Acetic Acid → 4-Hydroxy-2,3,5-trimethylbenzaldehyde

HRID 85009

Reaktionsgleichung

Reaktionsgleichung von HRID 85009
[CH3:1][C:2]1[C:7]([CH3:8])=[CH:6][CH:5]=[C:4]([CH3:9])[C:3]=1[OH:10].C1N2CN3CN(C2)CN1C3.[C:21](O)(=[O:23])C>>[CH3:8][C:7]1[C:2]([CH3:1])=[C:3]([OH:10])[C:4]([CH3:9])=[CH:5][C:6]=1[CH:21]=[O:23]

Komponenten

4

Edukt 3

HCID 176Acetic AcidHCID 4101HexamethylenetetramineHCID 170162,3,6-Trimethylphenol

Produkt 1

HCID 108990214-Hydroxy-2,3,5-trimethylbenzaldehydeAusbeute 90 %

Reaktionsbedingungen

Temperatur
125 °C

Versuchsvorschrift

A 500 ml three neck round bottom flask equipped with mechanical stirrer and pot thermometer, was charged with 50 g (0.36 mol) of 2,3,6-trimethyl-phenol, 200 ml glacial acetic acid and 20.61 g (0.14 mol) of hexamethylenetetramine. The reaction mass was refluxed for 2 hrs at 120-130° C. The completion of reaction was confirmed by TLC. 100 ml of acetic acid were distilled out at reflux temperature. The reaction mass was allowed to cool at 100° C. and 50 ml 20% sulphuric acid were slowly added over a period of 5-10 min. The mixture was stirred at 100° C. for 15-30 min. Heating was stopped and the reaction mass cooled to 20° C. in an ice bath. 500 ml process water were added and stirred for 10 min at 20-25° C. The reaction mass was filtered and washed with 300 ml process water. The crude product was dried at 60-80° C. under vacuum to afford 54 g (90%) of crude 2,3,5-trimethyl-4-hydroxy-benzaldehyde. Subsequently, a 1% one equivalent solution of sodium hydroxide was prepared in process water. 54 g of crude 2,3,5-trimethyl-4-hydroxy-benzaldehyde were added to it under stirring at room temperature. The mixture was stirred for 15-20 min and filtered. The residue was to be scraped as impurity. The filtrate was collected, acidified with 19.75 g of glacial acetic acid and filtered. The product was suck-dried under vacuum, dried at 60-80° C. for 3-4 hrs to give 48 g (80%) of pure 2,3,5-trimethyl-4-hydroxy-benzaldehyde as off-white amorphous solid (Table 1, no. 13). Melting point: 135-137° C. 1H NMR (400 MHz, CDCl3) δ 10.15 (s, 1H), δ 7.49 (s, 1H), δ 5.32 (bs, 1H), δ 2.58 (s, 3H), δ 2.28 (s, 3H), δ 2.22 (s, 3H).

Aufarbeitung

  1. customThe completion of reaction
  2. distillation100 ml of acetic acid were distilled out
  3. temperatureat reflux temperature
  4. temperatureto cool at 100° C.
  5. addition50 ml 20% sulphuric acid were slowly added over a period of 5-10 min
  6. temperatureHeating
  7. temperaturethe reaction mass cooled to 20° C. in an ice bath
  8. addition500 ml process water were added
  9. stirringstirred for 10 min at 20-25° C
  10. filtrationThe reaction mass was filtered
  11. washwashed with 300 ml process water
  12. dry with materialThe crude product was dried at 60-80° C. under vacuum

Quellen und Nachweise

ORD-Eintrag
ord-6167b6a83ded41da830a69e900aaff59
Quelldatensatz
uspto-grants-2014_09
Patentnummer
US08846982B2

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