Synthesis of diethyl malonate
Preparation of raw materials
To synthesize diethyl malonate, ethanol, chloroacetic acid, sodium cyanide, concentrated sulfuric acid and other raw materials need to be prepared. Ethanol needs to be selected with high purity to ensure a smooth reaction. Chloroacetic acid also needs to be of high quality and free of impurities. Sodium cyanide is highly toxic, so it must be used with caution and follow strict safety procedures. Concentrated sulfuric acid is a highly corrosive acid, and it is well protected during operation.

Reaction steps
1. ** Preparation of sodium chloroacetate **: In a clean reactor, pour an appropriate amount of chloroacetic acid, slowly add sodium hydroxide solution, and stir at the same time. This step is designed to neutralize chloroacetic acid and generate sodium chloroacetate. The reaction is carried out mildly, and the temperature needs to be controlled within a certain range to avoid overreaction.
2. ** Synthesis of sodium cyanoacetate **: The obtained sodium chloroacetate solution is added with sodium cyanide. This reaction needs to be carried out under specific conditions. Sodium cyanide is highly toxic, the environment is closed and well ventilated, and the reaction process and conditions are strictly monitored to ensure complete conversion.
3. ** Formation of diethyl malonate **: Mix sodium cyanoacetate with ethanol and add concentrated sulfuric acid dropwise. Concentrated sulfuric acid is used as a catalyst to promote the reaction. During the reaction process, pay close attention to changes in temperature and pressure, and adjust it in a timely manner. After the reaction is completed, diethyl malonate is purified through distillation, extraction and other processes.

Precautions
1. ** Safety is paramount **: Both sodium cyanide and concentrated sulfuric acid are extremely dangerous. Contact with sodium cyanide, the protective equipment is complete, and it should be thoroughly cleaned after operation. Use concentrated sulfuric acid, pour it carefully, and prevent splashing and hurting people. In case of inadvertent contact, take correct first aid measures immediately.
2. ** Control of reaction conditions **: Each step of the reaction requires strict requirements on temperature, pressure, and the proportion of reactants. Precise control is required to obtain high-purity products. Continuous monitoring of the reaction process, and timely adjustment of deviations.
3. ** Purification of product **: After the reaction, the product contains impurities and needs to be purified by suitable methods. Distillation and extraction operations are standardized to ensure the purity and quality of diethyl malonate.