Method for cleaner production of vitamin A intermediate product

[0044] Add 276 grams of diethyl phosphite, 114 grams of diethoxymethane, 50 grams of absolute ethanol, and 2 grams of p-toluenesulfonic acid into a dry 1000 ml glass flask, and heat up to 75-80 ° C for 5 hours , GC detected that the reaction of phosphite diester was complete, cooled to 20°C, added 5 grams of 28wt% sodium ethoxide ethanol solution to neutralize, distilled in a vacuum oil bath at 180°C, collected 130-136°C / 12 mbar fractions, and obtained methylene 265 grams of tetraethyl diphosphonate, GC purity 99.5%, yield 92.0%. The product has been compared with the standard product, and the GC peak time is the same, and the ion flow diagram of the GC-MS (gas chromatography-mass spectrometry) product is shown in figure 1 ; and the product has been confirmed by GC-MS to have the correct molecular weight, and the GC-MS mass spectrum is shown in figure 2 .

[0046] Add 276 grams of diethyl phosphite, 114 grams of diethoxymethane, and 2 grams of p-toluenesulfonic acid to a dry 1000 ml glass flask in sequence, raise the temperature to 75-80 ° C for 5 hours, and detect the diethyl phosphite by GC. The ester reaction is complete, cooled to 20°C, neutralized by adding 5 grams of 28wt% sodium ethoxide ethanol solution, distilled in a vacuum oil bath at 180°C, collecting fractions at 130-136°C / 12 mbar to obtain tetraethyl methylene diphosphonate 259 grams of ester, GC purity 99.3%, yield 89.9%.

[0048] Add 276 grams of diethyl phosphite, 85 grams of dimethoxymethane, and 2 grams of p-toluenesulfonic acid to the dry 1000 ml reaction kettle in sequence, gradually raise the temperature to 45-50 ° C for 2 hours, and normal pressure to 0.5 MPa, react at 85-90°C for 3 hours, GC detects that the reaction of phosphite diester is complete, cool to 20°C, add 5 grams of 28wt% sodium ethoxide ethanol solution to neutralize, distill at 180°C in a vacuum oil bath, collect at 130-136°C / 12 millibar fraction to obtain 261 grams of tetraethyl methylene diphosphonate, GC detection purity 99.1%, yield 90.6%.

[0049] Embodiment 4-embodiment 12: method step is as embodiment 1, difference is to prepare tetraethyl methylene diphosphonate or tetramethyl methylene diphosphonate under different conditions with different starting materials , the specific raw material ratio and reaction conditions, solvent, catalyst, neutralizer, product name, GC purity, product quality and yield are listed in t