反应详情

A 3-L round-bottomed, 4-necked flask is fitted with a 1-ft. fractionating column, variable reflux distillation head, air sparge tube, and a side arm containing a mercury thermometer and addition funnel. The air sparge rate is set to 30 mL/min. The flask is charged with ethylene glycol (310 g, 5 moles), methyl methacrylate (1200 g, 12 moles), cyclohexane (80 g, 1 mole), 73% dimethyltin dichloride in methanol (15 g, 0.05 moles), 25% sodium methoxide in methanol (10.8 g, 0.05 moles), 5.3 g (0.05 moles) of sodium carbonate, 8 g of MEHQ and 8 g of sodium bromide. The cyclohexane methanol azeotrope is removed via distillation. The methanol is removed from the overhead by washing it with water, and the cyclohexane is returned to the flask. The reaction is continued until the ratio of EGDMA to hydroxyethyl methacrylate exceeds 50:1. The excess methyl methacrylate and cyclohexane are removed via distillation, and the crude EGDMA is diluted with an equal weight of cyclohexane. The organic solution is washed twice with 20% of its weight of 20% caustic followed by brine. The separations of the organic and aqueous phases are in all cases rapid and sharp indicating the absence of polymer. The cyclohexane is removed from the product by distillation yielding 920 g (93%) of EGDMA.

1. customA 3-L round-bottomed, 4-necked flask is fitted with a 1-ft. fractionating column
2. temperaturevariable reflux
3. distillationdistillation head, air
4. customsparge tube
5. additiona side arm containing
6. additiona mercury thermometer and addition funnel
7. customThe air sparge rate
8. customThe cyclohexane methanol azeotrope is removed via distillation
9. customThe methanol is removed from the overhead
10. washby washing it with water
11. customThe excess methyl methacrylate and cyclohexane are removed via distillation
12. additionthe crude EGDMA is diluted with an equal weight of cyclohexane
13. washThe organic solution is washed twice with 20% of its weight of 20%
14. customThe cyclohexane is removed from the product by distillation