P-Cresol → Benzaldehyde, 2-hydroxy-5-methyl-

Temperature

62.5 °C

28.8 g of p-cresol (0.26 mol) are dissolved in 100 ml of water in a round-bottomed flask containing 80 g of NaOH. The mixture is heated to 60-65° C. and 40.5 ml of CHCl3 (0.51 mol) are added in several portions over a period of 30 to 40 min. The mixture is refluxed for 1 h and then cooled. The excess chloroform is removed by distillation under reduced pressure. The medium is acidified with dilute H2SO4 and then subjected to vapor entrainment. The distillate collected (±500 ml) is extracted with ether. The solvent is removed by distillation under reduced pressure. The residue is taken up in 100 ml of saturated sodium bisulfite solution. After vigorous stirring for 2 h, followed by leaving to stand for 1 h, the bisulfite adduct precipitated is collected by filtration and washed with ether. The bisulfite combination is decomposed by heating on a water bath in dilute H2SO4 for 30 min. The aldehyde is extracted with ether. The ether solution is dried over MgSO4. The solvent is removed under reduced pressure. The residue is recrystallized from ethanol.

1. temperatureThe mixture is refluxed for 1 h
2. temperaturecooled
3. customThe excess chloroform is removed by distillation under reduced pressure
4. distillationThe distillate collected (±500 ml)
5. extractionis extracted with ether
6. customThe solvent is removed by distillation under reduced pressure
7. customby leaving
8. waitto stand for 1 h
9. customthe bisulfite adduct precipitated
10. filtrationis collected by filtration
11. washwashed with ether
12. temperatureby heating on a water bath in dilute H2SO4 for 30 min
13. extractionThe aldehyde is extracted with ether
14. dry with materialThe ether solution is dried over MgSO4
15. customThe solvent is removed under reduced pressure
16. customThe residue is recrystallized from ethanol

ORD record

ord-4dd90db7261445549db787a27a005c89

Source dataset

uspto-grants-2002_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06355658B1