. -**Precautions**： -Avoid steaming and drying, and check the stability of residues regularly. -Use explosion-proof zeolites and temperature control devices. --- ###**General security measures** 1. **Risk assessment**: Consult the Material safety Data Sheet (MSDS) in advance to assess the thermodynamic and kinetic risks of the reaction. 2. **Small-scale trial**: Use the minimum feasible amount when trying for the first time, and gradually scale it up. 3. **Personal protection**: Wear chemical-proof clothing, goggles, gloves, and be equipped with emergency showers and eye washes. 4. **Ventilation and isolation**: Operate in a fume hood or explosion-proof area, away from fire sources and static electricity. 5. **Emergency plan**: Prepare fire extinguishers (such as CO灭火器 fire extinguishers), sandboxes, and emergency shutdown procedures. --- ###**Summary** Special caution is required for operations with severe exothermic effects, involving unstable intermediates or highly toxic substances. Strict compliance with operating procedures, combined with engineering control and personal protection, can minimize the risk of accidents.