Preparation method of vitamin A acetate
A technology of acetate and vitamin, which is applied in the field of preparation of vitamin A acetate, can solve problems such as difficult to handle, high price of triphenylphosphine, difficult production control, etc., and achieve an effect that is beneficial to industrial production
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Embodiment 1
[0062] Add 1249g (10mol) of bromoethanol and 290g (5mol) of acetone to a 3L three-necked flask, heat up to 40°C, add 1g (0.01mol) of concentrated sulfuric acid, keep the temperature for 6 hours, and the single-pass conversion rate of acetone is 26%. Separation by distillation, the temperature was 80°C, the pressure was 10KPaA, the number of plates = 50, and the reflux ratio was 10:1, to obtain 316.5g (1.1mol) of ketal compound with a GC purity of 99.8%. The ketal compound was qualitatively analyzed by NMR, 1H NMR (300MHz, CDCl3): δ=3.96(t, JH-H=6.3Hz, 4H), 3.69(t, JH-H=6.3Hz, 4H), 1.25(s, 6H).
[0063] Add 298.2g (2.1mol) of pentacarbonaldehyde, 500g of tetrahydrofuran, 49.9g (2.08mol) of magnesium powder into a 3L three-necked flask, raise the temperature to 60°C, and slowly drop the mixture of 289.9g (1mol) of ketal compound and 300g of tetrahydrofuran Add it to the three-necked flask, the dropping time is 4 hours, the reaction temperature during the dropping process does n...
Embodiment 2
[0067] Add 2498g (20mol) of bromoethanol and 290g (5mol) of acetone to a 3L three-necked flask, heat up to 50°C, add 0.86g (0.005mol) of p-toluenesulfonic acid, keep the temperature for 4 hours, and the single-pass conversion rate of acetone is 36%. The liquid was subjected to rectification and separation at a temperature of 120°C, a pressure of 15KPaA, the number of plates=50, and a reflux ratio of 10:1 to obtain 434.8g (1.5mol) of ketal compound 1 with a GC purity of 99.8%.
[0068] Add 269.8g (1.9mol) of pentacarbonaldehyde, 500g of tetrahydrofuran, 45.5g (1.9mol) of magnesium chips into a 3L three-necked flask, raise the temperature to 50°C, and slowly drop the mixture of 289.9g (1mol) of ketal compound and 300g of tetrahydrofuran Add it into the three-necked flask, the dropping time is 5h, the reaction temperature during the dropping process does not exceed 65°C, continue to react at 60°C for 2h after the dropping is completed, and slowly add the reaction solution into the...
Embodiment 3
[0072] Add 6245g (50mol) of bromoethanol and 290g (5mol) of acetone to a 3L three-necked flask, heat up to 50°C, add 1.72g (0.01mol) of p-toluenesulfonic acid, keep the temperature for 4 hours, and the single-pass conversion rate of acetone is 38%. The liquid was subjected to rectification and separation at a temperature of 50°C, a pressure of 2KPaA, the number of plates = 50, and a reflux ratio of 10:1 to obtain 463.8g (1.6mol) of ketal compound with a GC purity of 99.7%.
[0073] Add 255.6g (1.8mol) pentacarbonaldehyde, 1000g tetrahydrofuran, 43.2g (1.8mol) magnesium chips to a 3L three-necked flask, raise the temperature to 40°C, and slowly drop the mixture of 289.9g (1mol) ketal compound and 300g tetrahydrofuran Add it into the three-necked flask, the dropping time is 2h, the reaction temperature during the dropping process does not exceed 65°C, continue the reaction at 50°C for 5h after the dropping is completed, and slowly add the reaction solution into a 5L three-necked ...
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