Hydrochloric Acid → 1-(4-(2-Methylpropyl)phenyl)-1-propanone

In a 500 ml. 3-necked, round bottomed flask there was placed 25.50 ml. (40.14 g., 0.29 mmole) of phosphorus trichloride and 43.65 ml. (43.34 g., 0.58 mmole) of propionic acid. This mixture was stirred for 2.25 hours under nitrogen atmosphere at room temperature to prepare the propionyl chloride. By NMR propionyl chloride formation was complete in about 1.5 hours. Then 80 ml. of anhydrous methylene chloride was added and the resulting solution was cooled to about -5° C. (an ice-methanol bath). While stirring the cooled mixture 87.50 g. (0.66 mmole) of aluminum chloride (technical grade) was added. After 10 minutes of stirring 67.11 g. (0.50 mmole) of isobutylbenzene was added dropwise from an additional funnel over 55 minutes while maintaining the temperature of the mixture at about 0° to 5° C. The mixture was stirred for an additional 1.25 hours to insure as complete a reaction as possible and then poured into a solution of 250 ml. of ice water and 150 ml. of concentrated hydrochloric acid with vigorous stirring. The Friedal-Crafts reaction was complete in about 45 minutes under these conditions (by GLC analyses). The resulting mixture was extracted three times with 300 ml. portions of methylene chloride. The combined methylene chloride extracts were washed with 250 ml. of water and three times with 250 ml. of molar concentration aqueous sodium carbonate solution. The aqueous sodium carbonate extracts were back extracted with 100 ml. of methylene chloride and the combined methylene chloride layers were dried over sodium sulfate. The dried methylene chloride solution was concentrated under vacuum to give crude p-isobutylpropiophenone as a pale yellow oil weighing 97.85 g. By GLC analyses 3% methylene chloride was present. The chemical yield was about 95 g. or about 100% of theory.

1. custom3-necked, round bottomed flask there was placed
2. temperaturethe resulting solution was cooled to about -5° C. (an ice-methanol bath)
3. stirringAfter 10 minutes of stirring 67.11 g
4. temperaturewhile maintaining the temperature of the mixture at about 0° to 5° C
5. stirringThe mixture was stirred for an additional 1.25 hours
6. customa reaction as possible and
7. additionthen poured into a solution of 250 ml
8. customThe Friedal-Crafts reaction
9. waitwas complete in about 45 minutes under these conditions (by GLC analyses)
10. extractionThe resulting mixture was extracted three times with 300 ml
11. washThe combined methylene chloride extracts were washed with 250 ml
12. extractionThe aqueous sodium carbonate extracts were back extracted with 100 ml
13. dry with materialof methylene chloride and the combined methylene chloride layers were dried over sodium sulfate
14. concentrationThe dried methylene chloride solution was concentrated under vacuum

ORD record

ord-c494ccfa4b63469fa2715b5a4eadf5ae

Source dataset

uspto-grants-1979_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04142054