Hydrogen Bromide → 2,3-Dihydroxybenzaldehyde

HRID 37546

Reaktionsgleichung

Reaktionsgleichung von HRID 37546
[O:1]=[CH:2][C:3]1[CH:11]=[CH:10][CH:9]=[C:6]([O:7]C)[C:4]=1[OH:5].Br>C(O)(=O)C>[OH:5][C:4]1[C:6]([OH:7])=[CH:9][CH:10]=[CH:11][C:3]=1[CH:2]=[O:1]

Komponenten

4

Edukt 2

HCID 260Hydrogen BromideHCID 8991o-Vanillin

Produkt 1

HCID 905792,3-DihydroxybenzaldehydeAusbeute 70,2 %

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 176Acetic AcidLösungsmittel

Versuchsvorschrift

152.0 g (1.0 mol) of o-vanillin and 200 ml of azeotropic hydrobromic acid (47.5% strength) are stirred under reflux in 500 ml of glacial acetic acid for 2.5 hours. The acid mixture is then distilled off and the residue is subjected to fractional vacuum distillation. The redistilled fraction having a boiling point of 120°-125° C./12 mbar is purified by recrystallisation from 1 l of heptane (hexane is also possible and is recovered). 97 g (70% of theory) of 2,3-dihydroxybenzaldehyde of melting point 105°-107° C. are obtained.

Aufarbeitung

  1. distillationThe acid mixture is then distilled off
  2. distillationthe residue is subjected to fractional vacuum distillation
  3. customis purified by recrystallisation from 1 l of heptane (hexane
  4. customis recovered)

Quellen und Nachweise

ORD-Eintrag
ord-8e7891df21cc4ed39de4bc1a4c84a2c9
Quelldatensatz
uspto-grants-1995_05
Patentnummer
US05420308

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