| 70% |
|
(11) Add 400 mL of absolute ethanol to a 1000 mL three-neck reaction flask, turn on the stirrer. Add 42 g of anhydrous potassium carbonate and 36 g of ethyl 2-oxobutanoate, the intermediate product obtained in step (9), and stir well. (12) Turn on the integrated hot and cold exchanger and control it at 25 C. Slowly add 17.5 mL of acetaldehyde solution to the reaction flask through a peristaltic pump. The dropping time was controlled at 2h, and stirring was continued for 1h after the dropping was completed. The reaction solution was transferred to a rotary evaporator. (13) Turn on the rotary evaporator, raise the temperature to 79 C, and recover the ethanol solution at normal pressure for application. Collect the flask base and transfer to the reaction flask. (14) Turn on the magnetic stirrer, add 120 mL of 10% dilute hydrochloric acid to the reaction flask, and continue stirring for 30 min, then add 65 mL of ether solution for extraction, and transfer to a separatory funnel. (15) The layers were allowed to stand for 2 hours, and the organic layer was separated. The aqueous layer was extracted twice with 65 mL of an ether solution. After the layers were allowed to stand for separation, the aqueous layer was separated, and the organic layers were combined. (16) The organic layer obtained in step (14) was washed twice with 50 mL of a saturated sodium chloride solution, and the aqueous layer was separated after being separated. The organic layer was dried over anhydrous sodium sulfate, and then transferred to a rotary evaporator.(17) Turn on the rotary evaporator, heat to 35 C, recover ether at normal pressure, and apply it. The vacuum was turned on, and the distillation was performed under reduced pressure at a temperature of 90 to 95 C. and a vacuum pressure of 1333 Pa, and the distillate was collected to obtain 25 g of fenugreek lactone flavor product with a yield of 70%.The prepared fenugreek lactone was a colorless transparent liquid with strong fenugreek aroma and caramel aroma. The purity of the product was 98.36% by gas chromatography. The refractive index (20 C) was 1.491 and the relative density (25 C). It is 1.049, which is consistent with the literature value. |
| 18.5 kg |
With potassium carbonate; In ethanol; at 25℃; for 4h;Large scale; |
(12) First add 120kg of absolute ethanol to a 250L reaction kettle with a distillation tower through an ethanol high-level tank,Start the stirrer and meter in 29kg of anhydrous potassium carbonate through the hand hole of the reaction kettle.The intermediate product, ethyl 2-oxobutanoate, obtained in step (11) was metered in through a high-position tank and stirred well. (13) Turn on the reactor to circulate cooling water, and control the temperature of the kettle at 25 C.Slowly add 9 kg of acetaldehyde from the acetaldehyde high-level tank to the reaction kettle through a dropping pump.The dropping time was controlled at 2 hours. After the dropping was continued, stirring was continued for 2 hours, and then the reaction was terminated. (14) Open the steam valve of the reactor and the circulating cooling water valve of the condenser at the top of the tower, and raise the temperature to 79 C.Recover the ethanol solution at normal pressure. When the top of the tower is not discharged or the temperature of the top of the tower drops, the recovery of ethanol ends.The recovered ethanol is transferred to an ethanol high-level tank for application, and the reaction liquid at the bottom of the kettle is transferred to a cone-bottomed stirring pot. (15) Turn on the stirrer, add 10% hydrochloric acid to adjust the reaction solution to detect pH = 7, continue to stir for 1h, and then stand for 2h to separate the organic layer.The aqueous layer was metered into the dichloromethane solution for extraction 3 times, and 50 L of dichloromethane was added for each extraction.After standing and layering, the separated water layer was transferred to a sewage treatment station for processing, and the organic layer was combined and transferred to a 250L washing pot. (16) combining the organic layers obtained in step (15) into a washing pot,50 L of saturated sodium chloride solution was metered in and washed. After stirring for 2 hours, the layers were left to stand for 2 hours.It was applied during the next batch of washing, and the organic layer was transferred to a 250 L dehydration kettle filled with anhydrous sodium sulfate. (17) After the organic layer obtained in step (16) is dried and dehydrated with anhydrous sodium sulfate in a dehydration kettle for 2 h,Solid-liquid separation through solid-phase automatic filterThe liquid phase is transferred to the distillation kettle of the kettle distillation column, and the solid phase is returned to the dehydration kettle for the next batch application. (18) Open the steam valve of the distillation kettle in step (17) and raise the temperature to 40 C.Recover the dichloromethane solution at normal pressure and transfer it to the high dichloromethane tank for recycling.When the temperature at the top of the tower drops or no material is discharged from the top of the tower, it is applied after the recovery of methylene chloride.The vacuum was turned on, and distillation was performed under reduced pressure at a temperature of 90 to 95 C. and a vacuum pressure of 1333 Pa, and the distillate was collected to obtain 18.5 kg of fenugreek lactone flavor product. The GC conditions for product testing are: Column HP-5 (30m × 0.32mm × 0.25um); Detector FID, temperature 250 ; Injection:The injection volume is about 0.2ul, the split ratio is 1: 100, and the inlet temperature is 250 C; carrier gas:N2, flow rate 20L / min, pre-column pressure 34.47kPa; chromatography furnace temperature:The linear programmed temperature rise was from 80 C to 220 C, the rate was 10 C / min, and the retention time was 20 minutes. The detected fenugreek lactone synthetic flavor was a yellow transparent liquid.Has a strong fenugreek aroma and caramel-like aroma. The purity of the product is 98.21% by gas chromatography.The detection refractive index (20 C) was 1.491, and the relative density (25 C) was 1.0487. |
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