The main physical and chemical properties of ethyl 4-chloroacetoacetate include:
Appearance: transparent colorless to light yellow liquid with acetic acid odor.
Density: 1.2±0.1 g/cm³, boiling point varies from source to source, 235.5℃ (760 mmHg) under normal pressure, but may be as low as 103℃ under reduced pressure.
Melting point and flash point: melting point is -8℃, flash point is about 96.7℃.
Solubility: slightly soluble in water (47.5 g/L, 20℃), easily soluble in organic solvents.
Hazard: corrosive and toxic, contact requires strict protection, storage needs to be away from oxidants.
Specific applications
As a key pharmaceutical and pesticide intermediate, its main application areas include:
Pharmaceutical synthesis: intermediates used in the synthesis of antibiotics, antiviral drugs and cardiovascular drugs.
Pesticide production: participate in the synthesis of herbicides and insecticides, such as some chlorine-containing organophosphorus pesticides.
Fine chemicals: It also has potential uses in dyes, fragrances and other fields.
Preparation method and steps
The current mainstream industrial preparation method uses ethyl acetoacetate and sulfuryl chloride as raw materials. The specific process is as follows:
Low temperature reaction: Cool ethyl acetoacetate to 0~5℃, slowly add sulfuryl chloride, and maintain low temperature to control side reactions.
Post-reaction treatment: After stirring at room temperature for 2~4 hours, heat to 35~55℃ to remove the generated SO₂ and HCl gases.
Distillation recovery: Recover the unreacted ethyl acetoacetate by vacuum distillation at 85~95℃ to achieve raw material recycling.
Product refining: Cool to 30℃ to obtain a crude product, and the purity can reach 97%~99% after further purification.
Key technical points: The reactor needs to be equipped with a precise temperature control system (such as a spiral heat pipe and a circulating liquid pump) and an efficient stirring device to ensure reaction uniformity and safety.