反应详情

In a three neck 500 mL RB flask equipped with a reflux condenser, a Dean-Stark trap and under nitrogen, 2-butyl-2-ethyl-1,3-propanediol (35.33 g, 0.22 mol) and toluene (350 mL) were added. The resulting mixture was heated to reflux for 2 h. The resulting solution was cooled to RT and 4-ethylbenzenesulfonic acid (0.35 g) and tetraethylorthocarbonate (21.3 g, 0.11 mol) were added. The reaction mixture was heated to reflux and the azeotropic solution collected in the Dean-Stark trap. The azeotropic mixture was measured and removed from the trap and poured into brine. The toluene phase was separated giving ˜22 mL of ethanol, via shaking with brine. TLC of the reaction mixture showed the complete conversion of the starting diol. To the cooled reaction mixture was added triethylamine (3.0 mL). The reaction mixture was then concentrated at reduced pressure (rotovap) and then dried under vacuum. This crude material was then fractionally vacuum distilled and the fraction boiling at 170-18° C. at 1.8 torr and collected (24.72 g) as a water white clear liquid.

1. customIn a three neck 500 mL RB flask equipped with a reflux condenser
2. temperatureThe resulting mixture was heated
3. temperatureto reflux for 2 h
4. temperatureThe reaction mixture was heated
5. temperatureto reflux
6. customthe azeotropic solution collected in the Dean-Stark trap
7. customremoved from the trap
8. additionpoured into brine
9. customThe toluene phase was separated
10. customgiving ˜22 mL of ethanol
11. customTo the cooled reaction mixture
12. concentrationThe reaction mixture was then concentrated at reduced pressure (rotovap)
13. customdried under vacuum
14. distillationfractionally vacuum distilled
15. customthe fraction boiling at 170-18° C. at 1.8 torr and collected (24.72 g) as a water white clear liquid