反应详情

200 g (1.47 mol) of pentaerythritol (PE), 1.51 of glacial acetic acid and 17 ml of 48% HBr are refluxed for 1.5 h. A further 170 ml of 48% HBr are added and the reaction mixture is then boiled for another 3 h. The same procedure is repeated with the addition of 96 ml of HBr. The glacial acetic acid and water are then distilled off completely, 750 ml of 98% ethanol and 50 ml of 48% HBr are added to the viscous residue and approx. 500 ml of ethanol are removed by slow distillation. A further 750 ml of ethanol are subsequently added and then distilled off completely. After the addition of 500 ml of toluene, the solvent is distilled off and the same procedure is repeated. The viscous residue is boiled for several hours with 500 ml of dry ether, with stirring, until a white solid deposits. The solid is filtered off with suction, washed with dry ether, dried and recrystallized from chloroform/ethyl acetate=3:2. Yield: 50%. M.p.=75-76° C.

1. distillationThe glacial acetic acid and water are then distilled off completely
2. addition750 ml of 98% ethanol and 50 ml of 48% HBr are added to the viscous residue and approx. 500 ml of ethanol
3. customare removed by slow distillation
4. additionA further 750 ml of ethanol are subsequently added
5. distillationdistilled off completely
6. additionAfter the addition of 500 ml of toluene
7. distillationthe solvent is distilled off
8. waitThe viscous residue is boiled for several hours with 500 ml of dry ether
9. filtrationThe solid is filtered off with suction
10. washwashed with dry ether
11. customdried
12. customrecrystallized from chloroform/ethyl acetate=3:2