反应详情

温度

70 °C

A 500 ml three necked round bottom flask equipped with a mechanical stirrer, thermometer and reflux condenser was charged with 3.54 g (0.0266 mol) L-aspartic acid, 14.94 g (0.0798 mol) L-cysteic acid and 133 ml water. Add 8.51 g (0.2128 mol) sodium hydroxide and 5.64 g (0.0532 mol) sodium carbonate with moderate stirring. The reaction mixture exotherms to about 40° C. After all has dissolved, add 80 ml ethanol and 12.5 g (0.0665 mol) ethylene dibromide. Heat the reaction mixture to reflux (~84° C.) for 24 hours. Replace the reflux condenser with a short path distillation head and distill off the ethanol and excess ethylene dibromide. Place the flask in a water bath, heat to 70° C. and remove trace amounts of ethylene dibromide under high vacuum. The crude yield of the reaction mixture was 34.6 g. This mixture was determined to contain salt, L-aspartic acid disodium salt, L-cysteic acid disodium salt, Na4EDC, Na4EDDS and Na4EAC. The purity of this product was found to be about 50-70% sequestrant by C13 nuclear magnetic resonance analysis.

1. temperaturethermometer and reflux condenser
2. customexotherms to about 40° C
3. dissolutionAfter all has dissolved
4. temperatureHeat the reaction mixture
5. temperatureto reflux (~84° C.) for 24 hours
6. distillationReplace the reflux condenser with a short path distillation head
7. distillationdistill off the ethanol and excess ethylene dibromide
8. customremove trace amounts of ethylene dibromide under high vacuum