In the process of making controlled substances, the chemical reactions that need special attention mainly include the following categories to prevent accidents: 1. **Reaction of strong oxidants with combustibles**: When strong oxidants (such as hydrogen peroxide, nitric acid, potassium chlorate, etc.) react with combustibles (such as organic solvents, wood, paper, etc.), they may cause violent combustion or explosion. 2. **Acid-base neutralization reaction**: The reaction of strong acids and strong bases may release a lot of heat, causing a sudden rise in temperature and even splashing of solutions. Especially in large-scale operations, the reaction rate needs to be controlled. 3. **Gas generation reaction**: Some reactions will release toxic or flammable gases (such as hydrogen, carbon monoxide, etc.), which may cause pollution or explosion risks in confined spaces. Such reactions need to be carried out in a well-ventilated environment, and gas collection and treatment should be done well. 4. **Water reaction**: Some metals (such as sodium, calcium, etc.) react with water to generate hydrogen and release a lot of heat, which may cause fire or explosion, so such reactions need to be handled with special caution. 5. **Spouse reaction**: When synthesizing controlled substances, the reactants involved may interact with each other under certain conditions, produce unexpected by-products or trigger chain reactions. It is necessary to carefully monitor the reaction conditions. 6. **Thermal decomposition reaction**: Some compounds may undergo thermal decomposition under certain conditions, releasing toxic gases or causing explosions. Therefore, the temperature must be strictly controlled during the heating process. 7. **Photosensitive reaction**: Some chemical reactions are sensitive to light and may undergo unexpected reactions or decomposition under light conditions. They need to be carried out under light-proof conditions. When conducting these reactions, it is important to strictly follow the operating procedures, wear appropriate personal protective equipment, and ensure that there are complete emergency response measures and monitoring systems. At the same time, necessary safety training should be provided to laboratory personnel to improve safety awareness.