反应详情

温度

110 °C

To a 1000 ml four neck flask fitted with mechanical agitator, thermometer, Dean and Stark apparatus and water condenser, add 237.5 g (2.23 mol on pure substance) 80 wt.-% cyanoacetic acid in water, 440 g (3.38 mol) 2-ethylhexanol and 1.2 g (6.3 mmol) p-toluenesulfonic acid monohydrate. Afterwards, the mixture is heated to reflux (110° C.) under atmospheric pressure for 1 hour and the water (both initial and formed) is azeotropically distilled out using a Dean and Stark apparatus returning the upper organic layer to the reactor. After 1 hour and at a temperature of 130° C. gradually a vacuum of 400 mbar is applied using a water respirator. The azeotropic distillation is maintained for further 6 hours while gradually increasing the vacuum from 400 mbar to 30 mbar in order to maintain a temperature of 130° C. until no further water is removed. After releasing the vacuum the reaction mixture is cooled to 90° C. After the addition of about 100 ml water (pre heated to 90° C.), the mixture is stirred at 85-90° C. for 10 minutes before separation of the phases. The upper organic layer is transferred to a 1000 ml four neck flask fitted with mechanical agitator, thermometer, packed column (ID=30 mm, H=1200 mm, packing metal raschid rings D=7 mm), water condenser and distillate flasks. Excess 2-Ethylhexanol is distilled out at 130-140° C. under a vacuum of 10-30 mbar. When complete increase the vacuum to 1.5 mbar and distilled out 2-ethylhexyl cyanoacetate at 130-140° C. 2-Ethylhexyl cyanoacetate is obtained as a colourless liquid. The reaction yield is 92% (based on cyanoacetic acid).

1. temperatureAfterwards, the mixture is heated
2. distillationis azeotropically distilled out
3. customat a temperature of 130° C.
4. distillationThe azeotropic distillation
5. temperatureis maintained for further 6 hours
6. temperaturewhile gradually increasing the vacuum from 400 mbar to 30 mbar in order
7. temperatureto maintain a temperature of 130° C. until no further water
8. customis removed
9. temperatureis cooled to 90° C
10. additionAfter the addition of about 100 ml water (pre heated to 90° C.)
11. customfitted with mechanical agitator
12. distillationExcess 2-Ethylhexanol is distilled out at 130-140° C. under a vacuum of 10-30 mbar
13. temperatureWhen complete increase the vacuum to 1.5 mbar
14. distillationdistilled out 2-ethylhexyl cyanoacetate at 130-140° C