Prepn process of cyclic phosphonate compound

[0015] Example 1: Intramolecular dehydration and ring closure of methanol as solvent to synthesize HCA

[0016]

[0017] (1). Preparation of HPPA

[0018] 1400 kilograms of OPP, 1200 kilograms of phosphorus trichloride, 25 kilograms of zinc chloride are added in 5000 liters of reaction kettles, slowly be warming up to 70 ℃ of refluxes, then gradually be warming up to 120-165 ℃, maintain reaction 10-30 hours, the reaction solution by Colorless to orange is the end point of the reaction. After the reaction was completed, the temperature was lowered to 60-100° C., and 1600 kg of toluene was added to dissolve the generated DOP-Cl. The insolubles were removed by filtration. 400 kg of water was added dropwise to the filtrate for hydrolysis, and the hydrolysis reaction was carried out at 30-80° C. and completed in about 2 hours. After the reaction was completed, the material was lowered to 25° C., crystallization was precipitated, and centrifugation was performed to obtain 1967 kg of HPPA wet product with a solid content of 85%. The HPLC (normalization method) analysis product purity was 99.2%, and the OPP content was 0.2-1.5%.

[0019] (2). Preparation of HCA

[0020] 300 kilograms of above-mentioned HPPA wet products, 150 kilograms of methanol and 1.5 kilograms of BHT are dropped into the reactor, stirred and heated to 70-100 ℃, carry out atmospheric distillation for 1-2 hours, then be warming up to between 110-130 ℃ and carry out underpressure distillation (The pressure is kept below -0.095Mpa), and it is steamed until there is no fraction (about 0.5 hours). Introduce nitrogen to normal pressure, between 100-130 ℃, discharge to drier, solidify to obtain 255 kg of white flakes, HPLC (normalization method) analysis (the same below) product purity: 99.0%, yield 94.0 %% (calculated in OPP). Melting point: 118-119℃, OPP content 0.02%, chloride ion content 35ppm.

[0021] The product structure has been confirmed as HCA by NMR verification, and the NMR data are as follows:

[0022] 1 H NMR (CDCl 3 , 300MHz)δ9.050, 7.074(s, P-H), 7.29(d, J=8.4Hz, 1H), 7.29(t, J=8.4Hz, 1H), 7.41(td, J=8.4Hz, 0.9Hz, 1H), 7.55(td, J=7.8Hz, 3.0Hz, 1H), 7.75(t, J=7.8Hz, 1H), 7.92(ddd, J=13.2Hz, 7.8Hz, 0.9Hz, 1H), 7.96( d, J=8.4Hz, 1H), 7.98 (d, J=8.4Hz, 1H).

[0023] The melting point of HCA was determined with a Pekin-Elmer DSC-7 thermal analyzer, the heating rate was 20°C/min, and the DSC curve had only one absorption peak at 119°C.

[0024] Example 2 Ethanol is used as solvent to synthesize HCA by intramolecular dehydration and ring closure

[0025] Feeding and operation steps are the same as Example 1, and the solvent is replaced with 150 kilograms of ethanol. Obtained 254 kg of white flake product, purity: 99.1%, yield 93.6%. Melting point: 118-119℃, OPP content 0.03%, chloride ion content 30ppm.

[0026] Example 3 Intramolecular dehydration and ring closure of water as solvent to synthesize HCA

[0027] Feeding and operation steps are the same as Example 1, and the solvent is replaced with 150 kg of water. 255 kg of white flakes were obtained, purity: 99.2%, yield 94.0%. Melting point: 118-119℃, OPP content 0.01%, chloride ion content 30ppm.