4-Methylanisole → 4-Fluorobenzaldehyde

Temperature

30 °C

220.67 g of aluminum chloride (mol. Wt. 133.34; 1,654.9 mmol), 109.00 g (4-Methylanisole (mol. Wt. 122.17; 892.2 mmol), and about 500 g of fluorobenzene (mol. Wt. 96.10; 5,202.9 mmol) were charged to a 2 liter Parr®-brand 4522 stainless steel reaction vessel. To this mixture was added 5 drops of concentrated HCl. The vessel was sealed, heated to 30° C., and purged three times with carbon monoxide with the pressure of the vessel increased to 100 psi for each purging. After the third purge, the vessel was vented and a final introduction of CO was made at a pressure of about 550 psi, the pressure at which the reaction was maintained for the total reaction time of about 89 hours (the reaction temperature was maintained at 30° C. for the duration as well). Once the reaction was complete, the resultant mixture (exhibiting a orange-brown color) was poured into about 500 mL of ice water (which turned the solution a yellow color), to which was added 500 mL of cyclohexane. The top, organic layer was removed and washed three times with water using a separatory funnel and dried over magnesium sulfate. The residual organic phase was then distilled under vacuum to remove excess cyclohexane, fluorobenzene, and left about 60.90 g of 4-fluorobenzaldehyde product (mol. Wt. 124.11; 490.7 mmol; yield of approximately 64.3%). The 4-fluorobenzaldehyde product may then be easily separated from any residual 4-methylanisole by conversion into its corresponding bisulfite adduct, filtration, and decomposition of the bisulfite adduct under acidic or basic conditions.

1. customThe vessel was sealed
2. custompurged three times with carbon monoxide with the pressure of the vessel
3. temperatureincreased to 100 psi for each purging
4. customAfter the third purge
5. temperaturethe pressure at which the reaction was maintained for the total reaction time of about 89 hours (the reaction temperature
6. temperaturewas maintained at 30° C. for the duration as well)
7. additionwas poured into about 500 mL of ice water (which
8. additionwas added 500 mL of cyclohexane
9. customThe top, organic layer was removed
10. washwashed three times with water using a separatory funnel
11. dry with materialdried over magnesium sulfate
12. distillationThe residual organic phase was then distilled under vacuum
13. customto remove excess cyclohexane, fluorobenzene

ORD record

ord-f33dbead06e8457d9f643443689f28a2

Source dataset

uspto-grants-2001_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06300525B1