(S)-(-)-Propylene Carbonate synthesis

Yield: 97%

Reaction Conditions:

with sodium methylate in methanol at 60 - 115; for 25 h;

Steps:

1.1; 1.2; 1.3; 1.4; 1.5 Example 1 Synthesis method of (S)-propylene carbonate
(1) Feeding800 kg of S-propylene glycol, 1600 kg of dimethyl carbonate and 8 kg of sodium methoxide solution were added to the reaction vessel, and heating and stirring were started.The sodium methoxide solution is a 30% sodium methoxide/methanol solution;The S-propanediol has a propylene glycol content of 99.5%, a moisture content of 0.5%, and a specific rotation of ≥16.80-17. (2) Temperature rise reactionFirst stage heating reaction The temperature is raised to 60-65 ° C, at which time a solution (mainly methanol, a small portion of dimethyl carbonate) is distilled off, received in the receiving tank, and the solution is evaporated; Second stage heating reactionThereafter, after about 12 hours, the temperature is raised from 65 ° C to 90 ° C, the solution is kept distilled, and the product is distilled as a by-product alcohol-based fuel (methanol and dimethyl carbonate); Third stage temperature rise reactionHeating was continued, and the temperature was raised from 90 ° C to 115 ° C for 8 hours, and the heating was stopped. (3) Cooling downThe temperature was lowered from 115 ° C to 60 ° C. The temperature in the reaction vessel is ≤90 ° C, and the alcohol-based fuel (mixed solution of methanol and dimethyl carbonate) is distilled off; most of the steam distilled out at >90 ° C is dimethyl carbonate, and a small amount of methanol is used as a reaction raw material for recovery. (4) Decompression reaction under reduced pressureStart decompression under reduced pressure, using vacuum distillation, vacuum degree ≥ -0.08mpa, the temperature rises at a rate of 0.2 ° C per minute,Continue to distill the solution (a mixture of methanol and dimethyl carbonate),Keep the solution evaporated, when the temperature rises to 120 ° C, basically no solvent comes out at this time,The pressure reduction and desolvation can be stopped, and the temperature is lowered; the remaining liquid in the reaction tank is (S)-propylene carbonate. In the crude (S)-propylene carbonate, the (S)-propylene carbonate content is 97% or more. From the start of the preparation to the preparation of the crude product, the reaction time was 25 hours. (5) Distillation reactionTransfer the remaining liquid after decompression and decompression to the rectification bottle, and turn on the heating and stirring.Vacuuming, ensuring a vacuum degree ≥ 0.1Mpa, starting the steaming before the fraction, steaming out about 100kg of the former fraction, and then transferring the finished product.The materials in the rectification tank were all distilled off, the rectification was stopped, and (S)-propylene carbonate was collected. The (S)-propylene carbonate has the following quality indicators:1. Appearance: colorless clear liquid;2, SPC chemical purity content (%): ≥ 99.8;3, SPC optical purity content (%): ≥ 99.4;4. SPC isomer content (%): ≤ 0.6;5. Moisture (%): ≤ 0.1; The yield of the finished SPC is 97%; the specific rotation is -2 to -3;

References:

Weifang Huitao Chemical Co., Ltd.;Liu Jianwei;Zhang Quansheng;Wei Lanxing;Hua Xian CN109369401, 2019, A Location in patent:Paragraph 0017-0026