1. The diethyl phosphite was heated to 90 ° C and nitrogen was passed for 30 min. A small amount of initiator was added, vinyl chloride was introduced, and the addition reaction temperature was controlled to obtain diethyl 2-chloroethylphosphinate. Then, the addition product is added to concentrated hydrochloric acid for hydrolysis, and refluxed at 120-130 ° C for 24 hours to obtain Ethephon, and part of the water is distilled off to obtain Ethephon, which can be formulated.
The raw material of the method is easy to obtain, the equipment is simple, the investment is small, the three waste waters are easy to operate, and the unreacted raw materials are easily recovered, and the total yield is 60% based on phosphorus trichloride.
2. Direct addition of phosphorus trichloride and ethylene oxide, synthesis of Ethephon by molecular rearrangement and acid hydrolysis. The addition temperature is 20 to 25 ° C, the molecular ratio is 1:3 (excess ethylene oxide), the rearrangement reaction is 220 to 230 ° C, and the acid hydrolysis temperature is 160 to 170 ° C.
3. Direct synthesis of ClCH2CH2P(O)Cl2 from ethylene, phosphorus trichloride and air (or oxygen) at low temperature or high pressure, and hydrolyzed to Ethephon. The production process is simple and the cost is low, but the equipment requirements are high and the operation requirements are strict.
4. The complex is formed by dichloroethane and phosphorus trichloride catalyzed by anhydrous AlCl3, hydrolyzed into ClCH2CH2P(O)Cl2, and further water is added to form Ethephon. The purity of this method is high, but the operation is complicated and the yield is still low.
What are the production methods of Ethephon
